bluuebunny/crossref_metadata_2025 huggingface dataset:
P-2303. Active Surveillance and Antimicrobial Prophylaxis to Prevent Hyperammonemia Syndrome in Lung Transplant Recipients: A Single Center Cohort Study
Authors: Charles Drew , Lee Sara , Charya Ananth , Eberlein Michael , Saharia Kapil K
Published: January 2025

Background

Hyperammonemia syndrome (HS) is a life-threatening complication primarily affecting lung transplant recipients (LTR) and is associated with M. hominis and/or Ureaplasma spp infection. We implemented an active surveillance and prophylaxis protocol to improve outcomes associated with HS in LTR. Herein, we evaluate the impact of our protocol on outcomes of HS.

Methods

This is a single-center retrospective cohort study of adult LTR performed from 1/1/2019 to 1/31/2024. Our surveillance and prophylaxis protocol was implemented on 8/1/2022 and included PCR testing for M. hominis and Ureaplasma spp on post-operative bronchoscopy samples, measurement of serum ammonia levels, and azithromycin prophylaxis in our LTR. Comparisons between groups were performed using Chi-square or Fischer’s exact test for categorical variables and Student’s t test or Mann-Whitney U for continuous variables.

Results

One hundred and thirty-four adults received a lung transplant during the study period. Baseline characteristics are shown in Table 1. In total, 9 LTR (6.7%) were diagnosed with M. hominis or Ureaplasma spp. infection (Table 2). Of these, 3 LTR met criteria for definite HS (3/134, 2.2%) of whom two died. An additional 3 LTR had disseminated infection due to M. hominis without evidence of HS.

Following protocol implementation, 31/37 (83.8%) LTR had PCR testing for M. hominis and Ureaplasma spp. (Table 2). Ammonia levels were sent within 3 days of transplantation in 20/37 (54.1%) LTR. All patients received prophylaxis with azithromycin (or alternative agent) for at least 5 days or until PCR returned negative. Three LTR had either M. hominis or Ureaplasma spp infection detected following protocol implementation; none developed HS. One LTR developed disseminated M. hominis infection. However, screening was delayed by 10 days and prophylaxis was stopped after 5 days, prior to screening results being known.

Conclusion

The prevalence of HS in our cohort is similar to published reports. Adherence to our protocol was high for azithromycin prophylaxis and PCR testing, but low for ammonia levels. Importantly, no case of definite HS occurred following protocol implementation. Additional studies to determine optimal screening and prophylaxis strategies for HS are needed.

Disclosures

Kapil K. Saharia, MD, MPH, Eurofins Viracor: Advisor/Consultant
P-2308. Effect of Antibiotic Therapy on Preventing Subsequent Urinary Tract Infection in Early Kidney Transplant Recipients with Asymptomatic Bacteriuria
Authors: Kim Geonui , Chang Eui Jin , Bae Seongman , Jung Jiwon , Kim Min Jae , Chong Yong Pil , Lee Sang-Oh , Choi Sang-Ho , Kim Sung-Han
Published: January 2025

Background

The efficacy of treating asymptomatic bacteriuria during the early peri-transplantation period in kidney transplant (KT) recipient has not been properly assessed. In this study, we assessed the effectiveness of treating asymptomatic bacteriuria in first three months after KT and one month before, including bladder irrigation specimen obtained from operating room.

Methods

A single center retrospective cohort study was conducted on patient who underwent KT. KT recipient with asymptomatic bacteriuria within 30 days before and 90 days after the transplantation between January 2020 and January 2023 were included. The frequency of subsequent urinary tract infection (UTI) within 90 days of detecting asymptomatic bacteriuria was compared between antibiotic-treated and untreated groups.

Results

A total of 112 KT recipients with asymptomatic bacteriuria were included; of these, 33 (29 %) received antibiotic treatment while 79 (71 %) did not. Nineteen patients (17%) developed symptomatic UTIs within 90 days of detecting asymptomatic bacteriuria; 21% (7/33) in the antibiotic-treated group and 15% (12/79) in the untreated group (odds ratio, 1.53; 95% confidence interval, 0.53 to 4.24). Untreated asymptomatic bacteriuria was not significantly associated with subsequent UTI in multivariable logistic regression analysis (adjusted odds ratio, 1.32, 95% confidence interval, 0.45 to 3.85; p=0.61) after adjusting gender, vesicoureteral reflux, malignancy, type of donated kidney and induction immunosuppressive drug.

Conclusion

We found that antibiotic therapy for patients with asymptomatic bacteriuria during the early peri-transplantation period did not confera significant advantage in preventing subsequent UTIs. Prescribing antibiotics for asymptomatic bacteriuria in KT recipients should be approached with caution due to the potential risk of colonization or infection by resistant bacteria.

Figure 1.

