Hospital and community isolates of uropathogens at a tertiary hospital in South Africa

Abstract

This study investigated the profile of common uropathogens isolated from urine specimens submitted to the diagnostic Microbiology Laboratory at a tertiary teaching hospital and assessed their antimicrobial susceptibility patterns to commonly used antimicrobial agents. We did a retrospective analysis of laboratory reports for all urine specimens submitted for investigations over a one year period. Isolates were tested for susceptibility using the Kirby Bauer disc diffusion method to amoxicillin, ciprofloxacin, gentamicin, co-trimoxazole, nitrofurantoin, and for ESBL production.
Out of the total specimens (n=2203) received over the one year study period, 51.1% (1126) of the urine samples were culture positive, the majority (65.4%) being from females. The commonest isolate was Escherichia coli (39.0%) followed by Klebsiella species (20.8%) and Enterococcus faecalis (8.2%). The Gram-negative isolates displayed a very high level of resistance to amoxicillin (range 43% – 100%) and co-trimoxazole (range 29% - 90%), whereas resistance to gentamicin (range 0% - 50%) and ciprofloxacin (range 0% - 33%) was lower. E coli isolates were susceptible to nitrofurantoin (94%) and ESBL production was significantly higher (p = 0.01) in the hospital isolates compared to those from the community referral sites.
The culture positive rate for uropathogens was high with the majority being from females. E coli was the commonest aetiological agent identified and remains susceptible to nitrofurantoin. Resistance levels to amoxicillin and co-trimoxazole are very high for all Gram negative isolates and it is recommended that these antibiotics should not be used for the empiric treatment of urinary tract infections.