Publications by authors named "Kristin A Clothier"

21 Publications

  • Page 1 of 1

Generalized dermatophytosis caused by in 8 juvenile black bears in California.

J Vet Diagn Invest 2021 Nov 28:10406387211061143. Epub 2021 Nov 28.

California Animal Health and Food Safety Laboratory System, University of California-Davis, CA, USA.

From 2014-2019, 8 juvenile black bears () from different geographic regions were presented to the California Department of Fish and Wildlife because of emaciation, alopecia, and exfoliative dermatitis that resulted in death or euthanasia. Autopsy and histopathology revealed that all 8 bears had generalized hyperkeratotic dermatitis, folliculitis, and furunculosis. Skin structures were heavily colonized by fungal hyphae and arthrospores; fungal cultures of skin from 7 bears yielded , a zoophilic dermatophyte reported only rarely in non-equid species. Additional skin conditions included mites (5), ticks (2), and coagulase-negative sp. infections (2). No other causes of morbidity or mortality were identified. Molecular comparisons performed at the University of Texas Fungal Reference Laboratory determined that all isolates produced identical banding patterns, potentially representing a clonal population. Dermatophytosis is commonly localized and limited to the stratum corneum of the epidermis and hair follicles. Generalized disease with dermal involvement is rare in immunocompetent individuals; illness, malnutrition, age, or immunosuppression may increase susceptibility. Underlying causes for the severe disease impact in these bears were not evident after physical or postmortem examination. The mechanism by which bears from different geographic locations had severe, -associated dermatophytosis from a potentially clonal dermatophyte could not be explained and warrants further investigation.
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http://dx.doi.org/10.1177/10406387211061143DOI Listing
November 2021

Component Causes of Infectious Bovine Keratoconjunctivitis-Non-Moraxella Organisms in the Epidemiology of Infectious Bovine Keratoconjunctivitis.

Vet Clin North Am Food Anim Pract 2021 Jul;37(2):295-308

Department of Population Health & Reproduction, School of Veterinary Medicine, University of California Davis, 1 Shields Avenue, VM3B, Davis, CA 95616, USA.

Infectious bovine keratoconjunctivitis (IBK) is a multifactorial disease complex caused by opportunistic pathogens, classically those members of the genus Moraxella. However, IBK in some situations is associated with other potentially pathogenic agents, which include Mycoplasma bovoculi, Mycoplasma bovis, Ureaplasma diversum, bovine herpesviruses, and Chlamydia sp. Ocular infections that may resemble IBK are also caused by Listeria monocytogenes. These agents and their association with IBK are reviewed in this article.
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http://dx.doi.org/10.1016/j.cvfa.2021.03.005DOI Listing
July 2021

Relatedness of type IV pilin PilA amongst geographically diverse isolated from cattle with infectious bovine keratoconjunctivitis.

J Med Microbiol 2021 Feb;70(2)

Department of Arctic and Marine Biology, UiT The Arctic University of Norway, Framstredet 39, N-9037 Tromsø, Norway.

is frequently isolated from the eyes of cattle with infectious bovine keratoconjunctivitis (IBK; pinkeye). As with which has been causally linked to IBK, expresses an RTX (repeats in the structural toxin) cytotoxin that is related to cytotoxin. Pilin, another pathogenic factor in , is required for corneal attachment. Seven antigenically distinct pilin serogroups have been described in . Multiple different serogroups exist amongst type IV pilin encoded by , however, it is not known whether exhibits a similar degree of diversity in type IV pilin that it encodes. This study was done to characterize a structural pilin (PilA) encoded by isolated from cases of IBK to determine if diversity exists amongst PilA sequences. Ninety-four isolates of collected between 2002 and 2017 from 23 counties throughout California and from five counties in four other Western states were evaluated. DNA sequencing and determination of deduced amino acid sequences revealed ten (designated groups A through J) unique PilA sequences that were ~96.1-99.3 % identical. Pilin groups A and C matched previously reported putative PilA sequences from isolated from IBK-affected cattle in the USA (Virginia, Nebraska, and Kansas) and Asia (Kazakhstan). The ten pilin sequences identified were only ~74-76 % identical to deduced amino acid sequences of putative pilin proteins identified from the previously reported whole-genome sequences of derived from deep nasopharyngeal swabs of IBK-asymptomatic cattle. Compared to the diversity reported between structural pilin proteins amongst different serogroups of , PilA from geographically diverse isolates derived from IBK-affected cattle are more conserved.
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http://dx.doi.org/10.1099/jmm.0.001293DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8131017PMC
February 2021

Campylobacter pinnipediorum subsp. caledonicus and C. pinnipediorum subsp. pinnipediorum recovered from abscesses in pinnipeds.

