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Background C. difficile infection (CDI) remains a significant cause of morbidity and mortality. The most appropriate clinical scenario for CDI testing is unclear. The IDSA/SHEA guideline recommends testing patients with unexplained new-onset ≥3 stools in 24 hours. This study sought to evaluate clinical factors associated with a positive C. difficile PCR test. Methods We conducted a retrospective cohort study of adults (age > 18 years old) admitted to the University of Colorado Hospital for whom a C. difficile PCR, either as a standalone test or part of the Biofire® Filmarray® Gastrointestinal Panel (GI Panel), was ordered between October 1, 2015 and August 31, 2017. Data collected included time since admission to test order, hospital length of stay, history of CDI, antibiotic use in the past 90 days, clinical presentation in the 24 hours preceding test order (fever, leukocytosis, number of stools), and laxative or antibiotic administration within 24 hours of test order. Multivariate logistic regression was used to evaluate the association of the above variables with having a positive C. difficile PCR test. If multiple tests were ordered during a single hospital encounter, only the first test was included in our analysis. Results 3,070 tests were performed; of these, 72% were ordered in the first 72 hours of admission. Overall, 19% of tests were positive. After adjusting for clinical variables, patients with a prior history of C. difficile or who had received antibiotics in the past 24 hours were significantly more likely to have a positive test [OR 2.2 95% CI (1.54, 3.18) P < 0.0001] and [OR 16 95% CI (8.22, 31.41) P < 0.0001], respectively. Patients who used laxatives were significantly less likely to have a positive test [OR 0.75 95% CI (0.61, 0.91) P = 0.004]. The number of stools and presence of fever or leukocytosis were not significantly associated with a positive test. Conclusion Prior history of C. difficile and antibiotics use was highly associated with a positive C. difficile test, while laxatives use was associated with a negative test. The number of stools was not significantly associated with a positive C. difficile test, suggesting this may be less important clinical factor than previously believed; however, restricting testing in patients receiving laxatives is likely warranted. Disclosures All authors: No reported disclosures. [ABSTRACT FROM AUTHOR]

Background Up to 80% of cases of acute infectious gastroenteritis do not have an identifiable etiologic agent. Molecular syndromic diagnostic panels, such as the Biofire® Filmarray® gastrointestinal (GI) panel, can improve pathogen detection, including frequent causes of community-onset diarrhea. There are little data about the real-world use and test characteristics of the GI panel in the clinical setting. The objective of this study was to evaluate the patterns of use and clinical utility of the GI panel. Methods We conducted a retrospective cohort study of adults (age > 18 years) admitted to the University of Colorado Hospital for whom a GI Panel was ordered from October 1, 2015 to August 31, 2017. Primary outcomes included patient demographics and co-morbidities, time since admission to test order, and cumulative test results. Descriptive statistics were utilized to summarize the frequencies of the primary outcome measures. Results 1684 panels were ordered and completed during the study period compared with 1379 stand-alone C. difficile PCRs. Seventeen of the 22 components of the panel had been validated by our lab prior to the study period; therefore, results were only available for these pathogens. Most GI panels (78%) were ordered in the first 48 hours of admission, with 6% ordered between 48 and 72 hours after admission, and 16% >72 hours after admission. The GI panel yielded an organism 34% of the time. The most frequently identified organism was C. difficile (18.5%) followed by Norovirus (5.2%) and Enteropathogenic E. coli (5.1%). Conclusion Over a 2-year period at a University hospital, the GI panel only had a positive result in 20% of patients tested. Although most of the tests were ordered in the first 48 hours after admission, 22% were ordered after 48 hours, after which etiologies of hospital-onset diarrhea are expected to be more common. Among all GI Panel tests ordered, C. difficile was the most common organism identified, followed by Norovirus. Each of these organisms has an accurate and less costly alternative test. Stand-alone testing for C. difficile and Norovirus should be considered prior to the GI Panel for patients admitted to the hospital, particularly when admitted >48 hours. Disclosures All authors: No reported disclosures. [ABSTRACT FROM AUTHOR]

The article reports on a hospital outbreak of Carbapenem-resistant Klebsiella pneumoniae that produced New Delhi metallo-beta-lactamase (NDM). The Colorado Department of Public Health and Environment was notified of two patients with the disease on August 16, 2012. The article also mentions the importance of timely active surveillance cultures when the disease is identified.

Objective: To investigate an outbreak of New Delhi metallo-β-lactamase (NDM)-producing carbapenem-resistant Enterobacteriaceae (CRE) and determine interventions to interrupt transmission., Design, Setting, and Patients: Epidemiologic investigation of an outbreak of NDM-producing CRE among patients at a Colorado acute care hospital., Methods: Case patients had NDM-producing CRE isolated from clinical or rectal surveillance cultures (SCs) collected during the period January 1, 2012, through October 20, 2012. Case patients were identified through microbiology records and 6 rounds of SCs in hospital units where they had resided. CRE isolates were tested by real-time polymerase chain reaction for blaNDM. Medical records were reviewed for epidemiologic links; relatedness of isolates was evaluated by pulsed-field gel electrophoresis (PFGE) and whole genome sequencing (WGS). Infection control (IC) was assessed through staff interviews and direct observations., Results: Two patients were initially identified with NDM-producing CRE during July-August 2012. A third case patient, admitted in May, was identified through microbiology records review. SC identified 5 additional case patients. Patients had resided in 11 different units before identification. All isolates were highly related by PFGE. WGS suggested 3 clusters of CRE. Combining WGS with epidemiology identified 4 units as likely transmission sites. NDM-producing CRE positivity in certain patients was not explained by direct epidemiologic overlap, which suggests that undetected colonized patients were involved in transmission., Conclusions: A 4-month outbreak of NDM-producing CRE occurred at a single hospital, highlighting the risk for spread of these organisms. Combined WGS and epidemiologic data suggested transmission primarily occurred on 4 units. Timely SC, combined with targeted IC measures, were likely responsible for controlling transmission.