Expansion of acquired 16S rRNA methytransferases along with CTX-M-15, NDM and OXA-48 within three sequence types ofEscherichia colifrom northeast India

Background This study aimed to identify ten different 16S rRNA methyltransferase genes (rmtA, rmtB, rmtC, rmtD, armA, rmtF, npmA, rmtH, rmtEandrmtG)and their coexisting ESBL and carbapenemase with the emergence of threeE.coliclones within a single study centre. Methods A total of 329 non-duplicateE.coliisolates were studied to detect the presence of 16S rRNA methyltransferases along with beta-lactamases (TEM, SHV, OXA, VEB, GES, PER,CTX-M types, NDM, OXA-48,VIM, IMP and KPC) using PCR assay. Horizontal transferability were validated by transformation and conjugation analysis. Plasmid incompatibility typing and MLST analysis was also performed. Results A total of 117 isolates were found to be resistant to at least one of the aminoglycoside antibiotics. It was observed that 77 (65.8%) were positive for 16S rRNA methyltransferases. Among them thirty nine isolates were found to harbour onlybla(CTX-M-15), whereas combination of genes were observed in three isolates (bla(VEB)+bla(CTX-M-15)in 2 isolates andbla(PER) + bla(CTX-M-15)in 1 isolate).bla(NDM)andbla(OXA-48)like genes were found in 23 and 9 isolates, respectively. All the resistance genes were conjugatively transferable, and incompatibility typing showed multiple 16S rRNA methyltransferase genes were originated from a single Inc. I1 group. MLST analysis detected 3 clones ofE.coliST4410, ST1341 and ST3906. Conclusion The present study identified emergence of three clones ofE.coli, resistant to aminoglycoside -cephalosporin- carbapenem. This warrants immediate measures to trace their transmission dynamics in order to slow down their spread in clinical setting.