Clinical Characteristics and Outcomes Among Adults Hospitalized with Laboratory-Confirmed SARS-CoV-2 Infection During Periods of B.1.617.2 (Delta) and B.1.1.529 (Omicron) Variant Predominance - One Hospital, California, July 15-September 23, 2021, and December 21, 2021-January 27, 2022.

In mid-December 2021, the B.1.1.529 (Omicron) variant of SARS-CoV-2, the virus that causes COVID-19, surpassed the B.1.617.2 (Delta) variant as the predominant strain in California.§ Initial reports suggest that the Omicron variant is more transmissible and resistant to vaccine neutralization but causes less severe illness compared with previous variants (1-3). To describe characteristics of patients hospitalized with SARS-CoV-2 infection during periods of Delta and Omicron predominance, clinical characteristics and outcomes were retrospectively abstracted from the electronic health records (EHRs) of adults aged ≥18 years with positive reverse transcription-polymerase chain reaction (RT-PCR) SARS-CoV-2 test results admitted to one academic hospital in Los Angeles, California, during July 15-September 23, 2021 (Delta predominant period, 339 patients) and December 21, 2021-January 27, 2022 (Omicron predominant period, 737 patients). Compared with patients during the period of Delta predominance, a higher proportion of adults admitted during Omicron predominance had received the final dose in a primary COVID-19 vaccination series (were fully vaccinated) (39.6% versus 25.1%), and fewer received COVID-19-directed therapies. Although fewer required intensive care unit (ICU) admission and invasive mechanical ventilation (IMV), and fewer died while hospitalized during Omicron predominance, there were no significant differences in ICU admission or IMV when stratified by vaccination status. Fewer fully vaccinated Omicron-period patients died while hospitalized (3.4%), compared with Delta-period patients (10.6%). Among Omicron-period patients, vaccination was associated with lower likelihood of ICU admission, and among adults aged ≥65 years, lower likelihood of death while hospitalized. Likelihood of ICU admission and death were lowest among adults who had received a booster dose. Among the first 131 Omicron-period hospitalizations, 19.8% of patients were clinically assessed as admitted for non-COVID-19 conditions. Compared with adults considered likely to have been admitted because of COVID-19, these patients were younger (median age = 38 versus 67 years) and more likely to have received at least one dose of a COVID-19 vaccine (84.6% versus 61.0%). Although 20% of SARS-CoV-2-associated hospitalizations during the period of Omicron predominance might be driven by non-COVID-19 conditions, large numbers of hospitalizations place a strain on health systems. Vaccination, including a booster dose for those who are fully vaccinated, remains critical to minimizing risk for severe health outcomes among adults with SARS-CoV-2 infection.

A Roadmap to Implementing Antimicrobial Stewardship Principles in Long-term Care Facilities (LTCFs): Collaboration Between an Acute-Care Hospital and LTCFs.

Effective 28 November 2017, the Centers for Medicare & Medicaid Services (CMS) mandated long-term care facilities (LTCFs) to have antimicrobial stewardship programs (ASPs) in place. Although guidance exists for establishing ASPs in LTCFs, limited data exist on the "how." As comprehensive ASPs already exist in many acute-care hospitals (ACHs) and with the known "sharing of patients" between both settings, extending ACH ASP expertise to LTCFs will not only aid LTCFs in complying with the CMS mandate but will likely also facilitate in decreasing multidrug-resistant organisms and Clostridium difficile infection rates in patients at both organizations. Here, we provide a roadmap on how to implement ASPs in LTCFs, using examples from our own ACH's collaboration with local LTCFs to develop and sustain LTCF ASPs. We discuss critical elements to achieving successful LTCF ASPs, including the potential barriers and how to overcome them.

Gene polymorphism analysis of Yersinia enterocolitica outer membrane protein A and putative outer membrane protein A family protein.

BACKGROUND: Yersinia enterocolitica outer membrane protein A (OmpA) is one of the major outer membrane proteins with high immunogenicity. We performed the polymorphism analysis for the outer membrane protein A and putative outer membrane protein A (p-ompA) family protein gene of 318 Y. enterocolitica strains. RESULTS: The data showed all the pathogenic strains and biotype 1A strains harboring ystB gene carried both ompA and p-ompA genes; parts of the biotype 1A strains not harboring ystB gene carried either ompA or p-ompA gene. In non-pathogenic strains (biotype 1A), distribution of the two genes and ystB were highly correlated, showing genetic polymorphism. The pathogenic and non-pathogenic, highly and weakly pathogenic strains were divided into different groups based on sequence analysis of two genes. Although the variations of the sequences, the translated proteins and predicted secondary or tertiary structures of OmpA and P-OmpA were similar. CONCLUSIONS: OmpA and p-ompA gene were highly conserved for pathogenic Y. enterocolitica. The distributions of two genes were correlated with ystB for biotype 1A strains. The polymorphism analysis results of the two genes probably due to different bio-serotypes of the strains, and reflected the dissemination of different bio-serotype clones of Y. enterocolitica.

