bluuebunny/crossref_metadata_2025_split huggingface dataset:
2329. What Causes a Cluster to Grow? Factors Associated with a Nosocomial COVID-19 Cluster at a University Hospital in Central Tokyo
Authors: Osaka Hilary , Tagashira Yasuaki , Gu Yoshiaki , Takahashi Kunihiko 
Published: November 2023

Abstract

Background
Coronavirus disease 2019 (COVID-19) remains a significant threat to hospital infection control. Despite the decrease in severity and mortality associated with changes in the variants of concern and increased vaccination, SARS-CoV-2 transmissibility remains high, and nosocomial clusters continue to be reported in various countries. Although COVID-19 may be detected in multiple patients and healthcare workers (HCWs) in a given ward within a few days, it is uncertain whether these cases will develop into a large cluster.

Methods
The present, retrospective cohort study of nosocomial COVID-19 clusters was conducted at Tokyo Medical and Dental University Hospital from January 2022 to January 2023 using data from the hospital’s infection prevention and control team. A nosocomial COVID-19 cluster was defined as consisting of more than 2 COVID-19 cases occurring within 5 days in the same ward. Cases with a clear epidemiological link and clusters outside the ward were excluded. We collected information regarding community trends, the index case details, and each cluster's ward profile. Predictors of cluster expansion to more than 5 cases were also examined.

Results
66 clusters were identified at the hospital during the study period. The median number of COVID-19 cases per cluster was 3 (range: 2-22), and their median duration was 5 days (range: 1-27). 37 (56.1%), 25 (37.9%), and 4 (6.1%) clusters comprised both inpatients and HCWs, only HCWs, and only patients, respectively. The index case of 51 clusters (77.3%) was a HCW. 18 (27.3%) and 47 (72.7%) clusters contained &gt; 5 and &lt; 5 cases, respectively. No significant intergroup difference was found in terms of community prevalence, index case and ward characteristics, the rate of close contact or history of previous clusters. However, “clusters occurring during the non-epidemic period” and “infections &gt; 3 occurring within 3 days” tended to develop into clusters containing more than 5 cases.

Conclusion
Nosocomial clusters can occur anywhere, and predicting them is challenging. Further research is needed to identify the factors leading to cluster development and to establish effective infection prevention and control measures.

Disclosures
All Authors: No reported disclosures
2333. Knowledge, attitudes, and practices regarding vaccination against COVID-19 among medical students at a private university in Lima – Peru
Authors: Ramos-Rojas Benjamin , Lopez-Rivera Sebastian , Tafur-Bances Karla , Gonzales-Zamora Jose A , Alave Jorge 
Published: November 2023

Abstract

Background
Vaccination against COVID-19 is one of the most important measures to reduce the spread, morbidity, and mortality of the disease.

Methods
We conducted a cross-sectional study to evaluate knowledge, attitudes, and practices regarding vaccination against COVID-19 in medical students at Universidad Peruana Cayetano Heredia (UPCH), for which an online survey was administered through e-mail and WhatsApp in July 2022. The following independent variables were evaluated: To be in the clinical phase of medical school (last four years), having more online classes ( &gt;= 4 semesters with non-face-to-face classes), having received &gt;= 3 doses of COVID-19 vaccine, and having reliable sources of information (scientific articles, conferences, and seminars). Through linear regression multivariate analysis, we assessed the factors associated with the number of correct answers (knowledge), the standardized attitude index (attitudes), and the number of vaccine doses received (practice).

Results
A total of 352 medical students completed the survey. 96.6% of participants knew that vaccines improved immunity, and 91.2% believed they were effective in reducing hospitalizations, severe illness, and death. 98% of students agreed that the benefits of vaccination outweighed the risks, 90.9% would recommend the population to get vaccinated, and 59.1% agreed that vaccines were safe. 99.7% of respondents have received at least one dose of vaccine, of which 100% received at least two doses, 88% three, and 4.8% four or more. In the multivariate analysis, we found that being in the clinical phase of medical school was associated with a higher knowledge and a higher standardized attitude index. Having received &gt;=3 doses was associated with a higher standardized attitude index. Lastly, having a higher standardized attitude index was associated with having received more vaccine doses. (Table. 1)
Table 1

Conclusion
Regarding vaccination against COVID-19, medical students at UPCH have a high level of knowledge, a positive attitude, and good practices. Our study suggests that educational strategies in the pre-clinical phase may be needed to improve knowledge and attitudes regarding vaccination. Also, a higher standardized attitude index may predict a higher number of vaccine doses.

