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

Sep 27, 2026

Acinetobacter baumannii is described as an aerobic, Gram-negative, non-fermenting, non-motile organism and a major nosocomial pathogen responsible for high-mortality infections such as ventilator-acquired pneumonia, bacteremia, meningitis, and others. While resistance has been widely reported, local antibiotic resistance levels remained insufficient. This study aimed to detect multidrug-resistant A. baumannii isolates among Gram-negative bacteria from Federal Teaching Hospital, Gombe, Nigeria. A total of 1008 samples were processed and A. baumannii prevalence, susceptibility profiles, and multidrug resistance rates were assessed using Kirby-Bauer testing.

LanguageEnglish

CategoryHealthcare

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Pages17

Reading Time43 min

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Introduction

Materials and Methods

Results and Discussion

Conclusion

Original article Detection of Multidrug-Resistant Acinetobacter baumannii among Gram-Negative Bacteria Isolated from Clinical Samples Michael, G. a,b, Garba, L. b, *, Adamu, M.T. b, Manga, M.M. a,c, Yerima, A.A. b & Isa, S. b a Department of Medical Microbiology and Immunology, Federal Teaching Hospital Gombe, P.O. Box 0037,Off Ashaka road, Gombe State, Nigeria b Department of Microbiology, Faculty of Science, Gombe State University, PMB 127, Tudun Wada Gombe, Gombe State, Nigeria c College of Medical Sciences, Gombe State University, PMB 127, Tudun Wada Gombe, Gombe State, Nigeria 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. Keywords: Gram-negative bacteria, Acinetobacter species, nosocomial infections, susceptibility test, multi-drug resistance. Received: 12 May 2023 * Accepted: 11 December 2023 * DOI: [https://doi.org/10.29329/ijiasr.2023.629.2](https://doi.org/10.29329/ijiasr.2023.629.2) * Corresponding author: Lawal Garba, Department of Microbiology, Faculty of Science, Gombe State University, PMB 127, Tudun Wada Gombe, Gombe State, Nigeria. Email: [lagarpak@gmail.com](lagarpak@gmail.com) INTRODUCTION Acinetobacter baumannii is an important opportunistic pathogen causing about 80% of clinical infections of the 21st century (Odewale, Adefioye, Ojo, Adewumi, & Olowe, 2016; Almasaudi, 2018; Khaledi et al., 2019), and several nosocomial infections such as ventilator-associated infection (VAP), burn and wound infections leading to significant morbidity and mortality particularly in immunocompromised patients as well as those admitted in intensive care units (Basri et al., 2015; Azimi, Talebi, Pourshafie, Owlia, & Lari, 2015; Asif, Alvi, & Rehman, 2018). Report showed that, theA. baumannii has been isolated from blood, sputum, skin, pleural fluid, and urine samples, usually in device associated infections (Mayasari & Siregar, 2015) . This or

FAQs

What was the study aim regarding Acinetobacter baumannii?

The research aimed to detect multidrug-resistant A. baumannii isolates among Gram-negative bacteria collected from the Federal Teaching Hospital in Gombe, Nigeria.

How were clinical samples collected and bacterial isolates identified?

A total of 1008 clinical samples were cultured on MacConkey agar and blood agar, then Gram staining was performed. Gram-negative isolates were identified using conventional biochemical tests and confirmed with VITEK 2 COMPACT for A. baumannii.

Which antibiotics showed the highest sensitivity and resistance patterns?

Levofloxacin showed the highest sensitivity (60%), followed by gentamicin (55%). High resistance was reported against ceftriaxone (80%) and cefepime (75%), with other resistant agents also described in the results.

Sep 27, 2026

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