Dis Aquat Organ 2020 Nov 19;142:41-46. Epub 2020 Nov 19.

SRUC Veterinary Services, An Lochran, 10 Inverness Campus, Inverness IV2 5NA, UK.

Campylobacter pinnipediorum was described recently for isolates recovered from pinnipeds. The novel species was further split into 2 subspecies based on host and geography, with C. pinnipediorum subsp. pinnipediorum recovered from otariid seals in California (USA) and C. pinnipediorum subsp. caledonicus recovered from phocid seals in Scotland. We report details of the infections of 7 pinnipeds from which C. pinnipediorum was isolated: C. pinnipediorum subsp. caledonicus was isolated from 2 harbour seals Phoca vitulina and a single grey seal Halichoerus grypus, and C. pinnipediorum subsp. pinnipediorum was isolated from California sea lions Zalophus californianus. Six of the isolates were recovered from samples collected at post-mortem investigation. In 2 of the Scottish seals and in 3 of the California seals, C. pinnipediorum was the sole bacterial isolate recovered from abscesses present and suggests they may have resulted from conspecific or intraspecific bite wounds.
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http://dx.doi.org/10.3354/dao03544DOI Listing
November 2020

Bayesian estimation of diagnostic accuracy of fecal culture and PCR-based tests for the detection of in California cull dairy cattle.

PeerJ 2020 15;8:e8310. Epub 2020 Jan 15.

School of Veterinary Medicine, University of California, Veterinary Medicine Teaching and Research Center, Tulare, CA, United States of America.

Epidemiological studies of low prevalence disease problems are often hindered by the high cost of diagnostic testing. The objective of this study was to evaluate PCR screening of both individual and pooled fecal samples from culled dairy cows for the A gene of followed by culture to determine if the sensitivity and specificity were comparable to the results from traditional culture methods applied to individual samples. Cows from six different dairies were sampled in all four seasons. A total of 240 individual cow fecal samples, 24 fecal pools and 24 pools of 24-hour tetrathionate enrichment broth were tested. Diagnostic sensitivity of PCR screening followed by culture of PCR positive or indeterminate samples (i.e PCR-CUL method) was lower than that of culture (CUL) when applied to individual fecal samples (94.8%, 99.5%), however the specificity was comparable (99.6% and 97.7% respectively). For pools of five fecal samples and pools of five, 24 h tetrathionate broth samples, the specificity of both tests were comparable (∼98%); however, their sensitivity was only comparable in pooled fecal samples (∼93%) but greater for culture compared to PCR-CUL in pooled broth samples (∼99% versus ∼93%). Compared to culture results from testing of individual fecal samples, testing pooled fecal samples by culture had a relative sensitivity of 74% and relative specificity of 96%, testing pooled fecal samples by PCR-CUL resulted in relative sensitivity of 90% and relative specificity of 96%. Testing of pooled 24-hour enrichment broth by PCR-CUL increased the relative sensitivity and specificity to 100%. PCR testing followed by culture of positive or indeterminate samples is a time saving alternative to traditional methods. In addition, pooling of samples may be a useful method for decreasing cost if study aims can accommodate a moderate loss of relative sensitivity.
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http://dx.doi.org/10.7717/peerj.8310DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6969550PMC
January 2020

Validation of a real-time PCR assay for high-throughput detection of in chicken respiratory sites.

J Vet Diagn Invest 2019 Sep 26;31(5):714-718. Epub 2019 Jul 26.

