bluuebunny/crossref_metadata_2025 huggingface dataset:
P-1296. Community-acquired methicillin-resistant Staphylococcus aureus infections: 1 year of surveillance in 6 pediatric centers
Authors: Gentile Angela , Bakir Julia , Firpo Maria Veronica , Juarez Ximena S , Cancellara Aldo , Tapponnier Gabriela , Tinnirello Agostina , Lopez Oscar , Lopez Leandro , Pejito Maria Natalia , Papucci Santiago Lopez , Ensinck Gabriela
Published: January 2025

Background

Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) infections is emerging in the world and can have a serious evolution. The objective of this study were to study the hospitalization rate, the clinical-epidemiological and bacteriological pattern and the case fatality risk factors of CA-MRSA infection.

Methods

Cross-sectional observational epidemiological study, with prospective data capture. All patients ≤ 15 years of age with community-acquired Staphylococcus aureus (CA-SA) infection hospitalized in 6 pediatric sentinel units, between January and December 2023, were included. The rate of CA-MRSA cases per 10,000 hospital discharges was calculated. with 95 % confidence interval (95 % CI).

Results

Of a total of 201 patients with CA-SA infection, 131 (65.2 %) were CA-MRSA. The global hospitalization rate for CA-MRSA cases was 27.8 (23.3-32.9), with a higher rate in < 2 years 37,7 (27,9-49,8). Of the 131 cases: 56.5 % were male, median age 48.8 months (IQR 16.4-90.4), ≥ 2 years 64.9%, complete vaccination card 77.0 %, low socioeconomic level 54.2 %, overcrowding 15.3 %, underlying disease 29.0 %, passive smoking 24.4 %. The clinical presentations were (n; %): skin and soft tissue infection (SSTI 101; 77.1 %), arthritis (17; 13.0 %), osteomyelitis (12; 9.2 %), pneumonia (16; 12.2 %; 14 with pleural effusion and 3 necrotizing), sepsis (11; 8.4 %), bacteremia (4; 3.1 %), meningitis (1; 0.8 %). Conventional microbiological diagnosis was performed in 130 cases and molecular diagnosis in one. 4 cases had coinfection with group A beta hemolytic Streptococcus. Antibiotic resistance was for erythromycin 43.1 %, clindamycin 26.0 %, gentamicin 19.9 %, TMP-SMX 1.5 %. All strains were susceptible to vancomycin. Fatality rate: 1.5 % (2/131). No deceased case had an underlying disease. 18.2 % (2/11) of sepsis cases died (2-tailed Fisher exact p 0.006), however, there was no significant association in the multivariate analysis.

Conclusion

The high burden of CA-MRSA infection, the most common clinical form of SSTI, and the high profile of antibiotic resistance, highlight the importance of continuous clinical surveillance and alert for these infections.

Disclosures

All Authors: No reported disclosures
P-1306. Establishing Respiratory Syncytial Virus (RSV) Surveillance Methodology within the Indian Health Service
Authors: Desai Keya , Apostolou Andria , Houghton Sarah , Chukwuma Uzo
Published: January 2025

Background

American Indian and Alaska Native (AI/AN) populations have high rates of Respiratory Syncytial Virus (RSV)-associated hospitalizations among both infants and older populations. Due to underrepresentation, most national surveillance reports do not adequately describe the burden of disease in the AI/AN population. Currently, there is no standardized approach for RSV surveillance within the IHS. This work explores establishing RSV surveillance using IHS-specific electronic medical records (EMR) data. Additionally, this work aims to implement a standardized surveillance methodology across IHS for RSV and adaptable for other infectious diseases. The objective of this abstract is to describe the process of RSV surveillance methodology within the IHS.

Venn diagram of ICD and LOINC datasets

The above image is a representation of the Venn diagram of ICD and LOINC datasets. The two datasets are merged together to identify the overlapped records and unique ICD and LOINC records for RSV.

