Characterisation of enterobacteriaceae isolates from urinary tract infections in Harare, Zimbabwe

Abstract

Objective: To characterise and determine the prevalence of Enterobacteriaceae members causing Urinary Tract Infections (UTIs) in a Zimbabwean populace.
Design: A descriptive cross-sectional study of urine specimens from patients diagnosed with UTIs at a local private laboratory. Clear-mid-stream urine specimens from patients diagnosed with UTIs were cultured on Cysteine Lactose Electrolyte Deficient agar (CLED) and Blood Agar (BA). Enterobacteriaceae family antimicrobial susceptibilities were determined using the Mindray TDR 300B Auto-Microorganism identification and analysis machine. Isolates were also screened for extended spectrum beta lactamase production using the double disc diffusion method.
Setting: The study was conducted at Premier Service Medical Investments Clinical Laboratory (PSMICL) situated in the city of Harare. The laboratory receives urine specimens from different medical centres around the city and also areas surrounding the city such as Norton, Chitungwiza, Marondera, Kadoma, Bindura and Chinhoyi.
Inclusion Criteria: All patients diagnosed with urinary tract infections which were caused by a member of the Enterobacteriaceae family
Exclusion Criteria: All patients diagnosed with a urinary tract infections that were caused by organisms other than the Enterobacteriaceae members (Candida sp, Parasites (Schistosoma haematobium), Staphylococcussp, Streptococcus sp, Enterococcussp among other causative agents)
Results: Out of the 3933 patient specimens that were included into the study 715 (18.2%) had positive urine cultures, with 538 (75.2%) being confirmed Enterobacteriaceae members. The study showed that ESBL production was a common mode of resistance appearing in 23.4% of the isolates while AmpC production appeared in 22.3%.
Conclusion: Enterobacteriaceae members are the major causative agents of urinary tract infections with E coli being the leading causative agent. In the case of infections which are caused by isolates that are non ESBL and AmpC producers, fluoroquinolones and aminoglycosides can still be employed as empirical treatment. However for infections caused by ESBL and AmpC producing Enterobacteriaceae, carbapenems and amikacin can be employed for management of such infections.