Disclosures
All Authors: No reported disclosures
2335. Up-to-date COVID-19 vaccination coverage among healthcare personnel in nursing homes —National Healthcare Safety Network
Authors: Ananth Sushmitha , Reses Hannah E , Dubendris Heather , Barbre Kira A , Wong Emily , Lu Meng , Bell Jeneita 
Published: November 2023

Abstract

Background
To prevent morbidity and mortality associated with COVID-19 among nursing home residents, both residents and healthcare personnel (HCP) should remain up-to-date (UTD) with recommended COVID-19 vaccines, including the updated bivalent boosters. As of the first quarter of 2023 (December 26th, 2022 - March 26th, 2023) , the current Centers for Disease Control and Prevention (CDC) recommendation for UTD is defined as completion of primary series and receipt of bivalent booster, or primary series completion only if not yet eligible for booster. The objective of this project was to assess national COVID-19 UTD percentage among HCP in nursing homes by facility-characteristics.

Methods
We analyzed vaccination data reported by nursing homes to the CDC’s National Healthcare Safety Network during January 23rd–February 5th, 2023. Based on the right-skewed distribution of the percentage of HCP who are UTD, median was selected as the main summary measure of central tendency. We calculated median UTD (%) nationally and by facility-size tertiles (measured by number of HCP that were eligible to have worked at a facility for at least 1 day during the week of data collection), social vulnerability index (SVI) tertiles, and urbanicity.

Results
Among 14,857 nursing homes, median UTD (%) among HCP was 13.9% ; among smaller (&lt; 92 total HCP) and larger facilities ( &gt;145 total HCP) was 14.9% and 13.3%, respectively. Median UTD (%) for facilities located in low and high SVI areas was 15.3% and 12.8%, respectively. Median UTD (%) was 11.6% for facilities in non-metropolitan areas and 15.1% among those in metropolitan areas.

Conclusion
COVID-19 median UTD (%) among HCP working in nursing homes in the U.S. was low overall and in all stratifications by facility size, SVI, and urbanicity. This suggests that additional strategies are needed to improve UTD coverage in this population.

Disclosures
All Authors: No reported disclosures
2343. SARS-CoV-2 Spike Conformation Essentially Influences Vaccine Immunogenicity – Results from Two Clinical Phase I Trials of the Vector Vaccine Candidates MVA-SARS-2-S and MVA-SARS-2-ST
Authors: Fathi Anahita , Dahlke Christine , Hardtke Svenja , Mellinghoff Sibylle C , Mayer Leonie , Weskamm Leonie M , Krähling Verena , Müller-Kräuter Helena , Ly My L , Friedrich Monika , Hesterkamp Thomas J , Volz Asisa , Sutter Gerd , Becker Stephan , Addo Marylyn 
Published: November 2023

Abstract

Background
Recombinant Modified Vaccinia virus Ankara (MVA) is a replication-deficient viral vector platform with a favorable safety profile that is currently developed for multiple indications, including vaccines against emerging infections. We assessed the safety and immunogenicity of two MVA-based vaccine candidates against COVID-19 encoding the native or pre-fusion stabilized SARS-CoV-2 spike antigen, namely MVA-SARS-2-S and MVA-SARS-2-ST, in two clinical Phase I trials.

Methods
We conducted a first-in-human trial of the vaccine candidate MVA-SARS-2-S (NCT04569383) and a Phase Ib trial of the successor vaccine MVA-SARS-2-ST (NCT05226390) in healthy, SARS-CoV-2 immune-naïve adults aged between 18-55 (MVA-SARS-2-S) and 18-64 (MVA-SARS-2-ST) years. MVA-SARS-2-S expresses the native, full-length spike glycoprotein of SARS-CoV-2 (S), while MVA-SARS-2-ST delivers a pre-fusion stabilized spike antigen (ST). Both trials were designed as open-label dose-escalation trials and vaccinations were administered as a prime-boost regimen on days 0 and 28. Detailed safety and immunogenicity assessments were conducted at multiple timepoints throughout the study until day 168.

Results
In NCT04569383, 30 individuals received either 1 x 107 ± 0.5 log IU (IU=International Units, n=15, lower dose) or 1 x 108 ± 0.5 log IU (n=15, higher dose) of MVA-SARS-2-S. In NCT05226390, 8 participants received a lower (≥ 1 x 107 IU) and 7 participants a higher (≥ 5 x 107 IU) dose of MVA-SARS-2-ST. Both vaccines were well-tolerated and no vaccine-related severe adverse events (SAEs) occurred in either trial. However, seroconversion rates, measured as binding anti-SARS-CoV-2 S1 antibodies, could only be observed in 3/15 participants in the high dose cohort and none in the low dose cohort after vaccination with MVA-SARS-2-S. In contrast, all participants who received MVA-SARS-2-ST (n=15) achieved seroconversion independent of administered dose.

