bluuebunny/crossref_metadata_2025 huggingface dataset:
578. Performance of acid-fast stain, real-time PCR, and Xpert MTB/RIF in a bronchial washing for the Rapid Diagnosis of Mycobacterial infection in real-world
Authors: Hwang Joo-Hee , Hwang Jeong-Hwan , Choi Sung-Sik , Han Hyo-Jin , Lee Seung Yeob , Park Joonhong , Jo Dae Sun , Cho Yong Gon , Kim Dal Sik , Lee Jaehyeon
Published: November 2023

Background

Mycobacterium culture remains still the gold standard for diagnosing mycobacterium infections, but there are some limitations. Acid-fast stain and simultaneous molecular methods are recommended for early diagnosis and treatment. Bronchial washing has been reported to be an effective diagnostic sample, even in cases sputum smear tests are negative. Additionally, it can be used in multiple assays. Therefore, we analyzed the clinical performance of acid-fast stain, real-time PCR, and Xpert MTB/RIF assay compared to mycobacterial cultures in the same bronchial washing.

Methods

We screened laboratory data from January 2018 to December 2020 at Jeonbuk National University Hospital. We enrolled the samples that all the tests for analysis, acid-fast stain, rPCR, Xpert MTB/RIF, and mycobacterial culture, were ordered simultaneously. The study was approved by the Institutional Review Board of Jeonbuk National University Hospital (CUH 2022-05-036-001). In short, the bronchial washing was sent to a clinical microbiology laboratory. The cultures were done with 2% Ogawa medium and BacT/Alert MB culture bottle after NALC-NaOH. The rPCR and the Xpert MTB/RIF was done according to the manufacturer's guide. The statistical analysis was done with Excel 2016 and Analyse-it.

Results

A total of 1966 samples were enrolled, and the culture-positive sample is defined when either the solid or liquid cultures showed positive. In the mycobacterium culture, 12.8% were MTB positive, and 10.7% were non-tuberculosis Mycobacterium (NTM) positive. The sensitivity and specificity of acid-fast stain were 45.6% and 98.9%, respectively, compared to mycobacterium culture positive, including MTB or NTM. The sensitivity and specificity of rPCR in MTB and NTM are 85.7%/94.3% and 52.9%/99.3%, respectively, and Xpert MTB/RIF in MTB cases was 94.8% and 92.1% (Table 1).

Conclusion

The acid-fast stain is still a valuable diagnostic tool despite its low sensitivity because it is easy to prepare and it doesn't require specialized equipment or facilities. The rPCR for MTB showed reliable results. However, in rPCR for NTM, the sensitivity was much lower than MTB. Xpert MTB/RIF showed superior sensitivity than rPCR here. The assays should be used strategically in suspected mycobacterium infections.

Disclosures

All Authors: No reported disclosures
587. Research and Development of Image Recognition AI to Estimate Bacterial Species using Gram Stain Findings in Aerobic and Anaerobic Blood Culture Bottle
Authors: Miyatsuka Isao , Yamamoto Kei , Ohji Goh , Ohmagari Norio , Kurokawa Masami , Ebisawa Kei Furui , Ohnuma Kenichiro , Kusuki Mari , Nakada Mitsutaka , Maeta Shogo
Published: November 2023

Background

Background

In the highly fatal infectious disease of bacteremia, the ability to select antimicrobial agents at an earlier time is critical not only for early patient recovery, but also for reducing the development of resistant organisms. Gram staining of blood cultures is a useful test for early selection of antimicrobial agents, but it requires some skill in deciphering. Therefore, we developed an image analysis system for Gram stain images of blood cultures and have verified whether it is possible to estimate the bacterial species to facilitate the initial selection of antimicrobial agents, regardless of the level of proficiency.

Methods

Method

Slides and bacterial species-identification information from an anonymized Gram stain registry at two medical institutions, National Center for Global health and Medicine (NCGM) and Kobe University Hospital (KUH), were used for the study. 1113 cases of aerobic bottles and 1060 cases of anaerobic bottles were included. Mock-specimens were used for the rare bacteria. A total of 23,947 images were generated by capturing the observation field of view of an optical microscope with a smartphone. Table 1 shows the bacterial classification of aerobic bottles and Table 2 shows the bacterial classification of anaerobic bottles. The data were divided into training data and test data at a ratio of 8 to 2 for each category.Table 1.A total of 16 categories of bacteria were used for classification of aerobic bottlesTable 2.A total of 16 categories of bacteria were used for classification of anaerobic bottles

Results

The macro-average recall (sensitivity) and accuracy of the test data were 64% and 82% for aerobic bottles and 68% and 86% for anaerobic bottles, respectively. The results showed the possibility of classifying the performing bacterial species with an accuracy of over 70% using only Gram stained images via image recognition AI. For aerobic bottles in particular, the seven categories of GNR, GNC, GPR, GPC, yeast, No organism, and multiple bacteria are predicted to have 97% accuracy, and 90% macro average recall.

