Diagnostic performance of DNA probe-based and PCR-based molecular vaginitis testing.

Vaginitis is usually diagnosed empirically, microscopically, via cultures, or by molecular testing for the detection of bacterial vaginosis (BV), vulvovaginal candidiasis (VVC), or Trichomonas vaginalis (TV). The DNA probe-based technique detects BV by identifying Gardnerella vaginalis, VVC by identifying Candida spp., while real-time PCR-based detection methods identify BV by algorithmic analysis of the absence or presence of known vaginal flora. We examined 8,878 total orders placed for DNA probe-based identification (ID) and 10,464 total orders placed for molecular panel ID. We found that PCR-based BV test positivity reduced from 30% to 23% compared with the population tested with DNA probe-based testing. We also found that PCR-based testing VVC positivity increased from 6.3% and 11.6% when compared with DNA probe-based testing. Bayesian generalized linear analysis estimated a lower mean proportion of positive tests for BV in PCR-based molecular panels than DNA probe testing suggesting an under-call of BV. The same models estimated a higher mean proportion of positive tests for molecular vaginal panels than DNA probe testing suggesting an increased detection of candidal vaginitis. In addition, the mean (SD) age for patients with Candida albicans was 40.5 (40.0-41.1) years. Patients with Candida glabrata (now N. glabrata) were 5.2-8.1 (mean 6.7) years older than patients with Candida albicans. Our retrospective data analysis found that BD Max MVP's ability to discriminate between vaginal candidiasis versus other yeast will help to implement CDC (Centers for Disease Control and Prevention)-recommended treatment options. We also believe that providers' inattention to non-albicans treatment could be an issue nationwide. IMPORTANCE Using retrospective data from U.S. Food and Drug Administration-approved/cleared molecular vaginal panels, molecular methods were found to have higher detection for Candida vaginitis and lower detection for bacterial vaginitis when compared to probe-based methods. In addition, the differentiation of Candida and non-Candida yeast has not reached the physician community as we observed noncompliance in recommended therapy. Furthermore, the pros and cons of migrating to molecular testing from conventional microscopy for identifying bacterial vaginitis and fungal vaginitis have been examined and reported in this paper. Interestingly, the mean (SD) age for patients with Candida albicans was 40.5 (40.0-41.1) years. Patients with N. glabrata were 5.2-8.1 (mean 6.7) years older than patients with Candida albicans.

Campylobacter coli bacteremia associated with diarrhea.

Campylobacter coli (C. coli) is a gram negative, non-spore forming, mobile, curved, or spiral-shaped rod organisms and one of the most common gastrointestinal human pathogens. Campylobacter very rarely causes bacteremia. However, there are reports of bloodstream infection of C. coli and most of the Campylobacterbacteremia have been found among immunocompromised patients. In this study, a case of C. coli blood stream infection that was associated with diarrhea in an immunocompetent patient.

Presumptive positive with the Cepheid Xpert Xpress SARS-CoV-2 assay due to N mutations in the Delta variant.

The Cepheid Xpert® Xpress SARS-CoV-2 assay is 1 of the several real-time reverse transcription polymerase chain reaction (RT-PCR) assays that received Emergency Use Authorization from the United States Food and Drug Administration (FDA) for detection of SARS-CoV-2. Here we report 4 SARS-CoV-2 samples that were reported as presumptive positives on the Cepheid platform while reported as positives on alternative RT-PCR platforms. Whole genome sequencing indicated that the samples were Delta variants and had point mutations in the N gene which potentially interfered with SARS-CoV-2 detection. Two types of point mutations were found in these samples in the US CDC 2019-nCoV Real time PCR N2 Probe region: C29203T and C29200T. C29203T is a novel point mutation, and C29200T has not been previously reported in the Delta variants. This underlines the fact that mutations in the real-time RT-PCR assay target region could hinder accurate detection of SARS-CoV-2.

Can multidrug-resistant organisms become resistant to ultraviolet (UV) light following serial exposures? Characterization of post-UV genomic changes using whole-genome sequencing.

OBJECTIVES: No-touch disinfection systems like xenon- or mercury-based ultraviolet (UV) are now commonly being used for hospital room disinfection. However, serial exposure to UV light can potentially lead to the development of bacterial resistance. We sought to determine whether UV resistance develops due to serial exposure to UV light using 3 epidemiologically important multidrug-resistant microbial strains. METHODS: Methicillin-resistant Staphylococcus aureus (MRSA), carbapenemase-producing Klebsiella pneumoniae (KPC) and metallo-ß-lactamase-producing Klebsiella pneumoniae (MBL) were serially exposed to 25 growth-irradiation cycles of UV produced by a xenon-based UV (Xe-UV) lamp for 5 minutes or a mercury-based UV (Hg-UV) lamp for 10 minutes. After each UV exposure cycle, the surviving colony-forming units (CFUs) were measured and compared with the initial inoculum of each cycle for each strain, respectively. RESULTS: In each cycle, ˜1-10 million of MRSA, KPC, and MBL were used to test the effect of UV irradiation. Postexposure colony counts remained low (3-100 colonies) throughout the 25 serial exposures to both xenon- and mercury-based UV. The log-kill rate after each exposure showed no changes following UV disinfection by Xe-UV. The MRSA log-kill rate increased after repeated exposure to Hg-UV unlike KPC and MBL K. pneumoniae, which did not change. Whole-genome sequencing (WGS) analyses performed on these 3 strains demonstrated no significant genetic changes after multiple UV irradiation cycles. CONCLUSIONS: Exposure of multidrug-resistant bacteria to UV produced from 2 different UV sources did not engender UV resistance after 25 serial exposures, as demonstrated by WGS analysis; thus, UV disinfection is unlikely to generate UV-resistant hospital flora.

