An Environmental Shiga Toxin-Producing Escherichia coli O145 Clonal Population Exhibits High-Level Phenotypic Variation That Includes Virulence Traits.

Shiga toxin-producing Escherichia coli (STEC) serotype O145 is one of the major non-O157 serotypes associated with severe human disease. Here we examined the genetic diversity, population structure, virulence potential, and antimicrobial resistance profiles of environmental O145 strains recovered from a major produce production region in California. Multilocus sequence typing analyses revealed that sequence type 78 (ST-78), a common ST in clinical strains, was the predominant genotype among the environmental strains. Similarly, all California environmental strains belonged to H28, a common H serotype in clinical strains. Although most environmental strains carried an intact fliC gene, only one strain retained swimming motility. Diverse stx subtypes were identified, including stx1a, stx2a, stx2c, and stx2e. Although no correlation was detected between the stx genotype and Stx1 production, high Stx2 production was detected mainly in strains carrying stx2a only and was correlated positively with the cytotoxicity of Shiga toxin. All environmental strains were capable of producing enterohemolysin, whereas only 10 strains were positive for anaerobic hemolytic activity. Multidrug resistance appeared to be common, as nearly half of the tested O145 strains displayed resistance to at least two different classes of antibiotics. The core virulence determinants of enterohemorrhagic E. coli were conserved in the environmental STEC O145 strains; however, there was large variation in the expression of virulence traits among the strains that were highly related genotypically, implying a trend of clonal divergence. Several cattle isolates exhibited key virulence traits comparable to those of the STEC O145 outbreak strains, emphasizing the emergence of hypervirulent strains in agricultural environments.

Curli fimbriae are conditionally required in Escherichia coli O157:H7 for initial attachment and biofilm formation.

Several species of enteric pathogens produce curli fimbriae, which may affect their interaction with surfaces and other microbes in nonhost environments. Here we used two Escherichia coli O157:H7 outbreak strains with distinct genotypes to understand the role of curli in surface attachment and biofilm formation in several systems relevant to fresh produce production and processing. Curli significantly enhanced the initial attachment of E. coli O157:H7 to spinach leaves and stainless steel surfaces by 5-fold. Curli was also required for E. coli O157:H7 biofilm formation on stainless steel and enhanced biofilm production on glass by 19-27 fold in LB no-salt broth. However, this contribution was not observed when cells were grown in sterile spinach lysates. Furthermore, both strains of E. coli O157:H7 produced minimal biofilms on polypropylene in LB no-salt broth but considerable amounts in spinach lysates. Under the latter conditions, curli appeared to slightly increase biofilm production. Importantly, curli played an essential role in the formation of mixed biofilm by E. coli O157:H7 and plant-associated microorganisms in spinach leaf washes, as revealed by confocal microscopy. Little or no E. coli O157:H7 biofilms were detected at 4 °C, supporting the importance of temperature control in postharvest and produce processing environments.

One-sample proportion testing procedures for hypothesis of inequality.

The primary objective of a phase II single arm clinical trial is to determine whether a new treatment is of sufficient activity for a disease to warrant further development. This paper presents single arm one-stage and two-stage designs for testing the response rate of a test treatment against the response rate of an existing treatment. The null and alternative hypotheses are the response rate of the test treatment is equal and unequal to that of the existing treatment respectively. The testing procedures are calculated with exact binomial distribution. Two-stage designs presented minimize total sample size and satisfy type I and II error constraints, with flexibility in the fraction of the total sample size to use in the first stage.

Eat to Treat: The Methods and Assessments of a Culinary Medicine Seminar for Future Physicians and Practicing Clinicians.

Nutrition-associated chronic disease is an epidemic in the United States (US), yet most medical schools lack adequate nutrition education. We developed a six-session culinary medicine (CM) seminar entitled "Eat to Treat: A Nutrition Course for Future Clinicians" that teaches culinary skills, nutrition science, and counseling techniques to improve clinical nutrition management. The seminar was offered in-person to first-year medical students in a medical school-based teaching kitchen from 2017 to 2019. A virtual three-session course was also offered to practicing clinicians in 2020. Voluntary self-efficacy questionnaires were collected at the beginning of the first and last sessions of the student seminar, and paired t-tests determined the course's effect on survey items. A total of 53 first-year medical students attended the program over five semesters, and 39 students (73.6%) completed both surveys. All except one measure of self-efficacy were significantly higher at session 6 than session 1 (p < 0.05). A post-course survey was utilized for the clinician seminar and of the 31 participants, 14 completed the surveys; 93% and 86% of respondents agreed the course was clinically relevant and improved their confidence, respectively. We developed a CM curriculum that improved nutrition knowledge and confidence among a professionally diverse cohort and may represent a scalable education model to improve nutrition education in US medical schools.

Acute Isolated Right Ventricular Infarction: Unusual Presentation of Anterior ST-Segment-Elevation Myocardial Infarction.

Acute right ventricular infarction presenting with ST-segment elevation in the anterior precordial electrocardiographic leads is an unusual event. Anterior ST-segment elevation typically suggests occlusion of the left anterior descending coronary artery. It should be recognized, however, that occlusion of a right coronary artery branch can cause isolated ST-segment elevation in leads V1 and V2 on a standard 12-lead electrocardiogram. We describe the cases of 2 patients who presented with acute chest syndrome with isolated ST-segment elevation in leads V1 and V2. Emergency coronary angiograms revealed that acute thrombotic occlusion of the right ventricular marginal branch of the dominant right coronary artery caused the clinical manifestations in the first patient, whereas occlusion of the proximal nondominant right coronary artery was the culprit lesion in the second patient. Both lesions caused right ventricular myocardial infarction. The patients underwent successful primary percutaneous coronary intervention. These cases illustrate the importance of carefully reviewing angiographic findings to accurately diagnose an acute isolated right ventricular myocardial infarction, which may mimic the electrocardiographic features of an anterior-wall myocardial infarction.