title: Emergence of rifampicin, tigecycline, and colistin-resistant Acinetobacter baumannii in Iran; spreading of MDR strains of novel International Clone variants.
abstract: Multidrug-resistant Acinetobacter baumannii infections are serious challenges for clinicians because of A. baumannii propensity to acquire resistance to a wide spectrum of antimicrobial agents. In this study, 91 A. baumannii isolates from patients in tertiary intensive care units of three university hospitals in the north, central, and south of Iran were selected and tested for susceptibility to 22 antimicrobials; amplified restriction fragment polymorphism and multiplex polymerase chain reaction methods were used to determine genetic relationships and International Clone (IC) of A. baumannii isolates, respectively. Twenty-four genotypes were identified in A. baumannii isolates. About 91.2% of isolates categorized into 4 distinct clusters; one was more heterogeneous and observed across the three locations. A considerable number of the isolates (27.5%) belonged to the novel IC variant, sequence group 7 (SG7), which was geographically widespread in three locations. The drug resistance pattern showed that 14.2%, 20%, and 77% of the A. baumannii isolates were resistant to colistin, tigecycline, and rifampicin, respectively. Nine percent of isolates (8) showed simultaneous resistance to colistin, rifampicin, and tigecycline. Interestingly, all of them were susceptible to ampicillin-sulbactam and/or tobramycin. According to our results, SG7 could be considered as a pan-Iranian clone.
authors.affiliation: 1 Department of Microbiology, School of Medicine, Tehran University of Medical Sciences , Tehran, Iran .
authors.forename: Abbas
authors.initials: A
authors.lastname: Bahador
authors.forename: Mohammad
authors.initials: M
authors.lastname: Taheri
authors.forename: Babak
authors.initials: B
authors.lastname: Pourakbari
authors.forename: Zahra
authors.initials: Z
authors.lastname: Hashemizadeh
authors.forename: Hossein
authors.initials: H
authors.lastname: Rostami
authors.forename: Noormohamad
authors.initials: N
authors.lastname: Mansoori
authors.forename: Reza
authors.initials: R
authors.lastname: Raoofian
mesh_terms: D000151:Acinetobacter Infections / Q000188:drug therapy / Q000453:epidemiology* / Q000382:microbiology / Q000635:transmission; D040981:Acinetobacter baumannii / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification; D000667:Ampicillin / Q000627:therapeutic use; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D015373:Bacterial Typing Techniques; D002999:Clone Cells; D003091:Colistin / Q000494:pharmacology*; D024901:Drug Resistance, Multiple, Bacterial / Q000187:drug effects / Q000235:genetics*; D006801:Humans; D007362:Intensive Care Units; D007492:Iran / Q000453:epidemiology; D008826:Microbial Sensitivity Tests; D008911:Minocycline / Q000031:analogs & derivatives* / Q000494:pharmacology; D060885:Multiplex Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length; D015995:Prevalence; D012293:Rifampin / Q000494:pharmacology*; D013407:Sulbactam / Q000627:therapeutic use; D063128:Tertiary Health Care; D000078304:Tigecycline; D014031:Tobramycin / Q000627:therapeutic use
chemical_list: D000900:Anti-Bacterial Agents; C035444:sultamicillin; D000078304:Tigecycline; D000667:Ampicillin; D008911:Minocycline; D013407:Sulbactam; D012293:Rifampin; D014031:Tobramycin; D003091:Colistin