Methods

We investigated the utility of using administrative data from Federal, Tribal, and Urban Indian health facilities for RSV surveillance among AI/AN population for Fiscal Year (FY) 2023. We evaluated RSV administrative codes, such as Logical Observation Identifiers Names and Codes (LOINC), International Classification of Diseases (ICD) 9 and 10, to develop an algorithm for RSV records. The records that contained either an ICD 9 or ICD 10 code for RSV came from the ICD dataset; records that contained RSV-specific LOINC code came from the LOINC dataset. Final set of records were flagged as positive and negative RSV records.Table 1.Distribution of unique LOINC records by the type of tests

The table shows the distribution of the unique LOINC records by the four categories of type of tests. The categories include PCR, Antigen, Antibody and Culture tests.

Results

In FY 2023, 16396 records came from the ICD dataset and 151542 records came from the LOINC dataset. On merging ICD and LOINC datasets, 4623 records overlapped, 11830 records were unique to ICD dataset and 146959 records were unique to LOINC dataset. Of the records unique to LOINC dataset (146959), 81% (n=119698) represent PCR tests while antigen (n=13722) and antibody (n=13384) tests represent 9% respectively.

Conclusion

This study highlights the importance of using both ICD and LOINC codes for identifying RSV cases in EMR. It aids in understanding trends and burden among AI/AN population. Currently, we are conducting site validations to evaluate the surveillance methods across IHS. Additionally, surveillance reports and epidemiological studies generated using this standard approach could help target interventions for RSV and other infectious diseases.

Disclosures

All Authors: No reported disclosures
P-1307. AI-Optimized Assessment of Vaccination Strategies in Smallpox Reemergence: an LA Case Study
Authors: Learoyd Tristan , Pittman John E
Published: January 2025

Background

The resilience of Los Angeles (LA) to smallpox was evaluated using a modified Susceptible, Exposed, Infectious, Recovered, Hospitalized, Deceased (SEIRHD) model, which simulated its spread via an artificial intelligence (AI) mobility matrix and assessed different vaccination regimens (one dose primary series vs a two dose primary series) for outbreak control.

Methods

The matrix combined data from travel surveys, transportation authorities, GPS caches, and population density estimates from LA County. Fifteen LA government districts plus a 30-mile radius city limit were considered for differential force of infection and mobility matrix variables. Transmission parameters, derived from a review of 20th-century epidemics, assigned 90% transmission to households and 80% to workplaces. Residual immunity against smallpox was set at 8.8%. Intensive care unit (ICU) capacity within 30 miles of LA city limits was set as 2,500 beds per the California Health and Human Services Open Data Portal. One and two dose ring vaccine regimens initiated at day 7 were assessed in 16 districts and as a dispersed city model to understand zonal resilience in eradication and if contagion exceeded ICU capacity limits via an R-programed scenario.

Results

The naïve general scenario had an infection peak at day 73, with a hospitalization peak of 5,600,227 (day 80) of a susceptible population of 18,833,640. With a 50% effective one dose vaccine, contagion remained below the ICU threshold in the basic 30-mile radius model. However, in specific districts (1, 6-9, and 13-15), even a 95% effective one dose vaccine couldn’t maintain contagion below the ICU threshold according to the AI-assisted zonal model. Hypothetical one dose primary series vaccination regimens outperformed two dose regimens in both city-wide and zonal scenarios (P< 0.05). Zonal analysis based on housing conditions and mobility revealed that even with the most effective hypothetical one dose vaccine (95% efficacy after 7 days), 7 out of 15 LA district ICU thresholds were exceeded, indicating the importance of geospatial modelling.

Conclusion

The model highlights the importance of zone-based evaluations in preparedness and the need for high-efficacy single-dose vaccinations in ring vaccination.

