OCCURRENCE AND CHARACTERIZATION OF METHICILLIN RESISTANT Staphylococcus aureus IN PIGS
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Date
2018
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COLLEGE OF VETERINARY AND ANIMAL SCIENCES-MANNUTHY,THRISSUR
Abstract
Methicillin resistant Staphylococcus aureus (MRSA) has been detected
from pigs in many parts of the world and is having great potential to act as a
human pathogen. Exposure to livestock is considered as a major risk factor for
human colonization with MRSA. This study was conducted to evaluate the
occurrence and molecular characteristics of MRSA among healthy pigs. Nasal
swabs (n=119) were derived from four pig farms in Thrissur district and
Staphylococci were enumerated from the swabs by conventional culture methods.
The prevalence of S. aureus was 42.86 per cent by Polymerase Chain Reaction
(PCR). S. aureus isolates were characterized by Staphylococcal Protein A (spa)
typing and all the isolates belonged to six spa types with t091 (20%) being the
predominant spa type. Eleven new spa types were also identified in the study.
Methicillin resistance in S. aureus isolates were identified genotypically by
molecular characterization of mecA gene and the prevalence was 5.89 per cent.
The beta-lactam resistance gene, blaZ was detected in 62.75 per cent isolates.
Antibiogram studies of all the S. aureus isolates revealed that maximum resistance
was shown to gentamicin (76.47%) followed by azithromycin (74.77%), and
ciprofloxacin (70.59%). Phenotypic methicillin resistance, as indicated by the
resistance to oxacillin, was identified in 29.41 per cent of the isolates. The high
Multiple Antibiotic Resistance (MAR) indices obtained in the study indicated a
remarkable spread of resistance among the isolates due to frequent exposure to the
antibiotics. This study confirmed the occurrence of nasal colonization of MRSA
among healthy pigs which is a major threat to public health and should be viewed
seriously.