Conclusion
Both vaccine candidates were safe and well-tolerated. While MVA-SARS-2-S did not induce adequate immunogenicity, vaccination with the pre-fusion stabilized successor vaccine MVA-SARS-2-ST induced seroconversion in all vaccinees, demonstrating the significance of SARS-CoV-2 spike antigen conformation for vaccine immunogenicity.

Disclosures
Anahita Fathi, MD, Biotest: Honoraria Sibylle C. Mellinghoff, MD, Gilead: Grant|Octapharma: Advisor/Consultant
2353. SARS-CoV-2 Variants among US Veterans after COVID-19 Bivalent Vaccine Administration
Authors: Holodniy Mark , Pei Ying , Stack Gary , Wade Christopher L , Agrawal Yashpal , Barasch Nicholas , Baddoura Fady , Carmen Frias-Kletecka M , Stacey Klutts J , Wang-rodriguez Jessica 
Published: November 2023

Abstract

Background
The US Department of Veterans Affairs (VA) created the Sequencing For Research, Clinical, Epidemiology (SEQFORCE) Program in July 2021 to conduct SARS-CoV-2 Whole Genome Sequencing (WGS). Herein, we describe SARS-CoV-2 variants associated with COVID-19 infection, including after bivalent vaccination.

Methods
Demographics, COVID-19 vaccinations, hospitalizations, SARS-CoV-2 variants, and Charlson comorbidity index variables were extracted from VA data sources from 7/1/21-4/1/23. Eligible respiratory samples required a positive RT-PCR result from any platform with cycle threshold &lt; 30. WGS was performed using 3 different platforms (Clear Labs, Illumina, ThermoFisher) at the 9 laboratories and one analytic pipeline (PraediGene, Bitscopic) using Pangolin and Nextclade. Post-vaccine COVID-19 infection was defined as &gt; 2 weeks after COVID-19 vaccine receipt.

Results
Over 41,000 samples from 150 VA clinical sites across all geographical locations in the country have been analyzed by 9 SEQFORCE laboratories since July 1, 2021 (Figure 1), including 28,800 after vaccine breakthrough infection (Table 1). Since October 1, 2022, 3,087 patients had SARS-CoV-2 variants characterized including 986 after bivalent vaccination, 1,191 who were fully vaccinated (including Janssen), but not boosted and didn’t receive a bivalent vaccine dose, and 910 who were never vaccinated (Figure 2) according to VA records. Those who received bivalent vaccine were significantly older, male, and had higher Charlson morbidity scores compared to those not receiving a bivalent vaccine. There was no difference in infection rates based on type of bivalent vaccine received. Bivalent vaccine recipients had significantly more XBB and less BA.5 variants, compared to not receiving a bivalent vaccine (p &lt; 0.0001 for both comparisons).

Conclusion
VA established a SARS-CoV-2 sequencing consortium to track variants for clinical and epidemiological indications. Sample submission was voluntary and therefore may have limited geographic, temporal and clinical diversity among patient samples analyzed. Significantly more XBB and less BA.5 variants were found after bivalent vaccination infection compared to other contemporaneous variants among those not receiving bivalent vaccine.

Disclosures
M. Carmen Frias-Kletecka, MD, Sanofi: Honoraria
2959. Urinary tract colonizing abilities of fosfomycin (FOF) non-susceptible Klebsiella pneumoniae (KP) inner colonies (IC) arising from disk diffusion (DD) in an ascending mouse urinary tract infection (UTI) model
Authors: Bixby Morgan , Collins Lindsey , Salay Jenna , Clabots Connie , Hirsch Elizabeth B 
Published: November 2023

Abstract

Background
DD is a common method for FOF susceptibility testing against Enterobacterales, despite a lack of breakpoints for non-E. coli organisms. When extrapolating these breakpoints, methods for reading zone diameters from the breakpoint setting organizations are often extrapolated as well. With CLSI and EUCAST in disagreement on interpretation of IC that arise from DD, it is imperative that the clinical relevance of these IC is determined. We sought to determine the urinary tract colonizing ability of one clinical KP isolate via an ascending mouse UTI model.