Disclosures

Tristan Learoyd, MPharm MA MSc MBA PhD MRPharmS, Emergent: Employee John E. Pittman, PharmD, Emergent: Employee
P-1308. Survey of U.S. Hunters: Behaviors that May Increase Exposure to Chronic Wasting Disease
Authors: Boney Colton P , Lindenmuth Connor R , Trapp Nicholas J , Milbert Kevin J , Moore Tony L , Parker Robert W
Published: January 2025

Background

Chronic Wasting Disease (CWD) is caused by a prion leading to transmissible spongiform encephalopathy primarily in members of the Cervidae family such as deer, elk, and moose. At this time, there is insufficient data to suggest possible zoonosis. Although there have been no recorded cases of CWD in humans, studies have shown that squirrel monkeys (Saimiri sciureus) are susceptible to transmission of CWD in a laboratory setting. The goal of this survey was to collect and examine data about safe handling practices, awareness of CWD, testing use, and meat consumption among United States hunters.

Methods

The survey included questions regarding basic demographics, butchering, taxidermy, awareness of CWD, testing frequency/behaviors, and barriers to testing. Participants were recruited through state organizations as well as hunting/outdoors-associated social media pages. Hunters of deer, elk, or moose were invited to participate in the study if they had harvested one of those game species in the past five years. States were grouped in accordance with CDC-described regions to compare for statistical trends among the data.

Results

125 individuals participated in the survey. The majority consumed meat from all (82%) or most (9.6%) of their game. Respondents commonly tested none (67%) or some (20%) of the meat they consumed. Though 33.1% tested their harvest for CWD, 58% of those who tested did not wait for CWD test results before consuming the meat. In addition to meat consumption, 66% used meat processing plants, 86% participated in field dressing, and 41% taxidermized their animals at home. Barriers to testing included the belief that CWD was not in their respective area (44%) or that they did not have access to testing equipment and/or other resources (39%).

Conclusion

The survey highlighted that hunters who frequently consume meat from members of the Cervidae family in states with CWD are not frequently testing due to poor accessibility and lack of data monitoring endemic spread. This may lead to increased exposure risk for those unaware of the illness or believe that CWD is not in their game populations. More data is needed to understand the full extent of exposure risk as transmission risk of CWD to humans is further researched.

Disclosures

All Authors: No reported disclosures
P-1312. MPox Seroprevalence and Seroincidence among People who Inject Drugs in the Mexico-U.S. Border Region
Authors: Rimoin Anne , Halbrook Megan , Artamanova Irina , Panayampalli Subbian Satheshkumar , Townsend Michael , Priyamvada Lalita , Carson Will , Abramovitz Daniela , Chaillon Antoine , Smith David , Harvey-Vera Alicia , Vera Carlos F , Skaathun Britt , Strathdee Steffanie , Das Nabojeet , Rangel Gudelia
Published: January 2025

Background

We assessed seroprevalence and seroincidence against orthopoxvirus (OPXV) among people who inject drugs (PWID) in the U.S./Mexico border region during the COVID-19 pandemic.

Methods

Between 09/21-11/23, PWID who lived in either San Diego (SD; N=129) or Tijuana (TJ; N=343) underwent a baseline and follow-up visit involving interviewer-administered surveys and venipuncture. Sera were batch tested at the U.S. Center for Disease Control and Prevention using an OPXV generic IgG ELISA using JYNNEOS® vaccine as the viral antigen. Optical densities (OD) ≥0.1 were conservatively considered seropositive. Mpox seroprevalence was assessed after excluding known sources of anti-OPXV antibodies

Results

Of 472 participants enrolled, median age was 45 (IQR:38-53), 72.9% were male (3.2% of whom reported sex with men), 11.3% had HIV and 25.8% were unhoused. Although no symptoms consistent with Mpox were reported during the study, 50 (10.6%) had seropositive results at baseline, follow-up or both. Baseline OPXV seroprevalence was 19.4% in SD and 3.2% in TJ, and Mpox seroincidence was 8.97 (95%CI:4.09-13.85) per 100 person-years in TJ vs. 1.81 (95%CI: 0.00-5.35) in SD, with a median of 5.8 months of follow-up (IQR: 4.53 – 6.31 months). Excluding participants who reported Mpox vaccination (N=3), smallpox vaccination (N=73), or those born prior to 1971 who could have received smallpox vaccination (N=140), likely Mpox seroprevalence was 7.8% (23/296), with 13/23 seronegative at baseline but seropositive at follow-up. Of these 13 seroconveters, 5 were female of whom 2 were HIV+.

