Positive Cultures Research Articles

P-998. A multi-center observational study in Northern Italy to evaluate the impact of Sepsis bundle in Obstetric Settings: the SOS study

Abstract Background Maternal sepsis presents challenges in early detection and treatment. A pregnancy-specific sepsis scoring system (MEOWS) and management bundles for pregnant septic patients were recently introduced, but there is a lack of data on their effectiveness. Our study aims to assess the impact of implementing a Lombardy sepsis bundle for septic pregnant and puerperal patients.Table 1:Demographic and clinical data of the patients included Methods The SOS, a retrospective multicenter study across 7 Lombardy Hospitals, focuses on adult pregnant and puerperal women diagnosed with sepsis according to SCC [1]. Medical records from 2 periods were analyzed: pre-bundle implementation (May 2015 - May 2018) and post-bundle implementation (Jan 2019 - Jan 2022). The primary outcome was to describe clinical and microbiological data, while the secondary outcome was to evaluate the impact of the Sepsis bundle on the length of stay (LOS), the timing of antibiotic treatment, and the rate of positive blood cultures (BCs). Results Eighty patients (24 in the pre-bundle and 56 in the post bundle period) were found (Table 1). Overall, median age was 31 years, they had few underlying comorbidities and mostly were pregnant (rather than puerperal) in the moment of sepsis occurrence (Table 2). More than half of the post-bundle patients had a high MEOWS score (62%) and an mSOFA score of more than 1 (70%) (tablee 2). Microbiological data are detailed in Table 3, while outcome data in Table 4. No significant differences were found in the rate of positive BCs (p=1) between the 2 periods. Similarly, the rate of antibiotic treatment started before BCs collection, and the LOS did not significantly differ (p=0.40). However, in the post-bundle period there were both a marked increase in infectious disease (ID) consultations (p=0.003), and a reduction of neonatal Intensive Care Unit admission (p=0.013). Conclusion While the bundle did not significantly improve maternal outcomes, it led to an increased number of ID consultations, providing a more comprehensive understanding of sepsis severity, and a consequent reduction of neonatal severity conditions. Disclosures All Authors: No reported disclosures

P-1285. Particularities Of Non-Osteoarticular Brucellosis In Comparaison With Osteoarticular Cases

Abstract Background Osteoarticular (OA) brucellosis represent the most frequently described form of the sub-acute brucellosis. We aimed to study the clinical, laboratory and evolutionary features of non-osteoarticular (NOA) brucellosis in comparaison with OA cases. Methods We conducted a retrospective study including all patients hospitalized in the infectious disease department for sub-acute brucellosis between 1995 and 2022. Standard agglutination test titer > 1/160 and/or positive blood cultures to Brucella spp confirmed the diagnosis of brucellosis. Results We encountered 108 cases among which 30 cases had NOA brucellosis (27.8%). In total, NOA cases included neurobrucellosis (60%), Brucella endocarditis (23.3%) and genitourinary brucellosis (16.7%). Patients with NOA were significantly younger (30[21-44] years vs 52[37-60] years; p< 0.001). Vomiting (30% vs 2.6% ; p< 0.001) and nausea (16.7% vs 3.8%; p=0.036) were significantly more frequent among NOA cases, while night sweats (46.7% vs 70.5%; p=0.021) was significantly less frequent among NOA cases. Fever (86.7% vs 80.8%; p =0.471), weight loss (24.1% vs 38.5%; p= 0.166), myalgia (13.3% vs 23.1%; p=0.26) and asthenia (53.3% vs 44.9%; p=0.43) were noted among NOA and OA cases. Hepatomegaly was significantly more frequent among NOA cases (13.3% vs 2.6% ; p=0.049). A negative C-reactive protein (67.9% vs 24.2%; p< 0.001) and a normal erythrocyte sedimentation rate (75% vs 50.7%; p=0.027) were significantly more frequent among NOA cases. Leucopenia (6.7% vs 7.8%; p=1), thrombopenia (13.3% vs 6.4%; p=0.244) and hepatic cytolysis (6.7% vs 10.3%; p=0.723) were noted among NOA and OA cases. Treatment duration was significantly shorter among NOA cases (4[3-6] months vs 6[4-9] months; p< 0.001). Sequelae were significantly less frequent among NOA cases (3.3% vs 20.8%; p=0.37). A favorable disease evolution (83.3% vs 90.9%; p=0.311) and relapse (3.3% vs 9.1%; p=0.437) were noted among NOA and OA cases. Conclusion Clinical presentation of NOA brucellosis included vomiting and nausea more frequently, the presence of hepatomegaly and the absence of inflammatory markers, among younger patients. The treatment duration was significantly shorter in comparaison with OA brucellosis cases. Disclosures All Authors: No reported disclosures

P-1684. Characterization of Bacteremia and de-escalation practices among 13 public hospitals in Chile: Results from the 2022-2023 Chilean PPS

Abstract Background Antimicrobial resistance (AMR) is a global concern. Collecting data and implementing interventions to optimize antimicrobial (AM) use has significant potential to lower AMR.There is no information in Latin American Region on how prescribers are using data from positive blood culture results to de-escalate AM. We present a sub-analysis of the 2022-2023 Latin-PPS performed in Chile including the characterization of bacteriemia and de-escalation practices. Antimicrobial distribution to treat bacteremia Methods 13 public hospitals joined the Latin-PPS group. This PPS is based on the WHOPPS methodology. Each hospital conducted a survey in which everyday data from AM prescriptions was collected by ward. We include only patients that received AM related to documented bacteremia. The purpose of this study is to describe the etiological agents that caused bacteremia, AM use and compare the blood culture result with appropriate AM prescription. Most common etiological agents and antimicrobials used. Results Chilean PPS included 3,342 beds, where 1302 AM treatments were given and 1,928 AM were administered to a national prevalence of 38.84%. Bacteremia is the 6th most common diagnosis related to AM use and corresponds to 3,76% . We found 49 bacteremia episodes, 9 occurred in ICU. The most common etiological agent was Staphylococcus aureus (16/49). Table 1 describes: most common etiological agents and AM used. The AM distribution to treat bacteremia is shown in graphic 1. 37/49 (75.5%) bacteremia had an organism that matched an appropriate AM. 10 of those missed an opportunity of de-escalation and 7 possibly represented contaminations in which AM could be stopped. Conclusion The AM prescription in hospitalized patients in Chile is lower compared to other LMIC. We found opportunities for AM optimization by de-escalating or stopping AM when blood culture results are available in bacteremia. We plan to recommend evidence-based strategies implementation aiming to de-escalate AM to a narrow more tailored regimen by audit and feedback supported with guidelines. Also to raise awareness about the possibility of contamination when blood cultures isolate coagulase negative staphylococcus as an opportunity to stop antimicrobials. PPS is an effective method to detect antimicrobial prescription habits and prioritize Antimicrobial Stewardship activities with local data. Disclosures Dona Benadof, MD, Biomerieux: Grant/Research Support Mirta Acuña, MD, Pfizer: Grant/Research Support P. , PharmD, Eli Lilly: Stocks/Bonds (Private Company)|MSD: Advisor/Consultant|Pfizer: Advisor/Consultant Ruth A. Rosales, n/a, BECTON DICKINSON DE CHILE: Advisor/Consultant|BECTON DICKINSON DE CHILE: Speaker|Pfizer SA: Speaker

