bluuebunny/crossref_metadata_2025_split huggingface dataset:
P-1318. Epidemiology and Trends of Corynebacterium diphtheriae in the United States, 2016-2023
Authors: Berry Isha , Bampoe Valerie , Cole Matthew , Ju Hong , McCall Ingrid C , Fraire Marissa , Fueston Heather , Pawloski Lucia , Tobolowsky Farrell A , Tromble Erin 
Published: January 2025

Abstract

Background
Diphtheria, commonly resulting in severe respiratory or cutaneous disease, is caused by toxin-producing (i.e., toxigenic) strains of Corynebacterium diphtheriae. Non-toxigenic C. diphtheriae also cause disease, which is typically less severe but can be invasive. Non-toxigenic bacteria can acquire and express the toxin (tox) gene, providing a mechanism for diphtheria re-introduction to the United States (US). We examine the epidemiology, toxigenicity, and trends of C. diphtheriae isolates submitted to CDC from January 2016 to September 2023.
Corynebacterium Diphtheriae Isolates in the United States, by year

Methods
C. diphtheriae isolates submitted to CDC were cultured and tested by polymerase chain reaction for species confirmation and tox detection; toxin production was confirmed by Elek. Laboratory data were linked with epidemiological case data. Isolates were classified as non-toxigenic if they were tox-negative or toxigenic if tox-positive and Elek-positive. We examined temporal trends in reported isolates and describe demographic and epidemiologic case characteristics.

Results
A total of 1010 C. diphtheriae isolates were identified during 2016—2023; 99.0% (n=1000) were non-toxigenic, and 1.0% (n=10) were toxigenic. An annual average of 65 (range: 39-95) isolates were reported during 2016—2021; in 2022 and 2023 this increased to an average of 311 (range: 283-338) isolates reported per year. Median patient age was 43 years (range: &lt; 1-98), and 69.0% (n=697) were male. Isolates were primarily obtained from cutaneous (n=689, 68.2%), respiratory (n=133, 13.2%) and blood (n=127, 12.6%) sources. Among non-toxigenic cases with epidemiological data (n=800), major risk factors included housing instability (28.2%) and history of IVDU (20.9%). Eight of the 10 toxigenic cases reported recent international travel to a diphtheria-endemic country.

Conclusion
There has been an increase in C. diphtheriae isolates identified in the US; however, the majority of isolates were non-toxigenic and from cutaneous sites. Though toxigenic cases were infrequent, risk factors appear to differ between toxigenic compared with non-toxigenic cases. Awareness of case risk factors may help to effectively guide public health intervention and infection prevention and control measures prior to toxigenicity confirmation.

Disclosures
All Authors: No reported disclosures
P-1322. Transmission Dynamics of Escherichia coli Sequence Type 131 Amongst Community Dwelling Households: A Prospective Cohort Study
Authors: Perez Rebecca L , Tan Wei Cong , Singh Shweta Rajkumar , Vignesvaran Kithalaksmi , Mo Yin , Thu Aung Kyaw , Twee Hee Rick Ong , Tang Cheng Yee , Seah Ivan , Banerjee Ritu , Teo Jeanette , Tambyah Paul , Tan En Ying , Lok Kin Wesley Yeung 
Published: January 2025

Abstract

Background
Escherichia coli sequence type 131 (E. coli ST131) is a global pandemic clone associated with the rapid dissemination of CTX-M–class extended spectrum β-lactamase (ESBL) genes, conferring resistance to several antibiotic classes, and is a major cause of both healthcare and community-acquired extraintestinal pathogenic E. coli (ExPEC) infections. The drivers of E. coli ST131 pandemicity are not well-understood.
Figure 1. Prospective cohort study enrollment flowchart

Methods
Between February 2017 to November 2018, 34 hospitalized patients with E. coli positive cultures (including half with ST131-positive cultures) and their household coresidents were recruited to a prospective cohort study in which all household members provided up to 12 stool samples at 2-6 week intervals. The samples were screened for E. coli ST131 isolates using quantitative polymerase chain reaction (qPCR), and short-read whole genome sequencing (WGS) was conducted on all E. coli ST131-positive isolates.
Figure 2. Model estimates of E. coli ST131 acquisition rate and carriage duration

