Emergence of carbapenem non-susceptible multidrug resistant Acinetobacter baumannii strains of clonal complexes 103B and 92B harboring OXA-type carbapenemases and metallo-β-lactamases in Southern India

Rajagopalan Saranathan, Vaidyanathan Vasanth, Thamodharan Vasanth, Pidathala Raghavendra Venkata Shabareesh, P. Shashikala, Chandrakesan Sheela Devi, Ramakrishnan Kalaivani, Johny Asir, Pagal Sudhakar, K. Prashanth

Research output: Contribution to journalArticlepeer-review

20 Scopus citations

Abstract

The molecular epidemiology and carbapenem resistance mechanisms of clinical isolates of Acinetobacter baumannii obtained from a south Indian tertiary care hospital were investigated by repetitive extragenic palindromic sequence PCR (REP-PCR) and multi-locus sequence typing (MLST). Analysis of resistant determinants was achieved by PCR screening for the presence of genes encoding OXA-carbapenemases, metallo-β-lactamases (MBLs) and efflux pumps. REP-PCR generated around eight clusters of high heterogeneity; of these, two major clusters (I and V) appeared to be clonal in origin. Analysis of representative isolates from different clusters by MLST revealed that most of the isolates belonged to sequence type 103 of CC103B. Second most prevalent ST belonged to clonal complex (CC) 92B which is also referred to as international clone II. Most of the isolates were multi-drug resistant, being susceptible only to polymyxin-B and newer quinolones. Class D β-lactamases such as blaOXA-51-like (100%), blaOXA-23-like (56.8%) and blaOXA-24-like (14.8%) were found to be predominant, followed by a class B β-lactamase, namely blaIMP-1 (40.7%); none of the isolates had blaOXA-58 like, blaNDM-1 or blaSIM-1. Genes of efflux-pump adeABC were predominant, most of isolates being biofilm producers that were PCR-positive for autoinducer synthase gene (>94%). Carbapenem non-susceptible isolates were highly diverse and present throughout the hospital irrespective of type of ward or intensive care unit. Although previous reports have documented diverse resistant mechanisms in A. baumannii, production of MBL and OXA-type of carbapenamases were found to be the predominant mechanism(s) of carbapenem resistance identified in strains isolated from Southern India.

Original languageEnglish (US)
Pages (from-to)277-284
Number of pages8
JournalMicrobiology and Immunology
Volume59
Issue number5
DOIs
StatePublished - May 1 2015
Externally publishedYes

Keywords

  • Acinetobacter baumannii
  • Carbapenem non-susceptible
  • Metallo-β-lactamase
  • Oxacillinase

ASJC Scopus subject areas

  • Microbiology
  • Immunology
  • Virology

Fingerprint

Dive into the research topics of 'Emergence of carbapenem non-susceptible multidrug resistant Acinetobacter baumannii strains of clonal complexes 103B and 92B harboring OXA-type carbapenemases and metallo-β-lactamases in Southern India'. Together they form a unique fingerprint.

Cite this