Conclusion

The research has shown that it is possible to classify bacterial species to a certain extent only by observing the Gram stain images. Our goal is to narrow down and focus more on the clinically-meaningful bacterial species, and to improve the accuracy of our classification. Also, we are planning to make comparisons with specialists in the future.

Disclosures

Kei Yamamoto, MD, Canon medical systems: Grant/Research Support|CarbGeM: Grant/Research Support|CarbGeM: 7090302|Fujirebio: Grant/Research Support|Sanyo Chemical Industries: Grant/Research Support|VisGene: Grant/Research Support Goh Ohji, MD, PhD, DTMH, CarbGeM: Advisor/Consultant
591. Positivity of Blood Culture on Automated Incubation System After 72 Hours and Clinical Significance from the Large United States Tertiary Care Center
Authors: Patel Premalkumar M , Rivera Cynthia
Published: November 2023

Background

Hospitals commonly use automated blood culture incubation systems that provide continuous monitoring for routine blood cultures. Detecting microorganisms early on can help optimize the utilization of antibiotics (ABx) and enable clinicians to de-escalate or discontinue ABx as necessary, making it an important aspect of antimicrobial stewardship. The BD BACTEC Fx, an automated system for blood culture incubation, holds blood culture bottles until growth is demonstrated or for five days unless an extended incubation period is requested by the infectious disease physician. We conducted a clinical evaluation of the significance of positive blood cultures after 72 hours of incubation time.

Methods

After receiving approval from the institutional review board (IRB), we obtained positive blood cultures from July 2017 to June 2020, which we then stratified based on positivity from day one to day five. To evaluate clinical significance, we retrospectively reviewed charts for positive blood culture results on day four and day five. An Infectious Diseases subspecialty team determined the clinical significance of each case.

Results

During the time frame of July 2017 to June 2020, there were 120,320 blood cultures taken. Out of these, 7,558 were determined to be positive, with 76 being positive on day 4 and 22 being positive on day 5. Upon further inspection of patients with positive blood cultures, it was discovered that repeat blood cultures continued to be positive due to either untreated sources or a high burden of bacteremia. It was also found that bottles containing fungus, particularly candida glabrata and candida albicans, tested positive on day 4 requiring treatment. Table 1 and Table 2 contain more detailed results.

Blood cultures positive on day 4

Blood cultures positive on day 4 and clinical significance

Blood cultures positive on day 5

Blood cultures positive on day 5 and clinical significance

Conclusion

In our study we have found that not all positive blood cultures at 72 hours translate into clinical scenarios requiring antibiotic therapy. In fact, prolonged antimicrobial treatment in such cases may lead to unnecessary exposure to antibiotics and increased risk of antibiotic resistance. It is important to consider the full context of clinical and laboratory findings when interpreting blood culture results, as well as any potential sources of contamination.

Disclosures

All Authors: No reported disclosures
603. Determining Effect of Media and Disk Source on Reproducibility and Relationship between Broth Microdilution and Disk Diffusion Testing of Cefiderocol
Authors: Takemura Miki , Saiki Mizue , Yamashiro Hidenori , Anan Naomi , DeJonge Boudewijn L , Slover Christine M , Longshaw Christopher M , Henriksen Anne , Yamano Yoshinori
Published: November 2023

Background

Cefiderocol (CFDC) is a siderophore cephalosporin with broad activity against Gram-negative bacteria. Discrepancies in susceptibility testing for CFDC have been reported. In this study susceptibility testing was performed using broth and agar medium and disks from various manufacturers to evaluate the reproducibility across the different sources and determine the relationship between MIC and inhibition zone.

Methods

12 Enterobacterales, 12 P. aeruginosa, 12 A. baumannii with in vivo efficacy results in the murine thigh infection model under humanized PK of CFDC were evaluated. MICs were determined (10 replicates per media per isolate per day) using broth microdilution with iron-depleted cation-adjusted Mueller-Hinton broth (ID-CAMHB) prepared from BD BBL, BD Difco, Oxoid and Merck. The disk zone was determined (3 replicates per media/disk per isolate per day) with CFDC disks from Hardy and Liofilchem and Mueller Hinton Agar from BBL and bioMerieux. Testing was conducted for 3 days using the same inoculum for MIC and disk diffusion studies on each day. Susceptibility was interpreted according to 2023 CLSI breakpoints.

