Characterization of bla NDM -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 bla -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 (bla genes, while one isolate each harbored bla and bla genes, respectively. The bla genes in all the isolates were flanked by an upstream, truncated ISAba125, and downstream ble -trpF genes. Conjugation experiments showed that the NDM plasmids were readily transmissible. Further, the two bla -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.