Methods
The parent isolate, KP131—a clinical isolate from Boston, MA—had an MIC of 8 µg/mL and its IC from DD had an MIC of 1024 µg/mL. Immune competent female CBA/j mice (n = 35) were inoculated with an equal mix of KP 131 parent/IC culture via urinary catheter at 1µL/g mouse weight, which delivered a total of 1011 CFU/mL per mouse bladder. At 48 hours post-inoculation, mice were sacrificed, and kidneys/bladders were aseptically collected and individually homogenized. Homogenate was plated on both standard Mueller-Hinton agar (MHA) and MHA plates containing 32 µg/mL FOF + 25µg/mL glucose-6-phosphate. The number of parent colonies were determined by subtracting the FOF-supplemented plate counts from the standard MHA counts and proportions compared via Kruskal-Wallis test.

Results
Of 35 mice infected, 14.3% (n = 5) died prior to harvest. Bladder colonization occurred in 80% (n/N = 24/30) of mice and in one or both kidneys in 67% (n/N = 16/24) of mice when bladders were colonized; 25 total kidneys were colonized. Among these, IC accounted for 44.8% of bacterial burden in the bladder and 54.6% in the kidneys. There was no significant difference in the colonizing abilities of IC compared to the parents in the bladder (p = 0.289). However, the IC colonized at a significantly higher rate (p = 0.046) than the parent isolate in the kidney tissue.

Conclusion
Results from this preliminary study show that KP IC have the ability to colonize the urinary tract at near equal rates to the parent culture when in competition in a mouse UTI model, including a significantly greater colonization in kidney tissue. While this work is limited by use of a single parent/IC pair, future directions include expanding to additional KP isolates with various FOF phenotypes.

Disclosures
Elizabeth B. Hirsch, PharmD, Melinta Therapuetics: Honoraria|Merck and Company, Inc.: Grant/Research Support
2388. Factors Associated with COVID-19 Vaccination Among Racial/Ethnic Minority Populations with HIV, Miami-Dade County, Florida, 2022
Authors: Trepka Mary Jo , Ramirez-Ortiz Daisy , Jean-Gilles Michele , Ladner Robert , Li Tan , Sheehan Diana 
Published: November 2023

Abstract

Background
People with HIV (PWH) are at increased risk for COVID-19 complications and thus can significantly benefit from COVID-19 vaccination. PWH are also more likely to belong to racial/ethnic minority groups that have been underrepresented among vaccinated individuals. The objective of this analysis was to identify Health Belief Model (e.g., perceived susceptibility to and severity of COVID-19, perceived barriers, and benefits of COVID-19 vaccination) and Social Ecological Model (i.e., intrapersonal, interpersonal, and community/institutional-level) factors associated with vaccine uptake among PWH.

Methods
The cross-sectional survey was administered by telephone in English, Spanish or Haitian Creole from January–March 2022 to a sample of 299 adult PWH receiving medical case management services through the Miami-Dade County Ryan White Program (MDCRWP). Participants who received a primary vaccine series were classified as fully vaccinated, and those that received only 1 dose of a 2-dose vaccine series or no doses were classified as not fully vaccinated. Multivariable logistic regression was used to estimate adjusted odds ratios (aORs) of full vaccination with 95% confidence intervals (CIs). The final adjusted model included all sociodemographic characteristics selected a priori, as well as covariates with a p-value &lt; 0.2 in bivariate analyses. Analyses were weighted to be representative of the race/ethnicity and sex distribution of clients in the MDCRWP.

Results
The weighted percentages for full vaccination was 83.8% for the entire group, and 88.9% among Hispanics, 72.0% among African Americans, and 67.5% among Haitians. Being fully vaccinated was associated with Hispanic compared with African American race/ethnicity (aOR 5.44; 95% CI 1.50-19.77), not endorsing any misconceptions about COVID-19 vaccines (aOR 8.26; 95% CI 1.38-49.64), reporting encouragement to get vaccinated from their sources of information (aOR 20.82; 95% CI 5.84-74.14), and perception that ≥ 50% of social network was vaccinated (aOR 3.35; 95% CI 1.04-10.71) (Table 1).

Conclusion
Results highlight the importance of promoting accurate information from sources deemed trustworthy, and social networks in COVID-19 vaccine uptake among PWH.