Results

Good reproducibility of MIC was observed for the ID-CAMHB from each manufacturer for all isolates, except for 2 A. baumannii due to heavy trailing and skip. MIC variation was observed between ID-CAMHB from each manufacturer. Best categorical agreement with in vivo efficacy was observed for the MIC obtained with ID-CAMHB from BD BBL. Good reproducibility of disk inhibition zones were obtained for Enterobacterales and P. aeruginosa irrespective of the manufacturer of disks and agar medium. A. baumannii isolates with elevated MIC values frequently showed colonies in the inhibition zones, with more colonies appearing on BBL agar. This phenomenon was not reproducible, so larger variation of inner inhibition zones were observed with these isolates.

Conclusion

MIC determinations were reproducible with each ID-CAMHB medium, but variability was observed across the different ID-CAHMB; MICs obtained with BD BBL ID-CAMHB showed best correlation with in vivo data. Good categorical agreement was observed for MIC in BD BBL and BD Difco medium and disk zone, despite variable inhibition zones observed for A. baumannii.

Disclosures

Miki Takemura, n/a, Shionogi & Co., Ltd.: Stocks/Bonds Mizue Saiki, Ph.D., Shionogi & Co., Ltd.: employee Hidenori Yamashiro, Shionogi & Co., Ltd.: employee Naomi Anan, MSc, Shionogi & Co., Ltd.: employee Boudewijn L. DeJonge, PhD, Shionogi Inc.: Employee Christine M. Slover, PharmD, Shionogi,INC: Employee Christopher M. Longshaw, PhD, Shionogi BV: Employee Anne Henriksen, PhD, Shionogi: Employee Yoshinori Yamano, PhD, Shionogi HQ: Employee
606. Clinical Utility of Fungal Blood Cultures for the Diagnosis of Candidemia
Authors: Bheem Rishika , Hanisch Benjamin , Liu Benjamin M , Campos Joseph M , Ansusinha Emily , Hamdy Rana F
Published: November 2023

Background

Candidemia is the most common invasive fungal infection in hospitalized children, and the third most common cause of pediatric nosocomial bloodstream infections. The gold standard for diagnosis of Candida bloodstream infections is with blood cultures, and clinicians can order aerobic or fungal blood cultures when suspecting fungemia. The objective of this study is to investigate the additional utility of fungal blood cultures (in addition to aerobic blood cultures) for detecting Candida bloodstream infections.

Methods

This retrospective cohort study analyzed all patients < 21 years of age, admitted to Children’s National Hospital between January 1, 2010, and December 31, 2020, and had a positive fungal blood culture (using BHI-CG plates) for Candida species on day 1 of fungemia (Table 1). Demographic data, Candida species, the concomitant positive aerobic blood cultures (using the bioMérieux BACT/ALERT blood culture system) were collected from the electronic health records through structured chart review. The time to detection of positive blood cultures was calculated for the fungal and aerobic cultures drawn on day 1 of fungemia. P-value < 0.05 was considered statistically significant.Table 1:Definitions

Results

Thirty-one episodes of Candida fungemia (29 patients) were included in this study, of which 28 episodes also had an aerobic blood culture drawn on day 1 of fungemia that was positive for Candida species. All 31 episodes had an aerobic blood culture positive for Candida species within the duration of fungemia (Figure 1). The mean age of patients in the cohort was 5.7 ± 6.0 years with mean duration of admission of 67.1 days ± 79.6. C. parapsilosis was the most frequently identified Candida species (14), followed by C. albicans (10), C. lusitaniae (Clavispora lusitaniae) (2), C. tropicalis (1), C. krusei (Pichia kudriavzevii) (1) (Table 2). The mean time to positivity for aerobic blood cultures and fungal blood cultures were 26.4 ± 11.7 hours and 76.2 ± 29.6 hours, respectively (p < 0.001).Figure 1:Patient Population and Analysis FlowchartTable 2:Episodes of Candida by Species

Conclusion

All episodes of Candida species that grew on fungal cultures also had at least one aerobic culture positive for Candida species within the duration of fungemia. Aerobic blood cultures had a statistically significant shorter time to positivity for Candida than fungal blood cultures.

Disclosures

Benjamin Hanisch, MD, American Society of Transplantation: Board Member|Astellas Pharma Global Development, Inc.: Support for the present publication|NIH: Site PI for International Pediatric Fungal Network- funds to institution Joseph M. Campos, PHD, Accelerate Diagnostics: Honoraria|GenMark Diagnosticd: Honoraria
610. Voriconazole versus isavuconazole in patients with invasive aspergillosis: a retrospective study in a medically insured population across the United States
Authors: Chan Sophea , Stoudenmire Laura Leigh , Zhan Duna , Chen Xianyan , Henao Martínez Andrés F , Chastain Daniel B
Published: November 2023

Background

Isavuconazole demonstrated similar outcomes but improved tolerability versus voriconazole (VCZ) for invasive aspergillosis (IA). Despite this, VCZ remains the treatment of choice for IA. Therefore, we compared outcomes between patients with IA treated with VCZ versus isavuconazole (ISA).

