Publications by authors named "Claudia Hess"

61 Publications

In addition to birds' age and outdoor access, the detection method is of high importance to determine the prevalence of gastrointestinal helminths in laying hens kept in alternative husbandry systems.

Vet Parasitol 2021 Nov 28;299:109559. Epub 2021 Aug 28.

Clinic for Poultry and Fish Medicine, Department for Farm Animals and Veterinary Public Health, University of Veterinary Medicine Vienna, Austria. Electronic address:

The prevalence of gastrointestinal helminths was investigated in sixty-six commercial non-caged layer flocks. Twenty-nine flocks were housed indoors in aviaries or floor systems, nineteen flocks were kept in conventional free-range systems with outdoor access, and eighteen flocks in organic free-range systems. Flocks were investigated at end of rearing (mean age 17 weeks), peak of egg production (mean age 38 weeks) and before slaughter (mean age 74 weeks). Four different methods were applied to determine worm infestation. During necropsies, worm infestations were recorded and mucosal scrapings were evaluated for the presence of worm eggs. Faecal samples from each flock were investigated by simple flotation method and McMaster counting technique. No gastrointestinal helminths were found in pullets. During production, 87.9 % of the layer flocks were infected with at least one nematode species at the peak of production. The prevalence further increased significantly up to 98.5 % at the end of production (p=0.05). This increase could be ascribed mainly to infections with Ascaridia (A.) galli and/or Heterakis (H.) gallinarum which were most prevalent in all husbandry systems. Furthermore, their prevalence increased significantly with the age of birds (p=0.023; p < 0.001). With regard to the husbandry system, the prevalence of Capillaria spp. was significantly higher in flocks from outdoor systems compared to flocks that were kept indoors. Cestodes were only detected at the end of production with a prevalence of 15.2 % and significantly more flocks with access to outdoor run were found positive. Interestingly, H. gallinarum was found with a high prevalence indoor and in outdoor systems. Anthelminthic treatment did not impact the prevalence of nematode infections. Comparing four different methods for the detection of helminths it was revealed that their efficiencies varied depending on the worm species. Overall, the simple flotation method was superior to detect A. galli and Capillaria spp. This method proved also very efficient for the detection of H. gallinarum but the additional evaluation of the worm infestation during necropsy increased the level of prevalence. Cestodes were mainly found during necropsies when the worm infestation was evaluated. The detection of parasite eggs in mucosal scrapings from the intestines was the least effective method for all helminths. These findings lead to the recommendation to combine faecal investigations with an evaluation of the worm infestation during necropsy of at least five birds.
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http://dx.doi.org/10.1016/j.vetpar.2021.109559DOI Listing
November 2021

Aerosol is the optimal route of respiratory tract infection to induce pathological lesions of colibacillosis by a -tagged avian pathogenic in chickens.

Avian Pathol 2021 Oct 4;50(5):417-426. Epub 2021 Oct 4.

Clinic for Poultry and Fish Medicine, Department for Farm Animals and Veterinary Public Health, University of Veterinary Medicine Vienna, Vienna, Austria.

Pathogenesis of colibacillosis caused by avian pathogenic (APEC) in poultry is unclear and experimental studies reveal substantial inconsistency. In this study, the impact of three infection routes differing in the site of deposition of inoculum in the respiratory tract, were investigated. Two-weeks-old chickens were infected with a -tagged APEC strain via aerosol, intranasally or intratracheally, and sequentially sampled along with uninfected birds. At 1 and 3 days post infection (dpi), liver or spleen to body-weight ratios in all infected groups were significantly higher than in negative control, while at 7 dpi, such differences were significant in both organs in the aerosol-infected group. The infection-strain colonized tracheas and lungs in infected birds at 1 dpi and persisted until 7 dpi. Among infected groups, in lungs, bacterial load at 1 dpi was significantly lower in intranasally-inoculated birds. Histology revealed that, independent of infection route, lesions were mostly seen in the lower respiratory organs (lungs and air sacs) characterized by bronchitis/pneumonia and airsacculitis. Birds infected via aerosol showed the highest mean lesion score in lungs while intranasal application caused the mildest pathological changes, and difference between the two groups was significant at 1 dpi. In spleen, heterophilic infiltrations were prominent in affected birds. Interestingly, tracheas were pathologically unaffected. Altogether, the results demonstrated the importance of infection route, with aerosol being the most suitable to induce pathological lesions of colibacillosis without predisposing factors. Furthermore, the -tagged APEC strain was discriminated from native isolates enabling exact differentiation and enumeration. -tagged APEC strain was used for infection to differentiate from native .Pathologically, lungs, air sacs and spleen but not trachea were affected.The route of infection strongly impacts the pathological outcome with APEC.The infection with APEC via aerosol caused the most severe lesions in chickens.
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http://dx.doi.org/10.1080/03079457.2021.1978392DOI Listing
October 2021

An Outbreak of Pullorum Disease in a Young Layer Parent Flock in Austria Presented with Central Nervous System Signs.

Avian Dis 2021 03;65(1):159-164

Clinic for Poultry and Fish Medicine, Department for Farm Animals and Veterinary Public Health, University of Veterinary Medicine, Veterinaerplatz 1, 1210 Vienna, Austria.

The present report describes an outbreak of Pullorum disease in a young layer parent stock in Austria. The flock, which comprised 14,220 Lohmann brown layer chickens, experienced high mortality from the first week of life, reaching a total of 1905 chickens in the fifth week, when the flock was depopulated. Clinical signs included uneven size of the chicks, pasty vents, apathy, and diminished water and feed intake, with some birds presenting central nervous system signs such as tremors and torticollis. The postmortem investigation of 43 birds, of ages 1 to 4 weeks, revealed retained yolk sacs filled with caseous exudate, purulent airsacculitis, hepatitis with whitish pinpoint coalescing necrotic foci, splenitis with splenomegaly, hemorrhagic-mucoid enteritis in the small intestine, fibrinous typhlitis, nephromegaly, and urate deposits in the ureters and cloaca. Inflammation and/or necrosis were identified in liver, spleen, kidney, small intestine, and heart by histopathology. However, no histopathologic lesions were observed in the brain. was isolated from heart, liver, spleen, and brain in pure culture. Group-specific serotyping determined the presence of group D, with subspecies serovar Gallinarum being confirmed based on the Kauffmann-White scheme. A duplex PCR further identified subspecies serovar Gallinarum biovar Pullorum as the responsible agent for the outbreak. Subsequently, the grandparent flocks, from which the affected flock originated, were tested and found to be negative for Pullorum, with no other progenies from the same grandparents developing disease. Although the source of the pathogen could not be identified, such findings highlight the importance of "old" pathogens such as Pullorum causing sudden high mortality in chicks, even in a highly controlled environment.
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http://dx.doi.org/10.1637/aviandiseases-D-20-00091DOI Listing
March 2021

Deepoxy-deoxynivalenol (DOM-1), a derivate of deoxynivalenol (DON), exhibits less toxicity on intestinal barrier function, Campylobacter jejuni colonization and translocation in broiler chickens.

Gut Pathog 2021 Jul 3;13(1):44. Epub 2021 Jul 3.

Clinic for Poultry and Fish Medicine, Department for Farm Animals and Veterinary Public Health, University of Veterinary Medicine, Veterinärplatz 1, 1210, Vienna, Austria.

Background: Intestinal epithelial cells are challenged by mycotoxins and many bacterial pathogens. It was previously shown that the mycotoxin deoxynivalenol (DON) as well as Campylobacter (C.) jejuni have a negative impact on gut integrity. Recently, it was demonstrated that DON increased the load of C. jejuni in the gut and inner organs. Based on this finding, it was hypothesized the DON metabolite (deepoxy-deoxynivalenol, DOM-1) should be able to reduce the negative effects of DON on colonization and translocation of C. jejuni in broilers, since it lacks the epoxide ring, which is responsible for the toxicity of DON.