Prevalence of Yersinia enterocolitica in pigs slaughtered in Chinese abattoirs.

The distribution of Yersinia enterocolitica in slaughtered pigs in China was studied. A total of 8,773 samples were collected and examined from different pig abattoirs in 11 provinces from 2009 to 2011. Of these, 4,495 were oral-pharyngeal swab (tonsils) samples from pigs, 1,239 were from intestinal contents, and 3,039 were feces samples from abattoirs or local pigpens. The data showed that 1,132 strains were obtained, from which the isolation rate for Yersinia enterocolitica was 19.53% (878/4,495) from the tonsil samples, 7.51% (93/1,239) from intestinal contents, and 5.30% (161/3,039) from feces. Of the 850 pathogenic Yersinia strains, except for three of bioserotype 2/O:9 and three of bioserotype 4/O:3, most (844/850) were of bioserotype 3/O:3. Interestingly, pathogenic Y. enterocolitica accounted for the majority of the isolated strains from most provinces (85.17% to 100%), whereas from Heilongjiang, 96.52% (111/115) were classified as nonpathogenic biotype 1A with various serotypes, and only 3.48% of the strains (4/115) were pathogenic 3/O:3. All of the pathogenic strains were analyzed using pulsed-field gel electrophoresis (PFGE), and 49 patterns were obtained for the O:3 pathogenic strains; most of them were K6GN11C30021 (53.13%: 450/847) and K6GN11C30012 (21.37%: 181/847). Several strains from diarrhea patient samples revealed PFGE patterns identical to that from samples of local pigs, suggesting a possible link between porcine isolates and human infection. The results above suggested that Yersinia enterocolitica in slaughtered pigs from Chinese abattoirs was characterized by region-specific PFGE patterns and confirmed that strains isolated from pigs are closely related to those from human infections.

Tocilizumab treatment in critically ill patients with COVID-19: A retrospective observational study.

OBJECTIVE: Elevated levels of pro-inflammatory cytokines are observed in severe COVID-19 infections, and cytokine storm is associated with disease severity. Tocilizumab, an interleukin-6 receptor antagonist, is used to treat chimeric antigen receptor T cell-induced cytokine release syndrome and may attenuate the dysregulated immune response in COVID-19. We compared outcomes among tocilizumab-treated and non-tocilizumab-treated critically ill COVID-19 patients. DESIGN, SETTING, AND PARTICIPANTS: This was a retrospective observational study conducted at a tertiary referral center investigating all patients admitted to the intensive care unit for COVID-19 who had a disposition from the hospital because of death or hospital discharge between March 1 and May 18, 2020 (n = 96). The percentages of death and secondary infections were compared between patients treated with tocilizumab (n = 55) and those who were not (n = 41). MEASUREMENTS AND MAIN RESULTS: More tocilizumab-treated patients required mechanical ventilation (44/55, 80%) compared to non-treated patients (15/41, 37%; P < 0.001). Of 55 patients treated with tocilizumab, 32 (58%) were on mechanical ventilation at the time of administration, and 12 (22%) progressed to mechanical ventilation after treatment. Of patients treated with tocilizumab requiring mechanical ventilation, 30/44 (68%) were intubated within 1 day of administration. Fewer deaths were observed among tocilizumab-treated patients, both in the overall population (15% vs 37%; P = 0.02) and among the subgroup of patients requiring mechanical ventilation (14% vs 60%; P = 0.001). Secondary infections were not different between the 2 groups (tocilizumab: 31%, non-tocilizumab: 17%; P = 0.16) and were predominantly related to invasive devices, such as urinary and central venous catheters. CONCLUSIONS: Tocilizumab treatment was associated with fewer deaths compared to non-treatment despite predominantly being used in patients with more advanced respiratory disease.

Optimizing utilization of beta-lactam surgical prophylaxis through implementation of a structured allergy assessment tool in a presurgical clinic.

