This study shows the occurrence and dissemination of PMQR genes in Salmonella and E. coli in Europe with a defined quinolone resistance phenotype. We also report the first detection of qnrD in Salmonella collected in Europe.
Please cite this article as: Cavaco, L.M., Hasman, H., Aarestrup, F.M., on behalf of the MRSA collaborating group (MRSA-CG), Zinc resistance of Staphylococcus aureus of animal origin is strongly associated with methicillin resistance, Veterinary Microbiology (2010Microbiology ( ), doi:10.1016Microbiology ( /j.vetmic.2011 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. The test population consisted of 476 porcine MRSA isolates from ten European 30 countries, 18 porcine MRSA isolates from Canada and seven MRSA from China, 92 31
MRSA and 60 methicillin-susceptible S. aureus (MSSA) isolates from veal calves in the 32Netherlands and 88 porcine MSSA isolates from four European countries. Most porcine 33 MRSA (n=454) and all bovine MRSA belonged to clonal complex (CC) 398 whereas 37 34 of the pig MRSA from Europe and the seven Chinese isolates belonged to other CCs 35 and 3 isolates were not classified into a CC. 36All isolates were tested for susceptibility to zinc chloride and copper sulphate using 37 agar dilution and tested by PCR for the czrC gene encoding zinc resistance. 38Phenotypic zinc resistance (MIC>2mM) was observed in 74% (n=324) and 42% (n=39) 39 of European MRSA CC398 from pigs and veal calves respectively, and in 44% of the 40 Canadian isolates (n=8), but not among the Chinese isolates. Almost all (99%) zinc-41 resistant MRSA carried czrC. Of the 37 European non-CC398 MRSA, 62% were 42 resistant to zinc, but only 46% of them carried czrC,. The MICs of the MSSA isolates to 43 zinc chloride ranged from 1 to 4 mM and none carried czrC. The MICs of copper 44 sulphate were neither associated with methicillin resistance nor with the detection of 45
czrC. 46This study showed that zinc resistance and the czrC gene is widespread among 47 CC398 MRSA isolates. This suggests that the use of zinc in feed might have 48 contributed to the emergence of MRSA. 49 50
Forty Mycobacterium bovis isolates from cattle and goats were analyzed by using different repetitive genetic markers. The 23 M. bovis strains from goats were found to carry six to eight copies of the insertion sequence IS6110. In contrast, most of the bovine isolates contained only a single copy of this element. The standardized IS6110 fingerprinting by restriction fragment length polymorphism (RFLP), described for Mycobacterium tuberculosis strains, allowed the differentiation of caprine strains. Although this method was not useful for typing bovine isolates, the repetitive elements pTBN12 and DR proved to be suitable for this purpose. A procedure using PCR which amplifies IS6110 in the outward direction was found to be as sensitive as RFLP for typing M. bovis strains from goats. The use of PCR and RFLP methods based on the IS6110 polymorphism would be useful for epidemiological studies of caprine tuberculosis. The results are consistent with different strains of M. bovis being implicated in bovine and caprine tuberculosis.
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