California Animal Health and Food Safety Laboratory System, Davis Laboratory (Clothier, Torain, Crossley), School of Veterinary Medicine, University of California-Davis, Davis, CA.

is the causative agent of infectious coryza, a highly contagious respiratory disease in chickens. Given its fastidious nature, this bacterium is difficult to recover and identify, particularly from locations colonized by normal bacterial flora. Standard PCR methods have been utilized for detection but are labor-intensive and not feasible for high-throughput testing. We evaluated a real-time PCR (rtPCR) method targeting the HPG-2 region of , and validated a high-throughput extraction for this assay. Using single-tube extraction, the rtPCR detected 4 (ATCC 29545 and 3 clinical) isolates with a limit of detection (LOD) of 10 cfu/mL and a PCR efficiency of 89-111%. Cross-reaction was not detected with 33 non-, all close relatives from the family . Real-time PCR testing on extracts of 66 clinical samples (choana, sinus, or trachea) yielded 98.2% (35 of 36 on positives, 30 of 30 on negatives) agreement with conventional PCR. Duplicate samples tested in a 96-well format extraction in parallel with the single-tube method produced equivalent LOD on all isolates, and 96.8% agreement on 93 additional clinical samples extracted with both procedures. This rtPCR can be utilized for outbreak investigations and routine monitoring of susceptible flocks.
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http://dx.doi.org/10.1177/1040638719866484DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6727126PMC
September 2019

Surveillance for Avibacterium paragallinarum in autopsy cases of birds from small chicken flocks using a real-time PCR assay.

J Vet Diagn Invest 2019 May 11;31(3):364-367. Epub 2019 Apr 11.

California Animal Health and Food Safety Laboratory System, School of Veterinary Medicine, University of California-Davis, Davis, CA.

Infectious coryza is a severe respiratory disease of chickens associated with large economic losses in affected commercial flocks. The fastidious causative pathogen, Avibacterium paragallinarum, is difficult to recover and identify, resulting in delayed diagnosis and enhanced spread of the agent. Small poultry flocks are increasingly common in rural and suburban environments. We assessed the frequency of A. paragallinarum using real-time PCR and clinical conditions present in samples from such flocks submitted to the California Animal Health and Food Safety Laboratory System (Davis, CA) in 2018. From the 294 samples collected for our study, 86 (30%) were PCR-positive for A. paragallinarum. Juvenile birds (≤1 y) were significantly more likely to be PCR-positive ( p = 0.017), and birds diagnosed with respiratory disease had lower Ct values ( p = 0.001) than those without. Concurrent infections were also identified, including with Mycoplasma gallisepticum (18.6%), M. synoviae (18.6%), infectious bronchitis virus (12.8%), and infectious laryngotracheitis virus (7.0%). Only 46.5% of PCR-positive chickens had antemortem respiratory signs, making endemic infections in these flocks highly likely. Our study demonstrates that A. paragallinarum is present in small-flock operations including those without respiratory disease and may present a risk for airborne pathogen transmission to commercial poultry operations.
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http://dx.doi.org/10.1177/1040638719844297DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6838718PMC
May 2019

Frequency, serotype distribution, and antimicrobial susceptibility patterns of Salmonella in small poultry flocks in California.

J Vet Diagn Invest 2018 May 6;30(3):471-475. Epub 2018 Feb 6.

California Animal Health & Food Safety Lab System, School of Veterinary Medicine, University of California, Davis, CA.

Backyard poultry operations are increasingly popular and commonplace in both rural and suburban locations. Although Salmonella surveillance programs are well established for large commercial poultry systems, information on smaller operations is lacking. We identified the occurrence and serotype distribution of Salmonella spp. recovered from backyard flock cases submitted to the California Animal Health and Food Safety Laboratory System (Davis, CA) in 2012-2015, and evaluated minimum inhibitory concentration for 12 antimicrobials as well as the lesions associated with Salmonella spp. in these cases. From records of 2,347 backyard flock cases with 2,627 samples, 44 samples (1.7%) were positive for Salmonella spp. DNA by PCR, and 41 (1.6%) of these samples yielded a Salmonella isolate by culture for further characterization. Seventeen different serotypes, including 3 isolates identified to the serogroup level, were identified from these isolates. Antimicrobial resistance was infrequent; however, 2 multidrug-resistant isolates were identified. Enteric or systemic lesions associated with Salmonella recovery were uncommon, with 77.3% of cases having no disease attributable to Salmonella. Recovered serotypes overlap with those seen in commercial poultry as well as in foodborne outbreaks reported by the Centers for Disease Control and Prevention in humans. Zoonotic risks via contact and food product contamination make monitoring of backyard flocks for Salmonella a critical part of flock surveillance programs, and we propose a potential sampling scheme.
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http://dx.doi.org/10.1177/1040638718755418DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6505821PMC
May 2018

Draft Genome Sequence of Multidrug-Resistant Abortive from Northern California.

