title: The transferability of blaOXA-23 gene in multidrug-resistant Acinetobacter baumannii isolates from Saudi Arabia and Egypt.
abstract: Carbapenem-resistant Acinetobacter spp. have been increasingly reported worldwide including Saudi Arabia and Egypt. We examined 64, non-repetitive, Acinetobacter baumannii isolates collected in 2013 and 2014 from four different medical centres (two from Saudi Arabia and two from Egypt). All the isolates were resistant to ceftazidime and ciprofloxacin. The intI1 harbouring blaGES-11 and aac-6'-1b was detected in 19% (n=12) of the isolates. ISAba1 over-expression of blaADC gene was observed in 65% (n=42) of isolates. Of all the isolates 19% (n=12) had ISAba1 upstream of the blaOXA-51-like gene, 69% (n=44) carried the blaOXA-23 gene within the Tn2006 structure, 8% (n=5) had blaOXA-24-like gene and 9% (n=6) harboured either blaVIM-2 or blaNDM-1 gene. Eighty nine percent (n=57) of isolates were resistant to imipenem and had an MIC of ≥8mg/L. Pulsed-field gel electrophoresis (PFGE) typing revealed the presence of 23 different PFGE. Three PFGE types were very widespread, ST236 (CC104) (PFGE type 1, n=15), ST208 (CC92) (PFGE type 2, n=10), ST884 (CC unassigned) (PFGE type 3, n=7) in and across all four medical centres. The blaOXA-23 gene was found to be present on a 60kb transferable plasmid in both PFGE type 1 and 2 but was absent in PFGE type 3. This is the first study to report on the emergence of ST236 in Saudi Arabia and Egypt, and spread of distinct carbapenem resistant A. baumannii clones belonging to ST884, ST945 and ST1096 in Saudi Arabia.
authors.affiliation: Medical Microbiology, Polwarth Building, Foresterhill, Aberdeen AB25 2ZD, UK. Electronic address: bruno.lopes@abdn.ac.uk.
authors.forename: Bruno Silvester
authors.initials: BS
authors.lastname: Lopes
authors.affiliation: College of Pharmacy, King Saud University, 11451 Riyadh 2457, Saudi Arabia; Department of Microbiology and Immunology, Faculty of Pharmacy, Al-Azhar University, Cairo, Egypt.
authors.forename: Mohamed H
authors.initials: MH
authors.lastname: Al-Agamy
authors.affiliation: Medical Microbiology, Polwarth Building, Foresterhill, Aberdeen AB25 2ZD, UK.
authors.forename: Muhammad A
authors.initials: MA
authors.lastname: Ismail
authors.affiliation: College of Pharmacy, King Saud University, 11451 Riyadh 2457, Saudi Arabia; Department of Infection and Immunity, King Faisal Specialist Hospital & Research Center, Riyadh 11211, Saudi Arabia; Department of Microbiology and Immunology, Alfaisal University School of Medicine, Riyadh, Saudi Arabia.
authors.forename: Atef M
authors.initials: AM
authors.lastname: Shibl
authors.affiliation: Department of Infection and Immunity, King Faisal Specialist Hospital & Research Center, Riyadh 11211, Saudi Arabia; Department of Microbiology and Immunology, Alfaisal University School of Medicine, Riyadh, Saudi Arabia.
authors.forename: Ahmed A
authors.initials: AA
authors.lastname: Al-Qahtani
authors.affiliation: Department of Infection and Immunity, King Faisal Specialist Hospital & Research Center, Riyadh 11211, Saudi Arabia; Department of Microbiology and Immunology, Alfaisal University School of Medicine, Riyadh, Saudi Arabia.
authors.forename: Mohammed N
authors.initials: MN
authors.lastname: Al-Ahdal
authors.affiliation: Medical Microbiology, Polwarth Building, Foresterhill, Aberdeen AB25 2ZD, UK.
authors.forename: Ken J
authors.initials: KJ
authors.lastname: Forbes
mesh_terms: D040981:Acinetobacter baumannii / Q000235:genetics* / Q000302:isolation & purification*; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D015780:Carbapenems / Q000494:pharmacology; D002442:Ceftazidime / Q000494:pharmacology; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics*; D004534:Egypt; D016521:Electrophoresis, Gel, Pulsed-Field; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D015378:Imipenem / Q000494:pharmacology; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D058885:Multilocus Sequence Typing; D010957:Plasmids / Q000235:genetics; D012529:Saudi Arabia
chemical_list: D001426:Bacterial Proteins; D015780:Carbapenems; D015378:Imipenem; D002442:Ceftazidime
keywords: Acinetobacter baumannii; Carbapenems; Middle-East; OXA-23; Plasmid