Prevalence of extended spectrum -lactamases in multidrug resistant strains of Gram-negative bacteria

Extended spectrum beta-lactamases (ESBLs) are enzymes that are now becoming major sources of resistance to β-lactamase antibiotics more especially in enteric bacteria such as Klebsiella pneumoniae, P. aeruginosa and Escherichia coli. Increase in the frequency of the β-lactam resistance in bacteria has become a serious threat for treating bacterial infections caused by enterobacteriaceae. This study aims to determine the prevalence of ESBLs producers among enteric Gram negative bacteria isolated from patients in OAUTHC, Ile-Ife, Osun State. The subject used in this study involved patients presenting with evidence of hospital infections. The collected sputum specimens were processed for the isolation and identification of Gram negative bacilli. Resistance of the isolates to different antibiotics tested was determined using the standard disc diffusion method of Kirby-Bauer. Phenotypic and confirmatory test of the isolates were done for ESBL production using double disc synergy test (DDST) on Mueller Hinton agar according to CLSI 2013 guidelines. Results reveal that the highest occurrence of bacteria was recovered in Klebsiella species (35%), followed by Enterobacter sp. (13%), P. aeruginosa (10%), Escherichia coli and Salmonella sp. (7%) while the least occurs in Proteus sp. All the isolates were 100% resistance to class piperacillin, 76.6% to beta-lactamase inhibitor and 52% resistance to cephalosporins while they were susceptible to carbapenems, nitrofurans, and fluoroquinolones. The prevalence of ESBLs producing isolates was 51.1% while non-ESBL producing strains were 48.8%. Therefore, it can be concluded that extended spectrum beta lactamases are gradually increasing in Nigeria with co-resistance to some other classes of antibiotics which is very alarming. There is a limited number of drugs sensitivity for these bacteria and the drug of choice is imipenem, ciprofloxacin and ofloxacin.