Institute of Veterinary Bacteriology

Bern, Switzerland

Institute of Veterinary Bacteriology

Bern, Switzerland
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News Article | April 27, 2017
Site: phys.org

Macrococcus caseolyticus is a harmless bacterium naturally found on the skin of dairy cows which can spread to milk during the milking process. It can also be present in dairy products made from raw milk like e.g. cheese. Researchers of the Institute of Veterinary Bacteriology of the University of Bern have identified a new methicillin resistance gene in strains of M. caseolyticus isolated from milk. Transfer of the gene to Staphylococcus aureus, a bacteria found on the skin and mucosa of animals and humans, would have dramatic consequences for public health. This methicillin resistance gene would turn this bacteria into a hazardous methicillin-resistant S. aureus (MRSA), which is known to cause difficult-to-treat infections in hospitals. Acquired methicillin resistance in bacteria is associated with genes mecA, mecB, or mecC. However, none of these genes were present in the M. caseolyticus strains – they carried the novel resistance gene mecD. This discovery has now been published in Scientific Reports. Over the last years, researchers of Vincent Perreten's group at the Institute of Veterinary Bacteriology in Bern investigated M. caseolyticus present in milk of dairy cows suffering from mastitis. Mastitis is an infection of the udder which is frequently treated with penicillins and cephalosporins, which are antibiotics of the beta-lactam class like methicillin. These bacteria isolated from milk showed an unusual resistance pattern to beta-lactam antibiotics with a resistance profile resembling that of MRSA, but the known genes responsible for resistance were missing. "We were intrigued by this novel resistance in M. caseolyticus and wanted to know what was behind this resistance," says Vincent Perreten. Bacteria have the extraordinary ability to acquire novel genetic information such as antibiotic resistance genes. Using Next Generation Sequencing (NGS), the researchers rapidly found that the M. caseolyticus isolates acquired a novel antibiotic resistance island which contains a new methicillin resistance gene designated mecD. The new mecD gene confers resistance to anti-MRSA cephalosporins The group of Vincent Perreten demonstrated that the novel methicillin resistance gene mecD confers resistance to all classes of β-lactams including anti-MRSA cephalosporins. It was located on a "resistance island" which has been acquired by M. caseolyticus. Further experimental investigations of the "resistance island" showed that it also has the potential for integration into the chromosome of S. aureus. "It is not excluded that this event may happen in nature, since S. aureus and M. caseolyticus share the same habitats," says Perreten. M. caseolyticus containing the novel mecD gene has been so far mainly found in cattle but in one case it has been isolated from skin infection in a dog indicating that this bacteria has the potential to colonize different animal species. "So far, we do not have any indication of the presence of mecD in humans, but its transfer from M. caseolyticus to S. aureus would further limit therapeutic options of this nosocomial pathogen." Selection of this gene should be avoided limiting the inadequate use of antibiotics in animals and humans. "It is imperative to keep an eye on the evolution and spread of this novel resistance gene in both human and animal bacteria," says Perreten. Explore further: Fighting MRSA with new membrane-busting compounds More information: Sybille Schwendener et al. Novel methicillin resistance gene mecD in clinical Macrococcus caseolyticus strains from bovine and canine sources, Scientific Reports (2017). DOI: 10.1038/srep43797


Carranza P.,University of Zürich | Grunau A.,University of Zürich | Schneider T.,University of Zürich | Hartmann I.,Institute for Food Safety and Hygiene | And 8 more authors.
Proteomics | Year: 2010

The opportunistic food-borne pathogen Cronobacter sp. causes rare but significant illness in neonates and is capable to grow at a remarkably wide range of temperatures from 5.5 to 47°C. A gel-free quantitative proteomics approach was employed to investigate the molecular basis of the Cronobacter sp. adaptation to heat and cold-stress. To this end the model strain Cronobacter turicensis 3032 was grown at 25, 37, 44, and 47°C, and whole-cell and secreted proteins were iTRAQ-labelled and identified/quantified by 2-D-LC-MALDI-TOF/TOF-MS. While 441C caused only minor changes in C. turicensis growth rate and protein profile, 47°C affected the expression of about 20% of all 891 identified proteins and resulted in a reduced growth rate and rendered the strain non-motile and filamentous. Among the heat-induced proteins were heat shock factors, transcriptional and translational proteins, whereas proteins affecting cellular morphology, proteins involved in motility, central metabolism and energy production were down-regulated. Notably, numerous potential virulence factors were found to be up-regulated at higher temperatures, suggesting an elevated pathogenic potential of Cronobacter sp. under these growth conditions. Significant alterations in the protein expression profile and growth rate of C. turicensis exposed to 25°C indicate that at this temperature the organism is cold-stressed. Up-regulated gene products comprised cold-shock, DNA-binding and ribosomal proteins, factors that support protein folding and proteins opposing cold-induced decrease in membrane fluidity, whereas down-regulated proteins were mainly involved in central metabolism. © 2010 Wiley-VCH Verlag GmbH & Co. KGaA.