P-377. The Clinical and Economic Burden of Diagnosed or Reported Surgical Site Infections in Procedures Under Surveillance by the National Healthcare Safety Network

Abstract Background The attributable costs of surgical site infections (SSIs) have relied on diagnosis codes which have limitations. Moreover, the association between SSI with hospital-onset bacteremia and fungemia (HOB), a proposed quality metric, is not known. We quantified the attributable burden of SSI using two definitions with contemporary data. Methods We conducted a cross-sectional analysis using data from 85 hospitals within the BD Insights and Research Database from October 2015 through June 2019. Two definitions of SSI were considered. The first definition was ICD coded SSI with a National Healthcare Safety Network (NHSN) reportable procedure. The alternative definition was hospital-reported SSI that was identified by an infection preventionist and reported to the NHSN. HOB was defined as a positive blood culture collected within the hospital-onset period (on or after day 4 of hospitalization) for an eligible blood stream infection organism as defined by the NHSN. We estimated and compared key burden metrics - hospital cost, length of stay (LOS), and HOB – in hospitalizations with and without SSI and procedures under NHSN surveillance. Results There were 222,298 hospitalizations with a NHSN reportable procedure. The rate of ICD coded SSI under surveillance for 30-days and 90-days was 1.6 and 1.5 per 100 admissions, respectively. Hospital-reported SSI occurred in 0.17 per 100 admissions with a reportable procedure. SSI admissions compared to hospitalizations with the NHSN surveillance procedure without SSI was associated with statistically significant higher cost (attributable cost of ICD coded SSI: $8,908 for 30-days and $9,624 for 90-days; hospital-reported SSI: $29,638, P< 0.0001; Figure 1) and LOS (attributable LOS of ICD coded SSI: 5.6 days for 30-days and 6.6 days for 90-days; hospital-reported SSI: 10.7 days, P< 0.0001). HOB occurred in 3.4-6.6% of hospitalizations with SSI during the procedure surveillance period. The risk of HOB was 7-to-12-fold higher in procedure admissions with SSI compared to those without (Figure 2). Conclusion Regardless of how SSI was identified, SSI was associated with higher cost, longer LOS, and a high burden of HOB. SSIs may also be a novel risk factor for HOB, which should be considered in future quality programs. Disclosures ChinEn Ai, MPH, Becton, Dickinson and Company: BD employee|Becton, Dickinson and Company: Stocks/Bonds (Public Company) Molly Jung, MPH, Becton, Dickinson and Company: BD employee|Becton, Dickinson and Company: Stocks/Bonds (Public Company) Samantha Bastow, PharmD, MBA, Becton, Dickinson and Company: BD employee|Becton, Dickinson and Company: Stocks/Bonds (Public Company) Ghislene N. Adjaoute, MSBA, MSW, Becton, Dickinson and Company: BD employee|Becton, Dickinson and Company: Stocks/Bonds (Public Company) David L. Bostick, PhD, Becton, Dickinson and Company: BD employee|Becton, Dickinson and Company: Stocks/Bonds (Public Company) Kalvin Yu, MD, FIDSA, Becton, Dickinson and Company: BD employee|Becton, Dickinson and Company: Stocks/Bonds (Public Company)

P-1290. Invasive group A streptococcal infection in children in Toronto, Canada

Abstract Background Rising cases of invasive group A streptococcus (iGAS) in children have been reported globally. We assessed the epidemiology of pediatric iGAS over three decades. The annual incidence of invasive GAS infections in children in Toronto and Peel Region during the years 1992-2023 Methods Since 1992, the Toronto Invasive Bacterial Diseases Network has conducted surveillance for iGAS in Toronto/Peel Region, Canada. The National Microbiology Laboratory provides emm typing, and Statistics Canada supplies population data. iGAS data were analyzed by age group—toddlers (0-4 yrs), young children (5-9 yrs), and older children (10-17 yrs)— and over time from 1992 to 2024. emm types in pediatric cases per 100,000 population in Toronto and Peel Region from 1992 to 2023. Results 506 pediatric iGAS cases were identified. Figure 1 shows the incidence by age group. 61% of cases were male; 33% had underlying conditions. Main presentations were soft tissue infection (30%), bacteremia with no focus (22%), bone/joint infections (20%) and pneumonia (16%). Streptococcal toxic shock syndrome (STSS) occurred in 5.7% of cases, and necrotizing fasciitis (NF) in 2.6%. Positive blood cultures were found in 71% of cases, with additional sterile site cultures in 20%. emm1 (42%) and emm12 (16%) were the most common types (Figure 2), with M1UK comprising 63% of emm1 isolates in 2022/2023. During the period of pandemic restrictions (Mar 2020-Apr 2022), iGAS cases declined, and emm1 disappeared. As restrictions eased, emm1 and, to a lesser extent, emm12 rebounded (Figure 3). Seasonality, with increased winter/spring cases, became more pronounced (Figure 4). Toddlers had higher rates of bacteremia without focus (27% vs. 14%, p=0.01) and emm12 (20% vs. 8.4%, p=0.02) than older children. Younger children had higher rates of bone/joint infections than toddlers (28% vs. 16%, p=0.004). Rates of STSS, NF, and 30-day mortality were consistent across age groups and time, with no association to specific emm types, except for higher mortality in emm4 [12.5% vs. 3.6%, OR 3.8 (1.2-12.1)]. Increasing pneumonia rates over time were associated with emm1. In multivariate analysis, pneumonia [OR 7.2 (2.9-17.6)], NF [OR 15.5 (4.2-58)], and increased age [OR 1.8 (1.03-3.2)] predicted STSS. Monthly pediatric iGAS cases in relation to pandemic public health restrictions in Toronto and Peel Region from April 2018 to March 2024. Conclusion The recent rise in pediatric iGAS infections is a public health concern. Incidence has increased, but severity remains unchanged. emm1 transmission seems more susceptible to control by public health measures. Continuous surveillance is essential. Seasonality of iGAS in children in Toronto/Peel region, 1992-2023 Disclosures Allison McGeer, MD, AstraZeneca: Honoraria|GSK: Honoraria|Merck: Honoraria|Moderna: Honoraria|Novavax: Honoraria|Pfizer: Grant/Research Support|Pfizer: Honoraria|Roche: Honoraria|Seqirus: Grant/Research Support|Seqirus: Honoraria

