Gender and Age-Dependent Etiology of Community-Acquired Urinary Tract Infections

Abstract

Urinary tract infections (UTIs) are among the most frequent community-acquired infections worldwide.Escherichia coliis the most common UTI pathogen although underlying host factors such as patients’ age and gender may influence prevalence of causative agents. In this study, 61 273 consecutive urine samples received over a 22-month period from outpatients clinics of an urban area of north Italy underwent microbiological culture with subsequent bacterial identification and antimicrobial susceptibility testing of positive samples. A total of 13 820 uropathogens were isolated and their prevalence analyzed according to patient’s gender and age group. OverallEscherichia coliaccounted for 67.6% of all isolates, followed byKlebsiella pneumoniae(8.8%),Enterococcus faecalis(6.3%),Proteus mirabilis(5.2%), andPseudomonas aeruginosa(2.5%). Data stratification according to both age and gender showedE. coliisolation rates to be lower in both males aged ≥60 years (52.2%),E. faecalisandP. aeruginosabeing more prevalent in this group (11.6% and 7.8%, resp.), as well as in those aged ≤14 years (51.3%) in whomP. mirabilisprevalence was found to be as high as 21.2%.Streptococcus agalactiaeoverall prevalence was found to be 2.3% although it was shown to occur most frequently in women aged between 15 and 59 years (4.1%). Susceptibility ofE. colito oral antimicrobial agents was demonstrated to be as follows: fosfomycin (72.9%), trimethoprim/sulfamethoxazole (72.9%), ciprofloxacin (76.8%), ampicillin (48.0%), and amoxicillin/clavulanate (77.5%). In conclusion, both patients’ age and gender are significant factors in determining UTIs etiology; they can increase accuracy in defining the causative uropathogen as well as providing useful guidance to empiric treatment.