Methods

Patients with IA treated with either VCZ or ISA as monotherapy between January 1, 2017 and August 31, 2020 were identified from the IBM® MarketScan® Research Databases using ICD-10-CM diagnosis codes and national drug codes (NDC), respectively. The index date was the first fill date for either VCZ or ISA during the study period. To be included, patients were required to have continuous medical and pharmacy benefits enrollment before the index fill for either VCZ or ISA, throughout the treatment period, and for ≥ 28 days after treatment ended based on day supply. Patients with a history of liver transplant or hepatic dysfunction were excluded. Treatment completion, defined as fill history for ≥ 42 days, and adverse events, during the treatment and follow-up periods, were compared between those treated with VCZ and ISA.

Results

Of 563 patients with IA, 425 received VCZ and 138 received ISA. The mean age (51.4 ± 16.8 vs 51.9 ± 12.8 years, p=0.77) and proportion of male patients (52% vs 49%, p=0.61) were similar in both groups. The most common comorbidities among those treated with VCZ and those treated with ISA were chronic obstructive pulmonary disease (38% vs 27%, p=0.03), diabetes mellitus (22% vs 22%, p=0.98), and lymphoma (8% vs 14%, p=0.04). Similar proportions of patients in the VCZ group and ISA group had commercial insurance or Medicare (63% and 10% vs 71% and 12%, p=0.94 overall). Diagnosis of IA was evenly distributed between the inpatient and outpatient settings in each group. The rate of treatment completion was comparable between patients prescribed VCZ and those prescribed ISA (88% vs 91%, p=0.50). Adverse events were reported by 53% of patients treated with VCZ and 45% treated with ISA (p=0.11), though few patients switched therapy during the 6-week treatment period (n=4 for VCZ and n=1 for ISA).

Conclusion

VCZ was prescribed 3 times more often than ISA for IA, but rates of treatment completion and adverse events were similar between groups.

Disclosures

All Authors: No reported disclosures
617. Laboratory capacities to diagnose and treat Invasive Fungal Infections in Europe: results from an ECMM survey
Authors: Salmanton-Garcia Jon , Hoenigl Martin , Gangneux Jean-Pierre , Segal Ester , Cornely Oliver A
Published: November 2023

Background

Invasive fungal infections (IFI) are a major threat for patients under immunosuppression or with viral respiratory infections, like influenza or coronavirus disease 2019 (COVID-19). Access to appropriate tools is vital for early diagnosis and clinical management. The European Confederation of Medical Mycology (ECMM) survey on laboratory capacities in Europe aims to decipher the current diagnostic capacity and availability of treatments for IFIs in order to guide health professionals, patients, and policymakers.

Methods

The ECMM IFI diagnostic capacity survey is online accessible at www.clinicalsurveys.net/uc/IFI_management_capacity/. A campaign seeking for mycologist feedback was launched. The survey was disseminated to all European mycologists affiliated with the ECMM and via social media (i.e., LinkedIn or Twitter) and email. Collected variables were a) institution profile, b) perceptions on invasive fungal disease in the respective institution, c) microscopy, d) culture and fungal identification, e) serology, f) antigen detection, g) molecular tests and h) therapeutic drug monitoring.

Results

258 centers from 41 countries have participated in the survey (Figure 1). Germany (n=30), France (n=28), Italy, Spain (n=23, each) and Turkey (n=21) were the origin country of almost half of the respondents. Incidence of IFI was considered as very low or low in 46.9% of the institutions, and moderate in 38.0%. Candida spp. (95.0%) and Aspergillus spp. (89.9%) were considered the most relevant pathogens. All the institutions had access (on site or outsourced) to cultures (68.2% of which could also perform susceptibility tests in molds and yeasts, 26.4% only in yeasts, 4.7% in none and 0.8% only in molds). Regarding availability of other diagnostic tests, 84.5% could also utilize microscopy, 83.7% antigen detection tests (89.8% of which at least Aspergillus galactomannan test), 73.3% molecular tests (mainly PCR), and 62.4% to serology. At least one triazole was available for prescribing in 93.0% of the institutions, whereas at least one echinocandin in 90.3% and liposomal amphotericin B in 80.2%.

Conclusion

Europe is generally well prepared to diagnose and treat invasive fungal infections. However, some institutions miss access to certain diagnostic tools and antifungal drugs.