Genome Announc 2017 Apr 13;5(15). Epub 2017 Apr 13.

School of Veterinary Medicine, 100K Pathogen Genome Project, UC Davis, Davis, California, USA

is an enteric bacterium that can cause abortion in livestock. This is the release of a multidrug-resistant genome from an isolate that caused an abortion in a cow in northern California. This isolate is part of the 100K Pathogen Genome Project.
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http://dx.doi.org/10.1128/genomeA.00171-17DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5391421PMC
April 2017

Multilaboratory Survey To Evaluate Salmonella Prevalence in Diarrheic and Nondiarrheic Dogs and Cats in the United States between 2012 and 2014.

J Clin Microbiol 2017 05 15;55(5):1350-1368. Epub 2017 Feb 15.

Washington Animal Disease Diagnostic Laboratory, College of Veterinary Medicine, Washington State University, Pullman, Washington, USA.

Eleven laboratories collaborated to determine the periodic prevalence of in a population of dogs and cats in the United States visiting veterinary clinics. Fecal samples (2,965) solicited from 11 geographically dispersed veterinary testing laboratories were collected in 36 states between January 2012 and April 2014 and tested using a harmonized method. The overall study prevalence of in cats (3 of 542) was <1%. The prevalence in dogs (60 of 2,422) was 2.5%. Diarrhea was present in only 55% of positive dogs; however, 3.8% of the all diarrheic dogs were positive, compared with 1.8% of the nondiarrheic dogs. -positive dogs were significantly more likely to have consumed raw food ( = 0.01), to have consumed probiotics ( = 0.002), or to have been given antibiotics ( = 0.01). Rural dogs were also more likely to be positive than urban ( = 0.002) or suburban ( = 0.001) dogs. In the 67 isolates, 27 unique serovars were identified, with three dogs having two serovars present. Antimicrobial susceptibility testing of 66 isolates revealed that only four of the isolates were resistant to one or more antibiotics. Additional characterization of the 66 isolates was done using pulsed-field gel electrophoresis and whole-genome sequencing (WGS). Sequence data compared well to resistance phenotypic data and were submitted to the National Center for Biotechnology Information (NCBI). This study suggests an overall decline in prevalence of -positive dogs and cats over the last decades and identifies consumption of raw food as a major risk factor for infection. Of note is that almost half of the -positive animals were clinically nondiarrheic.
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http://dx.doi.org/10.1128/JCM.02137-16DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5405253PMC
May 2017

Draft Genome Sequences of Campylobacter jejuni Strains That Cause Abortion in Livestock.

Genome Announc 2016 Dec 1;4(6). Epub 2016 Dec 1.

School of Veterinary Medicine, UC Davis, Davis, California, USA

Campylobacter jejuni is an intestinal bacterium that can cause abortion in livestock. This publication announces the public release of 15 Campylobacter jejuni genome sequences from isolates linked to abortion in livestock. These isolates are part of the 100K Pathogen Genome Project and are from clinical cases at the University of California (UC) Davis.
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http://dx.doi.org/10.1128/genomeA.01324-16DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5137404PMC
December 2016

Genomic Comparison of Campylobacter spp. and Their Potential for Zoonotic Transmission between Birds, Primates, and Livestock.

Appl Environ Microbiol 2016 12 21;82(24):7165-7175. Epub 2016 Nov 21.

School of Veterinary Medicine, Department of Population Health and Reproduction, 100K Pathogen Genome Project, University of California, Davis, California, USA

