Publications by authors named "Glenn Francis Browning"

9 Publications

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Use of cefovecin in dogs and cats attending first-opinion veterinary practices in Australia.

Vet Rec 2020 Nov 21;187(11):e95. Epub 2020 Aug 21.

Asia Pacific Centre for Animal Health, University of Melbourne, Parkville, Victoria, Australia.

Background: Cefovecin is a long-acting third-generation cephalosporin commonly used in veterinary medicine. Third-generation cephalosporins are critically important antimicrobials that should only be used after culture and susceptibility testing. The authors describe the common indications for cefovecin use in dogs and cats, and the frequency of culture and susceptibility testing.

Materials And Methods: A cross-sectional study was performed using clinical records extracted from VetCompass Australia. A previously described method was used to identify records containing cefovecin. The reason for cefovecin use was annotated in situ in each consultation text.

Results: Over a six-month period (February and September 2018), 5180 (0.4 per cent) consultations involved cefovecin administration, of which 151 were excluded. Cats were administered cefovecin more frequently than dogs (1.9 per cent of cat consultations and 0.1 per cent of dog consultations). The most common reasons for cefovecin administration to cats were cat fight injuries and abscesses (28 per cent) and dermatitis (13 per cent). For dogs, the most common reasons for cefovecin administration were surgical prophylaxis (24 per cent) and dermatitis (19 per cent). Culture and susceptibility testing were reported in 16 cases (0.3 per cent).

Conclusion: Cefovecin is used in many scenarios in dogs and cats where antimicrobials may be either not indicated or where an antimicrobial of lower importance to human health is recommended.
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http://dx.doi.org/10.1136/vr.105997DOI Listing
November 2020

Mycoplasma bovis Membrane Protein MilA Is a Multifunctional Lipase with Novel Lipid and Glycosaminoglycan Binding Activity.

Infect Immun 2020 05 20;88(6). Epub 2020 May 20.

Asia-Pacific Centre for Animal Health, Melbourne Veterinary School, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Victoria, Australia.

The survival, replication, and virulence of mycoplasmas depend on their ability to capture and import host-derived nutrients using poorly characterized membrane proteins. Previous studies on the important bovine pathogen demonstrated that the amino-terminal end of an immunogenic 226-kDa (P226) protein, encoded by (the full-length product of which has a predicted molecular weight of 303 kDa), had lipase activity. The predicted sequence of MilA contains glycosaminoglycan binding motifs, as well as multiple copies of a domain of unknown function (DUF445) that is also found in apolipoproteins. We mutagenized the gene to facilitate expression of a series of regions spanning the gene in Using monospecific antibodies against these recombinant proteins, we showed that MilA was proteolytically processed into 226-kDa and 50-kDa fragments that were both partitioned into the detergent phase by Triton X-114 phase fractionation. Trypsin treatment of intact cells showed that P226 was surface exposed. , the recombinant regions of MilA bound to 1-anilinonaphthalene-8-sulfonic acid and to a variety of lipids. The MilA fragments were also shown to bind heparin. Antibody against the carboxyl-terminal fragment inhibited the growth of This carboxyl end also bound and hydrolyzed ATP, suggestive of a potential role as an autotransporter. Our studies have demonstrated that DUF445 has lipid binding activity and that MilA is a multifunctional protein that may play multiple roles in the pathogenesis of infection with .
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http://dx.doi.org/10.1128/IAI.00945-19DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7240078PMC
May 2020

Exploration of antibiotic resistance risks in a veterinary teaching hospital with Oxford Nanopore long read sequencing.

PLoS One 2019 30;14(5):e0217600. Epub 2019 May 30.

Department of Veterinary Biosciences, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Werribee, Victoria, Australia.

The Oxford Nanopore MinION DNA sequencing device can produce large amounts of long sequences, typically several kilobases, within a few hours. This long read capacity was exploited to detect antimicrobial resistance genes (ARGs) in a large veterinary teaching hospital environment, and to assess their taxonomic origin, genetic organisation and association with mobilisation markers concurrently. Samples were collected on eight occasions between November 2016 and May 2017 (inclusive) in a longitudinal study. Nanopore sequencing was performed on total DNA extracted from the samples after a minimal enrichment step in broth. Many ARGs present in the veterinary hospital environment could potentially confer resistance to antimicrobials widely used in treating infections of companion animals, including aminoglycosides, extended-spectrum beta-lactams, sulphonamides, macrolides, and tetracyclines. High-risk ARGs, defined here as single or multiple ARGs associated with pathogenic bacterial species or with mobile genetic elements, were shared between the intensive care unit (ICU) patient cages, a dedicated laundry trolley and a floor cleaning mop-bucket. By contrast, a floor surface from an office corridor without animal contact and located outside the veterinary hospital did not contain such high-risk ARGs. Relative abundances of high-risk ARGs and co-localisation of these genes on the same sequence read were higher in the laundry trolley and mop bucket samples, compared to the ICU cages, suggesting that amplification of ARGs is likely to occur in the collection points for hospital waste. These findings have prompted the implementation of targeted intervention measures in the veterinary hospital to mitigate the risks of transferring clinically important ARGs between sites and to improve biosecurity practices in the facility.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0217600PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6542553PMC
February 2020

Genomic Island 1B Variant Found in a Sequence Type 117 Avian Pathogenic Escherichia coli Isolate.

mSphere 2019 05 22;4(3). Epub 2019 May 22.

