Development of A Standardized Opsonophagocytosis Killing Assay for Group B Streptococcus and Assessment in an Interlaboratory Study.

The placental transfer of antibodies that mediate bacterial clearance via phagocytes is likely important for protection against invasive group B Streptococcus (GBS) disease. A robust functional assay is essential to determine the immune correlates of protection and assist vaccine development. Using standard reagents, we developed and optimized an opsonophagocytic killing assay (OPKA) where dilutions of test sera were incubated with bacteria, baby rabbit complement (BRC) and differentiated HL60 cells (dHL60) for 30 min. Following overnight incubation, the surviving bacteria were enumerated and the % bacterial survival was calculated relative to serum-negative controls. A reciprocal 50% killing titer was then assigned. The minimal concentrations of anti-capsular polysaccharide (CPS) IgG required for 50% killing were 1.65-3.70 ng/mL (depending on serotype). Inhibition of killing was observed using sera absorbed with homologous CPS but not heterologous CPS, indicating specificity for anti-CPS IgG. The assay performance was examined in an interlaboratory study using residual sera from CPS-conjugate vaccine trials with international partners in the Group B Streptococcus Assay STandardisatiON (GASTON) Consortium. Strong correlations of reported titers between laboratories were observed: ST-Ia r = 0.88, ST-Ib r = 0.91, ST-II r = 0.91, ST-III r = 0.90 and ST-V r = 0.94. The OPKA is an easily transferable assay with accessible standard reagents and will be a valuable tool to assess GBS-specific antibodies in natural immunity and vaccine studies.

A Program of Assessment Model for Point-of-Care Ultrasound Training for Pediatric Critical Care Providers: A Comprehensive Approach to Enhance Competency-Based Point-of-Care Ultrasound Training.

Point-of-care ultrasound (POCUS) is increasingly accepted in pediatric critical care medicine as a tool for guiding the evaluation and treatment of patients. POCUS is a complex skill that requires user competency to ensure accuracy, reliability, and patient safety. A robust competency-based medical education (CBME) program ensures user competency and mitigates patient safety concerns. A programmatic assessment model provides a longitudinal, holistic, and multimodal approach to teaching, assessing, and evaluating learners. The authors propose a fit-for-purpose and modifiable CBME model that is adaptable for different institutions' resources and needs for any intended competency level. This educational model drives and supports learning, ensures competency attainment, and creates a clear pathway for POCUS education while enhancing patient care and safety.

Quantification of SARS-CoV-2 neutralizing antibody by wild-type plaque reduction neutralization, microneutralization and pseudotyped virus neutralization assays.

Virus neutralization assays measure neutralizing antibodies in serum and plasma, and the plaque reduction neutralization test (PRNT) is considered the gold standard for measuring levels of these antibodies for many viral diseases. We have developed procedures for the standard PRNT, microneutralization assay (MNA) and pseudotyped virus neutralization assay (PNA) for severe acute respiratory syndrome coronavirus 2. The MNA offers advantages over the PRNT by reducing assay time, allowing increased throughput and reducing operator workload while remaining dependent upon the use of wild-type virus. This ensures that all severe acute respiratory syndrome coronavirus 2 antigens are present, but Biosafety Level 3 facilities are required. In addition to the advantages of MNA, PNA can be performed with lower biocontainment (Biosafety Level 2 facilities) and allows for further increases in throughput. For each new vaccine, it is critical to ensure good correlation of the neutralizing activity measured using PNA against the PRNT or MNA. These assays have been used in the development and licensure of the ChAdOx1 nCoV-19 (AstraZeneca; Oxford University) and Ad26.COV2.S (Janssen) coronavirus disease 2019 vaccines and are critical for demonstrating bioequivalence of future vaccines.

Decreasing Diagnostic Hysteroscopy Performed in the Operating Room: A Quality Improvement Initiative.

OBJECTIVES: At our institution, diagnostic hysteroscopy (DH), often combined with uterine curettage, commonly has been performed in the main OR with the patient under general anaesthesia. Our objective was to create targeted interventions aimed at decreasing the number of DHs performed in the OR by 75% over one year. METHODS: This quality improvement initiative had a quasi-experimental (time-series) design. To obtain baseline numbers of DHs performed each month, we conducted a retrospective chart audit at a university teaching hospital. We implemented the following three groups of interventions: (1) staff education and case review, (2) accessible sonohysterography, and (3) an operative hysteroscopy education program. Procedures were tracked prospectively over a 12-month intervention period and an additional 12-month maintenance period. RESULTS: One hundred eleven DHs were performed at baseline. During the intervention period, 33 DHs were performed, a 70% reduction from baseline. This resulted in related savings of $126 984 and 12.5 surgical days. In the final quarter of the intervention period, there was an 81% reduction in the number of DHs with adequate preoperative evaluation compared with baseline. Twenty DHs were performed in the maintenance period, an 82% reduction from baseline. The absolute number of complications from DH remained constant during the study period. CONCLUSION: Carefully planned and targeted interventions to change the culture at our institution decreased the number of DHs performed in the main OR. These initiatives improved patient care, saved costs, and improved OR utilization. Long-term follow-up showed maintenance of the improvements in the year subsequent to the interventions.