Results
Nine individuals (7.25%) carried E. coli ST131 for a median of 86.35 days [80% CrI: 30.03-188.8] (over three times higher than the cohort average of 27.33 days [80% CrI: 20.00-36.74]) and at high densities. The household coresidents of these individuals acquired E. coli ST131 at approximately twice the rate of those who did not coreside with a persistent high-density carrier (0.031 per day [80% CrI: .012-.10] and 0.016 per day [0.006-0.05], respectively; Odds Ratio: 2.61 [95% CI: 1.36 to 5.00] (p &lt; 0.01)). WGS analysis identified a high degree of sequence similarity between E. coli ST131 isolates obtained from different individuals and at multiple non-sequential timepoints in four of the nine families in which a high-density persistent carrier was resident, indicating potential repeated transmission events.

Multivariate and univariate regression analysis of risk factors associated with E. coli ST131 acquisition

Conclusion
These findings indicate that a proportion of high-density asymptomatic carriers in the community may act as reservoirs for E. coli ST131, with frequent transmission to household contacts representing a key driver of E. coli ST131’s pandemic success. Further studies in other settings are needed to understand high-density persistent carrier status and address this potential community-level reservoir in order to contain this multi-resistant pathogen and reduce its clinical impact.

Disclosures
Paul Tambyah, MBBS (S'pore), Diplomate, American Board of Internal Medicine and Infectious Diseases, Moderna: Grant/Research Support|Sanofi-Pasteur: Grant/Research Support
P-1325. Quality of Life and Severity of Symptoms in 1-year Follow Up of Patients Presenting with Acute Babesiosis: A Prospective Cohort Study with Validated Questionnaire
Authors: Zamor Rudline G , Maczaj Brigitte , Nath Sarath , Papamanoli Aikaterini , Maramara Bennadette , Lum Michael D , Zhang Xiaoyue , Yang Jie , Spitzer Eric , Mordue Dana , Marcos Luis A 
Published: January 2025

Abstract

Background
Tick-borne diseases are a growing public health concern in the US, particularly in New York. Babesia microti, a parasitic blood-borne piroplasm, causes the disease Babesiosis in humans. The aim of this prospective cohort study is to examine the frequency and severity of symptoms as well as the Quality of Life (QOL) after treatment in patients with Babesiosis (immunocompetent vs. immunocompromised) at up to 1-year of follow up.Table 1:Estimated ratio of VAS total score across time points within each immune group based on linear mixed effect model

Methods
Acute babesiosis adult patients with peripheral blood smear positive for Babesia (confirmed B. microti by PCR) were enrolled into a 1-year follow up cohort study. Twelve symptoms were evaluated by a Visual Analogue Scale (VAS) scoring system on presentation, and at 1, 6 and 12 months; higher scores represented worse status. QOL was assessed through a 36-Item Short Form Survey (SF-36) which taps eight health concepts; higher scores represented better status. Linear mixed-effects models were constructed to examine the change in VAS and SF-36 scores.Table 2:Estimated ratio of SF-36 concept score between immune groups at each time point based on linear mixed effect models

Results
Out of a total of 38 enrolled, 33 patients (mean age 60 ± 19 years; female 30.3%) completed their initial VAS. At baseline, fatigue had the highest frequency among all symptoms, 96.15% and 100%, in the immunocompetent and immunocompromised cohorts, respectively. Median VAS scores at baseline were 35.5 (immunocompetent, n=26) and 22.0 (immunocompromised, n=7). Compared to baseline, VAS total symptom scores significantly decreased at 1 month for the immunocompetent (n=20, p &lt; .0001) and immunocompromised groups (n=5, p=0.04). For SF-36 concepts, 29 patients completed the initial survey (immunocompromised, n=6). Within QOL, concept scores for physical functioning and general health were significantly increased at 6 months follow up in both cohorts. Nonetheless, in comparison to the immunocompetent group, the immunocompromised group had significantly lower scores, or worsened QOL, in general health concept at months 1 (p=0.04) and 6 (p=0.0004).

Conclusion
VAS scores significantly decreased for both groups, but more prominently for the immunocompetent group, and a difference in quality of life was identified. Immunocompromised patients had more prolonged symptoms and worsened quality of life during the 1-year follow up compared to healthy individuals.