Disclosures
All Authors: No reported disclosures
129. Evaluation of Two-Step Clostridioides difficile Testing on Treatment Exposure
Authors: Bennett Nicholas , Wilson Sydney , Aragon Laura , Boyd Sarah E 
Published: November 2023

Abstract

Background
Clostridioides difficile can colonize or cause symptomatic disease from mild diarrhea to severe colonic inflammation requiring surgical intervention. Multiple C. difficile diagnostics are available and national guidelines recommend standalone or combination testing methods. Testing has mostly shifted to polymerase chain reaction (PCR)-based, which has shown up to a 50% increase in reporting of C. difficile infection (CDI). A two-step testing method has also been used to discern colonization versus active infection. The National Healthcare Safety Network has proposed changes to CDI reporting to include results and treatment, emphasizing the importance of diagnostic and antimicrobial stewardship.

Methods
In 2021 Saint Luke’s Health System moved from C. difficile PCR standalone to two-step testing with PCR and enzyme immunoassay (EIA) toxin test. If PCR is positive, an EIA is run. Both results are reported including interpretation guidance. A retrospective cohort study was conducted to evaluate if two-step testing impacts antibiotic prescribing rates for C. difficile. The pre-implementation group included PCR-only and post- implementation was split into PCR +/ EIA - and PCR +/ EIA + groups.

Results
Treatment rates for C. difficile did not significantly change after implementation of two-step testing (100% pre- vs 92% PCR +/ EIA - and 97% PCR +/ EIA +, p = 0.093). For PCR +/ EIA - results, treatment initiation more often occurred prior to results being available compared to the post-implementation PCR +/ EIA + group and pre-implementation group (30.3% PCR +/ EIA - vs 19.6% PCR +/ EIA + and 7.8% pre-implementation, (p = 0.028)). C. difficile antibiotic prescribing rates at discharge were no different between groups as the highest rates of treatment continuation were seen in the PCR +/ EIA - group (79.4% PCR +/ EIA - 72.5% pre-implementation vs 71.7% PCR+/ EIA +, p = 0.706).

Conclusion
Despite PCR +/ EIA - results, clinicians tended to treat patients irrespective of PCR-only or two-step results. The impact of two-step C. difficile testing on treatment rates was limited and prescribing rates did not significantly change. The findings of this study warrant investigation into alternative solutions to promote aligned diagnostic and antimicrobial stewardship.

Disclosures
All Authors: No reported disclosures
2403. Outcomes in Infective Endocarditis due to Granulicatella species and Abiotrophia defectiva
Authors: McCartney Cindy , Bartley Patricia , Shrestha Nabin K 
Published: November 2023

Abstract

Background
Infective Endocarditis (IE) due to Granulicatella sp. and Abiotrophia defectiva (formerly known as nutritionally variant streptococci - NVS) remains a clinically important entity given difficulty in diagnosis, optimal management, and possible treatment failure outcomes. These microorganisms account for roughly 4-8% of all IE cases. To the best of our knowledge this study entails the largest single center registry in the US of Granulicatella sp. and A. defectiva IE looking at patient characteristics, survival and relapse outcomes and susceptibility data.

Methods
Retrospective chart review of 35 patients (13 A. defectiva, 20 Granulicatella sp. and 2 labelled as NVS) with IE admitted to our facility from January 1st, 2008, to January 1st, 2023.

Results
Patient characteristics including valves affected, presenting symptoms and complications can be seen in Table 1. Seven patients (20% - 5 for A. defectiva and 2 for Granulicatella sp.) had failed medical management at outside facilities prior to admission at our center. Valve replacement or repair was performed on 31 (88.6%) patients. Molecular testing was performed on 28 (80%) isolates of which all had positive identification. Susceptibilities were obtained in 22 (63%) isolates as summarized in Table 2 below. All isolates were found to be vancomycin-susceptible, and varying degrees of susceptibilities to ceftriaxone and penicillin depending on the species. Vancomycin therapy was used in 11 (31.4%) patients, ceftriaxone in 19 (54.3%) patients (combination of vancomycin and ceftriaxone in 3 patients), and penicillin in 8 (22.9%) patients. Adjuvant aminoglycoside therapy was used in only 2 (5.7%) patients (one combination with ampicillin and one with vancomycin). Average length of IV antibiotic therapy was 6 weeks post-surgery, and 5 patients were treated with an oral tail after IV antibiotics. Survival curves since hospitalization are demonstrated in Figure 1. There were no treatment failures or relapses of IE due to these organisms.

Conclusion
The majority of patients presented with constitutional symptoms, heart failure and embolic events. Five-year survival exceeded 80% and there were no relapses in this series. Most importantly, outcomes were excellent without the use of aminoglycosides contrary to guideline recommendations.

Disclosures
All Authors: No reported disclosures