Screening for Kocuria species among presumptive coagulasenegative staphylococcus isolates in cases of urinary tract infections in Enugu, Nigeria

Abstract

Urinary tract infections (UTIs) are one of the microbial infections caused mainly by bacteria, which account for majority of patients’ visit to out-patients’ clinics. Organisms in the genus Kocuria are emerging pathogens presently associated with UTIs, and are usually misidentified as coagulase-negative staphylococci (CoNS) because they are phenotypically similar. The aim of the study was to characterize bacteria associated with UTIs among out-patients suspected of having UTIs, and screen for Kocuria species, suspected among the isolates. Urine samples were collected aseptically from a total of 267 patients attending out-patients’ clinic at Enugu State University of Science and Technology Teaching Hospital, Parklane Enugu. Bacteria were isolated from the urine samples using appropriate microbiological and biochemical techniques. 16S rRNA gene sequencing was finally used to confirm isolates suspected to be Kocuria species as coagulasenegative Staphylococcus. Out of the 267 urine samples, 102 (38.2%) had UTIs. The bacteria mostly associated with the UTIs were Escherichia coli 41 (38.3%), followed by Klebsiella pneumoniae 23 (21.5%), Staphylococcus aureus 17 (15.9%), Coagulase-negative Staphylococcus 12 (11.2%), Enterococcus spp. 9 (8.4%) and Pseudomonas aeruginosa 5 (4.7%). This study showed that urinary tract infections caused by coagulase negative Staphylococcus can be attributed to Kocuria spp., when only phenotypic method of identification is employed. Therefore, genome-based methods such as 16S rRNA gene sequencing should be adopted for more accurate identification of clinical isolates.