Oxacillinase Gene Distribution, Antibiotic Resistance, and Their Correlation with Biofilm Formation inAcinetobacter baumanniiBloodstream Isolates


MICROBIAL DRUG RESISTANCE, vol.27, pp.637-646, 2021 (Journal Indexed in SCI) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 27
  • Publication Date: 2021
  • Doi Number: 10.1089/mdr.2020.0130
  • Page Numbers: pp.637-646


Objectives:The limitations of treatment options in bloodstream infections caused by multidrug-resistantAcinetobacter baumannii(MDRAB) have been related to high morbidity and mortality. The aim of our present study was to determine antimicrobial susceptibility profiles, molecular resistance patterns, and biofilm properties ofA. baumanniiisolated from bloodstream infections. Materials and Methods:In the present study, a total of 44A. baumanniibloodstream isolates were included. Antimicrobial susceptibility profiles and biofilm formation ability were assessed. The distribution of class D carbapenemases, ISAba1, ISAba1/blaOXA-23,blaNDM-1,mcr-1, andompAwas investigated by polymerase chain reaction (PCR). Arbitrarily primed-PCR (AP-PCR) was performed to evaluate clonal relationships. Results:A total of 32 isolates were MDRAB, whereas 6 isolates were also resistant to colistin withoutmcr-1positivity. All isolates were harboringblaOXA-51 gene, whereasblaOXA-23 positivity was 63.6%. Fifty percent of the isolates had ISAba1.ISAba1upstream ofblaOXA-23 was determined in 18 isolates. None of the isolates were positive forblaNDM-1 gene. Majority of the strains were strong biofilm producers (86.8%). A total of 56.8% of the isolates were positive forompAgene with no direct association with strong biofilm formation. However,blaOXA-51 + 23 genotype and trimethoprim-sulfamethoxazole resistance showed a significant relationship with biofilm formation. AP-PCR analysis revealed six distinct clusters ofA. baumannii. Conclusions:Herein, majority of theA. baumanniiblood isolates were characterized asblaOXA-51+OXA-23 carbapenemase genotype and were strong biofilm formers. None of the isolates were positive forblaNDM-1, which was promising. Resistant isolates were tended to form strong biofilms. Our results highlight the emergence of oxacillinase-producing MDRAB isolated from bloodstream with high biofilm formation ability.