Disclosures

Martin Hoenigl, n/a, Astellas: Grant/Research Support|Euroimmun: Grant/Research Support|F2G: Grant/Research Support|Gilead: Grant/Research Support|Immy: Grant/Research Support|MSD: Grant/Research Support|Mundipharma: Grant/Research Support|Pfizer: Grant/Research Support|Pulmocide: Grant/Research Support|Scynexis: Grant/Research Support Oliver A. Cornely, MD PhD, DZIF: Advisor/Consultant|DZIF: Board Member|DZIF: Grant/Research Support|DZIF: Honoraria|DZIF: Stocks/Bonds
618. The current state of laboratory mycology in Asia/Pacific: a survey from the EuropeanConfederation of Medical Mycology (ECMM) and International Society for Human andAnimal Mycology (ISHAM)
Authors: Salmanton-Garcia Jon , Wing-Yan Au , Hoenigl Martin , Chakrabarti Arunaloke , Cornely Oliver A
Published: November 2023

Background

Invasive fungal infections (IFI) in Asia/Pacific are a threat to patients with malignancies, uncontrolled diabetes mellitus or undiagnosed/untreated human immunodeficiency virus infection and acquired immunodeficiency syndrome (HIV/AIDS). Adequate and early access to diagnostic tools and antifungals is essential for the IFI clinical management and patient survival.

Methods

The IFI diagnostic capacity survey was online accessible at www.clinicalsurveys.net/uc/IFI_management_capacity/. The survey aimed to collect the following dimensions: a) institution profile, b) perceptions on IFI in the respective institution, c) microscopy, d) culture and fungal identification capacity, e) serology, f) antigen detection, g) molecular tests availability, and h) therapeutic drug monitoring.

Results

As of June 2022, 235 centres from 40 countries/territories in Asia/Pacific answered the questionnaire. More than half of them were from six countries: India (25%), China (17%), Thailand (5%), Indonesia, Iran, and Japan (4%, each). Candida spp. (93%) and Aspergillus spp. (75%) were considered the most relevant pathogens. Most institutions had access to microscopy (98%) or culture-based approaches (97%). Furthermore, 79% of them had access to antigen detection, 66% to molecular assays, and 63% to antibody tests. Access to antifungals varied between countries/territories. At least one triazole was available in 93% of the reporting sites (voriconazole [89%] was the most common mould-active azole), whereas 80% had at least one amphotericin B formulation, and 72% at least one echinocandin.

Conclusion

Currently, based on the provided replies, the resources available for the IFI diagnosis and management vary in Asia/Pacific countries/territories. Economical or geographical factors may play a key role in the incidence and clinical handling of this disease burden. Regional cooperation may be a good strategy to overcome shortcomings.

Disclosures

Martin Hoenigl, n/a, Astellas: Grant/Research Support|Euroimmun: Grant/Research Support|F2G: Grant/Research Support|Gilead: Grant/Research Support|Immy: Grant/Research Support|MSD: Grant/Research Support|Mundipharma: Grant/Research Support|Pfizer: Grant/Research Support|Pulmocide: Grant/Research Support|Scynexis: Grant/Research Support Oliver A. Cornely, MD PhD, DZIF: Advisor/Consultant|DZIF: Board Member|DZIF: Grant/Research Support|DZIF: Honoraria|DZIF: Stocks/Bonds
635. Morbidity and Mortality Associated with Respiratory Syncytial Virus Infections Among the Adult Hospitalized Patients
Authors: Bhargava Ashish , Szpunar Susan M , Malik Ambreen , Sharma Mamta , Johnson Leonard B
Published: November 2023

Background

Respiratory syncytial virus (RSV), commonly a virus of the fall and winter months, can be particularly serious in children under one year of age and in older adults or people with other comorbidities. Because of the precautions taken during the COVID-19 pandemic, recent RSV infections have deviated from the usual seasonal trend. The purpose of this study was to assess the overall morbidity and mortality in patients with RSV.

Methods

We conducted a multicenter historical cohort study of adult patients hospitalized for laboratory-confirmed RSV-related diseases in Ascension hospitals in southeast Michigan between January 2017 and December 2021. Hospitalized patients were identified using ICD 10 codes for RSV-related diseases. Electronic medical records were reviewed. Data were analyzed using the chi squared test, Student’s t test, and the Mann-Whitney U test using SPSS v. 29.0.

Results

Of 360 patients, the mean (sd) age of the cohort was 69.9 + 14.7 years, 228 (63.5%) were female and 227 (63%) were white. The mean body mass index (BMI) was 30.6 + 9.7 kg/m2 and 56.1% were smokers. The most common comorbidities were hypertension (66.7%), chronic lung diseases (57.2%), obesity (33.6%), diabetes mellitus (31.1%) and congestive heart failure (26.1%). The mean Charlson weighted index of comorbidity was 2.2 ± 1.9. Cough (79.2%) and shortness of breath (72.8%) was most common symptoms. Admission chest x-rays were abnormal in 44.7% of cases. RSV upper and lower respiratory tract infections (RTI) were present in 58.4% and 41.6% of patients, respectively. Antibiotics were given in 56.9% of patients. Mechanical ventilation was required in 11% and intensive care in 14.2 % of patients. Other complications were acute kidney injury in 23.3%, encephalopathy in 11.4%, and liver injury in 3.6 %; 13 (3.6%) patients died and 21 (5.8%) were readmitted within 30 days to an Ascension hospital.