The ithree institute, University of Technology Sydney, Ultimo, New South Wales, Australia

genomic island 1 (SGI1) is an integrative genetic island first described in serovars Typhimurium DT104 and Agona in 2000. Variants of it have since been described in multiple serovars of , as well as in , , , and several other genera. The island typically confers resistance to older, first-generation antimicrobials; however, some variants carry , , and genes that encode resistance to frontline, clinically important antibiotics, including third-generation cephalosporins. Genome sequencing studies of avian pathogenic (APEC) identified a sequence type 117 (ST117) isolate (AVC96) with genetic features found in SGI1. The complete genome sequence of AVC96 was assembled from a combination of Illumina and single-molecule real-time (SMRT) sequence data. Analysis of the AVC96 chromosome identified a variant of SGI1-B located 18 bp from the 3' end of , also known as the site, a known hot spot for the integration of genomic islands. This is the first report of SGI1 in wild-type The variant, here named SGI1-B-Ec1, was otherwise unremarkable, apart from the identification of IS in open reading frame (ORF) S023. SGI1 and variants of it carry a variety of antimicrobial resistance genes, including those conferring resistance to extended-spectrum β-lactams and carbapenems, and have been found in diverse serovars, , and other members of the SGI1 integrates into Gram-negative pathogenic bacteria by targeting a conserved site 18 bp from the 3' end of For the first time, we describe a novel variant of SGI1 in an avian pathogenic isolate. The presence of SGI1 in is significant because it represents yet another lateral gene transfer mechanism to enhancing the capacity of to acquire and propagate antimicrobial resistance and putative virulence genes. This finding underscores the importance of whole-genome sequencing (WGS) to microbial genomic epidemiology, particularly within a One Health context. Further studies are needed to determine how widespread SGI1 and variants of it may be in Australia.
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http://dx.doi.org/10.1128/mSphere.00169-19DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6531882PMC
May 2019

Population wide assessment of antimicrobial use in dogs and cats using a novel data source - A cohort study using pet insurance data.

Vet Microbiol 2018 Nov 18;225:34-39. Epub 2018 Sep 18.

Asia-Pacific Centre for Animal Health, Melbourne Veterinary School, Department of Veterinary Biosciences, Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Parkville, Victoria, 3052, Australia; National Centre for Antimicrobial Stewardship, Peter Doherty Institute, Grattan St, Carlton, Victoria, 3053, Australia.

Antimicrobial use in veterinary practice is under increasing scrutiny as a contributor to the rising risk of multidrug resistant bacterial pathogens. Surveillance of antimicrobial use in food animals is extensive globally, but population level data is lacking for companion animals. Lack of census data means cohorts are usually restricted to those attending veterinary practices, which precludes aggregating data from large cohorts of animals, independent of their need for veterinary intervention. The objective of this study was to investigate the exposure of dogs and cats to antimicrobials at a population level. A retrospective cohort study was performed using a novel data source; a pet insurance database. The rate of antimicrobial prescribing, and the rate of prescribing of critically important antimicrobials, was measured in a large population of dogs (813,172 dog-years) and cats (129,232 cat-years) from 2013 - 2017. The incidence rate of antimicrobial prescribing was 5.8 prescriptions per 10 dog years (95% CI 5.8-5.9 per 10 dog years) and 3.1 prescriptions per 10 cat years (95% CI 3.1-3.2 per 10 cat years). Critically important antimicrobials accounted for 8% of all the antimicrobials prescribed over the 4-year study. Cats were 4.8-fold more likely than dogs to be prescribed 3rd-generation cephalosporins. The level of antimicrobial exposure in dogs and cats was less than half that for the coincident human community. Data such as this provides a unique opportunity to monitor antimicrobial prescribing in veterinary medicine, which is a critical component of optimal antimicrobial stewardship.
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http://dx.doi.org/10.1016/j.vetmic.2018.09.010DOI Listing
November 2018

Does only the age of the hen matter in Salmonella enterica contamination of eggs?

Food Microbiol 2019 Feb 13;77:1-9. Epub 2018 Aug 13.