Kaplan-Meier estimates of UTI incidence in patients with asymptomatic bacteriuria after KT ; Log-rank test showed that treated group showed that UTI occurred later than untreated group. (p=0.37)

Disclosures

All Authors: No reported disclosures
P-2311. Logical Versus Absolute Lymphocyte Count-guided Preemptive Therapy for CMV Prevention in Solid Organ Transplant Recipients: A Randomized Controlled Trial
Authors: Lorcharassriwong Piyangkul , Boongird Sarinya , Kantachuvesiri Surasak , Yingchoncharoen Teerapat , Sutharattanapong Napan , Bruminhent Jackrapong
Published: January 2025

Background

A preemptive approach using plasma CMV DNA load monitoring is recommended among CMV-seropositive (R+) solid organ transplant recipients (SOTr). Lately, absolute lymphocyte count (ALC) has been proposed as a surrogate marker to predict CMV infection in SOTr. We hypothesized that a preemptive approach guided by immune assessment, using low ALC, could effectively prevent CMV infection, akin to the proposed routine preemptive therapy. We aimed to assess the efficacy of logical preemptive therapy (LOG) versus ALC-guided preemptive therapy for CMV infection in CMVR+ SOTr, along with cost-effectiveness.

Methods

A 1:1 open-labeled randomized controlled trial was conducted at a single transplant center from February to November 2023. All adult CMVR+ SOTr not receiving anti-thymocyte globulin were randomly assigned to two groups: the LOG Group, where patients underwent plasma CMV DNA load testing every 4 weeks for 12 weeks after transplantation, and the ALC group, where the quantity of CMV DNA load was initiated when the ALC was < 1,000 cells/mm3. Patients were then followed for 6 months after SOT to compare the occurrence of CMV infection and the CMV DNA load testing-related cost.

Results

A total of 98 eligible SOTr were included and assigned into two groups, 49 patients each. They all underwent kidney transplantation (KT) with a mean+SD age of 46+11 years old; 66.3% were male. Demographic data between the two groups were comparable. Twenty-five (25.5%) participants developed CMV infection within 6 months after KT. CMV infection was comparably observed in 13 (26.5%) participants in the LOG group vs. 12 (24.5%) participants in the ALC group, p=0.82. Of those, there were no significant differences in terms of asymptomatic CMV infection, CMV disease, and clinically significant CMV infection (p=NS, all). The total cost of plasma CMV DNA load testing (68 USD per test) was significantly lower in the ALC group compared to the LOG group (2,320 vs.10,014 USD, p< 0.01), respectively.

Conclusion

Immune-guided preemptive therapy directed by low ALC appears to be effective in preventing early CMV infection after SOT. A simple and universally available ALC test could potentially be used as a personalized and cost-effective marker to initiate preemptive therapy in moderate-risk CMVR+ SOTr. TCTR20220720007.

Disclosures

All Authors: No reported disclosures
P-2312. Impact of a Short Course Post-Operative Antibiotic Prophylaxis Duration on Nephrotoxicity in Lung Transplant Recipients
Authors: Stratton Paige , Kenney Rachel M , Veve Michael , Fitzmaurice Mary Grace , Alangaden George J , Franco-Palacios Domingo
Published: January 2025

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-2323. Utilizing Nanopore Sequencing Technology to Identify Saporvirus Genotypes in Fecal Samples from Young Children with Diarrhea in Al Ain City, United Arab Emirates
Authors: Alsuwaidi Ahmed R , George Junu , Abdelrahman Mahmoud , Alblooshi Abdulrahman
Published: January 2025

Background

Human sapoviruses are important pathogens causing diarrhea globally. They are increasingly detected in individuals with diarrhea due to the expanded utilization of molecular diagnostic methods. There are 18 genotypes known to infect human (GI.1-7, GII.1-8, GIV.1, and GV.1-2). Notably, the genetic characteristics of sapoviruses circulating in the United Arab Emirates (UAE) remain unclear.

This study aims to use next generation sequencing to analyze sapovirus genotypes in stool samples from children under five with diarrhea in Al Ain city.

Methods

Using multiplex one-step real-time PCR (Allplex™ Gastrointestinal Full Panel Assay), 15 sapovirus-positive stool samples were identified from stool specimens collected for a previous epidemiological study of pathogens causing diarrhea during the period from December 2017 and April 2019. After excluding isolates with low viral load (Ct >30), 8 isolates were used for genotyping studies. Total RNA was extracted using a stool total RNA isolation kit and confirmed by endpoint PCR. Viral RNA was retrotranscribed to cDNA, followed by viral genome amplification, purification, and quantification. After sequencing with Nanopore MinION technology, reads that passed quality control (score >7) were produced. Geneious Prime and Mega11 Software were then used for base-calling, mapping, and phylogenetic analysis.

Results

PCR amplicon-based platform was developed for sequencing human sapoviruses in order to reduce the cost of sequencing per sample. The system produced successful amplification in 7 out of 8 studied sapovirus-positive samples. All isolates showed close similarity with each other showing more than 99% similarity. Blast analysis of sequences of the amplicons revealed close similarity with East Asian isolates (99%). The closest Middle Eastern isolate was from Iran showing 87% similarity with the UAE isolates. Phylogenetic analysis revealed that seven of the eight sapovirus isolates were found to cluster within the GI.1 genotype.

Conclusion

Using Nanopore sequencing technology, GI.1 genotype was found to be the most prevalent sapovirus genotype among the studied isolates. The obtained data will enhance our knowledge on the molecular diversity of sapoviruses in the UAE and enrich the current sapoviruses genotyping protocols.

