Molecular characterization of Staphylococcus aureus isolated from bovine mastitis and close human contacts in South African dairy herds : genetic diversity and inter-species host transmission

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dc.contributor.author Schmidt, Tracy
dc.contributor.author Kock, Marleen M.
dc.contributor.author Ehlers, M.M. (Marthie Magdaleen)
dc.date.accessioned 2017-07-24T07:54:01Z
dc.date.available 2017-07-24T07:54:01Z
dc.date.issued 2017-04-06
dc.description.abstract Staphylococcus aureus is one of the most common etiological agents of contagious bovine mastitis worldwide. The purpose of this study was to genetically characterize a collection of S. aureus isolates (bovine = 146, human = 12) recovered from cases of bovine mastitis and nasal swabs of close human contacts in the dairy environment. Isolates were screened for a combination of clinically significant antimicrobial and virulence gene markers whilst the molecular epidemiology of these isolates and possible inter-species host transmission was investigated using a combination of genotyping techniques. None of the isolates under evaluation tested positive for methicillin or vancomycin resistance encoding genes. Twenty seven percent of the bovine S. aureus isolates tested positive for one or more of the pyrogenic toxin superantigen (PTSAg) genes with the sec and sell genes predominating. Comparatively, 83% of the human S. aureus isolates tested positive for one or more PTSAg genes with a greater variety of genes being detected. Genomic DNA macrorestriction followed by pulsed-field gel electrophoresis (PFGE) of the bovine isolates generated 58 electrophoretic patterns including: ST8 (CC8), ST97 (CC97), ST351 (CC705), ST352 (CC97), ST508 (CC45), ST2992 (CC97) and a novel sequence type, ST3538 (CC97). Based on PFGE analysis, greater genetic diversity was observed among the human S. aureus isolates. Bovine and human isolates from three sampling sites clustered together and were genotypically indistinguishable. Two of the isolates, ST97 and ST352 belong to the common bovine lineage CC97, and their isolation from close human contacts suggests zoonotic transfer. In the context of this study, the third isolate, ST8 (CC8), is believed to be a human clone which has transferred to a dairy cow and has subsequently caused mastitis. The detection of indistinguishable S. aureus isolates from bovine and human hosts at three of the sampling sites is suggestive of bacterial transmission and supports the need for vigilant monitoring of staphylococcal populations at the human-animal interface. which grouped into 10 pulsotypes at an 80% similarity level. The majority of the bovine isolates, 93.2% (136/146), clustered into four major pulsotypes. Seven sequence types (ST) were identified among the representative bovine S. aureus isolates genotyped, en_ZA
dc.description.department Medical Microbiology en_ZA
dc.description.librarian am2017 en_ZA
dc.description.sponsorship The University of Pretoria, National Health Laboratory Services, RESCOM, the National Research Foundation (NRF) Research Technology Fund (RTF14011560804) and the KZN Department of Agriculture and Rural Development. en_ZA
dc.description.uri http://www.frontiersin.org en_ZA
dc.identifier.citation Schmidt T, Kock MM and Ehlers MM (2017) Molecular Characterization of Staphylococcus aureus Isolated from Bovine Mastitis and Close Human Contacts in South African Dairy Herds: Genetic Diversity and Inter-Species Host Transmission. Front. Microbiol. 8:511. DOI: 10.3389/fmicb.2017.00511. en_ZA
dc.identifier.issn 1664-302X (online)
dc.identifier.other 10.3389/fmicb.2017.00511
dc.identifier.uri http://hdl.handle.net/2263/61417
dc.language.iso en en_ZA
dc.publisher Frontiers Research Foundation en_ZA
dc.rights © 2017 Schmidt, Kock and Ehlers. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). en_ZA
dc.subject Staphylococcus aureus en_ZA
dc.subject Bovine mastitis en_ZA
dc.subject Inter-species transmission en_ZA
dc.subject Pyrogenic toxin superantigen (PTSAg) en_ZA
dc.subject Pulsed-field gel electrophoresis (PFGE) en_ZA
dc.subject Multilocus sequence typing (MLST) en_ZA
dc.subject South African dairy herds en_ZA
dc.title Molecular characterization of Staphylococcus aureus isolated from bovine mastitis and close human contacts in South African dairy herds : genetic diversity and inter-species host transmission en_ZA
dc.type Article en_ZA


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