Causative pathogens and antibiotic resistance in community-acquired urinary tract infections in central South Africa.

BACKGROUND

Urinary tract infections (UTIs) are very common in community practice. Both the South African (SA) antibiotic stewardship programme (2015) and the Essential Medicines List for SA (2018) recommend ciprofloxacin as first-line treatment for community-acquired urinary tract infections (CAUTIs). The pathogens responsible for CAUTIs and their susceptibility profiles need to be documented, which is important for developing and updating treatment protocols.

OBJECTIVES

To determine the causative pathogens of CAUTIs in the greater Bloemfontein area, central SA, and to review their susceptibilities to commonly prescribed antibiotics.

METHODS

Urine samples sent for microscopy and culture between 2011 and 2015 by the three largest primary healthcare facilities in Bloemfontein were analysed retrospectively. Specimens with a significant count (>105 CFU/mL) of a single uropathogen were included. These results were obtained from the National Health Laboratory Service central data warehouse after the required consent. Data regarding age, gender, pathogen cultured and antimicrobial susceptibilities were captured. All calculations were carried out with statistical analysis software SPSS 17.0 (SPSS Inc., USA).

RESULTS

A total of 712 samples met the inclusion criteria. Women accounted for 481 (67.6%) of the infections. The prevalence of UTIs per age group was as follows: 1 month - 25 years (n=146; 20.51%); 26 - 50 years (n=324; 45.5%); and 51 - 75 years (n=199; 27.9%). The distribution of pathogens did not differ between age groups. Escherichia coli was the most prevalent uropathogen cultured from 410 (57.6%) specimens, followed by Klebsiella spp. from 97 (13.6%) and Enterococcus spp. from 71 (10.0%) specimens. E. coli showed resistance rates of 77.1% to amoxicillin, 15.6% to amoxicillin-clavulanate, 18.5% to ciprofloxacin, 4% to nitrofurantoin and 11% to trimethoprim-sulfamethoxazole (TMP-SMX). The distribution of uropathogens was different for men and women, with a lower prevalence of E. coli in men (p=0.045).

CONCLUSIONS

As expected, E. coli comprised most of the isolates, with a higher than expected number of Klebsiella isolates cultured. The susceptibility of E. coli to commonly prescribed oral antibiotics has decreased in the research setting, which mirrors a global trend. This study provides data showing that TMP-SMX and nitrofurantoin can be used safely as alternatives to first-line ciprofloxacin in CAUTIs in central SA.