Disclosures
All Authors: No reported disclosures
P-1329. Invasive Streptococcal Infections in People Experiencing Homelessness in Metro Atlanta — Fulton, DeKalb, and Cobb County, Georgia, 2010–2022
Authors: Scott Sarah E , Mosites Emily , Sefton Samantha , Thomas Stepy , Bezold Carla P , Farley Monica M 
Published: January 2025

Abstract

Background
People experiencing homelessness (PEH) are disproportionately affected by infectious diseases compared to people who are housed (non-PEH). In the western U.S., 9–25% of invasive pneumococcal disease (IPD) and group A Streptococcus (IGAS) cases are among PEH; disparities in IPD and IGAS by housing status are not well-documented in other regions.

Methods
Hospitalized IPD and IGAS cases among residents of 3 metro Atlanta counties (Fulton, DeKalb, & Cobb) ≥18 years occurring during 2010–2022 and their housing status at diagnosis were ascertained from the CDC-funded Georgia Emerging Infections Program. Recurrent cases ≤12 months apart were excluded. During 2010–2018, homelessness was defined by medical record documentation or residence in a shelter, mission, or medical respite. In 2019, the definition expanded to "unstable housing," which included transitional and single-room occupancy housing. Person-level case characteristics by housing status were calculated. Annual age-adjusted incidence per 100,000 population by housing status and incidence rate ratios with 95% confidence intervals were estimated using Poisson regression. Point-in-Time counts (PEH) and 2020 US Census data (non-PEH) were used as population denominators.

Results
During 2010–2022, 2,202 IPD cases in 2,119 people and 989 IGAS cases in 981 people were identified. Among people with IPD and IGAS, 88 (4%) and 55 (6%) were PEH, respectively (Tables 1–2). IPD and IGAS incidence rates were higher among PEH than non-PEH (Table 3). Among PEH with IPD, 65 (74%) were men and 81 (92%) were &lt; 65 years (vs. 1019 [50%] and 1320 [65%] in non-PEH). Among PEH with IGAS, 40 (73%) were men and 52 (95%) were &lt; 65 years (vs. 473 [51%] and 658 [71%] in non-PEH). PEH with IPD or IGAS were more likely to lack insurance. Both IPD and IGAS incidence among PEH increased before and after the homeless definition change; among non-PEH, incidence decreased (IPD) or was stable (IGAS) (Fig 1).

Conclusion
The rate of IPD and GAS cases was higher among PEH than non-PEH and increased during 2010–2022. IPD and IGAS cases among PEH occurred more frequently in men and people &lt; 65 years compared to non-PEH. Disparities in IPD and IGAS incidence by housing status exist within metro Atlanta and may be increasing. PEH should be prioritized in IPD and IGAS prevention efforts.

Disclosures
All Authors: No reported disclosures
P-1330. Knowledge of Lyme Disease and Prevention Practices Among Parents of Pediatric Patients in a Lyme-Endemic Area
Authors: Krishnan Sheila , Handel Andrew S 
Published: January 2025

Abstract

Background
Lyme disease (LD) is a growing public health concern in the US that disproportionately affects children and the elderly. Studies have also found that minority groups are more likely to present with later, severe manifestations of LD, suggesting missed opportunities for early diagnosis and treatment. Despite the prevalence, few assessments have been performed to measure tickborne disease knowledge among parents in endemic areas, including social determinants of health.Table 1.Respondents with Spanish language preference, household income &lt;$50,000, and highest education level of high school or below were more likely to misidentify the vector of Lyme disease or an image of the EM rash

Methods
An anonymous survey was conducted among parents/caregivers of patients at Stony Brook Children’s Hospital and its six ambulatory clinics in Long Island, NY (LI). The study was approved by the Stony Brook University Hospital IRB. Flyers were posted in patient rooms with QR codes linking to a Qualtrics™-based study, which displayed the informed consent statement and survey instrument. The flyers and survey were available in English and Spanish. Survey questions included demographics (income, level of education, etc), knowledge assessment (including identification of ticks as a vector and the erythema migrans (EM) rash), and tick bite prevention practices. Proportions were compared using χ2 tests.