Campylobacter is the leading cause of human gastroenteritis worldwide. Wild birds, including American crows, are abundant in urban, suburban, and agricultural settings and are likely zoonotic vectors of Campylobacter Their proximity to humans and livestock increases the potential spreading of Campylobacter via crows between the environment, livestock, and humans. However, no studies have definitively demonstrated that crows are a vector for pathogenic Campylobacter We used genomics to evaluate the zoonotic and pathogenic potential of Campylobacter from crows to other animals with 184 isolates obtained from crows, chickens, cows, sheep, goats, humans, and nonhuman primates. Whole-genome analysis uncovered two distinct clades of Campylobacter jejuni genotypes; the first contained genotypes found only in crows, while a second genotype contained "generalist" genomes that were isolated from multiple host species, including isolates implicated in human disease, primate gastroenteritis, and livestock abortion. Two major β-lactamase genes were observed frequently in these genomes (oxa-184, 55%, and oxa-61, 29%), where oxa-184 was associated only with crows and oxa-61 was associated with generalists. Mutations in gyrA, indicative of fluoroquinolone resistance, were observed in 14% of the isolates. Tetracycline resistance (tetO) was present in 22% of the isolates, yet it occurred in 91% of the abortion isolates. Virulence genes were distributed throughout the genomes; however, cdtC alleles recapitulated the crow-only and generalist clades. A specific cdtC allele was associated with abortion in livestock and was concomitant with tetO These findings indicate that crows harboring a generalist C. jejuni genotype may act as a vector for the zoonotic transmission of Campylobacter IMPORTANCE: This study examined the link between public health and the genomic variation of Campylobacter in relation to disease in humans, primates, and livestock. Use of large-scale whole-genome sequencing enabled population-level assessment to find new genes that are linked to livestock disease. With 184 Campylobacter genomes, we assessed virulence traits, antibiotic resistance susceptibility, and the potential for zoonotic transfer to observe that there is a "generalist" genotype that may move between host species.
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http://dx.doi.org/10.1128/AEM.01746-16DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5118927PMC
December 2016

Characterization of Pajaroellobacter abortibovis, the etiologic agent of epizootic bovine abortion.

Vet Microbiol 2016 Aug 7;192:73-80. Epub 2016 Jul 7.

Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis, CA 95616, USA. Electronic address:

Epizootic bovine abortion (EBA), first identified in the 1950s, is a major contributor of economic loss to western U.S. beef producers. The causative agent proved elusive for over fifty years until a novel Deltaproteobacteria was identified as the etiologic agent in 2005. The microbe, which has yet to be successfully cultured in vitro, has proven difficult to purify from necropsy tissues. Thus, phylogenetic characterization has been limited to analysis of the 16S ribosomal RNA (rRNA) gene (AF503916), which placed this bacterium in the order Myxococcales, suborder Sorangiineae, family Polyangiaceae and most closely related to Sorangium cellulosum. The focus of the current study was to further expand the morphologic characterization and taxonomic placement of this bacteria, named here as Pajaroellobacter abortibovis. Modified Gram staining, combined with transmission electron microscopy, provide strong evidence that the bacterium is gram negative. Flow cytometric analysis identified the presence of P. abortibovis in murine leukocytes. While attempts to sequence ten universally conserved protein-coding genes using previously published degenerative primers failed, redesigned primers based solely upon Deltaproteobacteria facilitated the partial sequencing of two genes; fusA (JQ173112) and pyrG (JQ173111). Primers designed in a similar fashion generated a partial sequence of the 23S rRNA gene (JQ173113) These sequences, combined with a revised 16S rRNA phylogenic analysis, support the placement of this bacteria as a unique genus separate from Sorangium.
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http://dx.doi.org/10.1016/j.vetmic.2016.07.001DOI Listing
August 2016

Phenotypic and Genotypic Characterization of Animal-Source Salmonella Heidelberg Isolates.

J Vet Med 2016 3;2016:6380890. Epub 2016 Jan 3.

Departments of Pathology, Microbiology, and Immunology, School of Veterinary Medicine, University of California, Davis, Davis, CA 95616, USA; Veterinary Medical Teaching Hospital, School of Veterinary Medicine, University of California, Davis, Davis, CA 95616, USA.

Salmonella enterica serotype Heidelberg (S. Heidelberg) is frequently implicated in human foodborne Salmonella infections and often produces more severe clinical disease than other serotypes. Livestock and poultry products represent a potential risk for transmission to humans. The purpose of this study was to evaluate 49 S. Heidelberg veterinary isolates for exponential growth rate (EGR), PFGE pattern, and antimicrobial resistance to evaluate these parameters as mechanisms by which S. Heidelberg emerged as a virulent foodborne pathogen. Isolates were categorized by species of origin; clinical or environmental sources; and time frame of recovery. Growth rates were determined in nutrient media using serial dilutions and colony counts; PFGE was performed according to the CDC PulseNet protocol. Minimum inhibitory concentration and susceptibility determinations were performed against antimicrobials important in human medicine. Eighteen unique PFGE patterns were detected in the isolates tested. Antimicrobial resistance was significantly greater (P < 0.05) for ten of 15 drugs in clinical over environmental isolates; for four drugs between the time frames; and for ten drugs between species of origin. The large genetic diversity present in isolates of this serotype may convey competitive advantages to this organism, while the presence of antimicrobial resistance represents a potential zoonotic risk via animal-source food products.
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http://dx.doi.org/10.1155/2016/6380890DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4735902PMC
February 2016

Effects of bacterial contamination of media on the diagnosis of Tritrichomonas foetus by culture and real-time PCR.

