Abstract
BackgroundStaphylococcus aureus is the predominant bacterium responsible for various diseases in animals and humans. Preventive strategies could be better implemented by understanding the prevalence, genetic patterns, and the presence of enterotoxin and biofilm-producing genes along with the antibiotic susceptibility of this organism. This study was conducted in Rajasthan, the northwestern state of India, holding the largest population of cattle that makes it the second largest milk producer in India and no such prior information is available on these aspects.MethodsA total of 368 individual quarter bovine raw milk samples were collected from 13 districts of Rajasthan, and screened for the presence of S. aureus. Microbiological and molecular approaches were followed for bacterial identification. Genetic diversity was determined by polymerase chain reaction-restriction fragment length polymorphism (PCR–RFLP) of coagulase gene (coa), whereas enterotoxin and biofilm-producing genes were studied by PCR analysis. Antibiotic strips were employed to study the antibiotic resistance among strains.ResultsIn all, 73 S. aureus strains were obtained from 368 bovine raw milk samples out of that only 30 showed the presence of coa. Nine types of coa patterns ranging from 730 to 1130 bp were observed among these isolates. PCR–RFLP of coa distinguished the isolates into 15 genotypic patterns, of which patterns I, IV, V, and VI were predominant. Of the isolates, 30% were positive for sec, 10% for sea, and 3.3% for seb; these genes are responsible for enterotoxin production, whereas all isolates were found positive for icaAD and eno. The prevalence rates of other biofilm-producing genes fnbA, clfB, ebpS, sasG, fnbB, sasC, cna, bap, fib and, bbp were 97, 93, 90, 80, 80, 77, 53, 27, 10, and 6.6%, respectively. Twenty-seven (90%) strains were multidrug resistant, of which 15 were methicillin resistant. Maximum sensitivity was reported for kanamycin and it could be considered as a drug of choice for controlling S. aureus mediated cattle infections in the studied regions.ConclusionsOverall, these strains could cause several diseases to humans, insisting the need for developing a stricter hygiene program for improving milking practices and animal health.
Highlights
Staphylococcus aureus is the predominant bacterium responsible for various diseases in animals and humans
Staphylococcus aureus is a part of the normal gut microbiota [7] but is a predominant microorganism implicated in clinical mastitis and Subclinical mastitis (SCM) [8] and is difficult to eliminate
The polymorphism in coa was studied by RFLP (Fig. 3), where fifteen (I–XV) RFLP patterns (Table 3 and Fig. 4) were observed
Summary
Staphylococcus aureus is the predominant bacterium responsible for various diseases in animals and humans. This study was conducted in Rajasthan, the northwestern state of India, holding the largest population of cattle that makes it the second largest milk producer in India and no such prior information is available on these aspects. The yield of animals within the state is not satisfactory due to various production diseases and is understood as the major factor responsible for economic losses to the dairy industry in India [3, 4]. Subclinical mastitis (SCM) with no sign of inflammation is more severe than clinical forms and is responsible for a huge loss to the dairy industry [5, 6]. The hygiene present in dairies and the literacy of handlers about safe milk production in Rajasthan are below satisfactory level [10]. Coagulase gene (coa) typing has been proven to be the most successful method to discriminate isolates at the strain level, recovered from different regions, mainly because of simple, accurate, and reproducible results obtained with this technique over other methods [13–15]
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 callMore From: Annals of Clinical Microbiology and Antimicrobials
Disclaimer: 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.
