Increasing rates of Acinetobacter baumannii infection and resistance in an oncology department

Objective: Acinetobacter baumannii is an opportunistic pathogen found in immunocompromised patients, especially cancer patients. This study was to investigate the clinical characteristics of cancer patients and the antimicrobial resistance of A. baumannii isolates. Materials and Methods: Clinical isolates were collected from the oncology department of a general teaching hospital, and the clinical and demographic information of patients was obtained from the hospital's information system. Antimicrobial susceptibility was examined using the agar dilution method. Carbapenemase-encoding genes were amplified by polymerase chain reaction, and sequence types were determined by multilocus sequence typing. Results: The isolation rate of A. baumannii increased annually in the oncology department. Multivariate analysis showed that only prior antibiotic use was an independent risk factor for A. baumannii infection. The use of antibiotics in A. baumannii-infected patients was significantly more frequent than in non-A. baumannii-infected patients. A. baumannii isolates were highly resistant to most tested antibiotics. The IMP-4 and VIM-2 genes were present in 6 and 2 isolates, respectively. Sixty isolates had 12 genotypes, and ST208 was the most common genotype. Conclusion: Our results suggest that the use of antibiotics and hospital environmental pollution may be the main causes of A. baumannii infection.