Do clinical microbiology laboratories report complete bacteriology in urine from patients with long-term urinary catheters?

Abstract

Bacteriuria associated with long-term urinary catheters (those in place for greater than or equal to 30 days) appears to be the most common nosocomial infection in U.S. medical care facilities. This bacteriuria is polymicrobial and dynamic and accompanied by fevers, catheter obstructions, bacteremias, and deaths. We compared the reporting by our research laboratory of bacteria present in urine from long-term-catheterized nursing home patients with that by two commercial laboratories. The commercial laboratories isolated significantly fewer bacterial species at 10(5) CFU/ml of urine specimen. Organisms well recognized as causes of urinary tract infections in noncatheterized patients (Escherichia coli, Proteus mirabilis, Klebsiella pneumoniae) were isolated in comparable frequencies by both the research and commercial laboratories. However, other organisms, including uncommon uropathogens like Providencia stuartii and Morganella morganii, which were actually among the most frequent bacteriuric species in these long-term-catheterized patients, were isolated significantly less frequently by the commercial laboratories. Reasons for the discrepancies are unclear but may involve use of different techniques. More complete reporting may lead to better understanding of the polymicrobial bacteriuria of long-term catheters and its associated complications. This, in turn, may result in improved patient care and infection control in nursing homes.