Antibiotic Resistance Pattern of Acinetobacter baumannii Strains: A Retrospective Study from Oman

BACKGROUND: Multidrug-resistant (MDR) Acinetobacter baumannii is of serious health concern and associated with high mortality. Data regarding the antibiotic resistance pattern of A. baumannii strains in Oman is limited. OBJECTIVES: To determine the antibiotic resistance pattern of A. baumannii from various clinical samples in a tertiary care hospital in the North-Batinah region of Oman. METHODS: A. baumannii isolates recovered from various clinical samples in the Microbiology laboratory of Sohar Hospital, Oman, during 2015–2019 were retrospectively analyzed. Organism identification and their antibiotic resistance patterns were performed as recommended by the Clinical and Laboratory Standards Institute. RESULTS: A total of 1890 A. baumannii nonduplicate isolates were found from clinical samples of 1326 patients. The isolates were more frequently isolated from elderly patients (40%) and in-patient department patients (67%). Infection/colonization was more common among patients treated in the medicine, intensive-care unit, and surgery departments. A. baumannii strains were highly resistant (50-83%) to most of the tested antibiotics, with the highest against ceftriaxone (83%) and ceftazidime (75%), and lowest against colistin (1%) and tigecycline (8%). Among the isolates, 67% (1265) were MDR strains. Of these, 22%, 32% and 16% were resistant to all six, five and four classes of the tested antibiotics. CONCLUSION: The study found that the frequency of isolation of MDR A. baumannii isolates in the northern region of Oman is high.