Results
78 respondents completed the survey, including 68 (87%) in English and 10 (13%) in Spanish. 12 (15%) reported living on LI for &lt; 5 years, and 17 (22%) reported household income &lt; $50,000, while 7 (9%) reported household income below $20,000. 21 (27%) reported highest level of education as high school. 18 (26%) did not correctly identify ticks as the vector for LD, while 14 (21%) did not correctly identify an EM. Respondents with Spanish preference, household income &lt; $50,000, and highest education level of high school or below were more likely to misidentify the vector of Lyme disease or an EM image (Table 1).

Conclusion
Knowledge of LD remains limited, even in endemic areas. This is more pronounced in those with lower income, education, and Spanish preference. Culturally and linguistically appropriate public health outreach should focus on education about disease transmission and early recognition.

Disclosures
All Authors: No reported disclosures
P-1332. Estimates of Waning Influenza Vaccine Effectiveness Against Laboratory-Confirmed Influenza in California, October 2023–March 2024
Authors: Zhu Sophie , Quint Joshua , León Tomás M , Sun Monica , Li Nancy , Tenforde Mark W , Jain Seema , Schechter Robert , Hoover Cora , Murray Erin 
Published: January 2025

Abstract

Background
Annually, an estimated 9.3 to 41 million persons experience influenza illness in the United States. Vaccination protects against influenza and associated complications, and vaccine effectiveness (VE) varies between and within seasons. Identifying declines in VE can guide appropriate public health actions. Mandatory influenza vaccine reporting to California’s immunization information system began January 1, 2023, and all influenza laboratory testing results, including negative results, were reportable starting June 15, 2023. We calculated VE of seasonal influenza vaccines against laboratory-confirmed influenza over time using public health data reported to the California Department of Public Health (CDPH).
Influenza vaccine effectiveness by time since vaccination (days) using mandatory reported California influenza laboratory and immunization data, October 2023–March 2024

Methods
We included influenza laboratory surveillance data for all persons aged ≥6 months during October 1, 2023–March 31, 2024, and immunization data during August 1, 2023–March 31, 2024. VE for laboratory-confirmed influenza was calculated using a case control design as 100% x (1 – adjusted odds ratio [aOR]); aOR was odds ratio of vaccination among case-patients that received a positive influenza test result versus control-patients that received a negative influenza test result. Using mixed-effects logistic regression, estimates were adjusted for age, ethnicity, and race as fixed effects; specimen week and county of residence were random effects. Estimates were stratified by time since vaccination.

Results
Overall, 18% of case-patients were vaccinated versus 31% of control-patients. Median time since vaccination was 85 days (range: 14–241 days) for cases and 87 days (range: 14–241 days) for controls. VE through March 31, 2024, was 43% against laboratory-confirmed influenza among persons aged ≥6 months. VE was 59% for persons vaccinated 14–29 days before their influenza test result; 52% for 30–59 days; 39% for 60–89 days; 34% for 90–119 days; and 35% for ≥120 days. Stratified by calendar month of testing, VE similarly declined with increasing time since vaccination.

Conclusion
Influenza vaccination reduced the risk of testing positive for influenza, but VE declined with time after vaccination. Timing immunization for maximum protection during periods of higher risk, along with additional preventive measures, might further reduce incidence.

Disclosures
All Authors: No reported disclosures
P-1334. Assessment of Immunity Gaps and Determination of Optimal Age for Measles-Containing Vaccine Booster Dose in Measles-Endemic Country
Authors: Ngamprasertchai Thundon 
Published: January 2025

Abstract

Background
Despite highly measles immunized countries, immunity gaps in adolescents and young adults are a key issue posing an obstacle to measles elimination. This study aims to identify the gaps by estimating the probability of age-stratified seropositivity and optimal age for measles-containing vaccine (MCV) booster administration to effectively fill the gaps in an endemic country.

Posterior (blue) vs empirical (gray) age-stratified seroprevalence curves. Posterior error
bars correspond to 95% credible intervals, while empirical error bars indicate 95% confidence intervals
generated using bootstrap resampling over 1000 iterations.

Methods
We retrospectively obtained measles serological results among individuals aged 13 to 39 years from multi-centre hospital between January 2018 and December 2021 in Thailand. We developed a dynamic probability model, stratifying seropositivity due to vaccination or natural infection. We calibrated the model to age-stratified seropositivity data within a Bayesian setting using the Metropolis-Hastings algorithm. A scenario analysis to determine the most effective age for MCV booster administration was also performed.

