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.
