Osteomyelitis Due to Mycobacterium goodii in an Adolescent, United States.

Osteomyelitis is a rare clinical manifestation of infection with nontuberculous mycobacteria (NTM). We report an adolescent with femoral osteomyelitis associated with prosthetic material due to an emerging pathogen, Mycobacterium goodii. Application of secA1 and 16S ribosomal RNA gene sequencing reliably determined the NTM species, enabling targeted antimicrobial therapy.

Diagnosis of Clostridium difficile Infections in Children.

The detection and diagnosis of Clostridium difficile infection in pediatric populations have some unique considerations in comparison to testing in adults. The testing methodologies, including toxigenic culture, cell cytotoxicity, antigen detection, and, more recently, molecular testing, are the same in all age groups. However, limited data exist on the specific performance characteristics in children. In this review, we focus on the challenges of testing in pediatric populations and assess the available data on test performance in these populations. Additionally, a review of the existing guidance for testing is provided.

Multicenter Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry Study for Identification of Clinically Relevant Nocardia spp.

This multicenter study analyzed Nocardia spp., including extraction, spectral acquisition, Bruker matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) identification, and score interpretation, using three Nocardia libraries, the Bruker, National Institutes of Health (NIH), and The Ohio State University (OSU) libraries, and compared the results obtained by each center. A standardized study protocol, 150 Nocardia isolates, and NIH and OSU Nocardia MALDI-TOF MS libraries were distributed to three centers. Following standardized culture, extraction, and MALDI-TOF MS analysis, isolates were identified using score cutoffs of ≥2.0 for species/species complex-level identification and ≥1.8 for genus-level identification. Isolates yielding a score of <2.0 underwent a single repeat extraction and analysis. The overall score range for all centers was 1.3 to 2.7 (average, 2.2 ± 0.3), with common species generally producing higher average scores than less common ones. Score categorization and isolate identification demonstrated 86% agreement between centers; 118 of 150 isolates were correctly identified to the species/species complex level by all centers. Nine strains (6.0%) were not identified by any center, and six (4.0%) of these were uncommon species with limited library representation. A categorical score discrepancy among centers occurred for 21 isolates (14.0%). There was an overall benefit of 21.2% from repeat extraction of low-scoring isolates and a center-dependent benefit for duplicate spotting (range, 2 to 8.7%). Finally, supplementation of the Bruker Nocardia MALDI-TOF MS library with both the OSU and NIH libraries increased the genus-level and species-level identification by 18.2% and 36.9%, respectively. Overall, this study demonstrates the ability of diverse clinical microbiology laboratories to utilize MALDI-TOF MS for the rapid identification of clinically relevant Nocardia spp. and to implement MALDI-TOF MS libraries developed by single laboratories across institutions.

Detection of SARS-CoV-2 infection in asymptomatic populations using the DiaSorin molecular Simplexa and Roche Cobas EUA assays.

Identification of asymptomatic patients is necessary to control the COVID-19 pandemic and testing is one of the measures to detect this population. We evaluated the clinical correlation of the DiaSorin Molecular Simplexa COVID-19 Direct (DiaSorin Molecular) and Roche Cobas 6800 SARS-CoV-2 (Roche) assays using 253 oropharyngeal (OP) swab specimens collected from asymptomatic patients. Agreement between DiaSorin Molecular and Roche was 97% (95% CI, 0.94 to 0.99), with a κ statistic of 0.90 (95% CI, 0.83 to 0.97) and a PPA of 89% (95% CI, 0.76 to 0.96) and NPA of 99% (95% CI, 0.97 to 0.99). Simple regression analysis of Ct values revealed a regression line of y = 1.065*X - 5.537 with a Pearson's r of 0.8542, indicating a good correlation between both platforms. The DiaSorin Molecular assay demonstrates clinical performance comparable to that of Roche in this population.

Identification of Mycobacterium porcinum in patients with cystic Fibrosis: Pathogen or contaminant?

