Outbreak of Multidrug-resistant Acinetobacter baumannii in a Tertiary Health Center from Northwestern Nigeria

Abstract

Abstract Background: In spite of its global notoriety and WHO alarm, Acinetobacter baumannii is still an understudied critical-priority pathobiont in Nigeria. We characterized its antimicrobial susceptibility profile and resistance genes during an outbreak. Materials and Methods: This cross-sectional study involved collection of patients’ urine samples and swabs from unit staff’s hands and ward environments for the identification of A. baumannii strains using standard morphologic and biochemical methods. The disk diffusion method was used to assess the antimicrobial susceptibility profile of the isolates with the production of extended-spectrum beta-lactamases (ESBLs) confirmed by the combined disk test screening method. Characterization of the resistance genes of the ESBL producers was carried out using polymerase chain reaction polymerase chain reaction technique. Results: A total of eight (six clinical and two nonclinical) A. baumannii isolates were identified. The overall isolate susceptibility and resistance rates to all the antimicrobial agents was 56.3% (27/48) and 35.4% (17/48), respectively. Similarly, all (8/8; 100.00%) isolates were susceptible to meropenem and 75.0% (6/8) to ampicillin-sulbactam while 62.5% (5/8) were resistant to trimethoprim-sulfamethoxazole and 50.0% (4/8) to each of ciprofloxacin and ceftazidime. In addition, 37.5% (3/8) of the isolates were multidrug resistant (MDR) with nonclinical isolates exhibiting more antimicrobial resistance than their clinical counterparts (9/12%–75.0% vs. 8/36%–22.2%). Phenotypic detection and molecular characterization revealed three ESBL-producing isolates that each harbored bla SHV and bla TEM genes with bla CTX-M gene being absent. Conclusion: MDR strains of A. baumannii harboring bla SHV and bla TEM genes were recovered from clinical and environmental sources during the outbreak, which was contained with preventive measures recommended.