Methods: A total of 180 broiler chickens were housed in floor pens on wood shavings with feed and water provided ad libitum. Birds were divided into six groups (n = 30 with 5 replicates/group): 1. Control, 2. DOM-1, 3. DON, 4. DOM-1 + C. jejuni, 5. DON + C. jejuni, 6. C. jejuni. At day 14, birds of groups 4, 5 and 6 were orally inoculated via feeding tube (gavage) with 1-ml of a PBS suspension containing 1 × 10 CFU of C. jejuni NCTC 12744. The performance parameters: body weight (BW), body weight gain (BWG), and feed intake of the birds were determined. At 7, 14, and 21 days post infection, samples from liver, spleen, duodenum, jejunum and cecum were aseptically collected and processed for bacteriological investigations. Finally, at each killing time point, segments of duodenum, jejunum and cecum were harvested and prepared for Ussing chamber studies to measure the paracellular mannitol fluxes.

Results: A significant decrease in body weight was observed for chickens receiving the DON diet with or without C. jejuni compared to the other groups. Furthermore, it was found that the co-exposure of birds to DON and C. jejuni resulted in a higher C. jejuni load not only in the gut but also in liver and spleen due to increased paracellular permeability of the duodenum, jejunum and cecum. On the contrary, DOM-1 supplementation in the feed improved the birds' performance and led to a better feed conversion ratio throughout the trial. Furthermore, DOM-1 did not negatively affect gut permeability and decreased the C. jejuni counts in the intestine and internal organs.

Conclusion: Altogether, the presence of DOM-1 in the feed as a result of the enzymatic biotransformation of DON leads to a lower C. jejuni count in the intestine and better feed conversion ratio. Moreover, this study demonstrates that the detoxification product of DON, DOM-1, does not have negative effects on the gastrointestinal tract and reduces the Campylobacter burden in chickens and also the risk for human infection.
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http://dx.doi.org/10.1186/s13099-021-00440-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8254355PMC
July 2021

Infection dynamics of Infantis strains displaying different genetic backgrounds - with or without pESI-like plasmid - vary considerably.

Emerg Microbes Infect 2021 Dec;10(1):1471-1480

Clinic for Poultry and Fish Medicine, Department for Farm Animals and Veterinary Public Health, University of Veterinary Medicine, Vienna, Austria.

Food-borne infections with are among the most common causes of human diseases worldwide, and infections with the serovar Infantis are becoming increasingly important. So far, diverse phenotypes and genotypes of . Infantis have been reported. Therefore, the present study aimed to investigate the infection dynamics of two different . Infantis strains in broilers. For this purpose, 15 birds were infected on day 2 of life with 10 CFU/ml of a pESI+ or a pESI- . Infantis strain, respectively. Ten uninfected birds served as in-contact birds to monitor transmission. In both groups, an increase of infection was observed from 7 days of age onwards, reaching its peak at 28 days. However, the pESI+ strain proved significantly more virulent being re-isolated from most cloacal swabs and organs by direct plating. In contrast, the pESI- strain could be re-isolated from cloacal swabs and caeca only when enrichment was applied. Although the excretion of this strain was limited, the transmission level to in-contact birds was similar to the pESI+ strain. Differences in infection dynamics were also reflected in the antibody response: whereas the pESI+ strain provoked a significant increase in antibodies, antibody levels following infection with the pESI- strain remained in the range of negative control birds. The actual findings provide for the first time evidence of . Infantis strain-specific infectivity in broilers and confirm previous observations in the field regarding differences in persistence on farms and resistance against disinfectants.
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http://dx.doi.org/10.1080/22221751.2021.1951124DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8300933PMC
December 2021

Typhlitis induced by Histomonas meleagridis affects relative but not the absolute Escherichia coli counts and invasion in the gut in turkeys.

Vet Res 2021 Jun 22;52(1):92. Epub 2021 Jun 22.

Clinic for Poultry and Fish Medicine, Department for Farm Animals and Veterinary Public Health, University of Veterinary Medicine, Vienna, Austria.

Unlike in chickens, dynamics of the gut microbiome in turkeys is limitedly understood and no data were yet published in context of pathological changes following experimental infection. Thus, the impact of Histomonas meleagridis-associated inflammatory changes in the caecal microbiome, especially the Escherichia coli population and their caecal wall invasion in turkeys was investigated. Birds experimentally inoculated with attenuated and/or virulent H. meleagridis and non-inoculated negative controls were divided based on the severity of macroscopic caecal lesions. The high throughput amplicon sequencing of 16SrRNA showed that the species richness and diversity of microbial community significantly decreased in severely affected caeca. The relative abundances of operational taxonomic units belonging to Anaerotignum lactatifermentans, E. coli, and Faecalibacterium prausnitzii were higher and paralleled with a decreased abundances of those belonging to Alistipes putredinis, Streptococcus alactolyticus, Lactobacillus salivarius and Lactobacillus reuteri in birds with the highest lesion scores. Although the relative abundance of E. coli was higher, the absolute count was not affected by the severity of pathological lesions. Immunohistochemistry showed that E. coli was only present in the luminal content of caecum and did not penetrate even severely inflamed and necrotized caecal wall. Overall, it was demonstrated that the fundamental shift in caecal microbiota of turkeys infected with H. meleagridis was attributed to the pathology induced by the parasite, which only led to relative but not absolute changes in E. coli population. Furthermore, E. coli cells did not show tendency to penetrate the caecal tissue even when the intestinal mucosal barriers were severely compromised.
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http://dx.doi.org/10.1186/s13567-021-00962-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8220719PMC
June 2021

: MALDI-TOF MS and Whole Genome Sequencing Confirm That Serotypes K, L and M Deviate from Well-Known Reference Strains and Numerous Field Isolates.

Microorganisms 2021 May 7;9(5). Epub 2021 May 7.

Clinic for Poultry and Fish Medicine, Department for Farm Animals and Veterinary Public Health, University of Veterinary Medicine, 1210 Vienna, Austria.

is one of the most important bacterial agents of respiratory diseases in poultry. For correct identification and characterization of this fastidious bacterium, reliable diagnostic tools are essential. Still, phenotypic tests are used to identify and serotyping is the most common method for characterization, despite known drawbacks and disadvantages such as divergent results, cross-reactivity between strains, or the non-typeability of strains. The intention of the present study was to evaluate MALDI-TOF MS and whole genome sequencing for the identification and characterization of . For this purpose, a selection of 59 well-defined reference strains and 47 field strains derived from outbreaks on Austrian turkey farms were investigated by MALDI-TOF MS. The field strains originated from different geographical areas in Austria with some of the isolates derived from multiple outbreaks on farms within a year, or recurrent outbreaks over several years. MALDI-TOF MS proved a suitable method for identification of to genus or species level except for 3 strains representing serotypes M, K and F. Phylogenetic analysis showed that most strains grouped within one cluster even though they were comprised of different serotypes, while serotypes F, K, and M clearly formed a different cluster. All field isolates from turkey farms clustered together, independent of the origin of the isolates, e.g., geographical area, multiple outbreaks within a year or recurrent outbreaks over several years. Whole genome sequencing of serotype M, K and F strains confirmed the extraordinary status and deviation from known fully-sequenced strains due to a lack of sequence similarity. This was further confirmed by alignments of single genes (16S-RNA and rpoB) and multilocus sequence typing although the demarcation was less obvious. Altogether, the results indicate that these three serotypes belong to a different species than , and might even be members of multiple new species.
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http://dx.doi.org/10.3390/microorganisms9051006DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8151311PMC
May 2021

The Mycotoxin Deoxynivalenol (DON) Promotes Multiplication in the Intestine of Broiler Chickens With Consequences on Bacterial Translocation and Gut Integrity.

