Background Standard diagnosis of urinary tract infection (UTI) via urine culture for pathogen identification (ID) and antimicrobial susceptibility testing (AST) takes 2–3 d. This delay results in empiric treatment and contributes to the misuse of antibiotics and the rise of resistant pathogens. A rapid diagnostic test for UTI may improve patient care and antibiotic stewardship. Objective To develop and validate an integrated biosensor assay for UTI diagnosis, including pathogen ID and AST, with determination of the minimum inhibitory concentration (MIC) for ciprofloxacin. Design, setting, and participants Urine samples positive for Enterobacteriaceae (n = 84) or culture-negative (n = 23) were obtained from the Stanford Clinical Microbiology Laboratory between November 2013 and September 2014. Each sample was diluted and cultured for 5 h with and without ciprofloxacin, followed by quantitative detection of bacterial 16S rRNA using a single electrochemical biosensor array functionalized with a panel of complementary DNA probes. Pathogen ID was determined using universal bacterial, Enterobacteriaceae (EB), and pathogen-specific probes. Phenotypic AST with ciprofloxacin MIC was determined using an EB probe to measure 16S rRNA levels as a function of bacterial growth. Measurements Electrochemical signals for pathogen ID at 6 SD over background were considered positive. An MIC signal of 0.4 log units lower than the no-antibiotic control indicated sensitivity. Results were compared to clinical microbiology reports. Results and limitations For pathogen ID, the assay had 98.5% sensitivity, 96.6% specificity, 93.0% positive predictive value, and 99.3% negative predictive value. For ciprofloxacin MIC the categorical and essential agreement was 97.6%. Further automation, testing of additional pathogens and antibiotics, and a full prospective study will be necessary for translation to clinical use. Conclusions The integrated biosensor platform achieved microbiological results including MIC comparable to standard culture in a significantly shorter assay time. Further assay automation will allow clinical translation for rapid molecular diagnosis of UTI. Patient summary We have developed and validated a biosensor test for rapid diagnosis of urinary tract infections. Clinical translation of this device has the potential to significantly expedite and improve treatment of urinary tract infections.

The World Health Organization has called for simple, sensitive, and non-sputum diagnostics for tuberculosis. We report development of a urine tuberculosis test using a colorimetric sensor array (CSA). The sensor comprised of 73 different indicators captures high-dimensional, spatiotemporal signatures of volatile chemicals emitted by human urine samples. The sensor responses to 63 urine samples collected from 22 tuberculosis cases and 41 symptomatic controls were measured under five different urine test conditions. Basified testing condition yielded the best accuracy with 85.5% sensitivity and 79.5% specificity. The CSA urine assay offers desired features needed for tuberculosis diagnosis in endemic settings.

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Clostridioides difficile is a leading cause of infectious diarrhea in humans, and it imposes a tremendous burden on the health care system. Current treatments for C. difficile infection (CDI) include antibiotics and fecal microbiota transplant, which contribute to recurrent CDIs and face major regulatory hurdles, respectively.

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