A diagnostic stewardship approach to prevent unnecessary testing of an enteric bacterial molecular panel.

IMPORTANCE: Testing for enteric bacterial pathogens in patients hospitalized for more than 3 days is almost always inappropriate. Our study validates the utility of the 3-day rule and the use of clinical decision support tools to decrease unnecessary testing of enteropathogenic bacteria other than C. difficile. Overriding the restriction was very low yield. Our study highlights the importance of diagnostic stewardship and further refines the criteria for allowing providers to override the restriction while monitoring the impact of the interventions.

Comparison of the analytical sensitivity of seven commonly used commercial SARS-CoV-2 automated molecular assays.

The SARS-CoV-2 pandemic has challenged molecular microbiology laboratories to quickly implement and validate diagnostic assays and to expand testing capacity in a short timeframe. Multiple molecular diagnostic methods received FDA emergency use authorization (EUA) and were promptly validated for use nationwide. Several studies reported the analytical and/ or clinical evaluation of these molecular assays, however differences in the viral materials used for these evaluations complicated direct comparison of their analytical performance. In this study, we compared the analytical sensitivity (lower limit of detection, LOD) of seven commonly used qualitative SARS-CoV-2 molecular assays: the Abbott Molecular RealTime SARS-CoV-2 assay, the NeuMoDx™ SARS-CoV-2 assay, the Roche Cobas®SARS-CoV-2 assay, the BD SARS-CoV-2 reagents for BD MAX™ system, the Hologic Aptima® SARS-CoV-2 assay, the Xpert Xpress SARS-CoV-2 test, and the GenMark ePlex SARS-CoV-2 test. The comparison was performed utilizing a single positive clinical specimen that was serially diluted in viral transport media and quantified by the EUA approved SARS-CoV-2 droplet digital PCR (ddPCR) assay. Replicate samples were prepared and evaluated for reproducibility across different molecular assays with multiple replicates per assay. Our data demonstrated that the seven assays could detect 100 % of replicates at a nucleocapsid gene concentration of (N1 = 1,267 and N2 = 1,392) copies/mL. At a one log less concentration, the Abbott, the Roche, and the Xpert Xpress assays detected 100 % of the tested replicates.

Multicenter Evaluation of BioFire FilmArray Meningitis/Encephalitis Panel for Detection of Bacteria, Viruses, and Yeast in Cerebrospinal Fluid Specimens.

Rapid diagnosis and treatment of infectious meningitis and encephalitis are critical to minimize morbidity and mortality. Comprehensive testing of cerebrospinal fluid (CSF) often includes Gram stain, culture, antigen detection, and molecular methods, paired with chemical and cellular analyses. These methods may lack sensitivity or specificity, can take several days, and require significant volume for complete analysis. The FilmArray Meningitis/Encephalitis (ME) Panel is a multiplexed in vitro diagnostic test for the simultaneous, rapid (∼1-h) detection of 14 pathogens directly from CSF specimens: Escherichia coli K1, Haemophilus influenzae, Listeria monocytogenes, Neisseria meningitidis, Streptococcus pneumoniae, Streptococcus agalactiae, cytomegalovirus, enterovirus, herpes simplex virus 1 and 2, human herpesvirus 6, human parechovirus, varicella-zoster virus, and Cryptococcus neoformans/Cryptococcus gattii We describe a multicenter evaluation of 1,560 prospectively collected CSF specimens with performance compared to culture (bacterial analytes) and PCR (all other analytes). The FilmArray ME Panel demonstrated a sensitivity or positive percentage of agreement of 100% for 9 of 14 analytes. Enterovirus and human herpesvirus type 6 had agreements of 95.7% and 85.7%, and L. monocytogenes and N. meningitidis were not observed in the study. For S. agalactiae, there was a single false-positive and false-negative result each, for a sensitivity and specificity of 0 and 99.9%, respectively. The specificity or negative percentage of agreement was 99.2% or greater for all other analytes. The FilmArray ME Panel is a sensitive and specific test to aid in diagnosis of ME. With use of this comprehensive and rapid test, improved patient outcomes and antimicrobial stewardship are anticipated.

Recognition of Streptococcus pseudoporcinus Colonization in Women as a Consequence of Using Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry for Group B Streptococcus Identification.

During a 14-month period of using matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) for group B streptococcus (GBS) identification, we recovered 32 (1%) Streptococcus pseudoporcinus isolates from 3,276 GBS screening cultures from female genital sources (25 isolates from pregnant women and 7 from nonpregnant women). An additional two S. pseudoporcinus isolates were identified from a urine culture and a posthysterectomy wound culture. These isolates were found to cross-react with three different GBS antigen agglutination kits, PathoDx (Remel) (93%), Prolex (Pro-Lab Diagnostics) (38%), and Streptex (Remel) (53%). New approaches to bacterial identification in routine clinical microbiology laboratories may affect the prevalence of S. pseudoporcinus.