Front Vet Sci 2020 9;7:573894. Epub 2020 Dec 9.

Clinic for Poultry and Fish Medicine, Department for Farm Animals and Veterinary Public Health, University of Veterinary Medicine, Vienna, Austria.

Deoxynivalenol (DON) is one of the major health concern in poultry production as it targets epithelial cells of the gastrointestinal tract and contributes to the loss of the epithelial barrier function. It is well-documented that DON severely compromises various important intestinal functions in coincidence with aggravated clinical symptoms in livestock. In addition, a prolonged persistence of intestinal pathogens (e.g., ) in the gut has also been reported in pigs and chickens, respectively. Similar to DON, recent studies demonstrated that an experimental infection has severe consequences on gut health. Through experimental infection, it was found that negatively affects the integrity of the intestine and promotes the translocation of bacteria from the gut to inner organs. So far, no data are available investigating the simultaneous exposure of DON and in broilers albeit both are widely distributed. Thus, the aim of the present study was to explore the interaction between DON and which is of a significant public and animal health concern as it may affect the prevalence and the ability to control this pathogen. Following oral infection of birds at 14 days of age with NCTC 12744, we show that the co-exposure to DON and has a considerable consequence on loads in chicken gut as well as on gut permeability of the birds. A reduced growth performance was found for DON and/or exposed birds. Furthermore, it was found that the co-exposure of DON and aggravated the negative effect on paracellular permeability of the intestine already noticed for the bacteria or the mycotoxin alone by the Ussing chamber technique at certain times or intestinal segments. Furthermore, the increased paracellular permeability promotes the translocation of and to inner organs, namely liver and spleen. Interestingly, loads in the intestine were higher in DON-fed groups indicating a supportive growth effect of the mycotoxin. The actual study demonstrates that co-exposure of broiler chickens to DON and has not only considerable consequences on gut integrity but also on bacterial balance. These findings indicate that the co-exposure of broiler chickens to DON and could have a significant impact on gut health and bacteria translocation leading to an increased risk for public health.
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http://dx.doi.org/10.3389/fvets.2020.573894DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7756001PMC
December 2020

Outbreaks of Streptococcus gallolyticus subsp. pasteurianus in goslings characterized by central nervous symptoms.

Avian Dis 2020 Dec 7. Epub 2020 Dec 7.

Clinic for Poultry and Fish Medicine, Department for Farm Animals and Veterinary Public Health, University of Veterinary Medicine, Veterinaerplatz 1, 1210 Vienna, Austria.

SummaryThe present report describes outbreaks of Streptococcus gallolyticus subsp. pasteurianus in young geese flocks in Austria. The flocks, which comprised 160-1450 goslings of 2 to 3 weeks of age, experienced increased mortalities The clinical signs were characterized by severe central nervous symptoms, namely leg paddling and torticollis. The post-mortem investigation revealed hepatitis, splenitis and low amount of liquid fluid in the coelomic cavity. Livers were of fragile texture, with white necrotic areas. The latter was also found in spleens. No macroscopic lesions were seen in brains. Bacteriological investigation followed by bacterial identification by MALDI-TOF MS and phylogenetic analysis based on partial 16S rRNA region revealed the presence in heart, liver, spleen and brain of Streptococcus gallolyticus subsp. pasteurianus . Histological investigation revealed multifocal necrosis in liver and spleen samples together with infiltration of mononuclear cells and heterophilic granulocytes. Furthermore, in the lesions coccoid bacteria could be identified. No histopathological changes were observed in brain samples from goslings, except in one bird in which accumulation of coccoid bacteria in blood vessels of the brain samples was present.Antibiotic sensitivity tests revealed identical profiles for all strains. The strains were susceptible to penicillins, cephalosporins, chloramphenicol, imipenem and tylosin. However, resistance was found against quinolones, aminoglycosides, tetracycline and trimethoprim-sulfamethoxazole which are commonly used to treat infections with gram-positive bacteria.
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http://dx.doi.org/10.1637/aviandiseases-D-20-00101DOI Listing
December 2020

An outbreak of Pullorum disease in a young layer parent flock in Austria presented with central nervous system signs.

Avian Dis 2020 Dec 4. Epub 2020 Dec 4.

Clinic for Poultry and Fish Medicine, Department for Farm Animals and Veterinary Public Health, University of Veterinary Medicine, Veterinaerplatz 1, 1210 Vienna, Austria.

SummaryThe present report describes an outbreak of Pullorum disease in a young layer parent stock in Austria. The flock, which comprised 14,220 Lohmann brown layer chickens, experienced high mortality from the first week of life reaching a total of 1,905 chickens in the fifth week, when the flock was depopulated. Clinical signs included uneven size of the chicks, pasty vents, apathy, diminished water and feed intake, with some birds presenting central nervous system signs such as tremors and torticollis. The post-mortem investigation of 43 birds, ages one to four weeks, revealed retained yolk sacs filled with caseous exudate, purulent airsacculitis, hepatitis with whitish pinpoint coalescing necrotic foci, splenitis with splenomegaly, hemorrhagic-mucoid enteritis in the small intestine, fibrinous typhlitis, nephromegaly and urate deposits in the ureters and cloaca. Inflammation and/or necrosis were identified in liver, spleen, kidney, small intestine and heart by histopathology. However, no histopathological lesions were observed in the brain. Salmonella spp. were isolated from heart, liver, spleen and brain in pure culture. Group specific serotyping determined the presence of group D, with serovar S. Gallinarum being confirmed based on the Kauffmann-White Scheme. A duplex PCR further identified S. Pullorum as the responsible agent for the outbreak. Subsequently, the grandparent flocks, from which the affected flock originated, were tested and found to be negative for S. Pullorum, with no other progenies from the same GPs developing disease. Although the source of the pathogen could not be identified, such findings highlight the importance of "old" pathogens such as S. Pullorum causing sudden high mortality in chicks, even in a highly controlled environment.
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http://dx.doi.org/10.1637/aviandiseases-D-20-00091DOI Listing
December 2020

Co-infection of Chicken Layers With and Avian Pathogenic Is Associated With Dysbiosis, Cecal Colonization and Translocation of the Bacteria From the Gut Lumen.

Front Microbiol 2020 30;11:586437. Epub 2020 Oct 30.

Clinic for Poultry and Fish Medicine, Department for Farm Animals and Veterinary Public Health, University of Veterinary Medicine Vienna, Vienna, Austria.