Vet Parasitol 2015 Mar 19;208(3-4):143-9. Epub 2015 Jan 19.

California Animal Health and Food Safety Laboratory System, School of Veterinary Medicine, University of California, Davis, 620 W. Health Sciences Drive, Davis, CA 95616, United States.

The venereal pathogen Tritrichomonas foetus causes early embryonic death and abortion in cattle. With no approved treatment, control involves detection of infected animals and their removal from the herd. Culture is the traditional diagnostic method; standard media are formulated to support protozoal growth while suppressing competing organisms which may prevent microscopic recognition of T. foetus. Real-time PCR increases diagnostic sensitivity and specificity over culture but requires intact T. foetus DNA for detection. The purposes of this study were 1) to evaluate the effects of resident preputial bacteria that are not suppressed by antimicrobials in a commercial culture medium (InPouch™) on T. foetus detection by culture and PCR, and 2) to determine the performance of a laboratory-prepared culture medium on T. foetus detection by culture and PCR in samples with and without this bacterial contamination. A known concentration of one of three different strains of T. foetus inoculated into InPouch™ (IP) or modified Diamonds-Plastridge media (DPM) were co-incubated with a smegma culture media (CONTAM) for 24h and examined microscopically for the presence of identifiable T. foetus. PCR was performed on IP samples to determine if CONTAM also affected T. foetus DNA detection. A PCR protocol was then validated in DPM that performed similarly to the established IP PCR method. IP and DPM with CONTAM were spiked with serial dilutions that mimic field infections of one of four T. foetus strains and evaluated by real-time PCR; cycles to threshold (Ct) values and "positive" classification were compared between media. T. foetus motility and morphology as well as media pH were severely altered in IP samples with CONTAM compared to those without as well as to DPM medium with and without CONTAM (P<0.0001). PCR testing demonstrated significantly greater Ct values were for T. foetus DNA (P<0.001) in IP contaminated with smegma bacteria compared to those without. When using T foetus concentrations that mimic field infections, IP samples with CONTAM had significantly higher Ct values (P<0.001) than DPM with CONTAM. Using the laboratory cut-off for "positive" on mean Ct values from these samples, significantly (P<0.01) more bulls would be identified using DPM than with IP if CONTAM was present. Results of this study indicate that bacteria which are not inhibited in media interfere with T. foetus identification by culture and PCR and adversely affect diagnostic sensitivity for this fastidious pathogen.
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http://dx.doi.org/10.1016/j.vetpar.2015.01.006DOI Listing
March 2015

Disseminated histoplasmosis in two juvenile raccoons (Procyon lotor) from a nonendemic region of the United States.

J Vet Diagn Invest 2014 Mar 20;26(2):297-301. Epub 2014 Feb 20.

1Kristin A. Clothier, CAHFS Davis, 620 W. Health Sciences Drive, Davis, CA 95616.

Two 6-month-old raccoon kits, which had been rescued and fostered in preparation for return to the wild, became acutely ill and died 3 weeks before scheduled release. At necropsy, the kits had grossly enlarged livers and spleens, diffusely consolidated lungs, and generalized lymphadenopathy. Histologically, extensive infiltrates of macrophages containing yeast organisms were identified in lung, liver, kidney, spleen, lymph nodes, intestinal tissues, brain, adrenal gland, bone marrow, and thymus of both animals. Histiocytic inflammation with accompanying fibrosis was widespread, with necrotic foci evident in lungs, spleen, and intestinal sections. Fungal organisms were observed on sheep blood agar plates; however, repeated subcultures to fungal media designed to induce conidial structures for fungal identification were unsuccessful. Partial DNA sequencing of the 28S ribosomal RNA gene of the blood agar isolate identified 100% homology with Ajellomyces capsulatus (anamorphic name Histoplasma capsulatum). The kits were rescued and fostered in the San Francisco Bay area and it is likely that the exposure to H. capsulatum occurred in this area. Histoplasma sp. infection in wild mammal species is often used as an indication of spore contamination of a geographic region. Northern California is not known to be an endemic region for H. capsulatum, which is not a reportable disease in this state. The presence of severe, disseminated disease and the need for molecular identification associated with the isolate from a nonendemic region identified in the present report may indicate genetic adaptation and altered characteristics of this agent and may warrant further investigation.
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http://dx.doi.org/10.1177/1040638714521207DOI Listing
March 2014

Pathology in practice. Soft tissue abscesses and vertebral osteomyelitis attributable to N farcinica infection in 2 calves.

