Journal Article

Carbapenem-resistance in Acinetobacter baumannii: prevalence, antibiotic resistance profile and carbapenemase genes in clinical and hospital environmental strains

Ajigbewu, Olaoniye Habeebat, Isiaka, Habeeb Salman, Adeyemi, Folasade Muibat, Wahab, Abideen Akinkunmi, Akinlade, Esther Abiodun, Yusuf-Omoloye, Nana Aishat, Dare, Alabi Peter, Oyedara, Omotayo Opemipo, Usamat, Alimat Olamide

2025

Overview

Background Acinetobacter baumannii , a Gram-negative member of the ESKAPE pathogen group, is known to develop resistance to several antibiotics rapidly, and carbapenem-resistant A. baumannii (CRAB) is highly implicated in life-threatening infections, especially within hospital settings. Objectives This study detected CRAB in clinical and hospital-environmental samples, evaluated the antibiotic resistance patterns and screened for prevalent carbapenemase genes in isolates from a hospital in Southwest Nigeria. Methods A total of 150 clinical and hospital environmental samples were analysed using culture-dependent and molecular methods for the detection of Acinetobacter baumannii. Antibiotic susceptibility test was done using the Kirby-Bauer disk diffusion technique. Phenotypic screening for carbapenemase was via simplified carbapenem inactivation method (sCIM), and molecular detection of bla KPC type, bla OXA−48−like , bla VIM type, bla NDM−1 , bla IMP variants and bla OXA−23−like genes by Polymerase chain reaction. Results Altogether, only 29.4% (42/143 isolates) of recovered isolates were identified as A. baumannii , giving a prevalence of 28.0% (42/150 samples), predominantly from sputum. All isolates had the gluconolactonase gene, while 5/42 had the bla OXA - 51 - like gene. Resistance to meropenem and cefiderocol was 100.0% and 88.1%, respectively, while gentamicin was most effective in vitro (7.1%); 54.8% were multidrug-resistant, and 88.1% (37/42) had MARI ≥ 0.2. Overall, 39/42 (92.9%) isolates had ≥ one or more carbapenemase genes; 61.9% (26/42) had the bla KPC type gene, 59.5% (25/42) had the bla IMP variants while 45.2% had the bla VIM type gene; no strain had the bla NDM−1 or the bla OXA−23−like gene. Conclusion This study reports the occurrence of MDR strains, and of bla KPC type, bla IMP variants and bla VIM type carbapenemase genes in A. baumannii isolates from clinical and hospital environmental samples, contributing to the pool of existing data on their occurrence. It also highlights the need for monitoring and continued surveillance of the strains, most especially in the clinical setting.

• Publisher: BioMed Central,BioMed Central Ltd,Springer Nature B.V,BMC
• Subject: Acinetobacter baumannii / Acinetobacter baumannii - drug effects / Acinetobacter baumannii - enzymology / Acinetobacter baumannii - genetics / Acinetobacter baumannii - isolation & purification / Acinetobacter Infections - epidemiology / Acinetobacter Infections - microbiology / Anopheles / Anti-Bacterial Agents - pharmacology / Antibacterial agents / Antibiotic resistance / Antibiotics / Bacterial infections / Bacterial Proteins - genetics / beta-Lactamases - genetics / bla IMP / bla KPC / bla VIM type / Carbapenem-resistant Acinetobacter baumannii / Carbapenemase / Carbapenems / Carbapenems - pharmacology / Cross Infection - epidemiology / Cross Infection - microbiology / Drug resistance / Drug resistance in microorganisms / Drug Resistance, Multiple, Bacterial / Environmental Microbiology / Female / Genes / Genetic aspects / Genetic research / Gentamicin / Gluconolactonase / Health aspects / Hospitals / Humans / Infection / Infections / Infectious Diseases / Internal Medicine / Male / Medical Microbiology / Medicine / Medicine & Public Health / Meropenem / Microbial Sensitivity Tests / Microbiological research / Mortality / Multidrug resistance / Nigeria - epidemiology / Parasitology / Pathogens / Physiological aspects / Polymerase chain reaction / Prevalence / sCIM / Sputum / Statistics / Tropical Medicine / Urine