Histomonosis in chickens often appears together with colibacillosis in the field. Thus, we have experimentally investigated consequences of the co-infection of birds with and avian pathogenic (APEC) on the pathology, host microbiota and bacterial translocation from the gut. Commercial chicken layers were infected via oral and cloacal routes with -tagged APEC with or without whereas negative controls were left uninfected. Except one bird, which died due to colibacillosis, no clinical signs were recorded in birds infected with bioluminescence gene tagged In co-infected birds, depression and ruffled feathers were observed in 4 birds and average body weight gain significantly decreased. Typhlitis caused by was present only in co-infected birds, which also had pronounced microscopic lesions in systemic organs such as liver, heart and spleen. The 16S rRNA gene amplicon sequencing showed that in co-infected birds, corresponding to the severity of cecal lesions, microbial species richness and diversity in caeca greatly decreased and the abundance of the group, and was relatively higher with a reduction of commensals. Most of the shared Amplicon Sequencing Variants between cecum and blood in co-infected birds belonged to members of while those assigned as and members of and were found mainly in negative controls. In infected birds, in the cecal lumen penetrated into deeper layers, a phenomenon noticed with higher incidence in the dead and co-infected birds. Furthermore, numbers of -tagged in caeca were significantly higher at every sampling date in co-infected birds. Altogether, infection of layers with and resulted in more severe pathological changes, dramatic shift in the cecal mucosa-associated microbiota, higher tissue colonization of pathogenic bacteria such as avian pathogenic in the gut and increased penetration of from the cecal lumen toward peritoneum. This study provides novel insights into the parasite-bacteria interaction highlighting the role of to support in the pathogenesis of colibacillosis in chickens.
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http://dx.doi.org/10.3389/fmicb.2020.586437DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7661551PMC
October 2020

Campylobacter jejuni increases the paracellular permeability of broiler chickens in a dose-dependent manner.

Poult Sci 2020 Nov 27;99(11):5407-5414. Epub 2020 Aug 27.

Department for Farm Animals and Veterinary Public Health, Clinic for Poultry and Fish Medicine, University of Veterinary Medicine, Vienna, Austria.

In recent years, several studies emphasize the deleterious effects of Campylobacter jejuni on the chicken intestine. In this context, it was shown that C. jejuni, contrary to the general belief, has a negative influence on the gut barrier in chickens. More precisely, we demonstrated that C. jejuni affects gut physiology characterized by changes in ion transport and transepithelial ion conductance, but the underlying mechanism is yet to be investigated. In the actual study, to determine epithelial paracellular permeability, the mucosal to serosal flux of C-mannitol in the small and large intestine was measured applying Ussing chamber. A total of seventy-five 1-day-old Ross 308 broiler chickens were housed in floor pens on wood shavings with feed and water provided ad libitum. Birds were randomly allocated to 3 different groups (n = 25 with 5 replicates/group) and infected at 14 d of age with a high (10 colony forming units [CFU]) or a low (10 CFU) dose of C. jejuni and a third group kept as noninfected control. Infection with the low dose of C. jejuni resulted in delayed cecal colonization but equalized at 21 d postinfection, independent of the dose. Invasion of liver and spleen with C. jejuni was only noticed in birds infected with 10 (CFU). Body weight (BW) and body weight gain of all birds infected with C. jejuni were lower than in the control group and varied with the dose of infection, confirming a negative correlation between the infection dose and birds BW. Mannitol flux in jejunum and cecum was significantly (P < 0.05) higher in all C. jejuni infected birds compared with control birds. Likewise, significant differences in mannitol flux of both jejunum and cecum were detected depending on the infection dose of C. jejuni. The correlation analyses revealed a positive relationship between Campylobacter dose and mannitol flux of both jejunum and cecum. Altogether, the actual results emphasize that the adverse effect of C. jejuni on gut permeability arises in a dose-dependent manner.
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http://dx.doi.org/10.1016/j.psj.2020.08.014DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7647851PMC
November 2020

Bacterial Infection in Chicken Embryos and Consequences of Yolk Sac Constitution for Embryo Survival.

Vet Pathol 2021 01 5;58(1):71-79. Epub 2020 Oct 5.

27260University of Veterinary Medicine, Vienna, Austria.

Bacterial infections in chicken eggs often cause mortality of embryos and clinical consequences in chicks but the pathological mechanism is unclear. We investigated the pathological changes and bacterial growth kinetics in dead and live embryos following infection with 2 strains with a different clinical background and with 1 Enteritidis strain. In 2 experiments, 12-day-old embryos were infected via the allantoic sac with 100 µl of 1 to 5 × 10 CFU/ml of one of the bacteria. In experiment 1, only dead embryos were sampled until 4 days postinfection (dpi), and surviving embryos were sampled at 5 dpi. In experiment 2, sampling was performed in dead and killed embryos sequentially at 1, 2, 3, and 4 dpi. The bacteria showed varying pathogenicity in embryos. The yolk sacs of dead embryos showed congestion, inflammation, damaged blood vessels, and abnormal endodermal epithelial cells. Such lesions were absent in the yolk sacs of negative control embryos and in those of embryos that survived infection. The livers and hearts of dead embryos showed congestion and lysed erythrocytes with no morphological changes in hepatocytes or myocardial cells. All bacteria multiplied rapidly in the yolks of infected embryos, although this did not predict survival. However, the livers of dead embryos contained significantly higher bacterial loads than the livers of the embryos that survived infection. The results provide evidence that lesions in the yolk sac, which have been neglected to date, coincide with embryonic mortality, underlining the importance of healthy yolk sacs for embryo survival.
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http://dx.doi.org/10.1177/0300985820960127DOI Listing
January 2021

Sequencing of five poultry strains elucidates phylogenetic relationships and divergence in virulence genes in Morganella morganii.

BMC Genomics 2020 Aug 24;21(1):579. Epub 2020 Aug 24.

Clinic for Poultry and Fish Medicine, Department for Farm Animals and Veterinary Public Health, University of Veterinary Medicine, Veterinärplatz 1, 1210, Vienna, Austria.

Background: M. morganii is a bacterium frequently associated with urinary infections in humans. While many human strains are sequenced, only the genomes of few poultry strains are available. Here, we performed a detailed characterization of five highly resistant Morganella morganii strains isolated in association with Escherichia coli from diseased domestic Austrian poultry flocks, namely geese, turkeys and chicken layers. Additionally, we sequenced the genomes of these strains by NGS and analyzed phylogenetic clustering, resistance and virulence genes in the context of host-specificity.

Results: Two strains were identified to be Extended Spectrum Beta Lactamase (ESBL) and one as AmpC beta-lactamases (AMP-C) phenotype, while two were ESBL negative. By integrating the genome sequences of these five poultry strains with all the available M. morganii genomes, we constructed a phylogenetic tree that clearly separates the Morganella genus into two clusters (M1 and M2), which approximately reflect the proposed subspecies classification (morganii and sibonii). Additionally, we found no association between phylogenetic structure and host, suggesting interspecies transmission. All five poultry strains contained genes for resistance to aminocoumarins, beta-lactams, colistin, elfamycins, fluoroquinolones, phenicol, rifampin and tetracycline. A comparative genomics analysis of virulence genes showed acquisition of novel virulence genes involved in secretion system and adherence in cluster M2. We showed that some of these genes were acquired by horizontal gene transfer from closely related Morganellaceae species and propose that novel virulence genes could be responsible for expansion of tissue tropism in M. morganii. Finally, we detected variability in copy number and high sequence divergence in toxin genes and provided evidence for positive selection in insecticidal toxins genes, likely reflecting host-related adaptations.

Conclusions: In summary, this study describes i) the first isolation and characterization of M. morganii from goose and turkey, ii) a large-scale genetic analysis of M. morganii and an attempt to generate a global picture of the M. morganii intraspecific phylogenetic structure.
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http://dx.doi.org/10.1186/s12864-020-07001-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7446228PMC
August 2020

Risks and disease aetiologies of compromised performance in commercial broilers kept at lower stocking density and limited antimicrobial use.

Avian Pathol 2020 Dec 14;49(6):621-630. Epub 2020 Sep 14.

Department for Farm Animals and Veterinary Public Health, Clinic for Poultry and Fish Medicine, University of Veterinary Medicine Vienna, Vienna, Austria.

