Prevalence and antimicrobial susceptibility of Extended Spectrum Beta-Lactamase (ESBL) producing gram-negative uropathogens in Sokoto, Nigeria

Abstract

Background: Extended Spectrum Beta-Lactamases (ESBLs) producing  Gram-negative uropathogens is now a major source of concern worldwide.
Objectives: The study was conducted to determine the prevalence and  susceptibility to antimicrobial of ESBL-producing Gram-negative uropathogens in Sokoto, Nigeria.
Materials and Methods: A total number of Three Hundred and Sixty Five (365) urine samples were analyzed between November, 2014 and February, 2015. Antimicrobial susceptibility testing was determined using the modified Kirby Bauer method.  Confirmation of ESBL phenotype was performed by Double-Disc Synergy Test  (DDST) method.
Results: Gram-negative uropathogens constitute 60.9% out of the 105 positive  cultures. Male patients were 54.7%, while females were 45.3%. Age group 19-40 constitutes 54.7%, while age group 41-60 was 32.8%, and 61 years and above  accounted for 12.5%. The isolates were highly resistant to Cotrimoxazole (71.9%), but highly susceptible to Nitrofurantoin (70.3 ). Out of the 64 Gram-negative  uropathogens E.coli constitute 29.7%, followed by Salmonella arizonae (23.4%),  Klebsiella oxytoca (10.9%), Enterobacter gergoviae (9.3%), Serratia marscense  (6.3%), and Citrobacter freundii (6.3%). Klebsiella pneumoniae (4.7%). Others  account for 1.6% each (Enterobacter aerogenes, Proteus mirabilis, Pseudomonas aeroginosa, Edwardsiella tarda, Burkholderia pseudomallei and Acinetobacter  iwoffii). Fifteen (15) (83.3%) were phenotypically confirmed using the Double-Disc Synergy Test (DDST) as ESBL producers of which E.coli account for 26.7%,  Enterobacter gergoviae (20%), Enterobacter aerogenes (6.7%) Klebsiella oxytoca (6.7%), Klebsiella pneumoniae (6.7%), Citrobacter freundii (13.3%), while Serratia marscense, Edwardsiella tarda, Acinetobacter iwoffii accounted for (6.7%) each.
Conclusions: Our findings document the presence of ESBL-producing Gram-negative uropathogens in Sokoto. E.coli and Enterobacter gergoviae were the predominant ESBL producers. Nitrofurantoin remains active in the majority of the isolates.

Keywords: ESBLs, Gram-negative uropathogens, Antimicrobial susceptibility.