Detection of antimicrobial resistant genes of bacteria isolated from Bovine Mastitic milk by PCR

Abstract

Bovine mastitis is a major problem in dairy industry resulting in heavy economic losses. Treatment effectiveness is often hindered by the emergence of antimicrobial resistance among bacteria causing mastitis. The present investigation aimed to detect the resistant genes in bacteria isolated from mastitic milk considering the commonly used antimicrobials. Genomic DNA was extracted from 19 coliforms and 11 Staphylococci isolates by a commercial kit. PCR was performed using specific primers with the sequence of F-TCGCCTGTGTATTATCTCCC and RCGCAGATAAA- TCACCACAATG for blaSHV gene responsible for betalactam resistance and F-GGTTCACTCGAACGACGTCA and RCTGTCCACAAGTTG- CATGA for tet(A) gene involved in tetracycline resistance. Of the 30 tested isolates, 80% (24) and 46.7% (14) were positive for BlaSHV and tet(A) gene respectively. Among the phenotypically resistant 20 isolates, tet(A) gene was not present in six isolates. Ninety six percent of 25 phenotypically resistant isolates carried blaSHV gene. In all isolates carrying tet(A) gene, blaSHV gene was present. High frequency of resistant genes highlights the need of novel therapeutic strategies for mastitis. Further molecular surveillance is recommended for improved control measures.