Carbapenem-resistant Acinetobacter baumannii: Current status of the problem in four Bulgarian university hospitals (2014–2016). (March 2019)

• Record Type: Journal Article
• Authors: Strateva, Tanya; Sirakov, Ivo; Stoeva, Temenuga; Stratev, Alexander; Dimov, Svetoslav; Savov, Encho; Mitov, Ivan
• Is Part Of: Journal of global antimicrobial resistance. Volume 16(2019)
• Page Start: 266
• Page End: 273
• Publication Date: 2019-03
• Subjects: Acinetobacter baumannii -- Carbapenem resistance -- Multidrug resistance -- OXA carbapenemases -- Molecular epidemiology; Drug resistance -- Periodicals; Drug resistance -- Periodicals; Drug resistance; Periodicals; 616.9041
• DOI: 10.1016/j.jgar.2018.10.027
• Languages: English
• ISSNs: 2213-7165

Abstract

Highlights: Antimicrobial susceptibility of carbapenem-resistant A. baumannii (CRAB) in 4 Bulgarian university hospitals (2014–2016). Molecular genetic investigations on carbapenem resistance mechanisms. Carbapenem-hydrolysing oxacillinase bla OXA-58 gene transferability was observed. Epidemiological typing of CRAB isolates in the monitored hospitals. Abstract: Objectives: A total of 226 carbapenem-resistant Acinetobacter baumannii (CRAB) isolates was collected during 2014–2016 from inpatients (age range 5–88 years) in four Bulgarian university hospitals (H1–H4) to assess their antimicrobial susceptibility and to explore carbapenem resistance mechanisms as well as the molecular epidemiology of the isolates. Methods: Antimicrobial susceptibility testing, multiplex PCR, DNA sequencing and electrotransformation experiments were performed. Epidemiological typing by random amplification of polymorphic DNA (RAPD)–PCR was also performed. Results: The resistance rates were as follows: imipenem, 90.7%; meropenem, 98.2%; doripenem, 100%; amikacin, 92.9%; gentamicin, 87.2%; tobramycin, 55.8%; levofloxacin, 98.2%; trimethoprim/sulfamethoxazole, 86.3%; tigecycline, 22.1%; colistin, 0%; and ampicillin/sulbactam, 41.6%. Intrinsic bla OXA-51-like genes were found in all of the isolates. The majority of the A. baumannii isolates harboured either bla OXA-23-like associated with the upstream-located IS Aba1 (26.1%) or bla OXA-40/24-like (46.7%), 45 isolates (19.9%) harboured both genes, and 1 isolate harboured bla OXA-58-like surrounded by IS Aba3C upstream and IS Aba3 downstream. The bla OXA-58 gene was transferable by electroporation indicating its plasmid location. Epidemiological typing revealed the dissemination of nosocomial CRAB with high clonal relatedness (70% similarity threshold) belonging to six, four, three and two clusters in H1, H2, H3, and H4 hospitals, respectively. Conclusions: The A. baumannii isolates studied were problematic nosocomial pathogens. Their multidrug resistance greatly limits therapeutic options. The persistence of endemic clones comprised of OXA carbapenemase-producing multidrug-resistant A. baumannii in the monitored hospitals over a period of ca. 3 years is of concern and requires continuous detailed investigations in the future.