The health status of broilers raised at lower stocking density and limited antimicrobial use (but routine anticoccidials) was assessed in order to identify prevalent causes of disease, mortality and reduced performance. "Dead-on-farm"(DOF) broilers from 145 commercial flocks were investigated at two different time points (TP1:7-14 and TP2:28-35 days of age); per sampling, 6-10 DOF broilers were selected for investigation and gross pathomorphological changes were assessed from 2717 birds in total. findings were substantiated by bacteriological, virological and parasitological investigations. Furthermore, production data of all flocks were collected and used to perform comprehensive statistical analysis. Overall, colibacillosis was found most important with a significant negative impact on flock health, productivity and profitability through all ages of broiler production. At TP1, primary reasons for mortality comprised yolk sac infections, generally found together with fibrinous polyserositis due to . Furthermore, femoral lesions, which correlated with increased flock mortality, were associated with detection of . At TP2, ascites was detected frequently in DOF broilers, correlating with increased production losses in the fourth and fifth weeks of life. No aetiological link between the presence of ascites and the detection of the investigated pathogens was observed, instead a positive correlation was noticed with altitude above sea level of the farm, and with the sex of the birds. Disease conditions could not be linked with the housing system. Presence of infectious bronchitis virus, avian reovirus and fowl adenovirus did not correlate with macroscopic lesions or a specific disease. In young broilers lesions of visceral organs due to bacterial infections dominated. Colibacillosis impacts broiler health, productivity and profitability independent of the age of birds. Disorders of the locomotor system were frequently observed throughout production. Older broilers frequently showed pathologic changes due to metabolic disorders. Overall, a shift from infectious towards metabolic disease conditions was noticed.
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http://dx.doi.org/10.1080/03079457.2020.1805411DOI Listing
December 2020

In-vitro testing of bacteriostatic and bactericidal efficacy of commercial disinfectants against Salmonella Infantis reveals substantial differences between products and bacterial strains.

Int J Food Microbiol 2020 09 14;328:108660. Epub 2020 May 14.

Clinic for Poultry and Fish Medicine, University of Veterinary Medicine Vienna, Veterinaerplatz 1, 1210 Vienna, Austria. Electronic address:

Salmonella (S.) Infantis is currently the most common serovar in broilers and boiler meat in the European Union. In the field, eradication of S. Infantis in affected poultry flocks is considered extremely difficult. Despite stringent cleaning and disinfection measures between the placement of flocks, recurrent infections are often reported. So far, the efficacy of disinfectants on S. Infantis has rarely been studied. Therefore, in the present in-vitro study the bacteriostatic and bactericidal efficacy of ten commercial disinfectants were tested against seven S. Infantis field isolates. Combinations of aldehyde and quarternary ammonium were the active compounds of five, peroxygen of three, cresol and alkylamines of one disinfectant, respectively. Investigations were performed according to standard protocols and regulations. Different concentrations of disinfectants were used to test the bacteriostatic efficacy. Different temperatures and low and high protein exposures were applied as variables to investigate the bactericidal efficacy. Following neutralization of the disinfectants an additional incubation step was introduced to investigate the revitalisation potential of S. Infantis. The bacteriostatic efficacy could be assessed for seven disinfectants. For three disinfectants a bacteriostatic effect was observed when the recommended concentration was used, whereas with four disinfectants only increased concentrations led to this effect. The bactericidal efficacy was not influenced by temperature, whereas high protein exposure decreased the efficacy of nine disinfectants. Furthermore, reactivation of S. Infantis was revealed after application of disinfectants for the majority of products. Interestingly, the strain of S. Infantis influenced the efficacy of the disinfectants. Overall, products based on aldehydes and quarternary ammonium compounds proved most efficient, followed by peroxgen, cresol and alkylamines.
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http://dx.doi.org/10.1016/j.ijfoodmicro.2020.108660DOI Listing
September 2020

First Report of Isolation of from Layer Chickens in Morocco with Decrease in Laying Performance.

Avian Dis 2019 12;63(4):727-730

Clinic for Poultry and Fish Medicine, Department for Farm Animals and Veterinary Public Health, University of Veterinary Medicine, Vienna 1210, Austria.

is a genus of the family of . It is well known as a commensal inhabitant of the respiratory and reproductive tract of healthy chickens. But in the last years, is increasingly reported in field cases with a decrease in laying performance due to infections of the reproductive tract. The aim of the present study was to investigate the implication of infection in layer flocks facing a decrease in laying performance in Morocco. Birds were received from five different laying hen farms in two regions in Morocco showing a drop of egg production. Necropsy revealed 46.1 % (24/52) of sampled birds showed variable lesions in ovaries, salpinx, and trachea. In fact, 24 birds were affected by salpingitis, 18 by oophoritis, and 11 birds by atrophy of ovaries. Furthermore, tracheitis was observed in 24 birds. Bacteriological investigation was done from different organs, and was found in ovaries ( = 20), trachea ( = 17), and cloaca ( = 3). Identification was based on growth morphology, Gram staining, and biochemical properties. Additionally, polymerase chain reaction test using specific primers for the genus identification was carried out. All isolates showed bands of 925 bp specific for expressing the virulent toxin GtxA. Antibiotic resistance testing was performed and revealed that isolates were sensitive to enrofloxacin, florfenicol, and gentamycin but resistant to ampicillin, erythromycin, oxytetracycline, and sulfamethoxazole-trimethoprim. The present study is the first report of in Morocco, demonstrating the need for further epidemiologic investigations as well as in regard to antibiotic resistance development.
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http://dx.doi.org/10.1637/aviandiseases-D-19-00119DOI Listing
December 2019

Antimicrobial Resistance Profiling of from Layers Reveals High Number of Multiresistant Strains and Substantial Variability Even Between Isolates from the Same Organ.

Microb Drug Resist 2020 Feb 17;26(2):169-177. Epub 2019 Sep 17.

Department for Farm Animals and Veterinary Public Health, Clinic for Poultry and Fish Medicine, University of Veterinary Medicine, Vienna, Austria.

In this investigation, data on antimicrobial resistance (AMR) profiles of 213 isolates were determined from 93 laying hens originating from 39 flocks. Each flock was sampled three times during its life time for the presence of . The broth microdilution method was applied comprising 21 antimicrobial substances. Multidrug resistance was found in 96.2% of the isolates. Most of the isolates were resistant to tetracycline (89.2%), tylosin (94.8%), enrofloxacin (58.2%), nalidixic acid (77.4%), and sulfamethoxazole (77.0%). Resistance against antimicrobial substances increased significantly with the age of birds. A total of 99 different AMR profiles were detected. On flock level, different AMR profiles were found in 71.8% of the flocks independent of the sampling time point. On bird level, identical AMR profiles were mostly found in isolates originating from the same organ of a single bird, but 22 such paired isolates differed in their AMR profile. Variations of AMR profiles were found within isolates from a single bird, but from different organs. Isolates from systemic organs were significantly more resistant to different antimicrobial substances compared to isolates from the reproductive tract. No influence could be found in regard to an increase of resistance and applied antibiotic treatment.
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http://dx.doi.org/10.1089/mdr.2019.0056DOI Listing
February 2020

Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry Is a Superior Diagnostic Tool for the Identification and Differentiation of Mycoplasmas Isolated from Animals.

J Clin Microbiol 2019 09 26;57(9). Epub 2019 Aug 26.

Unidad de Epidemiología y Medicina Preventiva, Facultad de Veterinaria, Universitad de Las Palmas de Gran Canaria, Las Palmas de Gran Canaria, Spain.