Conclusion

Our study finds elderly patients hospitalized with RSV had substantial comorbidities. While overall mortality was low, the hospital course and complications suggest a disease that was costly both in human and financial suffering. Our study supports a need for RSV preventable initiatives and immunizations for this susceptible adult population.

Disclosures

All Authors: No reported disclosures
660. Pediatric Rotavirus Hospitalization Rates in the Military Health System Before and During the COVID-19 Pandemic
Authors: Penfold Matthew , Prabhakar Sarah , Susi Apryl , Rajnik Michael , Nylund Cade M , Eberly Matthew
Published: November 2023

Background

Rotavirus, a vaccine preventable disease, causes significant morbidity and mortality in children < 5 years of age. Globally, the COVID-19 pandemic reduced the rates of pediatric vaccinations, and the Military Health System (MHS) was no different (Figure 1). This gap in immunizations left many children vulnerable to preventable illnesses, including rotavirus. We hypothesized that the reduction in rotavirus vaccine administration during the pandemic would lead to an increase in rotavirus related hospitalizations within the MHS.

Methods

A repeated monthly cross-sectional study was performed using inpatient data from the MHS to observe differences in rotavirus rates and risk factors before and during the COVID-19 pandemic. Data from March 2018 to February 2020 was considered pre-pandemic, while the following two years (until February 2022), were divided into COVID Year 1 and Year 2. Children included in the study were between 0-59 months of age and those with rotavirus were identified using ICD-10 codes. Poisson regression calculated rate ratios of rotavirus, adjusting for several demographic variables and time period at diagnosis. Monthly counts and rates of rotavirus were also documented.

Results

Across the cohort of 1.14 million MHS beneficiaries, there were 3,503 unique cases of rotavirus infections in hospitalized children < 5 years old (Table 1). During both Years 1 and 2 of COVID-19, there was a significant decrease in rotavirus related hospitalizations compared to the pre-pandemic period (Figure 2). Younger age was associated with increased risk. Patient sex, parent military rank, and region were not statistically significant (Table 2).

Conclusion

Despite the reduction in routine immunization administration to children in the MHS after the COVID-19 pandemic started, there was not an increase in rotavirus related hospitalizations. In the two years following the start of the pandemic, there was a statistically significant decrease in hospitalizations related to rotavirus in our cohort. Social distancing to include daycare closures, increased hygiene measures, and catch-up immunizations may explain this finding. Continued research into this topic will help determine if rotavirus related hospitalizations return to pre-pandemic levels.

Disclosures

All Authors: No reported disclosures
661. Mortality Rates and Resistance Profiles of Salmonella spp. Infections: Implications for Clinical Practice and Public Health Interventions
Authors: Rosso Fernando , Rebellon-Sanchez David E , Llanos-Torres Julio , Álvarez-Ortega Carolina , Hurtado-Bermudez Leidy J
Published: November 2023

Background

Salmonellosis is a frequent foodborne infection. There is not much information about the mortality and resistance profiles of Salmonella spp. infections in Latin America. The aim of the study was to determine overall mortality, related risk factors, and antibiotic resistance in patients with Salmonella infection attended at university hospital of Colombia between 2012 - 2021

Methods

Retrospective observational study. All patients with a microbiological confirmed diagnosis of Salmonella spp. were included. The sociodemographic, clinical and microbiological characteristics were described. Log binomial regression models were used to establish factors associated with mortality

Results

A total of 522 patients were included, 54.8% were females, the median age was 16 years (IQR= 1-50). Mortality occurs in 4.02% of the patients. The proportion of deaths was higher in patients with bacteremia (RR = 3.65, 95% CI 1.59 - 8.40) hematologic malignancy (RR = 2.39, 95% CI 0.90 - 6.29) and those who require treatment in the intensive care unit (ICU) (RR=7.92, 95% CI 3.14 -19.97). There was no significant difference in mortality among those younger than 15 years old than older (2.8% vs. 5.4%, p = 0.13). Factors associated with mortality were bacteremia (aPR = 3.41 CI95%, 1.08 - 10.76) and requirement of ICU (aPR = 8.13 CI95%, 1.82 - 37.76). An increase in resistance rates over the study period (trend chi2: p< 0.05). Increment in resistance was observed against ciprofloxacin (from less than 1% to 60%) and ampicillin/sulbactam (from 10.9% to 50%) (Fig. 1). No association was found between salmonella susceptibility and mortality