P-834. Epidemiology and Duration of Therapy in Patients with Gram-negative Bloodstream Infections: Retrospective Analysis 2.15.0.02.15.0.0

Abstract Background Longer courses of antibiotics can be associated with antimicrobial resistance and adverse effects. Randomized clinical trials support treating uncomplicated gram-negative bloodstream infections (GN-BSI) for a shorter duration with a consensus that a seven-day course of antibiotics is appropriate. Prior to the implementation of a GN-BSI treatment guideline at our institution, we aimed to assess the characteristics of patients with GN-BSI and the duration of antibiotic therapy (DOT). Methods We retrospectively reviewed adult inpatients with GN-BSI over a period of 6 months. Patients were excluded if they had a concomitant gram-positive bloodstream infection or if they were transitioned to comfort-focused care within 48 hours of their first positive blood culture. Complicated GN-BSI was defined as having any of the following: bone, joint, endovascular, or foreign body involvement, lack of source control, immunocompromised status, or failure to show clinical improvement or culture clearance within 72 hours. The primary outcome was the mean DOT in patients with GN-BSI. Results 100 patients met the inclusion criteria. Escherichia coli (54 cases) was most frequent organism. Urine (41) was the predominant source of bacteremia. Cefepime (48) was the most common empiric antibiotic. Of the 91 patients with available ceftriaxone susceptibility results, 84% had a susceptible organism. Of the 51 patients with a complicated GN-BSI, the leading cause was immunosuppression. Table 1 presents a comparative analysis of complicated vs. uncomplicated GN-BSI. Complicated GN-BSI had longer DOT (20 vs. 11 days, P< 0.005) and fewer patients transitioned to oral therapy (33% vs. 67%, P< 0.005). Conclusion At our institution, patients with uncomplicated GN-BSI have a shorter DOT and are more likely to transition to oral therapy than those with complicated GN-BSI. However, the mean DOT for uncomplicated infections remained longer than seven days and a large number of uncomplicated GN-BSI patients did not transition to oral therapy, indicating room for improvement in local practice through antimicrobial stewardship initiatives. Disclosures All Authors: No reported disclosures

P-868. Evaluating the Clinical Impact of Rapid Diagnostic Testing on Antimicrobial Stewardship Interventions

Abstract Background The management of bloodstream infections (BSIs) may be improved with rapid diagnostic identification. The updated Biofire FilmArray blood culture identification (BCID) 2 panel is able to detect extended-spectrum beta-lactamase and additional carbapenemase encoding genes amongst other resistance markers, allowing for earlier antimicrobial stewardship interventions. The purpose of this study was to evaluate the time to optimal antimicrobial therapy. Methods This was a single-center retrospective chart review of patients before and after the implementation of the updated BCID panel (BCID1 vs. BCID2, respectively). Adult patients were eligible for inclusion if they had a positive blood culture with an accompanying BCID panel result. Patients were excluded if they received concomitant treatment for an unrelated infection or had monomicrobial BSI with Staphylococcus species. The primary endpoint was time to initiation of optimal antimicrobial therapy from index blood culture, defined as pathogen and resistance gene directed therapy per hospital treatment algorithm. Secondary endpoints included time to active antimicrobial therapy, defined as empiric therapy shown to be active against index isolate(s) with an antimicrobial susceptibility report, and 30-day mortality. Results Overall, 143 patients were included in the BCID1 group and 175 patients in the BCID2 group. Time to optimal antimicrobial therapy was shorter in the BCID2 group compared to the BCID1 group (17.1 hours vs. 29.3 hours; p < 0.05). Time to active therapy was shorter in the BCID2 group compared to the BCID1 group (3.1 hours vs. 5.9 hours; p=0.03). Thirty-day mortality rate was lower in the BCID2 group compared to the BCID1 group (9.7% vs. 20.9%; p < 0.05). Conclusion Time to optimal and active antimicrobial therapy were significantly shorter after the implementation of the BCID2 panel. Furthermore, 30-day mortality was lower, indicating that optimized therapy per local hospital treatment algorithms may improve outcomes. Disclosures All Authors: No reported disclosures

P-77. Ceftaroline versus Daptomycin as Definitive Treatment for Methicillin-Resistant Staphylococcus aureus Bone and Joint Infections

