Prevalence of plasmid-mediated Ampicillinase C genes in some Gram-negative ESKAPEE bacteria isolated from tertiary hospitals in southwest Nigeria

Abstract

Background : Globally, hospital-acquired infections caused by multidrug resistant Gram-negative ESKAPEE pathogens has the highest probability of death. ESKAPEE bacteria may carry plasmids harbouring several resistance genes that code for β-lactamase enzyme like AmpC, which can be easily disseminated among bacteria. Method : Two hundred and twenty-six bacterial isolates of Klebsiella pneumoniae, Acinetobacter baumannii and Eschericia coli were obtained from clinical samples of in-patients from three tertiary hospitals in Southwest Nigeria (University College Hospital, Ibadan, Federal Medical Centre, Abeokuta and Obafemi Awolowo University Teaching Hospital, Ile-Ife). Isolates were identified using Analytical Profile Index (API) Kit (BioMerieux). Antibiotic susceptibility testing was done using the Kirby Bauer disc diffusion method. Production of Amp-C was phenotypically confirmed using Three-dimensional extract tests. Resistance genes were detected using Polymerase Chain Reaction. Result : Most (91.5%) of the isolates were multidrug resistant. Prevalence of phenotypic producers of AmpC was 19.9% while detection rates for AmpC genes was 3.5%, Phenotypic prevalence by isolates was E. coli (16.5%), Klebsiella pneumoniae (24.4%) and Acinetobacter baumannii (28.6%). The most predominant gene was blaFOX (62.5%). Wound samples from surgical wards had the highest (15.6%) prevalence of AmpC phenotypes. The antibiotics with least (48.3%) and highest (97.2%) resistance were Meropenem and Ampicillin respectively. AmpC producing Acinetobacter baumannii showed 100% resistance to Meropenem. Majority of the AmpC (95%) isolates were resistant to Ciprofloxacin and third generation Cephalosporins. Conclusion : There is high prevalence of AmpC beta-lactamase-producing Gram-negative bacteria in hospitalized patients with possibility of dissemination among hospitalized patients in tertiary healthcare facilities in Southwest Nigeria.