Characterization of blaNDM-harboring, multidrug-resistant Enterobacteriaceae isolated from seafood.

Carbapenem-resistant Enterobacteriaceae (CRE) have evolved into a major challenge to antibiotic therapy worldwide. The problem is more confounding when wider dissemination of CRE occurs in the community and the environment. In this study, six blaNDM-harboring Enterobacteriaceae, four Klebsiella pneumoniae, and two Escherichia coli, isolated from seafood, were characterized with respect to their antibiotic resistance and the genetic factors responsible for these resistances. The isolates were resistant to all β-lactam antibiotics, quinolones, trimethoprim-sulfamethoxazole, chloramphenicol, and tetracycline and were susceptible to colistin, polymixin B, fosfomycin, and tigecycline. Four isolates harbored New Delhi metallo β-lactamase (blaNDM-5 genes, while one isolate each harbored blaNDM-1 and blaNDM-2 genes, respectively. The blaNDM genes in all the isolates were flanked by an upstream, truncated ISAba125, and downstream bleMBL-trpF genes. Conjugation experiments showed that the NDM plasmids were readily transmissible. Further, the two blaNDM-positive E. coli isolates belonged to the multidrug-resistant ST131 clone. This study highlights the growing danger of seafood as carriers of multidrug-resistant bacteria leading to their wider dissemination in the community.