title: Spread of imipenem-resistant Acinetobacter baumannii co-expressing OXA-23 and GES-11 carbapenemases in Lebanon.
abstract: OBJECTIVE
  The acquisition of carbapenemases by Acinetobacter baumannii is reported increasingly worldwide, but data from Lebanon are limited. The aims of this study were to evaluate the prevalence of imipenem-resistant A. baumannii in Lebanon, identify resistance determinants, and detect clonal relatedness.
  
  
  METHODS
  Imipenem-resistant A. baumannii were collected from nine Lebanese hospitals during 2012. Antimicrobial susceptibility, the cloxacillin effect, and ethylenediaminetetraacetic acid (EDTA) synergy were determined. Genes encoding carbapenemases and insertion sequence ISAba1 were screened via PCR sequencing. ISAba1 position relative to genes encoding Acinetobacter-derived cephalosporinases (ADCs) and OXA-23 was studied by PCR mapping. Clonal linkage was examined by enterobacterial repetitive intergenic consensus PCR (ERIC-PCR).
  
  
  RESULTS
  Out of 724 A. baumannii isolated in 2012, 638 (88%) were imipenem-resistant. Of these, 142 were analyzed. Clavulanic acid-imipenem synergy suggested carbapenem-hydrolyzing extended-spectrum β-lactamase. A positive cloxacillin test indicated ADCs, while EDTA detection strips were negative. Genotyping indicated that 90% of isolates co-harbored blaOXA-23 and blaGES-11. The remaining strains had blaOXA-23, blaOXA-24, blaGES-11, or blaOXA-24 with blaGES-11. ISAba1 was located upstream of blaADC and blaOXA-23 in 97% and 100% of isolates, respectively. ERIC-PCR fingerprinting revealed 18 pulsotypes spread via horizontal gene transfer and clonal dissemination.
  
  
  CONCLUSIONS
  This survey established baseline evidence of OXA-23 and GES-11-producing A. baumannii in Lebanon, indicating the need for further surveillance.
authors.affiliation: Microbiology Laboratory, School of Pharmacy, Saint-Joseph University, Campus of Medical Sciences, Damascus Road, PO Box 11-5076 Riad El Solh, Beirut 1107-2180, Lebanon; Rodolphe Mérieux Laboratory, Beirut, Lebanon; Department of Pharmaceutical Sciences, School of Pharmacy, Lebanese International University, Bekaa, Lebanon. Electronic address: dalal.hammoudi@net.usj.edu.lb.
authors.forename: D
authors.initials: D
authors.lastname: Hammoudi
authors.affiliation: Microbiology Laboratory, School of Pharmacy, Saint-Joseph University, Campus of Medical Sciences, Damascus Road, PO Box 11-5076 Riad El Solh, Beirut 1107-2180, Lebanon; Rodolphe Mérieux Laboratory, Beirut, Lebanon; Department of Natural Science and Public Health, College of Sustainability Sciences and Humanities, Zayed University, Dubai, United Arab Emirates.
authors.forename: C Ayoub
authors.initials: CA
authors.lastname: Moubareck
authors.affiliation: Saint George Hospital and University of Balamand, Beirut, Lebanon.
authors.forename: N
authors.initials: N
authors.lastname: Hakime
authors.affiliation: Labib Medical Center, Saida, South Lebanon.
authors.forename: M
authors.initials: M
authors.lastname: Houmani
authors.affiliation: Bellevue Medical Center, Beirut, Lebanon.
authors.forename: A
authors.initials: A
authors.lastname: Barakat
authors.affiliation: Chtaura Hospital, Bekaa, Lebanon.
authors.forename: Z
authors.initials: Z
authors.lastname: Najjar
authors.affiliation: Farhat Hospital, Bekaa, Lebanon.
authors.forename: M
authors.initials: M
authors.lastname: Suleiman
authors.affiliation: Secours Populaire Libanais Hospital, Nabatieh, South Lebanon.
authors.forename: N
authors.initials: N
authors.lastname: Fayad
authors.affiliation: Mounla Hospital, Tripoli, North Lebanon.
authors.forename: R
authors.initials: R
authors.lastname: Sarraf
authors.affiliation: Microbiology Laboratory, School of Pharmacy, Saint-Joseph University, Campus of Medical Sciences, Damascus Road, PO Box 11-5076 Riad El Solh, Beirut 1107-2180, Lebanon; Rodolphe Mérieux Laboratory, Beirut, Lebanon.
authors.forename: D Karam
authors.initials: DK
authors.lastname: Sarkis
mesh_terms: D040981:Acinetobacter baumannii / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics / Q000302:isolation & purification; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics*; D003023:Cloxacillin / Q000494:pharmacology; D024881:Drug Resistance, Bacterial; D006801:Humans; D015378:Imipenem / Q000494:pharmacology*; D007861:Lebanon; D016133:Polymerase Chain Reaction; D001618:beta-Lactamases / Q000235:genetics*
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D015378:Imipenem; D001618:beta-Lactamases; C063912:carbapenemase; D003023:Cloxacillin
keywords: ERIC-PCR; GES-11; Imipenem-resistant Acinetobacter baumannii; OXA-23