Disclosures

All Authors: No reported disclosures
P-2325. Can activated partial thromboplastin time (aPTT) be used as a marker to predict bleeding and severity of Dengue fever in resource limited setting?
Authors: Bhalla Ashish , Bhalla Ashish Kumar , Kumar Ashok , Suri Vikas , Singh Harpreet , Dibhar Debaprasad , Sharma Navneet
Published: January 2025

Background

Bleeding in Dengue has been attributed to dysfunction in intrinsic pathway, however, there are no clear evidence of its use as a predictor of severity or mortality in adult patients with Dengue fever.

Our hypothesis is that prolonged aPTT is associated with life threatening bleeding and severity of Dengue fever.

Methods

a retrospective analysis of all patients diagnosed as Dengue fever admitted during the months of July to October 2023 was undertaken. The diagnosis of Dengue fever was established based on NS1 antigen positive (day 1-5) and/or IgM positive (day 7-12). Patients with dual infections, alternate diagnosis or secondary Dengue (IgG positive) were excluded. Details of the clinical parameters, haemogram, coagulation factors, liver and kidney function tests were recorded. The patients were classified as dengue without warning signs (mild), Dengue with warning signs (moderate) and dengue with Dengue shock syndrome(DSS)/ (DHF)Dengue hemorrhagic fever (severe) on the day of presentation. Progression to DSS/DHF during hospital stay, life threatening bleeding and mortality were the outcomes studied.

Results

195 patients were admitted but only 163 with complete clinical detail/ laboratory investigations were included in the study. The mean age was 31.8 years (range 13-80 years). Male : female ratio was 56%:44%. Average interval between onset of symptoms to clinical presentation was 7 days (range 5-11 days). Average duration of stay was 6.8 days. 80 patients (49%) had severe dengue at the time of presentation. 71 patients (43%) had bleeding with less than of them 50% having clinically significant bleeding. 103 patients (63%) patients had prolonged aPTT ( >35 seconds) at admission. 52 patients (32%) died. On multivariate analysis, prolonged aPTT and a low platelet count (< 10,000) at admission was not found to be associated with either clinically significant bleeding, severity of illness or mortality.

Conclusion

Severity, clinically significant bleeding and mortality in Dengue is not associated with either platelet count or APTT at presentation.

Limitation: our study included parameters at admission and did not include the lowest platelet counts and highest values of aPTT during admission.

Disclosures

All Authors: No reported disclosures
P-2328. Influenza and RSV Surveillance in the US Veterans Health Administration (VHA): 2023-2024 Season
Authors: Lucero-Obusan Cynthia A , Chung Joyce S , Schirmer Patricia , Edson Connor W , Oda Gina , Holodniy Mark
Published: January 2025

Background

Influenza and Respiratory Syncytial Virus (RSV) cause seasonal epidemics with substantial morbidity and mortality. Veterans Health Administration’s (VHA) large elderly population is at higher risk for complications, including hospitalization and death. Herein we summarize VHA’s annual surveillance data for influenza and RSV activity and vaccinations.

Methods

Influenza-like-illness (ILI) as well as influenza and RSV-coded outpatient visits and hospitalizations, laboratory testing, and antivirals were obtained from VHA data sources (10/1/2023-4/13/2024) and compared to prior years and CDC data. VHA and community vaccinations were captured starting August 1st each year, with rates calculated based on VHA users in each fiscal year. Influenza RT-PCR positive respiratory samples underwent whole genome sequencing (WGS) to analyze clade and antiviral resistance.

Results

Influenza vaccinations (including high dose) were increased compared to 2022-2023 (Table). Weekly ILI ranged from 0.6%-1.6% in primary/urgent care settings. Activity was highest for 2023 Week 52, matching national influenza trends and increased compared to last season (Fig.1). There were 28,853 influenza positives among 438,110 tests performed (6.6%). Median length of stay was 3 days in 4,059 hospitalizations. Among 139 deaths, 129 (92.8%) had Influenza A and 10 (7.2%) Influenza B (Table, Fig.2). 310 samples (in 5 states) were sequenced with no drug resistance mutations identified (237 A/H1; 30 A/H3; 43 B/Victoria), representing 4 subclades, which aligned with CDC reporting (Fig.3). Over 270,000 Veterans received an RSV vaccine in 2023-2024 (over 177,000 administered by VHA). RSV visits, hospitalizations and positive tests were increased compared to 2022-2023.

Conclusion

For 2023-2024, influenza vaccinations (including high dose) increased compared to prior years, and newly licensed RSV vaccines were available in VHA. Influenza and RSV activity was increased compared to the prior season. VHA influenza activity and WGS analysis tracks closely with national CDC reporting. Given risks associated with influenza and RSV in the elderly population, VHA will continue efforts to improve vaccination rates.

Disclosures

All Authors: No reported disclosures
P-60. Lineage dynamics are not the major drivers of Streptococcus pneumoniae serotype 3 vaccine escape
Authors: Stanley Sydney , Silva-Costa Catarina , Gomes-Silva Joana , Malley Richard , Ramirez Mario
Published: January 2025

Background

Streptococcus pneumoniae serotype 3 (Spn3) is included in the pneumococcal 13-valent conjugate vaccine (PCV13) but carriage and invasive disease persist worldwide. Previous work showed that the prevalent clonal complex 180 (CC180) of Spn3 is comprised of 3 genetically distinct lineages: clade Iα, Iβ, and II; a post-PCV13 shift towards increased incidence of clade II strains with a concomitant decrease in clade Iα and 1β incidence has been observed in the United States, England, and Wales. It was hypothesized that PCV13 is controlling clade Iα and 1β but not clade II, resulting in clade II expansion and ultimately rendering the vaccine ineffective against Spn3. It is imperative to test this hypothesis in other regional contexts given the implications on vaccine design and efficacy. Therefore, our group assessed the dynamics of Spn3 population structure and PCV13 in Portugal.