Asia-Pacific Centre for Animal Health, Melbourne Veterinary School, The Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Victoria, 3010, Australia. Electronic address:

Contamination of eggs with Salmonella enterica is a significant risk factor contributing to foodborne disease. Periods of peak egg contamination were identified by conducting longitudinal environmental and egg sampling in 7 layer flocks until they were 50 weeks of age. A total of 714 environmental samples and 8958 eggs were cultured using standard methods for the detection of salmonellae. Pooled egg contamination with Salmonella Typhimurium or Salmonella Infantis was detected at a true prevalence (TP) of 0.002 (95% CI = 0.001, 0.004) or 0.005 (95% CI = 0.004, 0.007), respectively. S. Typhimurium and S. Infantis were detected in individual egg components; in shell rinse at a TP of 0.014 (95% CI = 0.005, 0.038), in shell and membrane at a TP of 0.01 (95% CI = 0.003, 0.032), and in albumen and yolk content at a TP of 0.007 (95% CI = 0.001, 0.027). The concentration of salmonellae in all fractions was <1 CFU/mL. The TP of Salmonella enterica in eggs was highest at the onset of lay. Higher egg prevalence was associated with a lower body weight, higher egg production, higher egg weight and mass than the breed standard for age, and poorer feed conversion efficiency. Flock physiology appears to have an important influence on the detection of eggs contaminated with Salmonella enterica.
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http://dx.doi.org/10.1016/j.fm.2018.08.006DOI Listing
February 2019

Analysis of the Mycoplasma bovis lactate dehydrogenase reveals typical enzymatic activity despite the presence of an atypical catalytic site motif.

Microbiology (Reading) 2018 02;164(2):186-193

Asia-Pacific Centre for Animal Health, Melbourne Veterinary School, Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Parkville, VIC, Australia.

The lactate dehydrogenase (LDH) of Mycoplasma genitalium has been predicted to also act as a malate dehydrogenase (MDH), but there has been no experimental validation of this hypothesized dual function for any mollicute. Our analysis of the metabolite profile of Mycoplasma bovis using gas chromatography/mass spectrometry (GC/MS) and liquid chromatography/mass spectrometry (LC/MS) detected malate, suggesting that there may be MDH activity in M. bovis. To investigate whether the putative l-LDH enzyme of M. bovis has a dual function (MDH and LDH), we performed bioinformatic and functional biochemical analyses. Although the amino acid sequence and predicted structural analysis of M. bovisl-LDH revealed unusual residues within the catalytic site, suggesting that it may have the flexibility to possess a dual function, our biochemical studies using recombinant M. bovis -LDH did not detect any MDH activity. However, we did show that the enzyme has typical LDH activity that could be inhibited by both MDH substrates oxaloacetate (OAA) and malate, suggesting that these substrates may be able to bind to M. bovis LDH. Inhibition of the conversion of pyruvate to lactate by OAA may be one method the mycoplasma cell uses to reduce the potential for accumulation of intracellular lactate.
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http://dx.doi.org/10.1099/mic.0.000600DOI Listing
February 2018

Human Wound Infection with Mannheimia glucosida following Lamb Bite.

J Clin Microbiol 2015 Oct 22;53(10):3374-6. Epub 2015 Jul 22.

Monash Infectious Diseases, Monash Health, Clayton, Victoria, Australia Department of Microbiology, Monash Health, Clayton, Victoria, Australia Department of Medicine, Monash University, Clayton, Victoria, Australia.

Mannheimia spp. are veterinary pathogens that can cause mastitis and pneumonia in domestic cattle and sheep. While Mannheimia glucosida can be found as normal flora in oral and respiratory mucosa in sheep, there have been no reported cases of human infection with this organism.
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http://dx.doi.org/10.1128/JCM.01249-15DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4572521PMC
October 2015

Isolation and characterization of a novel herpesvirus from a free-ranging eastern grey kangaroo (Macropus giganteus).

J Wildl Dis 2013 Jan;49(1):143-51

School of Veterinary Science, The University of Melbourne, Parkville, Victoria 3010, Australia.

We isolated a macropodid herpesvirus from a free-ranging eastern grey kangaroo (Macropus giganteous) displaying clinical signs of respiratory disease and possibly neurologic disease. Sequence analysis of the herpesvirus glycoprotein G (gG) and glycoprotein B (gB) genes revealed that the virus was an alphaherpesvirus most closely related to macropodid herpesvirus 2 (MaHV-2) with 82.7% gG and 94.6% gB amino acid sequence identity. Serologic analyses showed similar cross-neutralization patterns to those of MaHV-2. The two viruses had different growth characteristics in cell culture. Most notably, this virus formed significantly larger plaques and extensive syncytia when compared with MaHV-2. No syncytia were observed for MaHV-2. Restriction endonuclease analysis of whole viral genomes demonstrated distinct restriction endonuclease cleavage patterns for all three macropodid herpesviruses. These studies suggest that a distinct macropodid alphaherpesvirus may be capable of infecting and causing disease in eastern grey kangaroos.
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http://dx.doi.org/10.7589/2012-01-027DOI Listing
January 2013
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