Occurrence and distribution of multiple antibiotic-resistant Enterococcus and Lactobacillus spp. from Indian poultry: in vivo transferability of their erythromycin, tetracycline and vancomycin resistance.

The objective of this study was to determine the
occurrence and distribution of antibiotic resistant (AR) lactic
acid bacteria (LAB) in Indian poultry. LAB from poultry farm
feces (n = 21) and samples from slaughter houses comprising
chicken intestine (n = 46), raw meat (n = 23), and sanitary
water (n = 4) were evaluated and compared with those from
organic chicken (OC) collected from nearby villages.
Screening studies showed 5–7 log units higher erythromycin
(ER), tetracycline (TC) and vancomycin (VAN) resistant LAB
from conventional poultry chicken (CC) compared to OC.
Molecular characterization of isolated cultures (n = 32) with
repetitive-PCR profiling and 16S rRNA gene sequencing revealed
their taxonomical status as Enterococcus faecium
(n = 16), Enterococcus durans (n = 2), Lactobacillus
plantarum (n = 10), Lactobacillus pentosus (n = 1) and
Lactobacillus salivarius (n = 3). The isolates were found to
harbor erm(B), msr(C), msr(A/B), tet(M), tet(L) and tet(K)
genes associated with Tn916 and Tn917 family transposons.
Expression studies through real-time PCR revealed antibioticinduced
expression of the identified AR genes. In vitro and
in vivo conjugational studies revealed transfer of ER and TC
resistant (ERR and TCR) genes with transfer frequencies of
10−7 and 10−4 transconjugants recipient−1, respectively.
Although no known VAN resistance (VANR) genes were detected,
high phenotypic resistance was observed and was
transferable to the recipient. From a public health point of view, this study reports Indian poultry as a major source of
high levels of AR bacteria contaminating the food chain and
the environment. Thus, urgent and determined strategies are
needed to control the spread of multiple AR bacteria.