Detection of Multidrug-Resistant Acinetobacter baumannii among Gram-Negative Bacteria Isolated from Clinical Samples

Abstract

Acinetobacter baumannii is an aerobic, Gram -negative cocco-bacilli, non-fermentative, non-motile, and non-fastidious organism belonging to the genus Acinetobacter. The A. baumannii has emerged as a worldwide nosocomial pathogen causing about 80% of nosocomial infections comprising ventilator-acquired pneumonia, bacteremia, meningitis, urinary tract infections, skin and soft tissues infections associated with high mortality rate of approximately 63.3%. Although literature shows sufficient information about the drug resistant A. baumannii, there has been inadequate reports on the antibiotic resistance level of this bacterium in the study area. The aim of this research was to detect Multidrug-resistant A. baumannii isolates among Gram-negative bacteria isolated from Federal Teaching Hospital, Gombe, Nigeria. A total of 1008 clinical samples were collected and cultured on MacConkey agar and Blood agar plates at 37o C for 18-24 hours. Following the incubation period, discrete colonies obtained were subjected to Gram staining. The Gram-negative isolates were identified based on conventional biochemical tests with further use of VITEK 2 COMPACT (BioMérieux, France) for confirmation of A. baumannii amongst the Gram-negative organisms. The results obtained showed that 263 Gram-negative organisms were isolated. A. baumannii accounted for 8.5% prevalence. Most of the A. baumannii isolated were from the male patients (75%) within the age range of 33-48 years. Antibiotic susceptibility test using Kirby Bauer method in accordance with CLSI guidelines was done on 20 A. baumannii isolates. The isolates were more sensitive to levofloxacin (60%), followed by Gentamicin (55%), then Ciprofloxacin and Tetracycline (50%) respectively. High level of resistance to Ceftriaxone (80%), Cefepime (75%), Ceftazidime (65%), Piperacillin-Tazobactam (55%), Ampicillin/Sulbactam (60%), Tigecycline (60%), Meropenem (55%) and Amikacin (60%). This study revealed that 15 (75%) of the A. baumannii were found to be multidrugresistant. Therefore, antibiotic stewardship is necessary to combat further dissemination of this organism.