Association between periurethral colonization with uropathogens and subsequent bacteriuria in catheterized patients.

Abstract

To determine the number of catheterized patients who develop bacteriuria due to the presence of organisms in their periurethral flora, which may subsequently cause Urinary Tract Infection (UTI) in these patients. Non-interventional, cohort study. This study was conducted on patients of Medical Intensive Care, Surgical and Urology Units of Combined Military Hospital, Lahore, from February to April 2006. A total of 60 hospitalized patients, who were catheterized for various underlying diseases, were included in the study. Urine samples and periurethral swabs were obtained from all patients and cultured on appropriate culture media. Various tests used for the identification of microorganisms were: Gram-staining, catalase test, coagulase test and esculin hydrolysis for the identification of Gram-positive bacteria, API 20e for Gram-negative bacilli, whereas lactophenol blue preparation and germ tube test were used for the identification of yeasts. Out of 60 patients, 41(68.3%) were males and 19 (31.7%) were females. The mean duration of catheterization was 4.5 days. In males, culture of periurethral swabs revealed coagulase negative staphylococci in 11 (40.7%), Staphylococcus aureus in 10 (37%) and Enterococcus fecalis in 3 (11.1%) patients. In females, the organisms isolated were coagulase negative staphylococci in 4 (25%), Staphylococcus aureus in 4 (25%), Enterococcus fecalis in 4 (25%), Pseudomonas aeruginosa in 2 (12.5%), Escherichia coli in 3 (18.6%) and Candida albicans in 3 (18.6%) patients. Twenty nine patients developed bacteriuria (p < 0.05). Escherichia coli was the commonest organism causing bacteriuria in either gender followed by other Gram-negative organisms. Coagulase negative Staphylococcus was isolated in the urine of one male patient only. In males, 2 (10%) out of 20 patients with Gram-negative bacteriuria were colonized by the same organism, whereas in females, 4 (44.4%) out of 9 bacteriuric patients were colonized by the same organism. Predominantly Gram-positive organisms colonized the periurethral area in males as well as in the majority of females, whereas Gram-negative bacteria were mainly responsible for the bacteriuria in both genders. There was a significant association between periurethral colonization and subsequent bacteriuria, however, prior colonization with a particular organism is not a decisive event in the initiation of bacteriuria.