title: Molecular identification of tigecycline- and colistin-resistant carbapenemase-producing Acinetobacter baumannii from a Greek hospital from 2011 to 2013.
abstract: An alarming increase in the resistance rates of tigecycline and colistin among carbapenemase-producing Acinetobacter baumannii recovered from a Greek hospital over a 3-year period (2011-2013) was investigated. The antimicrobial resistance profiles and carbapenemase gene content were determined for a collection of colistin- and/or tigecycline-resistant carbapenemase-producing A. baumannii isolates (n = 42), which were recovered consecutively during the study period. A gradual increase in the incidence of blaOXA-23 producers was observed from 2011 to 2013. A cluster of 21 isolates comprised tigecycline-resistant blaOXA-23 producers displayed a single antimicrobial resistance pattern. The emergence of two blaOXA-23 producers resistant to both tigecycline and colistin was documented. Furthermore, determination of the mechanisms of colistin and tigecycline resistance and molecular typing by the tri-locus sequence typing (3LST) scheme for nine isolates recovered from bloodstream infections were performed. Out of nine isolates, five tigecycline- and two colistin-resistant isolates were blaOXA-23 producers of 3LST ST101 corresponding to the international clone II recovered during 2012-2013. All nine isolates were positive for the presence of the adeB gene of the AdeABC efflux pump. Three colistin-resistant isolates possessed novel substitutions in PmrB, which may be implicated in colistin resistance. To the best of our knowledge, this is the first report of the acquisition of tigecycline and colistin resistance among blaOXA-23-producing A. baumannii of 3LST ST101 in Greece; thus, continuous surveillance and molecular characterization, prudent use of antibiotics and implementation of infection control measures for A. baumannii are urgent.
authors: Department of Microbiology, General Hospital of Nea Ionia, 'Konstantopouleio-Patission', Athens, Greece.
authors: Angeliki
authors: A
authors: Mavroidi
authors: Department of Microbiology, General Hospital of Nea Ionia, 'Konstantopouleio-Patission', Athens, Greece.
authors: Sofia
authors: S
authors: Likousi
authors: Department of Microbiology, General Hospital of Nea Ionia, 'Konstantopouleio-Patission', Athens, Greece.
authors: Eleftheria
authors: E
authors: Palla
authors: Intensive Care Unit, General Hospital of Nea Ionia, 'Konstantopouleio-Patission', Athens, Greece.
authors: Maria
authors: M
authors: Katsiari
authors: Department of Microbiology, General Hospital of Nea Ionia, 'Konstantopouleio-Patission', Athens, Greece.
authors: Zoi
authors: Z
authors: Roussou
authors: Intensive Care Unit, General Hospital of Nea Ionia, 'Konstantopouleio-Patission', Athens, Greece.
authors: Asimina
authors: A
authors: Maguina
authors: Department of Microbiology, General Hospital of Nea Ionia, 'Konstantopouleio-Patission', Athens, Greece.
authors: Evangelia D
authors: ED
authors: Platsouka
mesh_terms: D000151:Acinetobacter Infections / Q000453:epidemiology / Q000382:microbiology*; D040981:Acinetobacter baumannii / Q000187:drug effects* / Q000201:enzymology*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D003091:Colistin / Q000494:pharmacology*; D024901:Drug Resistance, Multiple, Bacterial; D015964:Gene Expression Regulation, Bacterial; D015971:Gene Expression Regulation, Enzymologic; D006115:Greece / Q000453:epidemiology; D006801:Humans; D008911:Minocycline / Q000031:analogs & derivatives* / Q000494:pharmacology; D000078304:Tigecycline; D013997:Time Factors; D001618:beta-Lactamases / Q000235:genetics / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D000078304:Tigecycline; D001618:beta-Lactamases; C063912:carbapenemase; D008911:Minocycline; D003091:Colistin