Conclusion

These preliminary data suggest a undetected Mpox circulation in the Mexico-U.S. border region between 2022 and 2023 and that asymptomatic or mildly symptomatic Mpox infection may be more common than previously recognized. Although the clinical implications of these findings remain unclear, expansion of Mpox vaccination to PWID may be warranted.

Disclosures

David Smith, MD, MAS, Bayer: Advisor/Consultant|Gilead: Advisor/Consultant|Model Medicines: Advisor/Consultant|Red Queen Therapuetics: Advisor/Consultant
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

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: < 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

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 < 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

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 < .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

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 < 65 years (vs. 1019 [50%] and 1320 [65%] in non-PEH). Among PEH with IGAS, 40 (73%) were men and 52 (95%) were < 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 < 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

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 <$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 < 5 years, and 17 (22%) reported household income < $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 < $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

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

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

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< 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< 0.01), ceftriaxone (CRO) (p< 0.01), or sulfamethoxazole-trimethoprim (SMX-TMP) (p< 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< 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
P-1365. Cefazolin Inoculum Effect in Methicillin Susceptible Staphylococcus aureus Recovered From the Nasal Cavity of Patients in Intensive Care Units in Colombia
Authors: Rincon Sandra , Carvajal Lina Paola , Ibarra Laura , Cadavid Maria José , Uribe Mauricio , Matiz Juan , Ordonez Diaz Karen M , Guevara-Pulido Fredy , Porras Alexandra , Ospina Leonardo , Mendez Yardany , Greenia Haley , de Paula Baptista Rodrigo , Arias Cesar A , Reyes Jinnethe
Published: January 2025

Background

Cefazolin is an alternative for the treatment of MSSA infections and first choice option for surgical prophylaxis. The cefazolin inoculum effect (CzIE), the increase in the MIC at high bacterial inocula is associated to therapeutic failures and increased mortality in deep-seated MSSA infections. The prevalence of the CzIE among nasal colonizing MSSA from ICU patients is currently unknown. The aim of this study was to investigate the CzIE in nasal MSSA recovered from patients admitted to ICUs in Colombia.

Methods

We evaluated 33 MSSA isolates recovered from nasal swabs of 29 patients admitted to ICU at 6 high-complexity Colombian hospitals (2019-2023). CFZ MIC using gold standard broth microdilution at high inoculum was done. The modified nitrocefin-based rapid test to identify the CzIE was performed, and diagnostic performance metrics were calculated. Whole genome sequencing was used to characterize BlaZ types and allotypes, Clonal Complexes CC and Accessory Gene Regulator (Agr) types.

Results

The CzIE was identified in 54.5% of nasal MSSA isolates. A high prevalence of nasal colonization with MSSA exhibiting the CzIE was detected (59%, 17 patients). Among 18 MSSA with the CzIE, type A BlaZ was the predominant β-lactamase (61%) and BlaZ-2 was the most common allotype (50%). Whereas among 15 MSSA lacking the CzIE, BlaZ type C was the most frequent (47%) and BlaZ-1 was the allotype predominant (40%). A high diversity of genetic lineages with eight CC was detected among the 33 MSSA. CC30 was the predominant lineage in MSSA displaying the CzIE (44%), while CC5 and CC30 (27% each one) were the most common in MSSA without the CzIE. Agr-III and Agr-I were predominant Agr types in 56% and 47% of MSSA with the CzIE and lacking the CzIE, respectively. Compared to the gold standard the modified rapid test identified nasal MSSA isolates showing the CzIE with a sensitivity of 100%, specificity of 93% and an overall accuracy of 97%.

Conclusion

We found an unexpected high prevalence (59%) of ICU patients colonized by MSSA exhibiting the CzIE, showing similar genetic features to MSSA with CzIE from invasive infections. Furthermore, our findings suggest that the nasal cavity of ICU patients may represent a reservoir for the dissemination of MSSA showing the CzIE, highlighting the importance of screening and surveillance.