In patients with ß-lactam allergies, administration of non-ß-lactam surgical prophylaxis is associated with increased risk of infection. Although many patients self-report ß-lactam allergies, most are unconfirmed or mislabeled. A quality improvement process, utilizing a structured ß-lactam allergy tool, was implemented to improve the utilization of preferred ß-lactam surgical prophylaxis.

Evaluation of a Modified Debate Exercise Adapted to the Pedagogy of Team-Based Learning.

Objective. To assess the impact of a debate exercise on self-reported evidence of student learning in literature evaluation, evidence-based decision making, and oral presentation. Methods. Third-year pharmacy students in a required infectious disease therapeutics course participated in a modified debate exercise that included a reading assignment and readiness assessment tests consistent with team-based learning (TBL) pedagogy. Peer and faculty assessment of student learning was accomplished with a standardized rubric. A pre- and post-debate survey was used to assess self-reported perceptions of abilities to perform skills outlined by the learning objectives. Results. The average individual readiness assessment score was 93.5% and all teams scored 100% on their team readiness assessments. Overall student performance on the debates was also high with an average score of 88.2% prior to extra credit points. Of the 95 students, 88 completed both pre- and post-surveys (93% participation rate). All learning objectives were associated with a statistically significant difference between pre- and post-debate surveys with the majority of students reporting an improvement in self-perceived abilities. Approximately two-thirds of students enjoyed the debates exercise and believed it improved their ability to make and defend clinical decisions. Conclusion. A debate format adapted to the pedagogy of TBL was well-received by students, documented high achievement in assessment of skills, and improved students' self-reported perceptions of abilities to evaluate the literature, develop evidence-based clinical decisions, and deliver an effective oral presentation.

Comparison of Growth and the Cytokines Induced by Pathogenic Yersinia enterocolitica Bio-Serotypes 3/O: 3 and 2/O: 9.

Pathogenic Yersinia enterocolitica is widely distributed in China where the primary bio-serotypes are 3/O: 3 and 2/O: 9. Recently, the distribution of 2/O: 9 strains are being gradually replaced by 3/O: 3 strains where presently 3/O: 3 strains are the major pathogenic Y. enterocolitica in China. To identify the growth conditions and cytokines induced by Y. enterocolitica and providing some clues for this shift, we performed competitive growth in vitro and in vivo for these two bio-serotype strains; and we also compared the cytokines induced by them in infected BALB/C mice. We found 2/O: 9 strains grew more in vitro, while 3/O: 3 strains grew more in vivo regardless of using single cultures or mixed cultures. The cytokines induced by the two strains were similar: interleukin-6 (IL-6), IL-9, IL-13, granulocyte colony-stimulating factor (G-CSF), chemokines (KC), monocyte chemotactic protein 1 (MCP-1), macrophage inflammation protein-1α (MIP-1α), tumor necrosis factor-α (TNF-α), and RANTES were statistically up-regulated upon activation of normal T cells compared to the control. The cytokine values were higher in mixed infections than in single infections except for IL-6, G-CSF, and KC. The data illustrated the different growth of pathogenic Y. enterocolitica bio-serotype 3/O: 3 and 2/O: 9 in vitro and in vivo, and the cytokine changes induced by the two strains in infected BALB/C mice. The growth comparisons of two strains maybe reflect the higher pathogenic ability or resistance to host immune response for Y. enterocolitica bio-serotype 3/O: 3 and maybe it as one of the reason for bacteria shift.

Canis lupus familiaris involved in the transmission of pathogenic Yersinia spp. in China.

To investigate canines carrying pathogens associated with human illness, we studied their roles in transmitting and maintaining pathogenic Yersinia spp. We examined different ecological landscapes in China for the distribution of pathogenic Yersinia spp. in Canis lupus familiaris, the domestic dog. The highest number of pathogenic Yersinia enterocolitica was shown from the tonsils (6.30%), followed by rectal swabs (3.63%) and feces (1.23%). Strains isolated from plague free areas for C. lupus familiaris, local pig and diarrhea patients shared the same pulsed-field gel electrophoresis (PFGE) pattern, indicating they may be from the same clone and the close transmission source of pathogenic Y. enterocolitica infections in these areas. Among 226 dogs serum samples collected from natural plague areas of Yersinia pestis in Gansu and Qinghai Provinces, 49 were positive for F1 antibody, while the serum samples collected from plague free areas were all negative, suggested a potential public health risk following exposure to dogs. No Y. enterocolitica or Yersinia pseudotuberculosis was isolated from canine rectal swabs in natural plague areas. Therefore, pathogenic Yersinia spp. may be regionally distributed in China.