Prevalence of Spn3 clonal complexes before and after the introduction of PCV13 in Portugal

Methods

We whole-genome sequenced 501 Spn3 strains from Portugal and analyzed over 1400 Spn3 whole genome sequences from published datasets for global comparisons. Phylogenetic tree construction, clade identification, clonal complex typing, and annotation of antimicrobial resistance (AMR) and virulence genes was used to evaluate changes in bacterial genetics.

Prevalence of Spn3 clades before and after the introduction of PCV13 in Portugal

Results

Consistent with previous work, the prevalence of clonal complexes significantly changed before and after the introduction of PCV13 in Portugal (p=4.94-12): CC180 increased from 29% of Spn3 strains to 65%. The prevalence of lineages also changed (p=2.33-13): clade Iα increased from 21% to 54% of Spn3 strains, while clade II was not detected pre-PCV13 but increased to only 5% post-PCV13. This contrasts with studies conducted elsewhere. The phylogenetic distribution of AMR alleles is similar across different regions, so altered antibiotic fitness does not explain the continued success of clade Iα over clade II in Portugal.

Conclusion

Our data suggests clade II is not the global driver of Spn3 PCV13 vaccine escape as clade Iα remains dominant in Portugal. Current work aims to determine if clade Iα allelic variants augment virulence and thus competitive fitness against clade II in Portugal. Informed vaccine design requires an understanding of the region-specific bacterial population structure and genetic features to optimize efficacy.

Disclosures

Richard Malley, MD, Amplitude Therapeutics: Board Member|Corner Therapeutics: Board Member|GSK: Advisor/Consultant|Merck: Advisor/Consultant Mario Ramirez, PhD, GSK: Advisor/Consultant|Merck Sharp and Dohme: Advisor/Consultant|Pfizer: Honoraria
P-64. Variations in the treatment of Cutibacterium acnes Infections of the Bones and Joints and Associated Outcomes
Authors: Elizabeth Yun Adrienne , Bhargava Ashish , Szpunar Susan M , Johnson Leonard B
Published: January 2025

Background

Cutibacterium acnes is an emerging pathogen in bone and joint infections. While treatment guidelines recommend the use of β-lactam therapy for C. acnes infections, the lack of routine susceptibility testing may result in wide variation in treatment regimens among physicians. We assessed the treatment regimens chosen by physicians for patients with bone and joint infections with C. acnes and the treatment outcomes of β-lactam and non-β-lactam regimens.

Methods

This was a multi-center, historical cohort study comparing treatment regimens in patients diagnosed with C. acnes for both native and prosthetic bone and joint infection. The study included patients with monomicrobial cultures positive for C. acnes and diagnosed with septic arthritis, prosthetic joint infections, osteomyelitis, or discitis between 7/1/2018- 6/30/2023. Data collected included antimicrobial therapeutic regimens, surgical intervention, as well as treatment failure and success. Data were analyzed using chi square test, Student’s t-test, and the Mann-Whitney U test.

Results

Among 49 included patients, 65.3% of infections resulted from prosthetic joint infection, 26.5% from osteomyelitis, and 8.2% from septic arthritis. The most common intravenous antibiotics chosen to treat C. acnes were ceftriaxone (51%), vancomycin (16.3%), and penicillin (6.1%) with a mean treatment duration of 43.4 days. The most common oral antibiotic treatment was doxycycline (20.4%), amoxicillin (18.4%), cephalexin/cefadroxil (12.2%) with a median outpatient treatment duration of 38 days (range 5, 364). Overall, there were no difference in treatment outcomes between patients treated with β-lactams vs, non-β-lactams at six months, including cure (58.8% vs. 71.4%, p=0.53), persistence of symptoms (26.5% vs. 14.3%, p=0.49), recurrence (17.6% vs. 28.5%, p=0.51), and requiring suppressive therapy (23.5% vs. 28.6%, p=0.78), respectively.

Conclusion

Physicians preferred β-lactam antibiotics for treating patients with bone and joint infections caused by C. acnes. There were no differences in outcomes for treating C. acnes bone and joint infections between β-lactam and non-β-lactam antibiotic regimens. Further studies should be performed to confirm this observation.

Disclosures

All Authors: No reported disclosures
P-111. Promising Efficacy of Nasal-Spraying Bacillus Spore probiotics for Supportive Treatment of Pneumonia in Children with RSV and Bacterial Co-infections
Authors: Bich Phung Thuy Thi , Van Nguyen Anh Thi , Thi Bui Huyen , Hoa Nguyen Anh , Minh Nguyen Hang , Hong Le Hanh Thi , Le Hoa Thi
Published: January 2025

Background

: Respiratory syncytial virus (RSV) and bacterial co-infections are primary cause of pneumonia. Recently, nasal-spraying Bacillus spore probiotics (LiveSpo NAVAX containing ≥ 5 billion/5mL B. subtilis and B. clausii spores) have demonstrated its effectiveness in supporting the treatment of acute respiratory tract infections caused by RSV and Influenza virus1,2.