Berset-Istratescu C.M.,Vetsuisse Faculty | Glardon O.J.,Vetsuisse Faculty | Magouras I.,University of Bern | Frey C.F.,Institute of Parasitology | And 2 more authors.
Veterinary Journal | Year: 2014

This study aimed to examine the aetiology of acute diarrhoea and the relapse rate in 100 client-owned dogs presented to a first-opinion clinic. History, physical examination, faecal testing and owner questionnaire data were collected at initial presentation (T0) and at either the time of relapse or at a recheck performed within 3months. All dogs received treatment according to their clinical signs. Of 96 dogs that completed the study, 37 (38.5%) relapsed during the study period, 21 (21.9%) relapsed within 3months, and 16 others (16.6%) at 3months to 1year after initial examination. Dogs that had undergone a change in housing location within 1month prior to presentation and dogs <1year old were significantly more likely to have positive parasitological analyses (P=0.02 and P=0.001, respectively). Pica was a risk factor for relapse (P=0.0002). © 2013 Elsevier Ltd.


PubMed | University of Bern, Institute of Veterinary Bacteriology, Institute of Parasitology, Vetsuisse Faculty and University of Leipzig
Type: Journal Article | Journal: Veterinary journal (London, England : 1997) | Year: 2014

This study aimed to examine the aetiology of acute diarrhoea and the relapse rate in 100 client-owned dogs presented to a first-opinion clinic. History, physical examination, faecal testing and owner questionnaire data were collected at initial presentation (T0) and at either the time of relapse or at a recheck performed within 3 months. All dogs received treatment according to their clinical signs. Of 96 dogs that completed the study, 37 (38.5%) relapsed during the study period, 21 (21.9%) relapsed within 3 months, and 16 others (16.6%) at 3 months to 1 year after initial examination. Dogs that had undergone a change in housing location within 1 month prior to presentation and dogs <1 year old were significantly more likely to have positive parasitological analyses (P=0.02 and P=0.001, respectively). Pica was a risk factor for relapse (P=0.0002).


Oevermann A.,University of Bern | Di Palma S.,Institute of Animal Pathology | Doherr M.G.,University of Bern | Abril C.,Institute of Veterinary Bacteriology | And 2 more authors.
Brain Pathology | Year: 2010

Listeriosis is a serious food-borne disease with increasing frequency in humans and ruminants. Despite the facts that in both hosts, listeriosis can occur as rhombencephalitis and ruminants are a reservoir of Listeria monocytogenes (LM) strains pathogenic for humans, little work has been done on the pathogenesis in ruminants. This study investigates the neuropathogenesis of listeric encephalitis in over 200 natural cases in cattle, sheep and goats by analyzing anatomical distribution, severity, bacterial load and temporal evolution of the lesions. Our results suggest that LM gains access to the brainstem of all three species via axonal migration not only along the trigeminal nerve, but also along other nerves. The ensuing encephalitis does not remain restricted to the brainstem. Rather, LM spreads further from the brainstem into rostral brain regions likely by intracerebral axonal migration. Significant differences in severity of the lesions and bacterial load were found between cattle and small ruminants, which may be caused by species-specific properties of antibacterial immune responses. As histopathological lesions of human rhombencephalitis caused by LM strongly resemble those of ruminants, the disease likely has a similar pathogenesis in both hosts. © 2009 International Society of Neuropathology.


PubMed | Animal Health Service Flanders, University of Bern, Institute of Veterinary Bacteriology and Ghent University
Type: | Journal: Veterinary microbiology | Year: 2016

Mycoplasma bovis is a highly contagious bacterium, which predominantly causes chronic pneumonia, otitis and arthritis in calves and mastitis in adult cattle. In humans, Mycoplasma species have been associated with post-surgical infections. The present study aimed to identify the bacteria associated with three outbreaks of infected seromas after caesarian section in Belgian Blue beef cattle. A total of 10 cases occurred in three herds which were in close proximity of each other and shared the same veterinary practice. M. bovis could be cultured from seroma fluid in five of the six referred animals, mostly in pure culture and was isolated from multiple chronic sites of infection (arthritis and mastitis) as well. DNA fingerprinting of the isolates targeting two insertion sequence elements suggested spread of M. bovis from chronic sites of infection (udder and joints) to the postsurgical seromas. Identical genetic profiles were demonstrated in two animals from two separate farms, suggesting spread between farms. Mortality rate in the referred animals positive for M. bovis in a seroma was 80% (4/5), despite intensive treatment. A massive increase in antimicrobial use was observed in every affected farm. These observations demonstrate involvement of mycoplasmas in outbreaks of postsurgical seromas in cattle.

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