title: Molecular characterization of carbapenem-insensitive Acinetobacter baumannii in Egypt.
abstract: OBJECTIVE
  This study investigated the prevalence of diverse Ambler class β-lactamase-encoding genes in 40 carbapenem-insensitive Acinetobacter baumannii isolates collected from two hospitals in Egypt during the period January-March 2012.
  
  
  METHODS
  The resistance levels to different groups of antimicrobial agents were determined. PCR was used to detect the different Ambler class β-lactamases encoding the following genes: blaTEM, blaSHV, blaCTX-M, blaVEB, blaPER, blaGES, blaVIM, blaIMP, blaSIM, blaSPM, blaGIM, blaNDM, blaADC, blaOXA-23, blaOXA-24, blaOXA-51, and blaOXA-58. ISAba1 and int1 were detected by PCR.
  
  
  RESULTS
  The isolates were 100% resistant to amoxicillin-clavulanate, aztreonam, cefepime, cefotaxime, and ceftazidime. Of the isolates, 5% were resistant to colistin, 45% to amikacin, 70% to imipenem, and 85% to ciprofloxacin. The blaADC- and blaOXA-51-like genes were detected in the entire collection. The prevalences of blaOXA-23, blaOXA-24, and blaOXA-58 were 50%, 7.5%, and 5%, respectively. However, the prevalences of blaTEM-, blaPER-, and blaGES-like genes were 87.5%, 55%, and 27.5%, respectively. SHV, CTX-M, VEB, KPC, and MBL encoding genes were not detected. The ISAba1 was found upstream to blaOXA-51, blaOXA-23, and blaADC in 85%, 80%, and 50%, respectively. Of note, 45% (18/40) of the isolates co-produced extended-spectrum β-lactamases (PER and GES) and carbapenemases (OXA-23 and OXA-58).
  
  
  CONCLUSIONS
  The blaADC-, blaTEM-, blaPER-, blaOXA-23-, and blaGES-like genes were found to be the most prevalent types of β-lactamase-encoding gene in A. baumannii collected from Egypt. A high level of carbapenem resistance is mediated by blaOXA-23, blaOXA-24, and blaOXA-58 (minimum inhibitory concentration (MIC) 32 to >256μg/ml), and a low level of carbapenem resistance is mediated by blaGES (MIC 4-16μg/ml) and by up-regulation of ISAba1-OXA-51 (MIC 1-4μg/ml). Class B MBL was not identified to play a role in carbapenem resistance in A. baumannii isolates from Egypt.
authors.affiliation: Pharmaceutics and Microbiology Department, College of Pharmacy, King Saud University, PO Box 2457, Riyadh 11451, Saudi Arabia; Microbiology and Immunology Department, Faculty of Pharmacy, Al-Azhar University, Cairo, Egypt. Electronic address: malagamy@ksu.edu.sa.
authors.forename: Mohamed H
authors.initials: MH
authors.lastname: Al-Agamy
authors.affiliation: Microbiology and Immunology Department, Faculty of Pharmacy, Modern Arts and Science University, Sixth of October City, Egypt.
authors.forename: Noha G
authors.initials: NG
authors.lastname: Khalaf
authors.affiliation: Microbiology and Immunology Department, Faculty of Pharmacy, Al-Azhar University, Cairo, Egypt.
authors.forename: Mahmoud M
authors.initials: MM
authors.lastname: Tawfick
authors.affiliation: Pharmaceutics and Microbiology Department, College of Pharmacy, King Saud University, PO Box 2457, Riyadh 11451, Saudi Arabia.
authors.forename: Atef M
authors.initials: AM
authors.lastname: Shibl
authors.affiliation: Clinical Pathology Department, Faculty of Medicine, Cairo University, Cairo, Egypt.
authors.forename: Amany
authors.initials: A
authors.lastname: El Kholy
mesh_terms: D000151:Acinetobacter Infections / Q000188:drug therapy / Q000453:epidemiology / Q000382:microbiology*; D040981:Acinetobacter baumannii / Q000201:enzymology / Q000235:genetics* / Q000302:isolation & purification; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D015780:Carbapenems / Q000627:therapeutic use; D004534:Egypt / Q000453:epidemiology; D005260:Female; D015870:Gene Expression; D006801:Humans; D008297:Male; D008826:Microbial Sensitivity Tests; D017720:Molecular Epidemiology; D010957:Plasmids; D018440:beta-Lactam Resistance / Q000235:genetics*; D001618:beta-Lactamases / Q000145:classification / Q000235:genetics* / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D015780:Carbapenems; D001618:beta-Lactamases
keywords: Antimicrobial resistance; Carbapenem-insensitive Acinetobacter baumannii; ESBL; PCR