J Am Vet Med Assoc 2013 Apr;242(8):1075-7

College of Veterinary Medicine, Western University of Health Sciences, Pomona, CA 91766, USA.

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http://dx.doi.org/10.2460/javma.242.8.1075DOI Listing
April 2013

Species characterization and minimum inhibitory concentration patterns of Brachyspira species isolates from swine with clinical disease.

J Vet Diagn Invest 2011 Nov;23(6):1140-5

Iowa State University Veterinary Diagnostic Laboratory, Department of Veterinary and Production Animal Medicine, Iowa State University, College of Veterinary Medicine, Ames, IA, USA.

Typhlocolitis and dysentery due to Brachyspira hyodysenteriae infection represent an economically important disease syndrome in growing pigs. Largely disappearing from U.S. swine herds in the late 1990 s and early 2000s, Brachyspira-associated disease and bacterial isolation from swine with clinical disease has increased in the last several years, and non-B. hyodysenteriae isolates are commonly identified. Antimicrobial resistance has been demonstrated in Brachyspira spp. isolates from Europe and Asia, and may be the reason for the resurgence in U.S. herds. Seventy-nine clinical isolates identified at the Iowa State University Veterinary Diagnostic Lab were tested with multiple polymerase chain reaction assays to establish species identity, and evaluated for minimum inhibitory concentrations (MICs) using an agar dilution method against lincomycin, gentamicin, valnemulin, tiamulin, salinomycin, and carbadox. Only 38.0% of isolates could be confirmed as the known pathogens B. hyodysenteriae (30.4%) or Brachyspira pilosicoli (7.6%). Twenty of the 79 isolates (25.3%) were identified as Brachyspira murdochii, and 13.9% could not be identified to species. The MIC values were consistently high against lincomycin and moderately high against gentamicin. The remaining antimicrobials had MICs that were at the low end of the test ranges. Brachyspira murdochii and Brachyspira spp. had significantly greater MIC values against several of these drugs than other Brachyspira spp. examined. The increased incidence of these less definitively characterized Brachyspira species with increased MIC values to commonly prescribed antimicrobials may, at least in part, explain the increased prevalence and severity of this disease complex in recent years. Further research is necessary to understand these changes.
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http://dx.doi.org/10.1177/1040638711425580DOI Listing
November 2011

Antimicrobial susceptibility patterns and sensitivity to tulathromycin in goat respiratory bacterial isolates.

Vet Microbiol 2012 Apr 25;156(1-2):178-82. Epub 2011 Oct 25.

Department of Veterinary Microbiology and Preventive Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA, USA.

Bacterial pneumonia is a common and often life-threatening respiratory problem in both meat and dairy goats. Options for approved antibiotic therapy in goats to combat these bacterial infections are severely limited and frequently drugs must be used in an extra-label manner. Tulathromycin, a triamilide macrolide antimicrobial drug shown to be effective against swine and cattle respiratory bacterial agents, has been identified as a potentially useful drug in caprines. The present study was conducted to determine the susceptibility of recognized bacterial respiratory pathogens to commonly prescribed antimicrobials, with a particular emphasis on the efficacy of tulathromycin against these agents. Minimum inhibitory concentration (MIC) testing using microbroth dilution was performed on a collection of 45 Mannheimia haemolytica, 11 Pasteurella multocida, and 11 Bibersteinia trehalosi isolates from the lungs of goats with clinical pneumonia. To further characterize efficacy of tulathromycin against these pathogens, minimum bactericidal concentration (MBC) testing and kinetic killing assays were conducted. Most isolates were susceptible to the antimicrobials tested; however, increased resistance as demonstrated by higher MIC values was seen in all species to penicillin, in P. multocida to sulfadimethoxine, and in B. trehalosi to the tetracyclines. All isolates were susceptible to tulathromycin, which demonstrated a high killing efficiency in both bactericidal assays. Results of this study indicate that most goat pneumonic bacterial pathogens remain susceptible to commonly prescribed antibiotics, although some evidence of resistance was seen to certain drugs; and that tulathromycin is highly effective against goat respiratory pathogens which could make it a valuable medication in this species.
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http://dx.doi.org/10.1016/j.vetmic.2011.10.025DOI Listing
April 2012

Mycoplasma bovis real-time polymerase chain reaction assay validation and diagnostic performance.

