This study analyzed 365 urine samples collected from November 2014 to February 2015 in Sokoto, Nigeria. Of the 105 positive cultures, 60.9% contained Gram-negative uropathogens. The most common isolates were E. coli (29.7%), Salmonella arizonae (23.4%), and Klebsiella species (15.6%). Many isolates were resistant to cotrimoxazole but susceptible to nitrofurantoin. Of the 64 Gram-negative isolates, 15 were confirmed as ESBL producers, with E. coli and Enterobacter species being the most common. The study concludes that ESBL-producing Gram-negative uropathogens are present in Sokoto, Nigeria.

1. PREVALENCE AND ANTIMICROBIAL SUSCEPTIBILITY OF EXTENDED SPECTRUM
BETA-LACTAMASE (ESBL) PRODUCING GRAM-NEGATIVE UROPATHOGENS
IN SOKOTO, NIGERIA
*T. Nuhu1
, R.O. Bolaji2
and B. O. Olayinka2
1
Department of Pharmaceutics and Pharmaceutical Microbiology, Usmanu Danfodiyo
University, Sokoto. (nuhu.tanko@yahoo.com)
2
Department of Pharmaceutics and Pharmaceutical Microbiology, Ahmadu Bello University,
Zaria. (busayoolayinka@yahoo.com)
ABSTRACT
Background: Infections of the urinary tract remains one of the most common bacterial
infections, with many of the implicated organisms being Gram-negative, with increasingly
resistant to antimicrobial agents.
Objective of the study: The study determined the prevalence and antimicrobial susceptibility of
ESBL-producing Gram-negative uropathogens in Sokoto, Nigeria.
Methodology: A total of 365 urine samples were analyzed between November, 2014 and
February, 2015. Antimicrobial susceptibility testing was determined by the modified Kirby
Bauer method. Confirmation of ESBL phenotype was performed by Double Disc Synergy Test
(DDST) method.
Results: One Hundred and Five (105) positive cultures, where Gram-negative uropathogens
constitute 60.9%. Average age of patients was 39.8 years, with range between 19 to 73 years.
Male patients were 54.7%, while females were 45.3%. Age group 19-40 years constituted 54.7%,
while 41-60years were 32.8%, and 61 years and above accounted for 12.5%. Isolates were mainly
resistant to Cotrimoxazole (71.9%), while susceptible to Nitrofurantoin (70.3%).

2. The 64 Gram-negative uropathogens were made up of E.coli (29.7%), Salmonella arizonae
(23.4%), Klebsiella spp (Klebsiella oxytoca and Klebsiella pneumoniae) (15.6%). Enterobacter
spp (Enterobacter gergoviae and Enterobacter aerogenes) (10.9%). Serratia marscense (6.3%)
and Citrobacter freundii (6.3%). Others account for 1.6% each (Proteus mirabilis, Pseudomonas
aeroginosa, Edwardsiella tarda, Burkholderia pseudomallei and Acinetobacter iwoffii).
Fifteen (15) of the isolates were confirmed ESBL producers, comprising E. coli (26.7%),
Enterobacter spp (26.7%), Klebsiella spp (13.3%), Citrobacter freundii (13.3%), while Serratia
marscense, Edwardsiella tarda, Acinetobacter iwoffii accounted for (6.7%) each.
Conclusion: The presence of ESBL-producing gram-negative uropathogens in Sokoto. E.coli
and Enterobacter spp were the predominant ESBL producers. Nitrofurantoin remains active in
the majority of the isolates.
Key words: ESBLs, Uropathogens, Antimicrobial susceptibility.