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Wieland B.,Lane College | Dhollander S.,Animal Health and Welfare Unit | Salman M.,Colorado State University | Koenen F.,Veterinary and Agrochemical Research Center
Preventive Veterinary Medicine | Year: 2011

In the absence of data, qualitative risk assessment frameworks have proved useful to assess risks associated with animal health diseases. As part of a scientific opinion for the European Commission (EC) on African Swine Fever (ASF), a working group of the European Food Safety Authority (EFSA) assessed the risk of ASF remaining endemic in Trans Caucasus Countries (TCC) and the Russian Federation (RF) and the risk of ASF becoming endemic in the EU if disease were introduced. The aim was to develop a tool to evaluate how current control or preventive measures mitigate the risk of spread and giving decision makers the means to review how strengthening of surveillance and control measures would mitigate the risk of disease spread. Based on a generic model outlining disease introduction, spread and endemicity in a region, the impact of risk mitigation measures on spread of disease was assessed for specific risk questions. The resulting hierarchical models consisted of key steps containing several sub-steps. For each step of the risk pathways risk estimates were determined by the expert group based on existing data or through expert opinion elicitation. Risk estimates were combined using two different combination matrices, one to combine estimates of independent steps and one to combine conditional probabilities. The qualitative risk assessment indicated a moderate risk that ASF will remain endemic in current affected areas in the TCC and RF and a high risk of spread to currently unaffected areas. If introduced into the EU, ASF is likely to be controlled effectively in the production sector with high or limited biosecurity. In the free range production sector, however, there is a moderate risk of ASF becoming endemic due to wild boar contact, non-compliance with animal movement bans, and difficult access to all individual pigs upon implementation of control measures. This study demonstrated the advantages of a systematic framework to assist an expert panel to carry out a risk assessment as it helped experts to disassociate steps in the risk pathway and to overcome preconceived notions of final risk estimates. The approach presented here shows how a qualitative risk assessment framework can address animal diseases with complexity in their spread and control measures and how transparency of the resulting estimates was achieved. © 2011 Elsevier B.V.

Jamrozy D.M.,Animal Health and Veterinary Laboratories Agency | Jamrozy D.M.,Kingston University | Coldham N.G.,Animal Health and Veterinary Laboratories Agency | Butaye P.,Ghent University | And 2 more authors.
Journal of Antimicrobial Chemotherapy | Year: 2014

Objectives: Previously described methicillin-resistant Staphylococcus aureus (MRSA) ST398 strains revealed a high frequency of phenotypic resistance to spectinomycin. However, only a few were found to carry the spc resistance determinant. The aim of this study was to identify the genetic mechanism of spectinomycin resistance among spc-negative MRSA ST398 strains. Methods: Nine spectinomycin-resistant, but spc-negative, MRSA ST398 strains were analysed. The strains were screened for carriage of the spw gene and tested for the presence of transferrable spectinomycin resistance. Plasmid DNAwas isolated from all strains and used in transformation assays. The plasmid identified as mediating resistance to spectinomycin was fully sequenced. The function of the novel spectinomycin resistance gene was confirmed by restriction digest inactivation and its distribution was determined using a PCR assay. Results: A single MRSA ST398 strain was spw positive. The remaining strains carried a plasmid that mediated resistance to spectinomycin. Sequence analysis of a single plasmid, termed pDJ91S, revealed that it was 3928 bp in size and contained three open reading frames: a novel spectinomycin resistance gene, designated spd, as well as a repN gene and a rec gene. The XmnI digest inactivation of the spd gene resulted in a 4-fold decrease in spectinomycin MIC. The spd gene was detected in seven other spectinomycin-resistant MRSA ST398 strains that carried a plasmid comparable in size to pDJ91S. Conclusions: A novel gene, designated spd, that confers resistance to spectinomycin has been identified on a small plasmid in MRSA ST398. © Crown copyright 2014.

Jamrozy D.M.,Animal Health and Veterinary Laboratories Agency | Jamrozy D.M.,Kingston University | Fielder M.D.,Kingston University | Butaye P.,Veterinary and Agrochemical Research Center | And 2 more authors.
PLoS ONE | Year: 2012