Methods

A randomized, double-blind, controlled clinical trial was conducted to evaluate the efficacy of LiveSpo NAVAX in the supportive treatment of severe pneumonia due to RSV and bacterial co-infections. A total of 120 eligible pediatric patients were randomly assigned to two groups: the Control group received 0.9% NaCl physiological saline, and the probiotic-intervention group (Navax group) received LiveSpo NAVAX three times a day.

Results

At day 3, the Navax group demonstrated significant reductions in both RSV and bacterial co-infection 15.7 and 40.8-fold greater than those observed in the control group. Notably, H. influenzae and S. pneumoniae were reduced by 22.8 and 17.2 folds, respectively. Additionally, the Navax group exhibited significant decreases in pro-inflammatory cytokines (IL-6, IL-8, TNF-α), with levels reduced by 1.4 - 3.6 folds, while also enhancing the immune system (IgA) by over 67.04%. Furthermore, the 16S rRNA metagenomic analysis revealed the restoration of nasal microbiota, with an increase in the density of beneficial genus such as Corynebacterium, Bacillus and a reduction in the density of harmful genus including Streptococcus, Haemophilus, and Moraxella.

Conclusion

Our data demonstrate that nasal-spray Bacillus spore probiotics supported the treatment of pneumonia in children by reducing RSV, co-infection bacterial loads, and pro-inflammatory cytokines.

Disclosures

All Authors: No reported disclosures
P-134. Sarcina ventriculi, pathogen or commensal? Case series and review of the literature
Authors: Al khouri Zaid , Al Qura'an Anood , Koppada Satya , Mubashir Maryam , Zia Hassaan , Pinargote Paulette , Salazar Wilmer
Published: January 2025

Background

Sarcina, or Clostridium, ventriculi (SV), is a non-motile, gram-positive coccus with anaerobic fermentative properties. Due to its rarity, comprehensive knowledge about it is lacking. This study aims to elucidate its epidemiology and common manifestations.

Methods

We searched PUBMED and EMBASE utilizing terms as 'Sarcina', 'Ventriculi', and 'Clostridium' with no restrictions. Figure 1 contains the PRISMA diagram for case selection.

Results

We identified 88 cases and included 2 cases from our institution. The mean age was 48 ranging from 10 months to 89 years with an equal distribution between genders. 21% had Diabetes mellitus type 2 and 50% had baseline GI comorbidity primarily affecting the esophagus or stomach in 27% respectively. 37% were concurrently on antacids and prokinetics. The most common symptoms were abdominal pain (58%), nausea/vomiting (41%), anorexia/weight loss (18%), and diarrhea (12%).  Pertinent labs were anemia, leukocytosis, and elevated inflammatory markers. Mural inflammation, ulcers, retained food with distension, pneumatosis, perforation, necrosis, masses, or obstruction were common on radiological and endoscopic workup. Organism was mostly isolated from gastric (73%) and esophageal (18%) tissue using endoscopic and/or surgical procedures (76 and 27%, respectively). It was also isolated from respiratory tissue (3%), anaerobic blood culture (3%), lymph nodes (2%), urine (1%), and cerebral ventricles (1%). Co-infection with candida in 8% and H. Pylori in 4% was noted. 57% received antibiotics, being combination therapy with metronidazole and fluroquinolones, the most therapy used.

77% had successful clinical recovery, 11% expired; the outcome for 12% of patients remains unknown. Antibiotic therapy was used in 67% and 40% of patients who clinically recovered and expired respectively.

Conclusion

In most cases, SV is a true pathogen responsible for symptoms rather than a commensal; however, larger-scale studies are needed to discern pathophysiology. Most cases present with an underlying GI comorbidity including dysmotility which might predispose to colonization. Metronidazole and fluroquinolones provide optimal clinical response.

Disclosures

All Authors: No reported disclosures
P-149. Clinical Profile and Antimicrobial Resistance Patterns of Salmonella Infection in Guatemala City
Authors: Elisa Rosales Ana , Barrios Andrea , Orozco Jarleny , Valenzuela Laura , Rodriguez Luis , Erdmenger Diego
Published: January 2025

Background

Salmonella infection is the second most common food-borne disease worldwide, causing over 155,000 deaths per year. Infection rates in low- and middle-income countries surpass those of high-income countries.

Several risk factors have been associated with higher mortality rates due to Salmonella infection, such as age, HIV infection, and antimicrobial resistance.

Although frequent in Central America, few data on risk factors associated to invasive Salmonellosis and mortality are available in the region.

Population General Characteristics

Methods

A retrospective cohort study was conducted at a third-level reference hospital in Guatemala City from 2022 to 2023. All cases of Salmonella infection identified through blood and stool cultures were included and evaluated for clinical factors and interest outcomes. Antimicrobial resistance patterns were identified according to the Clinical and Laboratory Standard Institute (CLSI) guidelines.

Clinical characteristics associated with mortality

Results

A total of 15 confirmed cases of Salmonella infection were identified. The mean age of the patients was 37.8 years (SD = 17.8). The majority of were male (86.6%). Over 73% had at least one comorbidity, with HIV being the most frequent, followed by chronic alcohol consumption.

