INTERPRETATION OF MULTIPLE ISOLATE URINE CULTURES IN ADULT MALE-PATIENTS

A retrospective analytical study examined the records of 220 adult mal es (mean age 64.9 years) to determine the relative probability that mu ltiple urine culture isolates (MUI) represent urinary tract infection (UTI) versus contamination or colonization. Nonculture laboratory data were used to determine the likelihood of UTI. Patients were classifie d into three categories: group 1 (those with single isolate cultures; n = 110), group 2 (those with MUI and either symptomatic UTI or an und erlying pathologic condition; n = 71) and group 3 (those with MUI and either surgically altered urinary passages or absence of UTI symptoms; n = 39). Nonculture laboratory data suggested UTI in 48.2% of patient s in group 1, 46.5% in group 2, and 23.1% in group 3. Patients in grou ps 1 or 2 with cultures yielding isolate counts of 10(5) colony formin g units/mL were 6.2 times more likely to be classified as having a UTI (by nonculture laboratory data) compared with patients having only on e or more of these two criteria. This study proposes a more objective approach to interpretation of MUI cultures using the results of noncul ture laboratory data, clinical profiles, and colony counts.