Abstract Background There are no comparative effectiveness studies of ceftaroline versus other antibiotics for MRSA bone and joint infections (BJI). We retrospectively compared the clinical outcomes of patients with MRSA BJI initially treated with vancomycin and then transitioned to either ceftaroline (VtoC) or daptomycin (VtoD). Methods This retrospective nested case-control study analyzed data from a large Midwest academic center collected from 2018-2022. Patients with MRSA BJI whose definitive treatment was ceftaroline were compared in a 1:2 ratio to patients whose definitive treatment was daptomycin. The primary outcome was clinical success after initial treatment course (i.e., at 6 weeks) defined by a composite endpoint which included resolution of signs and symptoms and no repeat surgery or re-admission for treatment of the index BJI. Results We identified 36 patients to be included in this case-control study, with 12 VtoC cases and 24 VtoD cases. The demographic make-up was similar, as was the frequency of comorbidities (including Charlson score). Of the VtoC patients, 42% had implant-related infection vs. 17% of the VtoD group (p=0.1). A larger proportion of VtoC patients had systemic MRSA infection as documented by positive blood cultures (58% vs 38%; p=0.2). More VtoC cases were direct ICU admits (50% vs 13%; p=0.04), required intubation (58% vs 17%; p=0.02), or were admitted to the ICU at any point during their stay (67% vs 29%; p=0.07). Transition away from vancomycin occurred at 14.3 vs 10.6 days (p=0.6). There was only a single clinical success in the 12 VtoC patients (8%) vs. 7/24 (29%) in the VtoD group (p=0.2), with the majority of cases being failures (30.5%), all-cause deaths (30.5%), or lost to follow-up (16.7%). Follow-up was 103 vs 123 days (p=0.8) in the two groups. Conclusion In this comparison of ceftaroline to daptomycin for MRSA BJI we found ceftaroline recipients to have more severe illness (as suggested by need for ICU care) and experience very little clinical success. We suspect that there is selection bias in that more severely ill cases anticipated to have poor outcomes were more likely to be transitioned to ceftaroline. Our next steps are to include more data and conduct a propensity score analysis to better understand what factors are associated with transition to ceftaroline. Disclosures All Authors: No reported disclosures

P-831. Six Years Retrospective Study on Staphylococcus aureus Bacteremia: Impact of Persistance and COVID-19 Pandemic on 30-Days Mortality

Abstract Background S. aureus bacteremia (SAB) is characterized by high risk of complications and a high mortality. Persistent S. aureus bacteremia (P-SAB) has been associated with worse outcome. The COVID-19 pandemic might have further increased the mortality for this condition. Our study aims to assess the prevalence and risk factors for P-SAB and its 30-day all-cause mortality and relative risk factors, with particular attention to the possible influence of SARS-CoV-2 infection.Table 1.Study population characteristicsQuantitative data are presented as median, interquartile range, qualitative data as absolute numbers, percentages; p values for comparison between persistent and non-persistent SAB by Mann-Whitney test and Chi-square test for continuous and categorical variables, respectively. (IQR: interquartile range; IVDU: intravenous drug users; BSI: bloodstream infection; CVC: central venous catheter; MRSA: methicillin-resistant S. aureus; TTE: transthoracic echocardiography; TEE: transesophageal echocardiography; ID: infectious diseases). Methods This is a retrospective study including all adult patients with monomicrobic SAB, from January 2017 to December 2022 at San Paolo Hospital, Milan. P-SAB was defined as a positive blood culture at 72 hours from the beginning of an active antibiotic therapy. Patients who didn’t perform follow-up blood cultures were excluded for analysis evaluating risk factors and mortality for P-SAB. Risk factors for P-SAB were evaluated by univariable logistic regression analysis. Kaplan-Meier curves with log-rank test and multivariable Cox regression analysis were performed for all-cause 30-day mortality, persistance and mortality risk factors.Table 2.Univariable analysis for risk factors associated with persistent S. aureus bloodstream infections.(OR: odds ratio; C.I.: confidence interval; CVC: central venous catheter; MRSA: methicillin-resistant S. aureus; MSSA: methicillin-sensible S. aureus; BSI: bloodstream infection; ID: infectious disease) Results In total 320 patients were diagnosed with SAB during the study period (population characteristics in Table 1); 184 patients had available follow-up blood cultures, 70 (38%) presented a P-SAB. Embolization was a risk factor for persistent bacteremia (OR 3.1, 95%C.I. 1.5-6.5, p=0.002), as well as the presence of CVC at SAB onset (OR 1.8, 95%C.I. 0.97-3.4, p=0.060) (Table 2). All-cause 30-day mortality for SAB was 25.3% (95%C.I. 19.7-30.9%), survival curve found no differences in mortality (Log-rank=0.080) for P-SAB (Figure 1). At multivariable analysis P-SAB presented more risk of mortality (aHR 2.06, 95% C.I. 0.86-4.9, p=0.100), along with a concomitant SARS-CoV-2 infection (HR 2.48, 95% C.I. 1.37-4.48, p=0.002) and comorbidities (aHR 1.16, 95% C.I. 1.03-1.32, p=0.020) (Table 3).Figure 1.Kaplan-Meier curve for 30-days mortality according to persistent SAB.(Grey curve: non-persistent S. aureus bacteremia; Black curve: persistent S. aureus bacteremia. P value by log-rank test) Conclusion P-SAB is associated with the presence of endovascular catheters and septic embolization, determining a higher 30-day mortality compared to non-P-SAB. Moreover SARS-CoV-2 coinfection showed to double mortality risk for SAB. Optimal management of patients with P-SAB must be further elucidated to reduce their relevant impact in daily practice.Table 3.Factors associated with 30-day mortality by fitting a univariable and multivariable Cox-regression analysis.(HR: hazard ratio; C.I.: confidence interval; aHR, adjusted hazard ratio; CVC: central venous catheter; MRSA: methicillin-resistant S. aureus; BSI: bloodstream infection; SAB: S. aureus bloodstream infection; ID: infectious diseases). Disclosures All Authors: No reported disclosures

P-322. Transmission of Methicillin-Resistant Staphylococcus aureus to Healthcare Personnel Gloves and Gowns: a Cohort Study of VA Hospitals in 5 States

Abstract Background The aim of this study was to determine the rate of MRSA transmission to healthcare personnel (HCP) gloves and gown and to determine which patient care interactions and HCP roles are associated with greater transmission of MRSA. Methods Patients with a positive MRSA clinical or surveillance culture within the past 7 days were enrolled at 5 VA medical centers. Research team members observed 5 HCP in the room for each patient and recorded any items that were touched on a standardized data collection form. After completion of tasks and prior to room exit, HCP gloves and gown were cultured separately. The primary outcome was a surrogate measure for transmission defined as “yes” if a HCP glove or gown was contaminated with MRSA. Results We enrolled 799 patients and obtained 3,832 glove and gown cultures. Transmission of MRSA to gloves or gown occurred 713/3832 (18.6%) of the time while 589/3832 (15.4%) of interactions resulted in contamination of gloves and 319/3831 (8.3%) of interactions resulted in contamination of gowns. The gloves and gown of physical therapists and occupational therapists were most frequently contaminated with transmission occurring in 24/84 (29%) and 11/38 (29%) of observations respectively (Table 1). Any interactions that involved touching the patient (patient alone or patient and environment) resulted in glove or gown contamination in 622/2901 (21.4%) of observations, while touching only the environment resulted contamination in 91/931 (9.8%) of observations. Specific patient care activities with the highest rates of transmission included touching the endotracheal tube (12/35, 34%) and assisting the patient with bathing and hygiene (89/283, 31%). Specific environmental items touched with the highest rates of transmission included the call button (75/221, 34%) and the lift (31/125, 27%) (Figure 1). Conclusion Contamination of HCP gloves and gowns with MRSA occurs frequently when caring for Veteran patients particularly when there is direct patient contact. Hospitals may consider optimizing contact precautions by using fewer precautions for low-risk interactions and more precautions for high-risk interactions. Disclosures Anthony Harris, MD, MPH, Innoviva: Advisor/Consultant|UpToDate: Infection Control Editor