Understanding false positives and the detection of SARS-CoV-2 using the Cepheid Xpert Xpress SARS-CoV-2 and BD MAX SARS-CoV-2 assays.

Several real-time RT-PCR assays have received Emergency Use Authorization from the United States Food and Drug Administration. The BD MAX™ SARS-CoV-2 assay, run by the BD MAX™ system, is a qualitative test that detects the SARS-CoV-2 specific nucleocapsid phosphoprotein gene regions, N1 and N2. The human RNase P gene is used as the endogenous nucleic acid extraction control. The Cepheid Xpert® Xpress SARS-CoV-2 assay, run by the GeneXpert system, detects the pan-sarbecovirus E gene and the N2 region of the N gene. We evaluated the performance characteristics of the BD and Cepheid assays using matched patient samples. We also analyzed comparative Ct values for both assays using 183 positive samples tested at this facility. In addition, we mitigated reporting false positive results without relying on interpretive software. We found that both systems showed comparable sensitivity. We found an approximately 3.5% false positive rate from the BD MAX™ system results.

Asynchronous Testing of 2 Specimen-Diversion Devices to Reduce Blood Culture Contamination: A Single-Site Product Supply Quality Improvement Project.

OBJECTIVE: Blood culture contamination above the national threshold has been a consistent clinical issue in the ED setting. Two commercially available devices were examined that divert an initial small volume of the specimen before the collection of blood culture to reduce skin contamination. METHODS: Prospectively, 2 different blood culture-diversion devices were made available in the unit supplies to ED clinicians at a single site during 2 different periods of time as a follow-up strategy to an ongoing quality improvement project. Blood samples were collected in the emergency department over a period of 16 months. A retrospective record review study was conducted comparing the use of the 2 specimen-diversion devices with no device (control group) for blood culture contamination rates. The main outcome of monthly blood culture contamination per device was tested using a Bayesian Poisson multilevel regression model. RESULTS: A total of 4030 blood samples were collected and analyzed from November 2017 to February 2019. The model estimated that the mean incidence of contaminated blood draws in the device A group was 0.29 (0.14-0.55) times the incidence of contaminated draws in the control group. The mean incidence of contaminated blood draws in the device B group was 0.23 (0.13-0.37) times the incidence of contaminated draws in the control group, suggesting that initial-diversion methods reduced blood culture contamination. CONCLUSION: Initial specimen-diversion devices supplement present standard phlebotomy protocols to bring down the blood culture contamination rate.

Clade-specific variation in susceptibility of Candida auris to broad-spectrum ultraviolet C light (UV-C).

BACKGROUND: Candida auris is an emerging and often multidrug-resistant fungal pathogen with an exceptional ability to persist on hospital surfaces. These surfaces can act as a potential source of transmission. Therefore, effective disinfection strategies are urgently needed. We investigated the efficacy of ultraviolet C light (UV-C) disinfection for C. auris isolates belonging to 4 different clades. METHODS: In vitro testing of C. auris isolates was conducted using 106 colony-forming units (CFU) spread on 20-mm diameter steel carriers and exposed to a broad-spectrum UV-C light source for 10, 20, and 30 minutes at a 1.5 m (5 feet) distance. Post-UV survivors on the coupons were subsequently plated. Colony counts and log reductions were recorded, calculated, and compared to untreated control carriers. Identification of all isolates were confirmed by MALDI-TOF and morphology was visualized by microscopy. RESULTS: We observed an increased susceptibility of C. auris to UV-C in 8 isolates belonging to clades I, II and IV with increasing UV exposure time. The range of log kill (0.8-1.19) was highest for these isolates at 30 minutes. But relatively no change in log kill (0.04-0.35) with increasing time in isolates belonging to clade III were noted. Interestingly, C. auris isolates susceptible to UV-C were mostly nonaggregating, but the isolates that were more resistant to UV exposure formed aggregates. CONCLUSIONS: Our study suggests variability in susceptibility to UV-C of C. auris isolates belonging to different clades. More studies are needed to assess whether a cumulative impact of prolonged UV-C exposure provides additional benefit.