Laboratory Diagnosis of Urinary Tract Infections: Guidelines, Challenges, and Innovations

The culture-based diagnosis of urinary tract infections (UTIs) present several challenges to clinical microbiologists, physicians, and the health care system in general because the diagnosis of UTI is not always straightforward. The 8 million office visits for the assessment of UTIs each year represent a significant health care cost of approximately $1 billion annually. The resulting 1.5 million hospitalizations further impact the health care system. UTIs represent 40% of nosocomial infections, and they are usually associated with urinary catheters. Importantly, catheter-associated urinary tract infections (CAUTIs) are one of the hospital-acquired complications chosen by the Centers for Medicare and Medicaid Services for which hospitals no longer receive additional payment. Although this rule may result in an increased focus on CAUTIs, increased education for health care workers, early catheter removal, and alternatives to indwelling catheterizations, it may also result in more urine specimens being submitted for culture. An increase in urine cultures will definitely have an impact on both clinical microbiology staffing and laboratory expenditures, especially if the urine cultures are positive for significant amounts of microbial growth. Therefore, it is imperative that the clinical microbiology laboratory employ well-documented guidelines for processing and interpreting urine cultures and implement state-of-the-art methodology, when appropriate. The purpose of this review is to discuss recent guidelines and recommendations for the collection and processing of urine specimens, interpretation of culture results, current challenges, and potential options for routine urine culture.