Abstract
BackgroundThe blaZ gene encoding penicillin resistance can be located either chromosomally or on plasmids. The aim of this study was to investigate the genetic relationships and to determine the location of the blaZ gene in S. aureus isolated in bovine mastitis in Finland and Sweden.MethodsSeventy-eight β-lactamase positive S. aureus isolates from bovine mastitis (34 from Finland and 44 from Sweden) were included in the study. The localization of blaZ gene was determined by Southern blotting. The blaZ genes of the isolates were sequenced and the sequences were translated to beta-lactamase proteins and further grouped as different protein signatures. The isolates and, as control, 33 Swedish and 36 Finnish beta-lactamase negative isolates were typed with pulsed-field gel electrophoresis (PFGE).ResultsIn 26 out of 34 Finnish isolates (76.5%) and in 25 out of 44 Swedish isolates (56.8%) the blaZ gene was localized on a plasmid. Six different protein signatures were found. One signature was found only in four Swedish isolates, but all other signatures were found both in Finnish and Swedish isolates. The PFGE results revealed a diversity of S. aureus clones. The protein signatures were not clearly associated with certain pulsotypes.ConclusionsThe plasmid location of the blaZ gene was not statistically significantly more common in Finland than in Sweden, and hence does not explain the higher proportion of penicillin-resistant isolates of S. aureus causing bovine mastitis in Finland compared to Sweden.
Highlights
The blaZ gene encoding penicillin resistance can be located either chromosomally or on plasmids
Bacterial isolates A total of 78 beta-lactamase positive S. aureus isolates from bovine mastitis (34 isolates from Finland and 44 isolates from Sweden) from previous surveys were included in the study
Location of the blaZ gene in penicillin-resistant strains Based on the Southern blotting, the blaZ gene was located on the chromosome in 27 isolates and on plasmids in 51 isolates
Summary
The blaZ gene encoding penicillin resistance can be located either chromosomally or on plasmids. The aim of this study was to investigate the genetic relationships and to determine the location of the blaZ gene in S. aureus isolated in bovine mastitis in Finland and Sweden. Resistance to benzylpenicillin is common among mastitis-causing staphylococci, but varies largely between countries [3]. Low prevalences of penicillinresistant S. aureus have been reported in Sweden (3.7 to 7.1%) and Norway (5.0 to 11.4%) [3,4,5,6] and in Canada (8.7%) [7]. High prevalences of penicillin-resistance have been reported for example in Estonia (61.4%). In a prevalence survey in Finland, 52.1% of S. aureus isolates were penicillin-resistant [10].
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