P-2312. Impact of a Short Course Post-Operative Antibiotic Prophylaxis Duration on Nephrotoxicity in Lung Transplant Recipients

Abstract Background Vancomycin plus an antipseudomonal β-lactam is used as lung transplant surgical prophylaxis, but an optimal post-operative duration is not defined. The study objective was to assess the impact of a shortened antibacterial surgical infection prophylaxis (SIP) duration on post-operative nephrotoxicity in lung transplant recipients. Table 1 Variables associated with AKI Methods IRB approved quasi experiment of lung transplant recipients who received SIP from 1/1/2016-9/30/2020 (pre-group) to 10/1/2020-7/31/24 (post-group). Intervention: implementation of shortened SIP duration to 72-hours of cefepime and vancomycin post-operatively. Inclusion: eGFR >30 mL/min/1.73m2 between transplant day ±2. Exclusion: renal replacement ≤ 3-months, simultaneous organ transplants, donor bronchi with Gram-positive bacterial growth, or new COVID-19 infection between transplant day ±7. The primary endpoint was the incidence of acute kidney injury (AKI), defined by the KDIGO criteria, while receiving post-operative vancomycin up to 14 days. Secondary endpoints were vancomycin consensus guideline (VCG) AKI definition at 14-days and time to AKI. Results 77 patients were included: 45 (58%) pre-, 32 (42%) post-intervention. 73% vs. 47% male (p=0.018). 49% vs. 34% (p=0.205) KDIGO AKI while on vancomycin. Post-group associated with approximately 40% decreased odds of developing KDIGO AKI (Table 1). Secondary endpoints: 33% vs. 19% VCG AKI (p=0.157). Median time to AKI was three days, with no differences detected between groups and AKI definitions. Similar rates of C. diff infection, positive bacterial respiratory cultures, new multidrug resistant organisms, surgical site infections. 57.8% vs. 84.4% patients received treatment for new pneumonias after SIP completion (p=0.013), with one new MRSA pneumonia in the pre-group and one in the post-group. Conclusion Implementation of a shortened antibacterial prophylaxis protocol for lung transplant resulted in numerically fewer AKIs. Maturation, regression to the mean, and reliance on manual chart review are all limitations of this retrospective study. Ongoing analysis of this intervention, such as with multicenter prospective studies, can help to characterize the decreased nephrotoxicity risk with shorter course prophylaxis post-transplant. Disclosures Rachel M. Kenney, PharmD, BCIDP, Medtronic Inc: Spouse is an employee, stockholder

P-937. Clinicomicrobiological Risk Factors for Infective Endocarditis in Viridans Group Streptococci Bacteremia

Abstract Background Viridans group streptococci (VGS) persist as the dominant cause of community-acquired native-valve endocarditis, contributing to 20% of cases. The incidence of streptococcal infective endocarditis (IE) exceeds that of Staphylococcus aureus IE, notably in Asia. However, the risk factors that guide the decision to conduct echocardiography to rule out IE in patients with VGS bloodstream infections (BSIs) remain unclear. Therefore, our study aimed to identify independent risk factors for IE in patients with VGS BSIs. Methods This retrospective study conducted at Seoul National University Hospital from January 2013 to December 2022 involved patients with VGS and nutritionally variant streptococcal BSIs, excluding single positive blood cultures and polymicrobial BSI cases. Independent risk factors were identified by multivariate logistic regression and sensitivity analyses according to echocardiography results, VGS species, or the inclusion of possible IE cases. Proportions of infective endocarditis by viridans group streptococci species. VGS species belonging to the mitis group are represented by the orange-coloured dots, and those in the non-mitis group are represented by the green-coloured dots. Circle size correlates with the number of IE cases attributed to each VGS species. Results Of 845 VGS BSI cases, 349 were analyzed and 86 IE cases were identified (24.6%). In the multivariate analysis, heart valve disease (adjusted odds ratio [aOR], 14.14, 95% confidence interval [CI], 6.14–32.58; P < 0.001), persistent bacteremia (aOR, 5.12, 95% CI, 2.03–12.94; P = 0.001), age (per year, aOR, 0.98; 95% CI, 0.96–1.00; P = 0.015), solid cancer (aOR, 0.26, 95% CI, 0.13–0.53; P < 0.001), and hematologic malignancy (aOR, 0.04; 95% CI, 0.01–0.41; P = 0.006) were independently associated with IE. Sensitivity analyses yielded consistent results; also, infection by a member of the mitis group was independent risk factor for IE (aOR, 6.50; 95% CI, 2.87–14.68, P < 0.001). Conclusion Younger age, heart valve disease, persistent bacteremia, absence of underlying hematologic malignancy or solid cancer, and BSI by a member of the mitis group were the independent risk factors for IE in VGS BSI patients. In conclusion, regular echocardiographic evaluation could be prudently considered based on these clinicomicrobiological risk factors. Disclosures All Authors: No reported disclosures

P-48. Uptake of pneumococcal vaccination after invasive pneumococcal diseases in two centers in northern Italy