J Vet Diagn Invest 2010 Nov;22(6):956-60

Iowa State University, Veterinary Department of Production Animal Medicine, 1600 S. 16th Street, Ames, IA 50011, USA.

Mycoplasma bovis is an important bacterial pathogen in cattle, producing a variety of clinical diseases. The organism, which requires specialized culture conditions and extended incubation times to isolate and identify, is frequently associated with concurrent infection with other pathogens which can potentially be more easily identified. Real-time polymerase chain reaction (real-time PCR) is a valuable diagnostic technique that can rapidly identify infectious agents in clinical specimens. A real-time PCR assay was designed based on the uvrC gene to identify M. bovis in diagnostic samples. Using culture as the gold standard test, the assay performed well in a variety of diagnostic matrices. Initial validation testing was conducted on 122 milk samples (sensitivity: 88.9% [95% confidence interval (CI): 68.4-100%], specificity: 100%); 154 lung tissues (sensitivity: 89.0% [95% CI: 83.1-94.9%], specificity: 97.8% [95% CI: 93.5-100%]); 70 joint tissue/fluid specimens (sensitivity: 92.3% [95% CI: 82.1-100%], specificity: 95.5% [95% CI: 89.3-100%]); and 26 nasal swabs (sensitivity: 75.0% [95% CI: 45.0-100%], specificity: 83.3% [95% CI: 66.1-100%]). Low numbers of other sample matrices showed good agreement between results of culture and PCR. A review of clinical cases from 2009 revealed that, in general, PCR was used much more frequently than culture and provided useful diagnostic information in conjunction with clinical signs, signalment, and gross and histopathologic lesions. Diagnostic performance of the real-time PCR assay developed as a testing method indicates that it is a rapid, accurate assay that is adaptable to a variety of PCR platforms and can provide reliable results on an array of clinical samples.
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http://dx.doi.org/10.1177/104063871002200618DOI Listing
November 2010

Comparison of Salmonella serovar isolation and antimicrobial resistance patterns from porcine samples between 2003 and 2008.

J Vet Diagn Invest 2010 Jul;22(4):578-82

Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, USA.

Food-borne Salmonella infections can produce symptoms from mild gastroenteritis to severe systemic disease and death, representing an important public health issue in U.S. livestock and livestock products, which have been implicated as frequent sources of Salmonella contamination. Concerns have been raised about the spread of antibiotic resistance in Salmonella strains, particularly those that originate from food animal sources, as a result of prophylactic and therapeutic antimicrobial use in these species. Longitudinal comparisons of Salmonella serovars isolated from porcine tissues submitted to the Iowa State University Veterinary Diagnostic Laboratory in 2003 and 2008 were conducted to evaluate changes in serovar dynamics and antimicrobial resistance. Incidence of recovered group C Salmonella enterica serovar Choleraesuis var. Kunzendorf decreased between 2003 and 2008, while recovery of group B strains Salmonella Typhimurium var. 5-(formerly, Copenhagen), Salmonella Agona, Salmonella Derby, Salmonella Heidelberg, and Salmonella Typhimurium increased. Significant changes in resistance interpretation were seen in Salmonella Derby with regard to spectinomycin and sulfadimethoxine; in Salmonella Heidelberg with regard to florfenicol, spectinomycin, and sulfadimethoxine; and in Salmonella Choleraesuis var. Kunzendorf, Salmonella Typhimurium, Salmonella Typhimurium var. 5-, and Salmonella Agona with regard to spectinomycin. Only 2 of 293 isolates in 2003 and 5 of 395 isolates in 2008 were resistant to enrofloxacin. Utilizing antibiotics approved for use in food animals to evaluate antimicrobial resistance provides more specific information on the selection pressure exerted on Salmonella populations through the use of these drugs.
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http://dx.doi.org/10.1177/104063871002200412DOI Listing
July 2010
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