Prevalence and phenotypic characteristics of Acinetobacter baumannii isolated from critically ill patients in two healthcare facilities in Ebonyi State, Nigeria

Abstract

Background: The intrinsic property of Acinetobacter baumannii to survive in harsh conditions on environmental surfaces and its ability  to resist commonly used antibiotics in hospitals make this pathogen to be one of the most prevalent causes of hospital infections. The  present study was aimed at determining the prevalence of A. baumannii among critically ill patients in two tertiary hospitals; Alex  Ekwueme-Federal University Teaching Hospital, Abakaliki (AE-FUTHA) and Mater Misericodiae Hospital Afikpo (MMHA) in Ebonyi State, southeast Nigeria.

Methodology: This was a hospital-based cross-sectional study of 300 consecutively selected critically ill hospitalized patients in the two  hospitals over a period of 6 months, from whom a total of 300 different clinical samples were collected. The specimens were processed by  standard microbiological culture methods at the Applied Microbiology Laboratory Unit of Ebonyi State University (EBSU), Abakaliki. All  isolated bacteria from cultures were phenotypically screened for A. baumannii by conventional biochemical test scheme and antibiotic susceptibility of test (AST) of confirmed isolates was done using the Kirby–Bauer disc diffusion technique, with AST results interpreted  according to the Clinical and Laboratory Standards Institute (CLSI) guideline.

Results: Of the 300 critically ill patients, clinical samples of  21 (7.0%) were positive for A. baumannii, with 20 (10.0%) of 220 samples from AE-FUTHA and 1 (1.3%) of 80 samples from MMHA. Analysis  of the different isolation sites showed that catheter urine (16.0%, 11/70) from AE-FUTHA and (2.0%, 1/50) from MMHA was the most  frequent site of A. baumannii isolation. A. baumannii isolates showed high resistance rates to tetracycline (100.0%), trimethoprim- sulphamethoxazole (100.0%), ceftriaxone (81.0%) and amikacin (81.0%), while low resistance rate was demonstrated to meropenem  (14.3%), imipenem (19.0%) and polymyxin B (33.3%). The multiple antibiotic resistance index (MARI) of the A. baumannii isolates was 12.1,  with average MARI value of 0.57.

Conclusion: Early diagnosis of infection caused by A. baumannii and its treatment with meropenem,  imipenem or polymyxin B can reduce the risks of mortality and morbidity in A. baumannii infection of critically ill patients.