BACKGROUND: Mycobacterium porcinum is a non-tuberculous mycobacterium (NTM) identified in potable water. The identification and clinical impact of M. porcinum in patients with cystic fibrosis (CF) has not been described. In our institution, M. porcinum was isolated exclusively during hospitalization in a cluster of patients with CF. METHODS: Patients with CF who were hospitalized between September 2016 and September 2018 and could expectorate sputum were included, and samples were processed per institutional guidelines. Post-hospitalization and one-year clinical outcomes on those who isolated M. porcinum in respiratory cultures were reviewed. Whole genome sequencing was performed on M. porcinum isolates obtained from patients and environmental sources to identify source of acquisition. RESULTS: Review of 14 CF patients with 16 M. porcinum isolates revealed rapid time to culture positivity within 0.8 (0.04-8.0) days after admission. M. porcinum was isolated in teenagers and adults irrespective of baseline pulmonary function, body mass index, or CF genotype. Whole genome sequencing suggested all isolates belong to the same M. porcinum strain and confirmed the source of acquisition to the ice machine. Review of patients' clinical course, including three patients who underwent lung transplantation, suggested a pseudo-outbreak with minimal clinical impact. CONCLUSIONS: NTM, including M. porcinum, are ubiquitous in potable water and institutional water reservoirs. Our findings suggest M. porcinum is a transient colonizer rather than a pathogen. Challenges exist in discerning the role of NTM as a contributor of pulmonary morbidity in patients with CF, and adherence to established guidelines regarding NTM related pulmonary disease remains important.

Clinical Evaluation and Utilization of Multiple Molecular In Vitro Diagnostic Assays for the Detection of SARS-CoV-2.

OBJECTIVES: To evaluate the clinical performance of 3 molecular assays for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). METHODS: We used 184 nasopharyngeal swab specimens to compare Abbott ID NOW COVID-19 (Abbott ID NOW), DiaSorin Molecular Simplexa COVID-19 Direct (DiaSorin Simplexa), and Roche cobas 6800 SARS-CoV-2 (Roche cobas) assays. In a separate analysis, 3 specimens (nasopharyngeal, oropharyngeal, and nasal) were collected from 182 unique patients presenting to the emergency department with suspicion of coronavirus disease 2019 and were tested utilizing Abbott ID NOW. To further characterize each assay, relative limits of detection were evaluated utilizing positive nasopharyngeal patient samples. RESULTS: The positive percent agreement was 91% (95% confidence interval [CI], 0.76-0.97) for Abbott ID NOW and 100% (95% CI, 0.90-1.00) for DiaSorin Simplexa and Roche cobas. The negative percent agreement was 100% (95% CI, 0.98-1.00) for all 3 assays. All swab types tested with the Abbott assay produced concordant results. Polymerase chain reaction assays had approximately 10 to 100 times lower limits of detection than Abbott ID NOW. CONCLUSIONS: Based on these evaluations, a multiplatform testing approach is proposed, depending on patient population and assay sensitivity, to address testing needs during a public health emergency.

A large scale clinical evaluation of the AmpliVue and Illumigene molecular tests for the identification of Clostridium difficile-associated diarrhea in adult and pediatric patients.

The AmpliVue (Quidel, San Diego, CA, USA) and Illumigene (Meridian Biosciences, Cincinnati, OH, USA) molecular tests were compared for the detection of C. difficile toxin in fresh fecal samples from adult and pediatric patients. A total of 758 samples were collected, in 3 clinical sites: Nationwide Children's (Columbus, OH, USA), Penn State Hershey (Hershey, PA, USA), Primary Children's (Salt Lake City, UT, USA). Each site tested the fecal specimens using both assays. Any discordant results were resolved by performing toxigenic culture. There were 16 discordant samples among the 3 sites. Following discordant resolution, the combined performance for all 3 sites for sensitivity, specificity, PPV, and NPV for AmpliVue was 96.1%, 99.2%, 96.1%, and 99.2%, respectively, while for Illumigene was 96.1%, 99.8%, 99.2%, and 99.2%, respectively. The AmpliVue and Illumigene methods are both relatively rapid and simple to use, sensitive, and specific for detection of C. difficile toxin and demonstrate similar performance.