Posterior median estimates for individual serostatus in the year 2020, stratified by age.

Results
The overall prevalence of measles seropositivity was 65.6% (N=543). Young adults (aged 21 to 30 years) displayed the lowest seropositivity at 59.3% (N=208) while individuals aged 31 to 39 years demonstrated the highest seropositivity at 87.3% (N=158). The average duration of vaccine induced immunity was estimated to be 16.0 years (95% credible interval (CI), 11.1 to 21.0 years); while natural exposure immunity was estimated to be lifelong. Posterior curves for the age-stratified seroprevalence (Figure 1A) exhibited a decreasing trend from ages 14 to 20 years but an upward trend from 26 to 30 years. The relative contribution of vaccine or natural exposure caused seropositivity was estimated for individuals stratified by age in the year 2020 (Figure 1B). The age at which a given individual’s serostatus reached a 50% probability of negativity was found to be approximately 20 years depending on measles circulation (Figure 1C).

Age at which a given seronegativity threshold is reached. Posterior medians (based on 1000
parameter combinations sampled uniformly at random without replacement) are shown with solid lines;
ribbons indicate 95% credible intervals.

Conclusion
Our findings highlight young adults aged 21 to 30 years as significant gaps in measles immunity, posing an increased risk of transmission. A single MCV booster dose at the age of 20 years potentially closes the gap and enhances measles elimination programmes.

Disclosures
All Authors: No reported disclosures
P-1345. Risk Factors for Ceftriaxone Resistant E. coli or K. pneumoniae Infections in Floor Patients
Authors: Westerkamp Holly , Knack Olivia , Adams Jenna , Albarillo Fritzie S 
Published: January 2025

Abstract

Background
In 2019, 1.3 million deaths worldwide were linked to antimicrobial resistant organisms. Resistant organisms are associated with poor outcomes including increased mortality and length of stay (LOS). Identification of local risk factors predisposing for resistant organisms can lead to rapid antimicrobial optimization.
Patient Population

Methods
In this retrospective, single center, observational cohort study, floor patients with ceftriaxone (CRO) resistant E. coli or K. pneumoniae via broth microdilution were screened from January 2022 to October 2023. Exclusion criteria included urine isolates, extended spectrum beta-lactamase (ESBL) or CRO resistant E. coli or K. pneumoniae isolate within 6 months of index culture, and intensive care unit (ICU) admission at time of index culture. The primary outcome was to identify risk factors for CRO resistant E. coli and K. pneumoniae in floor patients. Secondary outcomes included 14-day all-cause mortality, ICU admission rate, hospital LOS, and 30-day readmission rate. A list of patients was generated via MedMined™. REDCap™ was used for data collection. All statistical analyses were performed using IBM SPSS™. Significance was defined at p&lt; 0.05.
Multivariate Logistical Regression

Results
118 patients were included in the statistical analyses. The following risk factors found to be statistically significant were: fluoroquinolone (FQ) (p&lt; 0.01), ceftriaxone (CRO) (p&lt; 0.01), or sulfamethoxazole-trimethoprim (SMX-TMP) (p&lt; 0.01) use within 90-days of index culture; chronic obstructive pulmonary disease (p=0.01); ventilator or tracheostomy use at admission (p=0.03); active hematologic malignancy (p=0.01); poor functional status at admission (p=0.02); percutaneous endoscopic gastrostomy tube at admission (p=0.01); admission from a skilled nursing facility (SNF) (p=0.01). The significant risk factors were included in the multivariate logistic regression. FQ use (95% CI 0.98-16.35, p=0.05), SMX-TMP use (95% CI 2.08-29.24, p&lt; 0.01), hematologic malignancy (95% CI 1.40-129.36, p=0.02), and admission from a SNF (95% CI 1.29-36.27, p=0.02) were found to meet statistical significance.

Conclusion
FQ use and SMX-TMP use within 90-days of index culture, hematologic malignancy, and admission from a SNF were found to be independently associated with ceftriaxone resistance.

Disclosures
All Authors: No reported disclosures