Conclusion

Despite being a preventable and treatable disease, Salmonellosis still poses a public health concern. Our study highlights the persistence of mortality due to this condition and a significant increase in antibiotic resistance rates over the last decade. Vulnerable patient groups showed higher mortality rates

Disclosures

All Authors: No reported disclosures
671. Introduction of simultaneous Clostridioides difficile Antigen and Toxin A and B detection for diagnosis of C. difficile related diarrhea at Michael E. DeBakey VA Medical Center
Authors: Ashley Patrycja , Robins Alison , Morones Rosalba Gomez , Aguayo-Millan Claudia , Morales-Aseff Daniela , Rodriguez-Barradas Maria C
Published: November 2023

Background

Nucleic acid amplification test (NAAT) for diagnosis of Clostridioides difficile infection (CDI) is highly sensitive but is unable to distinguish colonization from infection. Antigen/toxin testing on the other hand may have lower sensitivity, especially early in infection with associated delay in diagnosis.

Methods

We conducted a retrospective study at Michael E. DeBakey VA Medical Center prior and post the introduction of simultaneous C.difficile GDH Antigen and Toxin A/B (GDH/Tox) detection.

Results

In the pre-intervention period 83 patients underwent NAAT, 16 patients had a positive test result (19.3%). In the post-intervention 120 patients were tested; 99 (82.5%) were negative for both GDH Antigen and toxin A/B (GDH-/tox-), 16 (13.3%) tested positive for the GDH Antigen but negative for Toxin A/B (GDH+/tox-) and 5 (4.2%) tested positive for both Antigen and Toxin (GDH+/tox+). Two patients (1.7%) who initially tested GDH+/tox- were subsequently retested due to persistent symptoms or evidence of colitis and were noted to have GDH+/tox+ result.

The rate of positivity of C.difficile testing in our institution decreased form 19.3% to 4.2% (p< .001) post introduction of the GDH/toxin A/B detection. The treatment rate of patients who had the test performed decreased from 18.1% to 9.2% (p=.062).

30-day readmission rate for any reason in the group that tested positive for CDI in the pre-intervention group was 18.5% (3 patients), with 30-day all-cause mortality 6.25% (1 patient). In the GDH+/tox+ and GDH+/tox- groups in the post-intervention period, the 30-day readmission rate for any cause was 9.5% (2 patients), and 30-day all-cause mortality was 6.25% (1 patient).

CDI testing results before and after the intervention.

Conclusion

Distinguishing asymptomatic carriage or colonization from CDI remains an important goal. Implementing GDH Antigen and toxin A/B C.difficile testing can help reduce the risk of inappropriate treatment of colonization and possibly reduce the risk for development of antibacterial resistant C.difficile strains, however in our case it initially missed 2 cases of CDI that fortunately was not associated with negative outcome. With use of the GDH/tox test repeat testing and/or treatment might be considered on case-by-case basis depending on persistence of symptoms or high suspicion of infection.

Disclosures

All Authors: No reported disclosures
672. Impact of Multistep Testing Algorithm on Hospital Acquired Clostridioides difficile Infection Rates
Authors: Betancourth Adriana C , Gill Arshpal , Bangash Salman , Abalos Charmaine , Bhanot Nitin , Min Zaw , Moffa Matthew A , Shively Nathan R , Walsh Thomas L
Published: November 2023

Background

Clostridioides difficile infection (CDI) is one of the leading causes of hospital-acquired (HA) infections. Clinically distinguishing true CDI versus colonization is challenging. Our center previously used a polymerase chain reaction (PCR) assay as a standalone test for diagnosing CDI. While PCR is very sensitive for diagnosing CDI, it cannot distinguish between CDI and asymptomatic colonization. A multistep testing algorithm, which consists of an initial C. difficile PCR test followed by a reflex enzyme immunoassay (EIA) for glutamate dehydrogenase (GDH) and Toxin A/B testing, was implemented in our institution. We conducted this study to determine the rates of HA-CDI and C. difficile colonization based on laboratory results.

Methods

This retrospective observational study was conducted at Allegheny General Hospital (Pittsburgh, PA, US). Patients with a positive C. difficile PCR assay at day 3 or later from admission date were included for analysis. The pre-intervention period was from August 2021 to February 2022 and post-intervention period was from August 2022 to February 2023. Before the intervention, results for C. difficile testing were reported as PCR positive (PCR+) or negative (PCR-). On July 2022, a multistep testing algorithm was implemented with an initial C. difficile PCR assay; if results were positive, a reflex EIA for GDH and Toxin A/B testing was performed and resulted as follows: Figure 1.

