Abstract:
The transmission of zoonotic
bacteria through consumption of raw milk is
complicated by the dissemination of
antimicrobial-resistant bacteria. The present
study was conducted to detect the occurrence
of antimicrobial-resistant bacteria (ESBL-
/AmpC-producing Klebsiella spp.) in cow’s
milk originating from healthy or infected
(mastitis) cattle in India. In total, 450 milk
samples were collected from apparently
healthy cattle and cattle suffering from
clinical or sub-clinical mastitis. Out of 455
Klebsiella spp., 67 (14.73%) isolates were
found to be ESBL producers in the doubledisc
diffusion test. The occurrence of ESBLproducing
Klebsiella spp. was significantly
(p < 0.05) higher in milk samples collected
from cattle suffering with mastitis than in
healthy cattle. Among the ESBL-producing
Klebsiella spp., 56 (83.6%) isolates were
also detected that produced AmpC β-
lactamases. All the ESBL and AmpCproducing
Klebsiella spp. possessed blaCTX-M
(100%) and blaAmpC (100%), respectively.
The present study revealed a higher
occurrence of class 1 integron in ESBLproducing
Klebsiella spp. isolates. All
ESBL-producing- Klebsiella spp. isolates
were multi-drug resistant. The ciprofloxacinand/
or levofloxacin-resistant Klebsiella spp.
isolates possessed the quinolone resistance
gene (qnrS). The co-trimoxazole-resistant isolates possessed the sul1 and sul2 genes.
Phylogenetic analysis of the studied isolates
revealed that strains isolated from the same
location had a clonal relationship. The study
increases consumer awareness of the need to
avoid raw milk consumption to prevent the
spread of antimicrobial resistance in the
community.isolates possessed the sul1 and sul2 genes.
Phylogenetic analysis of the studied isolates
revealed that strains isolated from the same
location had a clonal relationship. The study
increases consumer awareness of the need to
avoid raw milk consumption to prevent the
spread of antimicrobial resistance in the
community.