The high prevalence of methicillin-resistant Staphylococcus aureus (MRSA) ST398 among pigs in certain European countries and North America and its occurrence in other animal species raises a question concerning the molecular mechanisms mediating the success of this lineage. In this study a panel of S. aureus strains belonging to sequence type (ST) 5 (n = 4), ST8 (n = 5), ST15 (n = 5), ST22 (n = 8), clonal complex (CC) 30 (n = 8), CC97 (n = 8), CC130 (n = 4), CC151 (n = 4) and ST398 (n = 18) were screened by DNA microarray and PCR for the carriage of virulence and antimicrobial resistance genes. Isolates belonging to the same sequence type/clonal complex (ST/CC) were found to share similar virulence gene profiles. The ST398 lineage displayed the lowest content of virulence genes, which consisted mainly of genes detected among the majority or all of the analysed lineages. All MRSA ST398 isolates lacked accessory virulence genes that were detected in other ST/CC. In contrast to virulence genotype, the antimicrobial resistance genes profiles varied between isolates belonging to the same ST/CC and profile similarities could be observed for isolates from different lineages. MRSA ST398 isolates in particular displayed significant diversity and high content of antimicrobial resistance genes. This was comparable with certain MRSA belonging to other sequence types particularly the equine MRSA ST8. The apparent lack of significant virulence genes among MRSA ST398 strains, demonstrates that the lineage features a unique genetic background but no ST398-specific virulence markers could be identified. © 2012 Jamrozy et al.

Nemeghaire S.,Ghent University | Vanderhaeghen W.,Ghent University | Argudin M.A.,Veterinary and Agrochemical Research Center | Haesebrouck F.,Ghent University | Butaye P.,Ghent University
The Journal of antimicrobial chemotherapy | Year: 2014

OBJECTIVES: This study aimed at assessing the epidemiology and genetic diversity of methicillin-resistant Staphylococcus sciuri (MRSS) from different farm animal species.METHODS: Nasal swabs were collected from 200 pigs, 100 dairy cows, 100 beef cows, 150 veal calves and 200 broilers. Colonies were isolated on selective media containing cefoxitin and the mecA gene was detected by PCR. Antimicrobial resistance was determined by broth microdilution. The genetic diversity was assessed by PFGE and resistance and virulence genes were detected by microarray analysis.RESULTS: The total MRSS prevalence at the animal level was estimated at 9.5%, varying from ∼10% in veal (13.3%), broilers (12.5%) and dairy cows (10.0%) to 6.5% in pigs and 3.0% in beef cows. mecA was detected in all isolates. SCCmec elements of type III and non-typeable ones were seen most frequently. More than 90% of isolates were non-wild-type (NWT) for gentamicin, penicillin, tiamulin, clindamycin and quinupristin/dalfopristin. The frequency of NWT isolates for fusidic acid and trimethoprim ranged between 78% and 87%. PFGE analysis allowed distinction between two major clusters. Most isolates tested by microarray carried erm and tet genes. Virulence genes were also detected, including an isa gene encoding an immune-evasion factor and the hsdS2 gene encoding a site-specific deoxyribonuclease.CONCLUSIONS: This study shows that multiresistant MRSS is carried by different farm animal species. Although some animals shared the same strain, PFGE showed different patterns, indicating high diversity among the MRSS isolates recovered. The absence of clusters associated with a certain animal species suggests low host specificity. © The Author 2014. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Vandendriessche S.,Free University of Colombia | Vandendriessche S.,Veterinary and Agrochemical Research Center | Kadlec K.,Institute of Farm Animal Genetics | Schwarz S.,Institute of Farm Animal Genetics | Denis O.,Free University of Colombia
Journal of Antimicrobial Chemotherapy | Year: 2011

Objectives: Methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-susceptible S. aureus (MSSA), collected from 109 Belgian acute-care hospitals during a national survey in 2008, were investigated for macrolide-lincosamide (ML) resistance with particular emphasis on the analysis of erm(T)-carrying isolates. Methods: In total, 314 MRSA and 212 MSSA were collected and characterized by spa typing. The SCCmec type of MRSA was determined. Resistance to ML antibiotics was detected by agar dilution and resistant strains were screened by PCR for erm(A), erm(C) and msr(A). Five ML-resistant MSSA isolates, negative by PCR for the aforementioned genes, were further characterized. Results: Half of all MRSA isolates (n=157; 50.0%) were resistant to erythromycin and harboured the gene erm(A) (n=112), erm(C) (n=41), erm(A) + erm(C) (n=3) or msr(A) (n=1). The erm(A) gene was mainly present in MRSA spa-CC002-ST5-SCCmec II and spa-CC008-ST8-SCCmec IV (where CC stands for clonal complex and ST stands for sequence type); the distribution of erm(C) was more diverse. Thirty-five of the 40 erythromycin-resistant MSSA (18.9%) carried the gene erm(A) (n=17), erm(C) (n=9) or msr(A) (n=9). The remaining five MSSA were ST398-t571 isolates, which exhibited closely related ApaI PFGE patterns, harboured the gene erm(T) in the chromosomal DNA and did not exhibit additional resistances. These isolates were from severe infections in patients, of whom four had no contact and one had only indirect contact with livestock via a family member working in animal husbandry. Conclusions: The ML-streptogramin B ('MLS B') resistance genes erm(A) or erm(C) were detected in the majority of ML-resistant MRSA and MSSA isolates. The erm(T) gene was identified in MSSA ST398 isolates from five independent patients who lacked direct contact with livestock. © The Author 2011. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved.

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