Abstract Background Aim of this study is to evaluate factors associated with uptake of pneumococcal vaccination after invasive pneumococcal disease (IPD). Since pneumococcal infection doesn’t protect from future ones, vaccination is recommended in patients who recover from IPD. Table 1 Population's characteristics. Methods Retrospective, bicenter cohort study of patients hospitalized with invasive pneumococcal disease at IRCCS San Raffaele Hospital (Milan, Italy) and ASST Manzoni Hospital (Lecco, Italy) between January 1st 2015 and December 31st 2019. Patients older than 18 years with positive blood or cerebrospinal fluid cultures for Streptococcus pneumoniae were included. Patients who died before discharge and whose vaccinal record and discharge documentations were not available were excluded. All vaccination data were retrieved through Italian national vaccination portal (SIAVR). Follow-up data were updated until March 31st, 2024. The characteristics of patients who were vaccinated (VAX) and were not vaccinated (UNVAX) after the event were compared using the chi-square test for categorical variables and the Mann-Whitney U-test for continuous variables. Table 2 Characteristics of vaccination cycles. Results The characteristics of the 211 included patients are described in table 1, completed vaccination cycles in table 2. Only 26 patients (12.3%) received an indication at discharge to get vaccinated for S. pneumoniae, and 47 (22.2%) patients were vaccinated during the observation period, after a median of 6.6 (2.3-29.9) months after the event. There was no difference in age between the two groups (70.7 [60.1-78.4] vs 69.5 [58.8-78.5], p-value=0.82), while a greater proportion of VAX patients was male (33 [70.2%] vs 86 [52.4%], p-value=0.03). Charlson comorbidity index was similar between the two groups (5 [3-6] vs 5 [3-6], p-value=0.845), but a significant higher percentage of VAX patients had lymphoma (8 [17%] vs 8 [4.9%], p-value=0.006). Patients who received an indication to vaccinate were significantly more likely to receive pneumococcal vaccination (16 [34%] vs 10 [6.1%], p-value< 0.001). Conclusion Our cohort revealed low pneumococcal vaccination uptake, with inadequate frequency of vaccination indication at discharge. Reinforcing prevention culture among patients and physicians is imperative. Disclosures Antonella Castagna, MD, Bristol-Myers Squibb: Advisor/Consultant|Gilead Sciences, Inc.: Advisor/Consultant|Gilead Sciences, Inc.: Grant/Research Support|Gilead Sciences, Inc.: Honoraria|Janssen: Advisor/Consultant|Janssen: Grant/Research Support|Janssen: Honoraria|Merck Sharp & Dohme: Advisor/Consultant|Merck Sharp & Dohme: Grant/Research Support|Merck Sharp & Dohme: Honoraria|ViiV Healthcare: Advisor/Consultant|ViiV Healthcare: Grant/Research Support|ViiV Healthcare: Honoraria

P-805. Factors associated with mortality and morbidity of patients with methicillin-resistant Staphylococcus aureus bacteremia in a regional hospital

Abstract Background Methicillin-resistant Staphylococcus aureus (MRSA) bacteremia is a critical health issue. This retrospective study aimed at identifying factors associated with adverse clinical outcomes in MRSA bacteremic patients admitted to Kwong Wah Hospital, an 800-bed regional hospital in Hong Kong, China. It was approved by the Kowloon Central/Kowloon East Cluster Research Ethics Committee, Hospital Authority (KC/KE-23-0107/ER-4). Methods Patients aged 18 years or above with MRSA bacteremia between 2020 and 2022 were identified. Their demographics and clinical background were summarized in Table 1. The primary and secondary outcomes were 30-day all-cause mortality and intensive care unit (ICU) admission, respectively. Results Of the 115 patients included, 112 (97.4%) received intravenous vancomycin as the first line antibiotic, 59 (51.3%) developed complicated bacteremia and 17 (14.8%) necessitated second line antibiotics (Figure 1). Thirty-six (31.3%) died within 30 days of positive blood culture for the first time and 14 (12.2%) needed ICU care. Among the 44 (38.3%) patients attended by an infectious disease (ID) doctor, there was a higher chance to receive echocardiogram (77.3% vs 56.3%), computed tomography (52.3% vs 8.45%), surgical removal of infective foci (43.2% vs 12.7%), and numerically lower deaths (20.5% vs 38.0%) compared to those who were not. ID consultation, along with younger age, lower Charlson comorbidity index, longer duration of antibiotics, and those without altered mental status or hypothermia, were noted to favor survival in univariate analysis (Table 2). By multivariate logistic regression, older age, higher C-reactive protein, altered mental states, and shorter antibiotic duration were significantly associated with mortality while ID consultation, vancomycin MIC >= 1 μg/mL, and congestive heart failure were associated with ICU admission (Table 3). Conclusion MRSA bacteremia resulted in high mortality. ID consultation might have contributed to a greater effort in searching for surgically removable infective foci and a numerically lower death rate. Its association with ICU admission might suggest that sicker patients require greater expertise from ID doctors. Disclosures All Authors: No reported disclosures

P-116. Impact of a gastrointestinal molecular panel in the tropics: going beyond E. histolytica

Abstract Background Acute diarrhea (AD) is a major cause of illness and hospital admissions, particularly in humid tropical climates. These infections can escalate rapidly, making an early and accurate diagnosis crucial for effective treatment. However, due to the variety of pathogens and the limitations of conventional diagnostic tests, clinicians often resort to empiric treatments based on epidemiological data. This study explores how effective a gastrointestinal molecular panel (GI panel) can be in identifying specific pathogens in a tertiary health center. Methods This observational, descriptive, cross-sectional study analyzed the clinical records of patients over 18 years old with symptoms of AD. These patients underwent treatment and took the FilmArray GI Panel between March 2021 and December 2022. The study also compared the results obtained by ova and parasite tests and/or stool culture, when available. Viral, Bacterial & Parasitic infections Source: Statistical registry of the authors Results Out of 59 patients (median age: 48 years; 57.63% female), the GI panel identified at least one pathogen in 66.1% (39/59) of samples, with 32.2% (19/59) showing two or more pathogens. Bacteria were the most common cause of infection (62.7%), with enteroaggregative E. coli (18.6%), Shigella/enteroinvasive E. coli (18.6%), and enteropathogenic E. coli (15.3%) being the most prevalent. Viruses accounted for 11.9% of cases, with Norovirus GI/GII (5.1%) and Adenovirus F 40/41 (3.4%) being the most common. Protozoa made up 6.8% of cases, primarily Cryptosporidium (5.1%) and Cyclospora cayetanensis (1.7%). Out of 21 patients with a bacterial target in the GI panel, only one received a positive stool culture (Salmonella sp.). The 4 protozoa-positive samples were not detected through an ova and parasite test, and no stool sample was positive for Entamoeba histolytica (32 ova and parasite tests). Conclusion It is necessary to rethink the etiology of AD in low- and middle-income countries like the Dominican Republic, which has long been based on low-sensitivity routine tests. Despite being in the tropics, protozoa were not the most frequent pathogens, and E. histolytica was largely absent, regardless of the diagnostic method used. Diagnostic routine tests should be revised to include targets that may be missed due to method limitations. Disclosures Rita A. Rojas-Fermin, MD,FIDSA, Gilead: Advisor/Consultant|Pfizer: Advisor/Consultant|Pfizer: Honoraria

