• A Agodi, E Voulgari, M Barchitta, A Quattrocchi, P Bellocchi, A Poulou, C Santangelo, G Castiglione, L Giaquinta, M A Romeo, G Vrioni, and A Tsakris.
• University of Catania, Department GF Ingrassia, Catania, Italy.
• J. Hosp. Infect. 2014 Apr 1; 86 (4): 260-6.

BackgroundInfections caused by multidrug-resistant (MDR) Acinetobacter baumannii have become an important healthcare-associated problem, particularly in intensive care units (ICUs).AimTo investigate the emergence of carbapenem- and colistin-resistant A. baumannii infections in two Sicilian hospitals.MethodsFrom October 2008 to May 2011, a period which included two Italian Nosocomial Infections Surveillance in ICUs network (SPIN-UTI) project surveys, all carbapenem-resistant A. baumannii isolates from the ICUs of two hospitals in Catania, Italy, were prospectively collected. Minimum inhibitory concentrations (MICs) were measured by agar dilution, and phenotypic testing for metallo-β-lactamase (MBL) production was performed. Carbapenem resistance genes and their genetic elements were identified by polymerase chain reaction and sequencing. Genotypic relatedness was assessed by pulsed-field gel electrophoresis (PFGE) and multi-locus sequence typing. Patient-based surveillance was conducted using the SPIN-UTI protocol and previous antibiotic consumption was recorded.FindingsTwenty-six carbapenem-resistant A. baumannii were identified. Imipenem and meropenem MICs ranged from 4 to >32 mg/L, and 15 isolates exhibited high-level colistin resistance (MICs >32 mg/L). PFGE demonstrated that all isolates belonged to a unique clonal type and were assigned to ST2 of the international clone II. They harboured an intrinsic blaOxA-51-like carbapenemase gene, blaOxA-82, which was flanked upstream by ISAba1.ConclusionsThe dissemination of clonally related isolates of carbapenem-resistant A. baumannii in two hospitals is described. Simultaneous resistance to colistin in more than half of the isolates is a problem for effective antibiotic treatment. Prior carbapenem and colistin consumption may have acted as triggering factors.Copyright © 2014 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

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