Disclosures

All Authors: No reported disclosures
P-1377. Rates of Screening of Sexually Transmitted Infections in Male Military Trainees who Present with Dysuria
Authors: Malone Catherine Sophia , Osuna Angela , Winkler Erin , Jung Ga O , Yun Heather , Marcus Joseph
Published: January 2025

Background

A high burden of sexually transmitted infections (STIs) exists among trainees entering United States Air Force Basic Military Training (BMT). While women entering training are universally screened for STIs, men, who account for the majority of trainees, are rarely tested. The rates of testing among symptomatic men who present with dysuria during BMT are unknown. Furthermore, rates of follow-up testing among male service members who present with dysuria during BMT are unknown.

Demographics of 82 men diagnosed with dysuria or urinary tract infection during BMT, 2019-2023

Methods

All male basic trainees who received a diagnostic code of dysuria or urinary tract infection between 2019-2023 were retrospectively analyzed to evaluate their diagnostic workup and follow-up over the three years after diagnosis. To assess the impact of presumptive STI therapy on subsequent follow-up, patients who received empiric treatment for STIs were compared to those who did not, with a focus on evaluating future STI testing rates and incidence. Nominal variables were compared using Fisher’s Exact Test while continuous variables were analyzed using the Mann-Whitney U test.

Diagnostic Workup and follow-up for male basic trainees diagnosed with dysuria or urinary tract infection compared by receipt of empiric antibiotics for sexually transmitted infections

Results

Of the 102,382 men who entered BMT during the study period, 82 (0.08%) were diagnosed with dysuria or a urinary tract infection during training. Dysuria accounted for the majority of diagnoses (79%) (Table 1). 70% of symptomatic men were tested for gonorrhea and chlamydia (GC/CT). Among those tested, 23% had a positive GC/CT test. Only 25 (30%) received any additional follow-up STI testing in their next 3 years in the military, with a positivity rate of 12%. Those who were empirically treated for STIs were more likely to have a documented sexual history (80% vs. 45%, p=0.004), receive a GC/CT test (96% vs. 57%, p=0.002), and have additional STI testing in the 3 years after diagnosis (46% vs. 23%, p=0.04) (Table 2).

Conclusion

There is limited data on the diagnostic workup and follow-up of men presenting with symptoms of dysuria during BMT. This study found that despite a high positivity rate for STIs in symptomatic men, sexual history documentation and STI screening were inconsistent in this population. As males account for the vast majority of basic trainees, efforts to accurately capture the burden of STIs are imperative to limit the impact on military populations.

Disclosures

All Authors: No reported disclosures
P-1382. Utilization of Doxycycline Post-Exposure Prophylaxis at a Midwestern United States HIV/PrEP Clinic
Authors: Codling Gabriel , Havens Josh , Lyden Elizabeth , Bares Sara H , Scarsi Kimberly , Sunagawa Shawnalyn
Published: January 2025

Background

Limited real-world data exist regarding usage of doxycline post-exposure prophylaxis (doxyPEP). We evaluated appropriate doxyPEP prescribing and monitoring following implementation of a doxyPEP protocol at the University of Nebraska Medical Center (UNMC) Specialty Care Clinic.

Methods

We retrospectively evaluated patients receiving doxyPEP between 3/1/2023-2/29/2024. Patients receiving doxycycline for other indications were excluded. The primary outcome was adherence to the UNMC doxyPEP protocol. Secondary outcomes included total doxyPEP doses prescribed, sexually transmitted infection (STI) incidence in the doxyPEP cohort compared to 2023 UNMC STI incidence, and factors associated with protocol adherence or STIs while prescribed doxyPEP. We performed descriptive statistics for cohort characteristics and outcomes. Fisher’s exact test or student t-test was used to assess associations of patient characteristics with protocol adherence or STIs while on doxyPEP.