P-926. A Comparative Analysis of Infection-Related Mortality and Relapse Rate: Restarting vs. Continuing Antibiotic Regimens in Endocarditis Patients Post-Cardiac Intervention

Abstract Background The duration of antibiotic therapy post cardiac intervention (PCI) for treatment of infective endocarditis (IE) remains controversial despite current clinical guidelines. There is paucity of data on the PCI antibiotic duration relating to pathogens, presence of an infected cardiovascular implantable electronic device (CIED), vegetation size, and duration of bacteremia. Due to these limitations, antibiotic therapy may be extended although the impact in clinical practice remains unknown. Methods This was a retrospective study comparing outcomes in patients with IE admitted to The Ohio State Wexner Medical Center who underwent valve replacement and/or CIED extraction from January 2013 to November 2017 based on whether the course of antibiotic therapy was restarted PCI (extended group) or if antibiotics prior to cardiac intervention were included in the total antibiotic duration (continuation group). Patients who completed the full course of antibiotics prior to cardiac intervention were excluded. The primary outcome was a composite of one-year infection-related mortality and IE relapse PCI. The proportional win-fractions regression model was used to compare the composite outcome between the groups. Results 235 patients met study inclusion criteria, 182 in the extended group and 53 in the continuation group. Patient demographics are shown in table 1. 91.5% of patients had positive blood cultures (n = 215) with a median bacteremia duration of 4 days with the most common pathogen being Staphylococcus aureus as shown in figure 1. 79.6% of patients had OR cultures sent (n = 187) shown in table 2. The average antibiotic duration PCI was 39.7 days. 5 patients had bacteremia at the time of surgery. The study revealed no statistically significant difference between the two groups in the primary outcome (Win Ratio 1.59, CI: 0.80-3.15, p-value 0.18) shown in table 3. Conclusion For patients with IE requiring surgical intervention, the outcome of one year mortality and infection relapse was not significantly different between the two groups after adjusting for potential confounders. This study suggests that extending antibiotics may not be associated with improved survival or infection relapse, however prospective studies are needed to confirm these findings. Disclosures All Authors: No reported disclosures

P-806. How close are we to achieving the trifecta of optimal treatment duration, route of therapy, and repeat blood culture testing for uncomplicated gram-negative bacteremia?

Abstract Background A 2021 consensus document outlined recommendations for treatment duration, oral antibiotic use, and need for repeat blood cultures in patients with uncomplicated gram-negative bacteremia. Data support 7 days of effective therapy and oral step-down therapy in clinically stable patients. Repeat blood cultures were not recommended except for patients with concern for endovascular infection. We sought to evaluate the percentage of our gram-negative bacteremia cases that would be defined as uncomplicated and how well our practices for these cases aligned with the 2021 recommendationsTable 1.Antibiotic days of therapy Methods This retrospective cohort study included adult patients hospitalized between 1/1/2022 and 12/31/22 who had a blood culture with growth of a gram-negative organism and who received ≥ 4 days of antibiotics for the bacteremia. Effective therapy required both use of an antibiotic to which the organism was susceptible and source control. Unnecessary IV therapy was defined as continuation of IV therapy in patients with clinical stability for ≥ 24 hours who had an oral treatment option available.Table 2.Repeat blood cultures Results During 2022, 251 unique patients were hospitalized with gram-negative bacteremia and received ≥ 4 days of antibiotics, 130 (52%) of whom were classified as having uncomplicated bacteremia. The average duration of effective therapy was 11.8 days and 74.6% of patients received ≥ 10 days. Unnecessary IV therapy was continued for an average of 3.8 days and 33 (34%) were not transitioned to an orally available option by day 4 of clinical stability. Repeat blood cultures were done in 86 (66%) patients but were indicated in only 18 (14%). Twenty-two (26%) repeat blood cultures were collected < 48 hours after the initial positive blood culture Conclusion Using the 2021 consensus recommendations as a guide, more than half of patients with uncomplicated gram-negative bacteremia at our institution received longer than recommended durations of therapy, were not transitioned to an oral option when clinically stable and had repeat blood cultures done when not indicated. A multifaceted intervention to achieve the trifecta of optimal treatment duration, route of therapy, and repeat blood culture testing for uncomplicated gram-negative bacteremia is planned. Disclosures All Authors: No reported disclosures

