title: Sequential outbreaks of multidrug-resistant Acinetobacter baumannii in intensive care units of a tertiary referral hospital in Italy: combined molecular approach for epidemiological investigation.
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.
authors.affiliation: Department of Health Sciences, University of Genoa, Genoa, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Ansaldi
authors.forename: P
authors.initials: P
authors.lastname: Canepa
authors.forename: M
authors.initials: M
authors.lastname: Bassetti
authors.forename: M
authors.initials: M
authors.lastname: Zancolli
authors.forename: M P
authors.initials: MP
authors.lastname: Molinari
authors.forename: A
authors.initials: A
authors.lastname: Talamini
authors.forename: F
authors.initials: F
authors.lastname: Ginocchio
authors.forename: P
authors.initials: P
authors.lastname: Durando
authors.forename: M
authors.initials: M
authors.lastname: Mussap
authors.forename: G
authors.initials: G
authors.lastname: Orengo
authors.forename: C
authors.initials: C
authors.lastname: Viscoli
authors.forename: G
authors.initials: G
authors.lastname: Icardi
mesh_terms: D000151:Acinetobacter Infections / Q000453:epidemiology* / Q000382:microbiology; D040981:Acinetobacter baumannii / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D015373:Bacterial Typing Techniques; D015780:Carbapenems / Q000494:pharmacology; D004269:DNA, Bacterial / Q000235:genetics; D004196:Disease Outbreaks; D024901:Drug Resistance, Multiple, Bacterial; D005260:Female; D006785:Hospitals, University / Q000706:statistics & numerical data*; D006801:Humans; D007362:Intensive Care Units / Q000706:statistics & numerical data*; D007558:Italy / Q000453:epidemiology; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D017720:Molecular Epidemiology; D058885:Multilocus Sequence Typing; D016133:Polymerase Chain Reaction / Q000379:methods; D013045:Species Specificity; D001618:beta-Lactamases / Q000235:genetics
chemical_list: D000900:Anti-Bacterial Agents; D015780:Carbapenems; D004269:DNA, Bacterial; D001618:beta-Lactamases