In veterinary diagnostic laboratories, identification of mycoplasmas is achieved by demanding, cost-intensive, and time-consuming methods that rely on antigenic or genetic identification. Since matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) seems to represent a promising alternative to the currently practiced cumbersome diagnostics, we assessed its applicability for the identification of almost all mycoplasma species isolated from vertebrate animals so far. For generating main spectrum profiles (MSPs), the type strains of 98 , 11 , and 5 species and, in the case of 69 species, 1 to 7 clinical isolates were used. To complete the database, 3 to 7 representatives of 23 undescribed species isolated from livestock, companion animals, and wildlife were also analyzed. A large in-house library containing 530 MSPs was generated, and the diversity of spectra within a species was assessed by constructing dendrograms based on a similarity matrix. All strains of a given species formed cohesive clusters clearly distinct from all other species. In addition, phylogenetically closely related species also clustered closely but were separated accurately, indicating that the established database was highly robust, reproducible, and reliable. Further validation of the in-house mycoplasma library using 335 independent clinical isolates of 32 mycoplasma species confirmed the robustness of the established database by achieving reliable species identification with log scores of ≥1.80. In summary, MALDI-TOF MS proved to be an excellent method for the identification and differentiation of animal mycoplasmas, combining convenience, ease, speed, precision, and low running costs. Furthermore, this method is a powerful and supportive tool for the taxonomic resolution of animal mycoplasmas.
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http://dx.doi.org/10.1128/JCM.00316-19DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6711924PMC
September 2019

Characterization of Species Isolated from Bovine Quarter Milk Samples.

Animals (Basel) 2019 Apr 27;9(5). Epub 2019 Apr 27.

Department of Farm Animal and Public Health in Veterinary Medicine, University Clinic for Ruminants, University of Veterinary Medicine, 1210 Wien, Austria.

is considered as a major mastitis pathogen, with considerable epidemiological information on such infections while the epidemiology of coagulase-negative staphylococci (CNS) is more controversial. The aim of this study was to use matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) technology for identification of staphylococci isolated from bovine milk at species level and to characterize them in reference to presentation, somatic cell count (SCC), bacterial shedding (cfu) and antimicrobial resistance patterns. A total of 200 staphylococcal isolates ( = 100; CNS = 100) originating from aseptically collected quarter milk samples from different quarters of dairy cows were included in the study. They originated from cases of clinical (CM) and subclinical mastitis (SCM) or were isolated from milk with SCC ≤ 100,000 cells/mL in pure culture. We found staphylococci predominantly in cases of SCM ( = 120). In low-SCC cows, 12 and 32 CNS isolates were detected. Eighteen percent of each were associated with CM. Eleven CNS species were identified, ( = 26) and ( = 40) predominated. CNS, particularly those in low-SCC cows, showed higher MIC90 (minimal inhibitory concentration) values for penicillin, ampicillin, cefoperazone, pirlimycin and marbofloxacin. Based on the present results, a careful interpretation of laboratory results is recommended to avoid antimicrobial therapy of staphylococci without clinical relevance and to ensure prudent use of antimicrobials.
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http://dx.doi.org/10.3390/ani9050200DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6563082PMC
April 2019

Feeding of deoxynivalenol increases the intestinal paracellular permeability of broiler chickens.

Arch Toxicol 2019 07 27;93(7):2057-2064. Epub 2019 Apr 27.

Department for Farm Animals and Veterinary Public Health, Clinic for Poultry and Fish Medicine, University of Veterinary Medicine, Veterinärplatz 1, 1210, Vienna, Austria.

In recent years, the deleterious effects attributed to mycotoxins, in particular on the intestine, faced increased attention and it was shown that deoxynivalenol (DON) causes adverse effects on gut health. In this context, it has been repeatedly reported that DON can alter the intestinal morphology, disrupt the intestinal barrier and reduce nutrient absorption. The underlying mechanism of a compromised intestinal barrier caused by DON in chickens has yet to be illustrated. Although, DON is rapidly absorbed from the upper parts of the small intestine, the effects on the large intestine cannot be excluded. Additionally, a damaging effect of DON on the gut epithelium might decrease the resistance of the gut against infectious agents. Consequently, the objectives of the present studies were: (1) to investigate the impact of DON on the epithelial paracellular permeability by demonstrating the mucosal to serosal flux of C-mannitol in the small and large intestine applying Ussing chambers and (2) to delineate the effects of DON on the colonization and translocation of Escherichia coli. Both parameters are well suited as potential indicators for gut barrier failure. For this, a total of 75 one-day-old Ross 308 broiler chickens were housed in floor pens on wood shavings with feed and water provided ad libitum. Birds were randomly allocated to three different groups (n = 25 with 5 replicates/group) and were fed for 5 weeks with either contaminated diets (5 or 10 mg DON/kg feed) or basal diets (control). Body weight (BW) and BW gain of birds in the group fed with 10 mg/kg DON were significantly lower than in group with 5 mg/kg DON and the control group. Moreover, the mannitol flux in jejunum and cecum was significantly (P < 0.05) higher in DON-fed groups compared to control birds. Consistent with this, DON enhanced the translocation of E. coli with a higher number of bacteria encountered in the spleen and liver. Altogether, the actual results verified that DON can alter the intestinal paracellular permeability in broiler chickens and facilitates the translocation of enteric microorganisms such as E. coli to extra-intestinal organs. Considering that moderate levels of DON are present in feed, the consumption of DON-contaminated feed can induce an intestinal breakdown with negative consequences on broiler health.
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http://dx.doi.org/10.1007/s00204-019-02460-3DOI Listing
July 2019

Reclassification of Bisgaard taxon 37 and taxon 44 as Psittacicella melopsittaci gen. nov., sp. nov., Psittacicella hinzii sp. nov. and Psittacicella gerlachiana sp. nov. within Psittacicellaceae fam. nov. of the order Pasteurellales.

Int J Syst Evol Microbiol 2019 Feb 13;69(2):350-355. Epub 2018 Dec 13.

4​Department of Veterinary Animal Sciences, University of Copenhagen, Stigbøjlen 4, 1870 Frederiksberg C, Denmark.

Bacteria isolated from lesions as well as apparently normal tissues of psittacine birds have previously been reported as taxon 37 and taxon 44 of Bisgaard. 16S rRNA gene sequence comparisons revealed a distant relationship to members of Pasteurellaceae at the species, genus and family levels. The polar lipid profile consisted of the major components phosphatidylethanolamine and phosphatidylglycerol. A new family Psittacicellaceae fam. nov. is proposed with the type genus Psittacicella gen. nov. The new genus Psittacicella includes the type species Psittacicella melopsittaci sp. nov. with type strain B96/4 (=CCUG 70858=DSM 105476), Psittacicella hinzii sp. nov. with type strain 111 (=CCUG 52861=CCM 8842) and Psittacicella gerlachiana sp. nov. with type strain EEAB3T1 (=CCUG 70857=DSM 105477). In addition to the major polar lipids, strain 111 possessed the non-identified aminophospholipids APL1 and APL2 and trace amounts of four lipids (L1-L4) whereas strain B94/4 showed the minor unidentified aminophospholipids APL3 and APL2 and trace amounts of unidentified lipid L3. These results demonstrate that strain B96/4 can be distinguished from 111 based on presence/absence of the unidentified lipids APL1 and APL3. The total polar lipid profile of strain EEAB3T1 differed from B96/4only in one minor lipid. Strain B96/4 can further be distinguished from 111 by acid formation from trehalose and raffinose and the α-glucosidase test. Strains 111 and EEAB3T1 can be separated based on acid formation from trehalose and the α-glucosidase test. Strains B96/4 and EEAB3T1 can be separated by acid formation from raffinose and eight signature indels in the RpoB protein.
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http://dx.doi.org/10.1099/ijsem.0.003133DOI Listing
February 2019

Identical Genetic Profiles of Escherichia coli Isolates from the Gut and Systemic Organs of Chickens Indicate Systemic Bacterial Dissemination, Most Likely Due to Intestinal Destruction Caused by Histomonosis.