The most common presentation included fever, diarrhea, and abdominal cramps. Only 6.6% of patients reported constipation. Over 46% of strains exhibited at least one mechanism of resistance, with 40% of showing resistance to fluoroquinolones, suggesting the presence of a GyrA-ParC phenotype.

The most common complication identified was Acute Kidney Injury in 46.6% of cases, with Hemolytic Uremic Syndrome present in 13.3% of cases. The overall mortality rate due to salmonellosis was 26.6% (Table 1).

Age over 50 years, sex, HIV infection, and ESBL resistance were significantly associated with in-hospital mortality, after adjusting for other clinical variables (Table 3).

Adjusted variables associated with mortality

Conclusion

The study identified a higher resistance to fluoroquinolones and case-mortality compared to other reports in the region. Although ESBL-producing strains were rare in the study, this resistance pattern was significantly associated with mortality due to salmonella infection. The uncontrolled use of antibiotics in the country may present as a major concern in the future treatment and management of salmonellosis.

Disclosures

All Authors: No reported disclosures
P-154. Malaria In Tunisia : Eradicated Or Still Endemic ?
Authors: Hammami Fatma , Rekik Khaoula , Smaoui Fatma , Chakroun Amal , Marrakchi Chakib , Koubaa Makram , Ben Jemaa Mounir
Published: January 2025

Background

Although malaria has been eradicated in Tunisia since 1979, our country remains exposed to the potential risk of resurgence. We aimed to study clinical, laboratory and therapeutic features of malaria.

Methods

We conducted a retrospective study including all patients hospitalized in the infectious disease department for malaria between 2000 and 2022.

Results

We encountered 92 cases, among whom 85 were males (92.4%). The mean age was 30±11 years. Fifteen patients received malaria chemoprophylaxis (16.3%). Returned travellers developed symoptoms after 10[5-25] days of returning home. Countries involved in importation were Ivory Coast (31.5%), Mauritania (8.9%) and Senegal (6.5%). The revealing symptoms included fever (90.2%), chills (87%), cephalalgia (79.3%) and diarrhea (26.1%). Arthromyalgia and vomiting were noted 46 cases (50%), each. Thrombopenia (65.2%), elevated C-reactive protein levels (43.5%), lymphopenia (39.1%), anemia (31.5%) and hepatic cytolysis (27.1%) were reported. There were 23 cases of severe malaria (25%). Palsmodium falciparum was identified in 68 cases (74%) and Plasmodium vivax in 8 cases (8.9%). Gametocytes were detected in 8.9% of the cases. Patients were treated with artemether/lumefantrine (71.7%) or quinine (19.6%). The disease evolution was favorable in 90 cases (97.8%). Apyrexia was noted after 2±1 days of treatment. Two patients were dead (2.2%).

Conclusion

Travellers to malaria endemic countries should be aware of the risk of malaria in order to follow preventive measures and to promptly consult in case of symptoms. An early diagnosis followed by the adequate treatment might prevent severe forms and death.

Disclosures

All Authors: No reported disclosures
P-168. Antimicrobial Resistance Patterns at a Private Referral Hospital in Blantyre, Malawi
Authors: Cappiello Matthew , Lim Lindsay S , Rambiki Tadala , Chala Dosso Kalkidan , Felix Mandala Freedom , Infante Juan , Liu Eugene W
Published: January 2025

Background

Antimicrobial resistance (AMR) is expected to be a global health security risk in Africa in coming decades. While AMR data is available from Malawi public hospitals, data from Malawi’s burgeoning private hospital sector is limited.

Initial Hospital Antibiogram Data, Fall 2021 - Spring 2022

Methods

An antibiogram was obtained for clinical blood and urine cultures from October 2021 through April 2022 at a private referral hospital in southern Malawi (n=684). Logistic regression was used to assess for patient-related determinants of AMR, as well as effects on patient outcomes.

Tests of Association for AMR Determinants

Results

High AMR rates were seen in E. coli (37.4% ceftriaxone, 35.8% ciprofloxacin, 32.5% trimethoprim), as well as unexpected carbapenem resistance (7.4% of tested isolates). Statistically significant tests of association linked both fluoroquinolone (X2 = 4.91, p=0.027) and third-generation cephalosporin resistance (X2 = 3.67, p=0.05) to patients who had increased numbers of antecedent hospital encounters. Fluoroquinolone resistance was associated with increased risk for acute-care follow up within 30 days of antibiotic prescription (X2 = 4.73, p=0.03). Third-generation cephalosporin resistance (suggestive of ESBL production) showed association with older age (X2 = 20.009, p=< 0.001) and female gender (X2 = 5.58, p=0.018) A multiple logistic regression model examining variables associated with ceftriaxone-resistant Enterobacterales showed increased risk of patient death (OR 5.99, CI 1.37–26.17, p=0.017), as well as higher Charlson comorbidity index (OR 1.14, CI 1.02-1.28, p=0.024).

Over 40% of patients with culture-positive results were treated empirically, without follow up for review of sensitivities. Choice of empiric antibiotic differed from national guidelines, with only 32% UTI patients and 8.4% pharyngitis patients receiving recommended first-line regimens. Local point-prevalence data sometimes appeared to be discordant with national data. As one example, all three recommended cystitis regimens on national formulary guidelines displayed >=30% resistance rates on local antibiogram data, including ciprofloxacin, nitrofurantoin, and cefuroxime.