Results

Characteristics of the cohort and prescriptions are listed in Table 1. Primary and secondary outcomes are reported in Tables 2 and 3. Of 90 patients receiving doxyPEP prescriptions, 30% were not prescribed in concordance with UNMC protocol; the most common reason was missed STI screenings (89%). There were 145 chlamydia/gonorrhea (CT/GC) and 163 syphilis screenings obtained from 90 patients; 13% of the patients on doxyPEP were diagnosed with an STI. Between patients prescribed doxyPEP and 2023 UNMC STI incidence, there was no difference in incidence of GC/CT (p > 0.05); however, syphilis incidence was lower (p=0.01) in patients on doxyPEP. There were no characteristics associated with doxyPEP protocol adherence. Age, reason for care, and number of STIs within 12 months of first doxyPEP prescription were significantly associated with an STI diagnosis while on doxyPEP.

Conclusion

Appropriate doxyPEP prescribing patterns occurred for 70% of prescriptions; missed STI screenings was the most common reason for protocol non-adherence. Patients with HIV and with > 1 STI in the past 12 months were more likely to be diagnosed with an STI while on doxyPEP. As utilization expands, it is necessary to ensure appropriate follow-up and monitoring.

Disclosures

Josh Havens, PharmD, Gilead Sciences: Grant/Research Support|Medscape: Advisor/Consultant|ViiV Healthcare: Advisor/Consultant Sara H. Bares, MD, Gilead Sciences: Expert Testimony|Janssen: Grant/Research Support|ViiV Healthcare: Grant/Research Support Kimberly Scarsi, PharmD, Organon, Inc.: Grant/Research Support|Viiv Healthcare: Grant/Research Support
P-1398. Implementation of a Doxycycline for Post-Exposure Prophylaxis Protocol at a Large Academic HIV Clinic
Authors: Pellegrino Rachael , Lokant Matthew , Patel Nishant , Vojtek Christina , Jagadeesan Priya , Ito Andrea , Merkhofer Richard M , Moore Emily , Reasoner Kaitlyn , Zou Michael , Katona Austin , Turner Megan , Zhang Jim , Terndrup Christopher , Kelly Sean , Smiley Casey
Published: January 2025

Background

The use of doxycycline post-exposure prophylaxis (DoxyPEP) lowers the incidence of gonorrhea, chlamydia, and syphilis in men who have sex with men and transgender women living with HIV or taking pre-exposure prophylaxis (PrEP) for HIV. We aimed to implement a standardized protocol to increase the number of appropriate DoxyPEP prescriptions and decrease bacterial sexually transmitted infections (STI) in our clinic population.

Methods

Based on existing evidence, a DoxyPEP clinic protocol and flowchart (Figure 1) were developed and implemented in November 2023 at an academic clinic providing HIV and PrEP services. Interventions included provider education and display of the flowchart in clinical workspaces. The number of new DoxyPEP prescriptions was collected by chart review for the 10 months prior to and 5 months after implementation and compared by t-test. Baseline patient characteristics and STI diagnoses for the clinic population living with HIV were described. Pre- and post-implementation surveys were used to assess provider practices and comfort with DoxyPEP prescribing.

Results

Of persons with HIV prescribed DoxyPEP in the pre-implementation period, 72.1% had at least 1 bacterial STI and 34.4% had >1 bacterial STI in the preceding 10 months (Table 1). There were significantly more DoxyPEP prescriptions (p< 0.001) in the 5-month post-implementation period [148 new prescriptions, 29.6/month] compared to the 10-month pre-implementation period [70 new prescriptions, 7/month] (Figure 2).

Post-implementation, there was an increase in providers who felt comfortable or very comfortable counseling a patient on DoxyPEP (86% vs 60%) and assessing a patient’s eligibility for DoxyPEP (85% vs 60%). Most respondents (86%) reported use of the protocol, and of these providers, all reported it easy or very easy to use. Nine of the fourteen DoxyPEP prescribers (64.3%) in the post-implementation period had not prescribed DoxyPEP prior to the intervention.

Conclusion

Implementation of a standardized DoxyPEP protocol using education and updated policy increased providers’ comfort with and prescribing of DoxyPEP and can help inform future implementation efforts. Further assessment of post-implementation STI rates and patient characteristics are planned.

Disclosures

Sean Kelly, MD, ViiV: Advisor/Consultant