Avian Dis 2018 09;62(3):300-306

A Clinic for Poultry and Fish Medicine, Department for Farm Animals and Veterinary Public Health, University of Veterinary Medicine Vienna, Vienna, Austria.

In laying and breeding chickens, pathomorphological signs of histomonosis often coincide with colibacillosis. Thus, we investigated the systemic spread of Escherichia coli in chickens affected with histomonosis and colibacillosis by characterizing their pheno- and genotypic profiles. For this, 29 birds from 11 affected flocks were necropsied and up to three E. coli isolates each from intestine, heart, and liver of the birds were isolated. A total of 251 isolates were characterized by serotyping, phylogenetic grouping, detection of virulence-associated genes (VAGs), and pulsed-field gel electrophoresis (PFGE). All birds showed egg peritonitis, and fibrinous typhlitis was additionally recorded in 18 birds. Presence of Histomonas meleagridis in ceca was confirmed by PCR and histopathology. Escherichia coli serotype O2:K1 was found to be the most prevalent (37.4%), whereas 31.1% of strains were not typeable. The majority of isolates collected from the intestine and extraintestinal organs belonged to phylogroups B2 (54.1%), D (21.5%), or A (19.5%). Isolates from these phylogroups harbored a higher number of VAGs. Macrorestriction analysis showed that 60.6% of total isolates from all organs tested were included in eight PFGE types. Isolation of E. coli with identical genomic profiles from the intestine and extraintestinal organs of the same or different birds in the same flock indicates for systemic dissemination of the bacteria, independent of E. coli genotype. Intestinal destruction due to H. meleagridis can be considered as the most plausible cause of bacterial dissemination, ultimately leading to colibacillosis.
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http://dx.doi.org/10.1637/11816-021818-Reg.1DOI Listing
September 2018

Soluble nondigestible carbohydrates improve intestinal function and increase caecal coliform load in broiler chickens.

J Anim Physiol Anim Nutr (Berl) 2018 Dec 16;102(6):1615-1624. Epub 2018 Sep 16.

Department of Animal Science, Georgikon Faculty, University of Pannonia, Keszthely, Hungary.

Diets rich in various soluble nondigestible carbohydrates (sNDCs) were evaluated on different intestinal characteristics (histological, physico-chemical and microbiological) of chickens and compared with a maize-based diet as a control. A total of 160 Ross 308 male chickens were kept in deep litter pens (n = 40) and fed their appropriate diets from Day 1 to Day 35 of life. Four isocaloric and isonitrogenous diets, differing in their sNDC content, were composed; control (containing maize as the only cereal), maize-wheat-based (M + W) and maize-based supplemented with either 20 g/kg inulin (M + I) or 30 g/kg lactose (M + L). All of the diets tested decreased ileal crypt depth, ileal muscle layer thickness and increased caecal coliform counts relative to the control group. Villus-crypt ratio increased only in the M + L group. Ileal digesta of chickens fed the M + W diet had the highest ileal viscosity and the highest caecal butyrate, valerate and total short-chain fatty acid concentrations while the lowest pH was observed in caecal contents of chickens fed the M + I diet. The diet had no effect on ileal or caecal goblet cell and intraepithelial lymphocyte numbers. Lactobacillus counts in the caecal content remained unchanged. According to the present study, various sNDC sources may have beneficial gut health effects, however, some of the intestinal variables are dependent on the type of sNDCs.
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http://dx.doi.org/10.1111/jpn.12985DOI Listing
December 2018

Re-thinking the chicken-Campylobacter jejuni interaction: a review.

Avian Pathol 2018 Aug 11;47(4):352-363. Epub 2018 Jun 11.

a Clinic for Poultry and Fish Medicine, Department for Farm Animals and Veterinary Public Health , University of Veterinary Medicine , Vienna , Austria.

Chickens are recognized as an imperative source of thermophilic Campylobacter spp., carrying this microorganism in high numbers in their intestinal tract. For a long time, Campylobacter jejuni has been considered as a commensal microorganism which colonizes its primary host rather than infecting it, in the absence of any obvious clinical signs. However, recent studies question this and argue for a deeper understanding of the host-bacteria interaction. Following oral uptake, it was demonstrated that C. jejuni interacts intimately with the gut epithelium and influences cellular functions of the host, with consequences on nutrient absorption. The immune reaction of the host which was revealed in some studies confirmed the infectious nature of C. jejuni. In agreement with this, an increased expression of pro-inflammatory cytokine genes was noticed. The ability to induce intestinal damage and to modulate the barrier function of the intestinal epithelia has further consequences on gut integrity, as it facilitates the paracellular passage of C. jejuni into the underlying tissues and it supports the translocation of luminal bacteria such as Escherichia coli to internal organs. This is associated with an alteration of the gut microbiota as infected birds have a significantly lower abundance of E. coli in different parts of the intestine. Some studies found that the gut microbiota influences the infection and translocation of C. jejuni in chickens in various ways. The effects of C. jejuni on the intestinal function of chickens already indicate a possible interference with bird performance and welfare, which was confirmed in some experimental studies. Furthermore, it could be demonstrated that a Campylobacter infection has an influence on the movement pattern of broiler flocks, supporting experimental studies. The intense interaction of C. jejuni with the chicken supports its role as an infectious agent instead of simply colonizing the gut. Most of the findings about the impact of Campylobacter on chickens are derived from studies using different Campylobacter isolates, a specific type of bird and varying experimental design. However, experimental studies demonstrate an influence of the aforementioned parameters on the outcome of a certain trial, arguing for improved standardization. This review summarizes the actual knowledge of the host-pathogen interaction of C. jejuni in chickens, emphasizing that there are still major gaps despite recently gained knowledge. Resolving the cascade from oral uptake to dissemination in the organism is crucial to fully elucidating the interaction of C. jejuni with the chicken host and to assess the clinical and economic implications with possible consequences on preventive interventions.
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http://dx.doi.org/10.1080/03079457.2018.1475724DOI Listing
August 2018

Escherichia coli isolates from femoral bone marrow of broilers exhibit diverse pheno- and genotypic characteristics that do not correlate with macroscopic lesions of bacterial chondronecrosis with osteomyelitis.

Avian Pathol 2018 Jun 14;47(3):271-280. Epub 2018 Mar 14.

a Clinic for Poultry and Fish Medicine, Department for Farm Animals and Veterinary Public Health , University of Veterinary Medicine , Vienna , Austria.

The pheno- and genotypic relatedness among Escherichia coli isolates from broilers with and without macroscopic lesions of the femoral head were investigated. In total, 219 isolates obtained from the bone marrow were characterized by serotyping, antimicrobial resistance (AMR) profiles, phylogenetic grouping, detection of virulence-associated genes (VAGs) and pulsed-field gel electrophoresis (PFGE). Serotyping revealed that 48.4% of the isolates were assigned to one of the three serotypes (O78:K80: 21.0%, O2:K1: 18.7%, O1:K1: 8.7%). Substantial phenotypic variation was also noticed in AMR testing as most of the birds harboured E. coli isolates with different AMR profiles, which is of high clinical relevance. The majority of isolates could be classified into phylogenetic groups D (54.3%) and B2 (25.6%), followed by A (11.4%) and B1 (8.7%). Virulotyping showed that the highest number of isolates contained genes iucD (86.8%) and iss (84.9%), whereas papC (16.0%) and astA (12.3%) were present in least number of isolates. PFGE resulted in 58 different profiles from 200 typeable isolates. No correlation was found between specific serotypes, AMR profiles, phylogenetic groups, PFGE types or VAG profiles of E. coli and the occurrence of bacterial chondronecrosis with osteomyelitis, contradicting the hypothesis of a specific bacterial pheno- or genotype being involved in the disease.
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http://dx.doi.org/10.1080/03079457.2018.1440065DOI Listing
June 2018

Influence of alternative husbandry systems on postmortem findings and prevalence of important bacteria and parasites in layers monitored from end of rearing until slaughter.

