Sequential outbreaks of multidrug-resistant Acinetobacter baumannii in intensive care units of a tertiary referral hospital in Italy: Combined molecular approach for epidemiological investigation

F. Ansaldi, P. Canepa, M. Bassetti, M. Zancolli, M. P. Molinari, A. Talamini, F. Ginocchio, P. Durando, M. Mussap, G. Orengo, C. Viscoli, G. Icardi

Research output: Contribution to journalArticlepeer-review

Abstract

A laboratory-based surveillance study was conducted from January 2007 to May 2010 in San Martino Tertiary Referral Hospital in Genoa, Italy in which the molecular epidemiology of multidrug-resistant Acinetobacter baumannii was investigated in the five intensive care units (ICUs). A total of 53 A. baumannii strains were isolated from patients admitted to ICUs (69.8%) and to other epidemiologically linked hospital wards (30.2%) and were genotyped by repetitive extragenic palindromic polymerase chain reaction (REP-PCR), multilocus sequence typing (MLST) and adeB sequence typing. REP-PCR fingerprinting analysis, MLST and adeB typing results were well correlated and allowed us to classify strains causing epidemic events into three major epidemic clones: A (REP-I/ST4, adeB-STII genotype) isolated for the first time in May 2007, B (REP-IV/ST95, adeB-STI genotype) from November 2007 to May 2009 and C (REP-VII/ST118, adeB-STII genotype) from July 2008 to May 2010. MLST results demonstrated that epidemic clones A and C were related as they were members of the widespread clonal complex CC92. The genetic determinants of carbapenem resistance were investigated and resistance associated with the presence of the bla OxA-58-like gene with ISAba2 and ISAba3 elements flanking it in clone A, and with the bla OxA-23-like gene flanked by ISAba1 in clones B and C. A molecular approach allowed the prompt introduction of infection control measures and the evaluation of data in a global epidemiological context.

Original languageEnglish
Pages (from-to)134-140
Number of pages7
JournalJournal of Hospital Infection
Volume79
Issue number2
DOIs
Publication statusPublished - Oct 2011

Keywords

  • Molecular epidemiology
  • Multidrug-resistant Acinetobacter baumannii
  • Multilocus sequence typing
  • Outbreak
  • Repetitive extragenic palindromic polymerase chain reaction (REP-PCR)

ASJC Scopus subject areas

  • Microbiology (medical)
  • Infectious Diseases

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