Usefulness of next-generation DNA sequencing for the diagnosis of urinary tract infection

Acute urinary tract infection (UTI) is a highly common clinical condition. Although bacterial culture is the gold standard diagnostic test, false negative results may be possible, leading to the pathogen being unidentified. In recent years, bacterial DNA sequencing analysis has garnered much attention, but clinical studies are rare in Japan. In this study, we assessed the usefulness of next-generation DNA sequencing (NGS) analysis for acute UTI patients. We thus performed an observational, retrospective case series study. Urine and blood samples were collected from ten acute UTI patients, of whom four had also been diagnosed with urosepsis. Seven variable regions of bacterial 16S rRNA genes were amplified by PCR and then sequenced by IonPGM. The identified bacterial species were compared with those identified using the culture tests and the clinical parameters were analyzed. As a result, the NGS method effectively identified predominant culture-positive bacteria in urine samples. The urine NGS also detected several culture-negative species, which have been reported to be potentially pathogenic. Out of four urosepsis cases, three were pathogen-positive in blood NGS results, while two were pathogen-negative in blood culture. In one sepsis case, although blood culture was negative for Escherichia coli, this species was detected by blood NGS. For non-sepsis cases, however, blood NGS, as well as blood culture, was less effective in detecting bacterial signals. In conclusion, NGS is potentially useful for identifying pathogenic bacteria in urine from acute UTI patients but is less applicable in patients who do not meet clinical criteria for sepsis.