Vet Rec 2018 03 6;182(12):350. Epub 2018 Feb 6.

Department for Farm Animals and Veterinary Public Health, Clinic for Poultry and Fish Medicine, University of Veterinary Medicine Vienna, Vienna, Austria.

In the present study 66 layer flocks housed in different alternative husbandry systems were monitored from placement of birds on the farm until slaughter to evaluate a possible influence on the occurrence of selected non-infectious as well as infectious diseases. Postmortems were performed and the occurrence of extraintestinal and was investigated. No specific postmortem findings were seen in pullets. Non-infectious diseases were mainly found in layers. Most prominent postmortem findings in layers were reproductive tract lesions and the presence of intestinal helminths. From each flock and from approximately 65 per centof the flocks were isolated. No significant differences were seen in regard to the housing system, but the prevalence of increased with the age of birds. The majority of reproductive tract lesions could be associated with alone or co-infections. The prevalence of and was not influenced by the housing system, but significantly increased with age. Cestodes were present in six flocks. Histomonosis was detected twice. was found in 5 pullet and 20 layer flocks. Additional investigations were performed on demand. Again, reproductive tract lesions were the most prominent postmortem findings. In one flock each histomonosis or erysipelas was diagnosed, respectively. Severe affection by was found once. Necrotic enteritis was seen in two layer flocks.
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http://dx.doi.org/10.1136/vr.104632DOI Listing
March 2018

Presence of Avibacterium paragallinarum and Histopathologic Lesions Corresponds with Clinical Signs in a Co-infection Model with Gallibacterium anatis.

Avian Dis 2017 Sep;61(3):335-340

Clinic for Poultry and Fish Medicine, Department for Farm Animals and Veterinary Public Health, University of Veterinary Medicine, Veterinaerplatz 1, 1210, Vienna, Austria.

Recently we demonstrated that co-infection with Avibacterium paragallinarum and Gallibacterium anatis leads to increased severity of clinical signs of infectious coryza in birds. The present study examined the interaction of these two pathogens in chickens by evaluation of histologic lesions in sinus infraorbitalis and nasal turbinates, applying a defined scoring scheme ranging from 0 to 3. Furthermore, for the first time, an in situ hybridization (ISH) technique was applied to detect A. paragallinarum in tissues. The samples were received from vaccinated and nonvaccinated birds that were infected with A. paragallinarum and/or G. anatis. Vaccinated birds were mostly devoid of any histopathologic lesions except a few birds with lesion score 1 at 7 and 14 days postinfection (dpi). Likewise, nonvaccinated birds infected with G. anatis only did not present microscopic changes in the sinus infraorbitalis, except in a single bird at 7 dpi. Interestingly, median lesion scores caused by G. anatis infection were significantly higher in the nasal turbinates of infected birds than in negative control at 7 and 14 dpi. The most prominent histologic changes were recorded from sinus infraorbitalis and nasal turbinates of nonvaccinated birds that were infected either with A. paragallinarum only or together with G. anatis. ISH demonstrated positive signals for A. paragallinarum in exudates present in the lumen or attached to the epithelial layer of investigated tissues. Such signals were mainly detected in tissues from birds with the highest histopathologic lesion scores.
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http://dx.doi.org/10.1637/11609-021317-RegRDOI Listing
September 2017

High prevalence of Brachyspira spp. in layers kept in alternative husbandry systems associated with frequent species variations from end of rearing to slaughter.

Avian Pathol 2017 Oct 24;46(5):481-487. Epub 2017 May 24.

a Clinic for Poultry and Fish Medicine, Department for Farm Animals and Veterinary Public Health , University of Veterinary Medicine Vienna , Vienna , Austria.

A longitudinal survey was conducted to investigate the presence of Brachyspira species in layer flocks. A total of 66 layer flocks kept in alternative husbandry systems were sampled at three time points: end of rearing, at peak of lay and at end of lay. Content from caecal samples of freshly killed birds was cultured at each sampling time point and processed for further investigations. Gross pathological lesions in caeca were recorded during post mortem investigation. Spirochaetes were isolated from 50 flocks: three flocks were positive at all three sampling points, 25 flocks at two and 22 flocks at one sampling point, respectively. The presence of Brachyspira spp. could not be related to specific gross pathological caecal lesions or antibiotic treatments. The number of positive flocks increased with the age of birds. Furthermore, organic flocks were more often positive than flocks from barn systems. In total 80 spirochaetal cultures were obtained. B. intermedia (43.8%) was the most common species, followed by B. pulli (13.8%) and B. pilosicoli (12.5%). Brachyspira murdochii and B. innocens were found in 5.0% and 2.5%, respectively, whereas 11.3% of Brachyspira isolates could not be identified to species level. In 11.3% of the samples mixed infections were detected. Finally, the longitudinal survey revealed for the first time a possible shift in the Brachyspira species in a substantial number (32%) of layer flocks during their lifetime.
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http://dx.doi.org/10.1080/03079457.2017.1315049DOI Listing
October 2017

Coinfection of Avibacterium paragallinarum and Gallibacterium anatis in Specific-Pathogen-Free Chickens Complicates Clinical Signs of Infectious Coryza, Which Can Be Prevented by Vaccination.

Avian Dis 2017 Mar;61(1):55-63

Clinic for Poultry and Fish Medicine, Department for Farm Animals and Veterinary Public Health, University of Veterinary Medicine, Veterinaerplatz 1, 1210, Vienna, Austria.

Avibacterium paragallinarum and Gallibacterium anatis are recognized bacterial pathogens both infecting the respiratory tract of chickens. The present study investigated outcomes of their coinfection by elucidating clinical signs, pathologic lesions, and bacteriologic findings. Additionally, the efficacy of a commercially available vaccine to prevent diseases caused by A. paragallinarum and G. anatis was evaluated. Birds inoculated with G. anatis alone did not present any clinical signs and gross pathologic lesions in the respiratory tract. However, clinical signs of infectious coryza were reproduced in nonvaccinated birds that were challenged with A. paragallinarum alone or together with G. anatis . Such clinical signs were more severe in the coinfected group, including the death of four birds. Some of the birds that were vaccinated and challenged showed mild clinical signs at 7 days postinfection (dpi). Inflammation of sinus infraorbitalis was the most prominent gross pathologic lesion found in the respiratory tract of nonvaccinated birds inoculated either with A. paragallinarum and G. anatis or A. paragallinarum alone. In the reproductive tract, hemorrhagic follicles were observed in nonvaccinated birds that were infected either with G. anatis alone or together with A. paragallinarum . In vaccinated birds, no gross pathologic lesions were found except in one bird that was coinfected with both the pathogens characterized by mucoid tracheitis. Bacteriologic investigations revealed that multiplication of G. anatis at 7 dpi was supported by the coinfection with A. paragallinarum . Altogether, it can be concluded that simultaneous infection of A. paragallinarum and G. anatis can increase the severities of disease conditions in chickens. In such a scenario, vaccination appears to be an effective tool for prevention of the disease, as protection was conferred based on clinical, pathologic, bacteriologic, and serologic data.
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http://dx.doi.org/10.1637/11481-081016-RegDOI Listing
March 2017
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