Logistic Regression for Determinants of ESBL Enterobacterales

Multiple logistic regression model

Conclusion

Further research needs to assess best practices for stewardship in regional private hospitals, as well as determinants for AMR that encompass markers of healthcare utilization.

Demographic Descriptive Statistics

Disclosures

All Authors: No reported disclosures
P-171. Epidemiology of Carbapenem-Resistant Gram-Negative Organisms across sites participating in CDC’s Global Action in Healthcare Network-Antimicrobial Resistance Module — Ethiopia, Greece, and India, October 2022-February 2024
Authors: Robinson Matthew
Published: January 2025

Background

A rising burden of carbapenem-resistant Enterobacterales (CRE) worldwide, in particular CRE producing plasmid-encoded carbapenemases (CPOs), has prompted global concern for rapid spread of resistance and difficult to treat infections. Data from low- and middle-income countries characterizing CRE is limited. CDC’s Global Action in Healthcare Network – Antimicrobial Resistance Module aims to prevent, detect, and respond to CP-CRE in healthcare settings.

Methods

CRE clinical isolates identified by antimicrobial susceptibility testing across select high-risk, inpatient, and outpatient settings in 8 hospitals in Ethiopia, Greece, and India were tested for carbapenemase production with modified carbapenem inactivation method and/or identification of KPC, NDM, VIM, IMP, and OXA-48-like carbapenemases using lateral flow assays (Greece and India) or KPC, NDM, VIM, and OXA-48-like using real-time polymerase chain reaction (Ethiopia).

Distribution of carbapenemase detection by country, Enterobacterales (N = 3,497) — Ethiopia, Greece, and India, October 2022-February 2024

Results

During October 2022– February 2024, 14,078 Enterobacterales isolates in 3 countries were evaluated for carbapenem resistance; 3,060 (22%) were carbapenem resistant (Table). Carbapenem resistance was common across settings for Klebsiella pneumoniae (42-54%) but was lower and more variable for Escherichia coli (1-27%) and Enterobacter cloacae complex (7-31%). Testing for carbapenemase production and/or mechanism was performed for 3,497 CRE isolates, which identified carbapenemase production or a mechanism in 3,239 (93%) of CRE isolates. Among CRE tested for carbapenemases, the most common carbapenemases identified were KPC in Greece and NDM in India and Ethiopia; multiple carbapenemases were identified in 793 (24%) of carbapenemase producers (Figure).

Conclusion

In this global cohort, the majority of CRE tested for carbapenemase production were identified as carbapenemase-producing and the dominant carbapenemase detected by species varied by country. Collaboration, coordinated action, and innovative strategies are needed to both reduce spread of these highly resistant organisms in endemic settings and increase preparedness to prevent emergence and spread of novel carbapenem resistance mechanisms in the future.

Disclosures

All Authors: No reported disclosures
P-217. Risk Factors Associated with Clostridioides difficile Infection and Mortality in a Referral Hospital in Nicaragua
Authors: Balitán-Amoreti Carlos , Marenco-Avilés Sunaya , Porras-Cortés Guillermo D
Published: January 2025

Background

Clostridioides difficile infection (CDI) is one of the main problems among healthcare-associated infections. Some studies report an increase in the incidence of this infection causing enterocolitis in hospitalized patients and eventually being associated with various complications, mortality, and increased hospital costs. The data about the epidemiology and outcomes of CDI in Nicaragua are insufficient. The aim of this study was to determine risk factors associated with CDI infection and mortality in patients admitted to a referral hospital (Dr. Fernando Vélez Paiz Hospital) in Managua, Nicaragua.Table 1.Clinical Factors Associated in Patients with and without Clostridioides difficile Infection

Methods

It is an analytical nested cohort study. A total of 150 patients hospitalized in different services of the hospital between January 2020 and December 2022 and who started with in-hospital diarrhea (defined as the absence of pre-existing diarrhea prior to hospitalization and onset 72 hours after admission to the hospital) were included. Of the150 patients, 50 were defined as CDI cases and 100 as controls without CDI. The diagnosis of CDI was made by molecular method (real-time RT-PCR) using Xpert C. difficile®. Differences between cases and controls were analyzed.Figure 1.Comparative Mortality Rate in Patients with and without Clostridioides difficile Infection

Results

The mean age of the patients was 52.8±18.7 years-old, 52% were men, and 50% had an associated chronic disease. A higher proportion of patients with CDI had a history of antibiotic use (98% vs 52%, p< 0.001), use of proton pump inhibitors (46% vs 25%, p=0.009), previous hospitalization (94% vs 46%, p< 0.001), and previous surgery (64% vs 25%, p< 0.001) (Table 1). Mortality in patients with CDI was 20% vs. 11% in controls (Figure 1). In the univariate analysis, the risk factors for CDI were the classic ones, such as previous use of antibiotics (ceftriaxone, quinolones, clindamycin), previous hospitalization, previous surgery, and use of proton pump inhibitors. The multivariate analysis found that previous use of ceftriaxone (OR: 6.40; 95%CI: 2.09–19.59) and clindamycin (OR: 3.0; 95%CI: 1.01–8.92) were significantly associated with CDI (Table 2). Regarding mortality, a significant association was found with age over 60 years-old (OR: 4.33; 95%CI: 1.02-18.41).Table 2.Risk Factors in Multivariate Analysis for Clostridioides difficile Infection and Mortality

Conclusion

Prior use of ceftriaxone and clindamycin are independent risk factors for CDI. Patients with CDI over 60 years-old have a higher risk of mortality.

