title: The role of bla(OXA-like carbapenemase) and their insertion sequences (ISS) in the induction of resistance against carbapenem antibiotics among Acinetobacter baumannii isolates in Tehran hospitals.
abstract: This study aimed to evaluate the occurrence and dissemination of bla(OXA-like) carbapenemase genes and their insertion sequences among Acinetobacter baumannii isolates, taken from different hospitals in Tehran city and also their roles in the induction of resistance to carbapenem drugs. A total number of 100 non duplicate Acinetobacter baumannii with different origins, were isolated from patients with proved nosocomial infections at eight university hospital in Tehran city. Antimicrobial susceptibility of these strains was done by E-test against 7 antimicrobial agents according to CLSI guideline. PCR of bla(OXA-51-like), bla(OXA-23-like), bla(OXA-24-like), bla(OXA-58-like), IS(ABA-1), IS(1133) was carried out by specialized primers and then these strains were typed by REP-fingerprinting. Colistin, imipenem and meropenem were the most sensitive antibiotics against Acinetobacter baumannii isolates with 96%, 51% and 51% sensitivity respectively. All the isolates had a bla(OXA-51-like) intrinsic to these species. The rates of bla(OXA-23), 23 and 58-like were 38%, 32% and 1% respectively. Coexistence of bla(OXA-51/23/24-like) was observed among 16% of these isolates. All bla(OXA-23-like) carbapenemase genes had only one IS(ABA1). REP fingerprinting showed 5 genotypes among carbapenem resistant isolates, 16 of them being genotype A. This study emphasized on the major role of bla(OXA-like) carbapenemase, particularly bla(OXA-23-like) carbapenemase and their IS(ABA1), in the dissemination of carbapenem resistant Acinetobacter baumannii. This study confirmed a presumptive role of IS element neighboring the carbapenemase gene in the elevation of resistance to carbapenem drug among Acinetobacter baumannii isolates for the first time in Iran.
authors.affiliation: Department of Epidemiology and Biostatistics, School of Medicine, Ilam University of Medical Sciences, Iran.
authors.forename: Khairollah
authors.initials: K
authors.lastname: Asadollahi
authors.forename: Eshrat
authors.initials: E
authors.lastname: Alizadeh
authors.forename: Mehdi
authors.initials: M
authors.lastname: Akbari
authors.forename: Morovat
authors.initials: M
authors.lastname: Taherikalani
authors.forename: Mohammad
authors.initials: M
authors.lastname: Niakan
authors.forename: Abbas
authors.initials: A
authors.lastname: Maleki
authors.forename: Parisa
authors.initials: P
authors.lastname: Asadollahi
authors.forename: Setareh
authors.initials: S
authors.lastname: Soroush
authors.forename: Mohammad-Mahdi
authors.initials: MM
authors.lastname: Feizabadi
authors.forename: Mohammad
authors.initials: M
authors.lastname: Emaneini
mesh_terms: D040981:Acinetobacter baumannii / Q000187:drug effects* / Q000235:genetics; D015780:Carbapenems / Q000494:pharmacology*; D004251:DNA Transposable Elements; D024881:Drug Resistance, Bacterial; D007492:Iran; D001618:beta-Lactamases / Q000502:physiology*
chemical_list: D015780:Carbapenems; D004251:DNA Transposable Elements; C466679:beta-lactamase OXA-23; D001618:beta-Lactamases; C410345:beta-lactamase OXA-24; C534889:beta-lactamase OXA-58, Acinetobacter baumannii