Addressing the Diversity-Validity Dilemma Using Situational Judgment Tests.

PURPOSE: To examine the magnitudes of score differences across different demographic groups for three academic (grade point average [GPA], old Medical College Admission Test [MCAT], and MCAT 2015) and one nonacademic (situational judgment test [SJT]) screening measures and one nonacademic (multiple mini-interview [MMI]) interview measure (analysis 1), and the demographic implications of including an SJT in the screening stage for the pool of applicants who are invited to interview (analysis 2). METHOD: The authors ran the analyses using data from New York Medical College School of Medicine applicants from the 2015-2016 admissions cycle. For analysis 1, effect sizes (Cohen d) were calculated for GPA, old MCAT, MCAT 2015, CASPer (an online SJT), and MMI. Comparisons were made across gender, race, ethnicity (African American, Hispanic/Latino), and socioeconomic status (SES). For analysis 2, a series of simulations were conducted to estimate the number of underrepresented in medicine (UIM) applicants who would have been invited to interview with different weightings of GPA, MCAT, and CASPer scores. RESULTS: A total of 9,096 applicants were included in analysis 1. Group differences were significantly smaller or reversed for CASPer and MMI compared with the academic assessments (MCAT, GPA) across nearly all demographic variables/indicators. The simulations suggested that a higher weighting of CASPer may help increase gender, racial, and ethnic diversity in the interview pool; results for low-SES applicants were mixed. CONCLUSIONS: The inclusion of an SJT in the admissions process has the potential to widen access to medical education for a number of UIM groups.

Incremental Contributions of FbaA and Other Impetigo-Associated Surface Proteins to Fitness and Virulence of a Classical Group A Streptococcal Skin Strain.

Group A streptococci (GAS) are highly prevalent human pathogens whose primary ecological niche is the superficial epithelial layers of the throat and/or skin. Many GAS strains with a strong tendency to cause pharyngitis are distinct from strains that tend to cause impetigo; thus, genetic differences between them may confer host tissue-specific virulence. In this study, the FbaA surface protein gene was found to be present in most skin specialist strains but largely absent from a genetically related subset of pharyngitis isolates. In an ΔfbaA mutant constructed in the impetigo strain Alab49, loss of FbaA resulted in a slight but significant decrease in GAS fitness in a humanized mouse model of impetigo; the ΔfbaA mutant also exhibited decreased survival in whole human blood due to phagocytosis. In assays with highly sensitive outcome measures, Alab49ΔfbaA was compared to other isogenic mutants lacking virulence genes known to be disproportionately associated with classical skin strains. FbaA and PAM (i.e., the M53 protein) had additive effects in promoting GAS survival in whole blood. The pilus adhesin tip protein Cpa promoted Alab49 survival in whole blood and appears to fully account for the antiphagocytic effect attributable to pili. The finding that numerous skin strain-associated virulence factors make slight but significant contributions to virulence underscores the incremental contributions to fitness of individual surface protein genes and the multifactorial nature of GAS-host interactions.

Differences in SpeB protease activity among group A streptococci associated with superficial, invasive, and autoimmune disease.

The secreted cysteine proteinase SpeB is an important virulence factor of group A streptococci (GAS), whereby SpeB activity varies widely among strains. To establish the degree to which SpeB activity correlates with disease, GAS organisms were recovered from patients with pharyngitis, impetigo, invasive disease or acute rheumatic fever (ARF), and selected for analysis using rigorous sampling criteria; >300 GAS isolates were tested for SpeB activity by casein digestion assays, and each GAS isolate was scored as a SpeB-producer or non-producer. Highly significant statistical differences (p < 0.01) in SpeB production are observed between GAS recovered from patients with ARF (41.5% SpeB-non-producers) compared to pharyngitis (20.5%), invasive disease (16.7%), and impetigo (5.5%). SpeB activity differences between pharyngitis and impetigo isolates are also significant, whereas pharyngitis versus invasive isolates show no significant difference. The disproportionately greater number of SpeB-non-producers among ARF-associated isolates may indicate an altered transcriptional program for many rheumatogenic strains and/or a protective role for SpeB in GAS-triggered autoimmunity.