"Urinary Tract Infection"-Requiem for a Heavyweight.

"Urinary tract infection" ("UTI") is an ambiguous, expansive, overused diagnosis that can lead to marked, harmful antibiotic overtreatment. "Significant bacteriuria," central to most definitions of "UTI," has little significance in identifying individuals who will benefit from treatment. "Urinary symptoms" are similarly uninformative. Neither criterion is well defined. Bacteriuria and symptoms remit and recur spontaneously. Treatment is standard for acute uncomplicated cystitis and common for asymptomatic bacteriuria, but definite benefits are few. Treatment for "UTI" in older adults with delirium and bacteriuria is widespread but no evidence supports the practice, and expert opinion opposes it. Sensitive diagnostic tests now demonstrate that healthy urinary tracts host a ubiquitous, complex microbial community. Recognition of this microbiome, largely undetectable using standard agar-based cultures, offers a new perspective on "UTI." Everyone is bacteriuric. From this perspective, most people who are treated for a "UTI" would probably be better off without treatment. Elderly adults, little studied in this regard, face particular risk. Invasive bacterial diseases such as pyelonephritis and bacteremic bacteriuria are also "UTIs." Mindful decisions about antibiotic use will require a far better understanding of how pathogenicity arises within microbial communities. It is likely that public education and meaningful informed-consent discussions about antibiotic treatment of bacteriuria, emphasizing potential harms and uncertain benefits, would reduce overtreatment. Emphasizing the microbiome's significance and using the term "urinary tract dysbiosis" instead of "UTI" might also help and might encourage mindful study of the relationships among host, aging, microbiome, disease, and antibiotic treatment.