The selectivity of a range of culture media for the detection of Salmonella was assessed using 435 strains of gram-negative bacteria. These media showed limited ability to inhibit non-Salmonella strains found in stool samples. We report the evaluation of alafosfalin as a selective agent for isolation of Salmonella from stool samples. Susceptibility studies with this agent showed that non-typhi Salmonella strains were relatively resistant (mean MIC, 10.2 mg/liter) compared to many coliforms including Escherichia coli (mean MIC, 0.7 mg/liter). A chromogenic medium, ABC medium, was modified to incorporate alafosfalin and was compared with standard ABC medium and Hektoen enteric agar for the isolation of Salmonella from 1,000 stool samples. On direct culture, modified ABC medium showed higher recovery of Salmonella (53.6%) compared with either ABC medium (35.7%) or Hektoen enteric agar (48.2%). We conclude that alafosfalin is a useful selective agent for the isolation of Salmonella from stool samples.There is a wide range of culture media available for the isolation of Salmonella. Traditional media such as deoxycholate citrate agar, Hektoen enteric (HE) agar, and xylose lysine decarboxylase agar (XLD) rely mainly on the detection of hydrogen sulfide production and/or nonfermentation of lactose by Salmonella (12). Although these media may be highly effective, they are nonspecific, and a number of species may produce colonies resembling Salmonella (4, 12).The introduction of chromogenic media which employ enzyme substrates has allowed an increased specificity in the detection of Salmonella (7). Rambach agar (10) and Salmonella detection and identification medium (SM-ID) medium (M. C. Poupart, M. Mounier, F. Denis, J. Sirot, C. Couturier, and F. Villeval, Abstr. 5th Eur. Congr. Clin. Microbiol. Infect. Dis, abstr. 1254Dis, abstr. , 1991 were the first media of this type. Rambach agar uses a chromogenic substrate for ␤-galactosidasein conjunction with propylene glycol, which is fermented by Salmonella spp. to generate acid (10). SM-ID medium is based on similar principles incorporating X-Gal and glucuronic acid (Poupart et al., Abstr. 5th Eur. Congr. Clin. Microbiol. Infect. Dis.). ABC medium, more recently commercialized, contains a combination of two chromogenic substrates, and Salmonella is detected on the basis of its production of ␣-galactosidase (9). In recent years a range of media have been manufactured which rely on the detection of esterase activity by Salmonella using chromogenic substrates (2,5,6,8).Despite over a decade of development in the field of chromogenic media for Salmonella, there is much evidence to suggest that traditional media may offer a superior recovery rate for the direct isolation of Salmonella from stool samples ( Microbiol. 2001Microbiol. , abstr. C170 p. 188, 2001. In this study we assess the selectivity of a selection of both chromogenic and conventional agars for Salmonella and investigate a novel approach to the selective isolation of Salmonella using a "suicide substrate," alafos...

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Past research and theory suggest that youth aggression is maladaptive, caused by factors such as cognitive bias, personal defect, or frustration. We sought to identify the extent and circumstances in which aggression is socially adaptive in the school context, by conducting a systematic review and meta-analysis of the links between youth aggression and peer nominations of popularity and likeability. Bayesian multilevel meta-analysis was used to analyse 1,133 effects from 255 studies with a total of 556,363 participants in elementary, middle, and high school. Aggression was negatively associated with likability: -0.28 [95% credibility interval (CrI): -0.41 -0.13] and positively associated with popularity: 0.16 [95% CrI: 0.06 0.25], regardless of the type of aggression and several other possible moderators. We discuss the implications of these findings for aggression interventions and highlight the importance of acknowledging the upsides of aggression for youth, measuring, and targeting indirect aggression.

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In this paper, we examine whether the nomination of Donald Trump for president affected decisions to run for Congress in 2016 in states with later filing deadlines. We theorize that the perception among potential candidates that Donald Trump would be a weak nominee had the potential to entice high-quality Democratic candidates (defined as those who have previously held an elective office) to run for Congress as it became increasingly clear that Donald Trump would be the Republican presidential nominee. We also examine an alternative hypothesis that the impending Trump nomination enhanced political amateurs’ perception they could win in 2016, enticing them to run for Congress. Using a novel dataset from PredictIt, we find support for the second hypothesis, with more political amateurs running as the Trump nomination became more likely. These findings suggest that Donald Trump’s nomination had important consequences that went beyond the presidential race.