P-412. Staphylococcus aureus Hand Colonization in 321 Adult Inpatients

Abstract Background Staphylococcus aureus (SA) hand colonization is understudied. Table 1. shows the total number of subjects with each stated characteristic, as well as the number and percent of subjects with each characteristic stratified among those with positive enrollment hand cultures and those with negative hand enrollment cultures. Methods We tested 328 adults in 2 general medicine hospital units < 3 days after admission, and for 219 of them < 2 days before discharge, for SA colonization of hands, nares, inguinal skin, and oropharynx, by direct plating and broth enrichment. Comorbidities were assessed by ICD-10 codes.Figure 1.Venn Diagram showing distribution of positive S. aureus enrollment cultures from 4 body sites in 138 colonized adult inpatients Venn diagram showing 138 of 328 (42.1%) study subjects who were found to have colonization with S. aureus at one or more of the following 4 body sites: throat (T), inguinal skin/groin (G), hand (H), or nares (N). Shows each study subject in a mutually exclusive group of single-site or multibody-site colonization. For example, 15 (4.6%) had only hand (H) colonization, while 26 (7.9%) had colonization at all 4 body sites. Results The median age was 57.5 years (IQR 39.5-70.5), 55.8% were male, 32.9% had diabetes mellitus, 78.4% had a cardiovascular diagnosis, median study enrollment was for 3 days (IQR 1-7) and 42.1% had SA colonization at 1 or more site. 36.0% (118/328) were administered 1 or more antimicrobial drug; IV vancomycin (32%) and cefepime (25%) were most common (Table 1). SA grew from 28.4% (91/321) of enrollment and 25.6% (56/219) of discharge hand cultures. Enrollment hand colonization (HCe) was associated with carriage at each other tested body site (p< 0.001). The nose was most (65/91, 71%) and the groin, least (42/91, 46%) commonly co-colonized with HCe (Fig. 1). Of those with groin colonization, 85% (42/49) also had HCe (Fig. 1). HCe was more common in younger patients (median 49 vs. 60 years, p=0.045) and in patients without circulatory disease (26/67, 38%, p=0.03). There was a non-significant trend toward lower rates of HCe among patients with an infectious diseases diagnosis (25/113, 22.1%, p=0.064). For those with HCe, hand colonization was present in 67% (37/55) tested at last culture, with a mean LOS of 7.6 days. Additionally, 11% (18/161) gained hand colonization at last culture (GHCLC) which was not associated with age, sex, race, any specific comorbid condition, duration of stay, nor IV vancomycin, cefepime, or metronidazole use. GHCLC was less likely for those who received ceftriaxone (0/40 vs. 17/115, p=0.007) during their hospital stay. Among 100 subjects tested at enrollment and 7 days, HCe persisted in 13/22 (59%) and was acquired by 8/78 (10%) others; 5/8 who gained hand colonization at 7 days were colonized at enrollment at another body site. Conclusion Hand S. aureus colonization is common in hospitalized adults, particularly among patients who were younger, had groin colonization, and those without circulatory disease. New hand colonization occurred before discharge and was less common in those who received ceftriaxone. Disclosures Michael Z. David, MD PhD, Covance: Grant/Research Support|GSK: Grant/Research Support|Johnson & Johnson: Advisor/Consultant

P-1139. Surveying Antibiotic Treatment for Pediatric Patients with Suspected Urinary Tract Infections at Madigan Army Medical Center

Abstract Background Urinary tract infections (UTIs) are one of the most common bacterial infections in pediatric patients presenting to the Emergency Department (ED). However, the gold standard for diagnosis is a urine culture which takes 24-48 hours to result leading to antibiotics started empirically while results are pending. This study was implemented with the primary aim of evaluating the antibiotic management of pediatric patients who were seen at a single medical center ED with suspected UTI. Methods Using the electronic medical record we identified pediatric cases (ages 2 months-18 years) where UTI was diagnosed in the ED during 2023 using the ICD-10 code. Data collected on each case included demographics, laboratory work-up, prescribed medications, and follow-up. Outcomes were categorized as confirmed, unknown, or negated. A confirmed UTI required an abnormal urinalysis and single species growth exceeding 50,000 cfu/mL; UTI was negated when growth was < 10,000 cfu/mL. Descriptive statistics and comparison tests were used as appropriate. Results There were 80 UTI diagnoses in 70 patients. 18 (22.5%) cases were confirmed and 36 (45%) were negated (Table 1). We analyzed 54 cases with confirmed or negated UTIs: 15 (27.8%) had follow-up with primary care (PCM) within 96 hours of their ED visit. When UTI was negated, 4 cases (11%) had antibiotics discontinued and all had PCM follow-up within 96 hours (p=0.043) (Table 2). Enterococcus-UTI accounted for 75% of cases where empiric treatment was inadequate. Of those without confirmed UTI, 3 returned to the ED with adverse effects from antibiotics and 2 with multiple inconclusive evaluations were referred to urology. The ED providers notified families with positive urine culture results, but no one was notified if the urine culture was negative. Conclusion Many pediatric patients who are treated for UTI in our ED have inconclusive or negative workups resulting in unnecessary antibiotic use, ED visits for antibiotic complications, and subspecialty referrals. Our current system does not support the discontinuation or tailoring of unnecessary or inappropriate antibiotics unless patients have close follow-up. Antibiotic stewardship requires systematic support within the ED to limit unnecessary antibiotics and the inherent complications that follow. Disclosures All Authors: No reported disclosures

P-1516. Addition of Single-Dose Aminoglycosides to Empiric Beta-Lactam Therapy in Septic Shock in a Setting with High Antimicrobial Resistance Rates

Abstract Background At the Detroit Medical Center (DMC), the addition of an aminoglycoside (AMG) to β-lactam therapy is recommended in patients with septic shock due to high resistance rates; however, studies assessing the benefit of such combinations have yielded conflicting results. The objective of this study is to compare the outcomes of patients with septic shock who receive empiric β-lactam therapy with and without an AMG.Figure 1.Mortality Outcomes Methods This is a retrospective cohort study from 5/2021 to 7/2023. Patients were included if they met the following: 2 of 4 SIRS criteria, received vasopressors, serum lactate > 2 mmol/L, and appropriate empiric antimicrobial therapy within 24 hrs of admission . Patients who received an AMG within 24 hrs of admission were included in the AMG cohort, and those who did not were included in the control group. Key exclusion criteria were COVID-19, burn injury, and transfer to hospice care within 4 days of admission. The primary outcome was all-cause mortality at 7 days ; secondary outcomes included 30-day mortality, vasopressor-free days by day 7, ventilator-free days by day 28, and nephrotoxicity by day 7.Table 1.Patient and treatment characteristics Results Seventy-six patients were included (AMG=38; Control=38). The most common source of infection in AMG and control groups was pulmonary (44% vs. 31%, p=0.18). More AMG patients had a presumed SSTI source (17% vs. 0.0%, p=0.0049) patients, positive blood culture (79% vs. 26%, p< 0.0001), prior history of MDRO pathogen (22% vs. 0.0%, p=0.003), and received meropenem as initial empiric therapy (40% vs. 3%, p< 0.0001). APACHE II scores were similar (30 vs. 28, p=0.09). Time to appropriate antibiotic therapy was 4.8 hrs in the AMG group vs. 6.4 hrs in the control group, p=0.81. There were no differences in 7-day mortality (47% vs. 40%, p=0.49), 30-day mortality (63% vs. 53%, p=0.3527), vasopressor-free days by day 7 (2 vs. 2, p=0.08), or ventilator-free days by day 28 (2.5 vs. 8.5, p=0.31). There were also no differences in nephrotoxicity by day 7 (50% vs. 67%, p=0.23).Table 1.Patient and treatment characteristics, continued Conclusion Further evaluations should be conducted to determine whether an AMG in combination with β-lactams should be used in patients with septic shock.Table 2.Other clinical outcomes Disclosures All Authors: No reported disclosures