Occurrence of Acquired 16S rRNA Methyltransferase-Mediated Aminoglycoside Resistance in Clinical Isolates of Enterobacteriaceae within a Tertiary Referral Hospital of Northeast India

Jayalaxmi Wangkheimayum; Deepjyoti Paul; Debadatta Dhar; Rajlakshmi Nepram; Shiela Chetri; Deepshikha Bhowmik; Atanu Chakravarty; Amitabha Bhattacharjee

doi:10.1128/AAC.01037-16

Occurrence of Acquired 16S rRNA Methyltransferase-Mediated Aminoglycoside Resistance in Clinical Isolates of Enterobacteriaceae within a Tertiary Referral Hospital of Northeast India

Antimicrob Agents Chemother. 2017 May 24;61(6):e01037-16. doi: 10.1128/AAC.01037-16. Print 2017 Jun.

Authors

Jayalaxmi Wangkheimayum¹, Deepjyoti Paul¹, Debadatta Dhar², Rajlakshmi Nepram¹, Shiela Chetri¹, Deepshikha Bhowmik¹, Atanu Chakravarty², Amitabha Bhattacharjee³

Affiliations

¹ Department of Microbiology, Assam University, Silchar, India.
² Department of Microbiology, Silchar Medical College and Hospital, Silchar, India.
³ Department of Microbiology, Assam University, Silchar, India ab0404@gmail.com.

Abstract

The methylation of a ribosomal target leads to a high level of resistance to all clinically relevant aminoglycoside antibiotics, so early detection of these resistance determinants will help to reduce the incidence of treatment failures as well as lessen the dissemination rate. Here, we characterized different 16S rRNA methyltransferases responsible for aminoglycoside resistance and their epidemiological background in clinical isolates of Enterobacteriaceae in a tertiary referral hospital in India. All aminoglycoside-resistant isolates were screened for different 16S rRNA methyltransferases by PCR assay, and incompatibility typing of the conjugable plasmid harboring resistance genes was performed by PCR-based replicon typing. An assay for the stability and elimination of these resistance plasmids was performed. The coexistence of extended-spectrum β-lactamases and metallo-β-lactamases was also detected, and the heterogeneity of these isolates was determined by enterobacterial repetitive intergenic consensus PCR. The PCR assay revealed the presence of armA, rmtA, rmtB, rmtC, and rmtD in single and multiple combinations, and these were carried by a diverse group of Inc plasmids. Plasmids harboring these resistance determinants were highly stable and maintained until the 55th serial passage, but SDS treatment could easily eliminate the plasmids harboring the resistance determinants. The coexistence of bla_TEM, bla_PER, bla_GES, and bla_SHV, as well as bla_VIM and bla_NDM, within these isolates was also detected. Strains with different clonal patterns of aminoglycoside resistance were found to spread in this hospital setting. We observed that the 16S rRNA methyltransferase genes were encoded within different Inc plasmid types, suggesting diverse origins and sources of acquisition. Therefore, the present study is of epidemiological importance and can have a role in infection control policy in hospital settings.

Keywords: 16S rRNA methyltransferase; Enterobacteriaceae; aminoglycoside; stability.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Aminoglycosides / pharmacology*
Drug Resistance, Bacterial / genetics
Enterobacteriaceae / drug effects
Enterobacteriaceae / genetics*
India
Microbial Sensitivity Tests
Plasmids / genetics
RNA, Ribosomal, 16S / genetics*
Tertiary Care Centers / statistics & numerical data

Substances

Aminoglycosides
RNA, Ribosomal, 16S