Disclosures

All Authors: No reported disclosures
P-224. Accurate Clostridioides difficile Ribotype Prediction from Whole Genome Sequencing Data Using Machine Learning
Authors: Qi Peng , McKay Susannah , Paulick Ashley , Vlachos Nick , Adamczyk Michelle , Friedman Bree E , Weber Bonnie , Gargis Amy , Halpin Alison L
Published: January 2025

Background

Clostridioides difficile is a healthcare-associated pathogen recognized as the most common cause of infectious diarrhea in healthcare settings. PCR-based ribotyping, which employs heterogeneity of the ribosomal intergenic spacer region for discrimination, has historically been the preferred method for C. difficile typing. However, ribotyping is laborious and exhibits inter-laboratory variation which significantly limits its utility as a universal typing scheme.

The increasing adoption of whole genome sequencing (WGS) provides the opportunity for universal prediction of ribotypes (RTs) from WGS data. Machine learning (ML) offers the opportunity to predict RTs from genomic features which are more amenable to reliable resolution by WGS analysis than the repetitive sequences which define RTs.

Methods

Here we employed 8 different ML models using a dataset of 2,283 C. difficile isolates collected through surveillance activities (2012-2018) with both CDC’s capillary-based PCR-ribotyping and whole genome multi-locus sequence type data (6,786 loci; BioNumerics v7.6). The dataset was divided into training (75%) and testing (25%) sets to train and test each model. Models were improved with hyperparameter tuning. Accuracy was calculated from the predicted RTs compared to the PCR-based RTs of the test set. We combined the top three models based on probability distribution of correct/incorrect predictions to enhance performance. The final model was applied on WGS data for 2,194 isolates collected during 2019-2020.

Results

The top performing models were Support Vector Machine (linear kernel) (93.2% accuracy), Xgboost (92.6%), and Logistic Regression (92.6%). The final combined model achieved 94.3% accuracy overall with 44/51 RTs reliably predicted (99.2%). Three RTs could not be reliably predicted (64.0%); one RT could not be predicted due to the insufficient number of isolates available in the dataset. Application of the final model on the 2019-2020 dataset reliably predicted 93.2% (1816/1948) of RTs called; 11% of isolates lacked a RT call.

Conclusion

Use of ML on WGS data shows promise as a universal method for accurate C. difficile RT prediction and thus for identifying clinically important strains while providing an important bridge to connect WGS with historical RT trends.

Disclosures

All Authors: No reported disclosures
P-226. Assessing the Risk Factors for Catheter Related Bloodstream Infections (CRBSI) among Cancer Patients with Long Term Central Venous Catheters (LCVC) for Implementing Preventive Interventions
Authors: Haddad Andrea , Wilson Dib Rita , Chaftari Anne-Marie , Jiang Ying , Moussa Mohammad , Dagher Hiba , Philip Ann , Hachem Ray Y , Raad Issam I
Published: January 2025

Background

Catheter Related Bloodstream Infection (CRBSI) remains a leading cause of morbidity, mortality, and escalating costs in cancer patients with LCVC despite advancements in medical care and the implementation of BSI bundle. Several risk related studies have been published in cancer patients but did not include strict definition of CRBSI and relied on Central Line-Associated Blood Stream Infections (CLABSI) definitions in the setting of Mucosal Barrier Injuries (MBI) which might be emerging from the gut rather than the catheter. Our study aims at determining specific subgroups of cancer patients who are most susceptible for CRBSIs to determine the potential effectiveness of preventive interventions such as catheter locks.

Independent predictors of CRBSI by multivariate logistic regression analysis

Methods

We retrospectively reviewed cancer patients with indwelling LCVC that remained in place for at least 3 weeks between 2018 and 2022. By simple random sampling, we compared 200 patients who developed a definite CRBSI to 400 patients who did not. A definite CRBSI was defined according to the stringent criteria by the Infectious Diseases Society of America.

Results

Among cancer patients with CRBSI, 82% had hematological malignancy. Over 50% of the catheters had 2 lumens. Patients with CRBSI were more likely to receive blood products through the catheter (81% vs 45%, p< 0.0001). The median time from catheter insertion to CRBSI was 51 days. Of the identified pathogens causing CRBSI, 62% were gram positive bacteria, 37% gram negative bacteria and 2% candida. By multivariate logistic regression analysis, the leading independent significant risk factors were the presence of multiple catheters in place, neutropenia, allogeneic transplants, followed by blood product administration, multiple catheters inserted within the past year, and basilic site insertion (table 1).

Conclusion

Cancer patients with LCVC are susceptible to CRBSI, particularly those who are neutropenic, had allogeneic transplants, have multiple catheters, received blood products, or had basilic site insertion. Effective preventive interventions such as antimicrobial locks and antimicrobial catheters with prolonged activity should be primarily implemented in these highest risk populations.

Disclosures

All Authors: No reported disclosures