Aetiology of community-acquired urinary tract infection and antimicrobial susceptibility patterns of uropathogens isolated

Bahadin J, Teo SSH, Mathew S
Correspondence: Dr Juliana Bahadin, juliana.bahadin@singhealth.com.sg

ABSTRACT
Introduction Antibiotic resistance among uropathogens causing urinary tract infection (UTI) is increasing worldwide. In most cases of UTI, family physicians can provide empirical treatment without the benefit of a pre-therapy urine culture. Knowledge of the aetiology and antimicrobial susceptibility patterns of uropathogens is important in order to determine the best empiric treatment option. This study aimed to determine the aetiology and antimicrobial susceptibility of uropathogens in culture-positive, community-acquired UTIs over a one-year period.
Methods This is a retrospective analysis of medical case records. All patients who were diagnosed and coded with UTI and had urine culture done were analysed. The prevalence of the UTI-causing organism and its antibiotic susceptibility was tabulated. Results were analysed with descriptive statistics. The chi-square and Fisher’s exact tests were applied for categorical variables.
Results The commonest organism isolated for all age groups and gender was Escherichia coli (74.5 percent) and Klebsiella spp. (8.7 percent). Among the oral antibiotics widely used in primary care in Singapore, the Enterobacteriaceae family was most susceptible to amoxicillin/clavulanate. There was no significant difference in the susceptibility of common oral antibiotics when tested against the Enterobacteriaceae for both male and female patients and between patients older than 65 years and those 65 years and below.
Conclusion Empirical treatment of community-acquired UTI with cotrimoxazole, ciprofloxacin, cephalothin and ampicillin is inadequate. Amoxicillin/clavulanate should be the drug of choice for empirical treatment instead.

Keywords: aetiology, antimicrobial susceptibility, community-acquired urinary tract infection, empirical treatment, uropathogens
Singapore Med J 2011; 52(6): 415-420