The HA-CDI rates before and after implementation of a multistep testing algorithm were compared.

Results

A total of 112 unique patients were included. HA-CDI in the post intervention period decreased by 53% after the intervention (N=57 [pre-intervention] versus N=26 [post-intervention]; P < 0.001). During the post-intervention period, there were 55 PCR+ C. difficile assays, of which 29 (53%) were resulted as "indeterminate, likely C. difficile colonization." Of the 29 indeterminate results, 23 (79%) still received CDI therapy.

Conclusion

Our study demonstrated that a multistep C. difficile testing algorithm significantly reduced the rates of HA-CDI in our institution. We found that the majority of patients still received CDI therapy despite having a negative EIA toxin result. We plan to analyze the clinical impact of this multistep testing algorithm in a follow-up study.

Disclosures

Thomas L. Walsh, MD, Accelerate Diagnostics: Advisor/Consultant
673. Sniffing Out Adherence: Evaluation of a Clostridioides difficile guideline at a Tertiary Academic Medical Center
Authors: Mei Tiffany , Campion Maureen , Vazquez Gabriela Andujar , Foong Kap Sum , Doron Shira
Published: November 2023

Background

Tufts Medical Center’s (TMC) Antimicrobial Stewardship Team (AMT) in collaboration with gastroenterology (GI) developed an institutional treatment algorithm to guide appropriate inpatient management of Clostridioides difficile infection (CDI). The CD treatment algorithm was revised in April 2022 to reflect updated national clinical practice guidelines and disseminated to TMC providers. Our study aimed to assess provider compliance to TMC’s CD treatment algorithm.

Methods

A retrospective study of adult patients hospitalized from April 15, 2022 to October 31, 2022 and tested for CD was conducted. We collected patient demographics, white blood cell count, serum creatinine (SC), length of stay, CD treatment, Infectious Diseases (ID) & GI consult, occurence of severe CDI (defined as white blood cell > 15 K/uL or SC > 1.5 mg/dL), occurrence of recurrent CDI, and immunocompromised status (defined by having had organ or bone marrow transplant, receiving immunomodulatory therapy or chronic steroids). A 2-step Clostridioides difficile (CD) testing algorithm was used. For CD toxin A/B & glutamate dehydrogenase antigen (GDH) indeterminate results, reflex to nucleic amplification test (NAAT) was performed only with AMT approval.

Results

A total of 111 inpatients had CD toxin/GDH stool testing; 70 (63%) positive and 41 (37%) indeterminate. Of patients who had an indeterminate CD toxin/GDH, none had subsequent CD NAAT testing, and none receive CDI treatment. Of the others, 81 (73%), 23 (21%), and 7 (6%) were diagnosed with non-severe, severe, and fulminant CDI, respectively. The overall adherence to the institutional CD treatment algorithm was 58% (figure 1). More patients were appropriately treated with oral vancomycin (11, 65%) compared to those who were appropriately treated with fidaxomicin (9, 24%). Guidance adherence was (3) 38% among patients who had one or more recurrent episodes of CD, and none received suggested ID or GI consultation for additional CDI treatment consideration.

Conclusion

Adherence to institutional CD treatment algorithm was low. This study highlights opportunities to improve prescription of first line CDI therapy, especially among patients who are at higher risk for recurrence.

Disclosures

Maureen Campion, PharmD, BCIDP, Shinoigi: Speaker
674. Host and Pathogen Risk Factors for Fulminant Clostridioides difficile Infection
Authors: Chua Hubert C , Eubank Taryn A , Jo Jinhee , Garey Kevin W , Gonzales-Luna Anne J
Published: November 2023

Background

Fulminant Clostridioides difficile infection (FCDI) is associated with high rates of mortality and morbidity; however, risk factors for FCDI are poorly understood. The objective of this study was to identify clinical and microbiological factors predictive of FCDI.

Methods

This was a multicenter cohort study involving adult hospitalized patients diagnosed with an incident case of CDI (2015-22). Leftover stool samples were collected for ribotyping and determination of binary toxin presence (CDT; assumed presence in ribotypes 019, 027, 075, and 078-126). Disease severity was defined according to IDSA-SHEA CDI severity classification utilizing laboratory values obtained within 24 hrs of a positive CDI diagnostic test. FCDI was defined as CDI with hypotension (systolic blood pressure ≤ 90 mmHg), shock, ileus, or megacolon. Risk factors predictive of FCDI were assessed through multivariable logistic analysis.

Results

Overall, 440 patients aged 62±18.2 years were identified (58.9% female). In univariate analysis, hypoalbuminemia (odds ratio [OR], 4.94; 95% confidence interval [CI], 2.94-8.31) and infection with a CDT-producing strain (OR, 1.99; 95% CI, 1.16-3.42) were associated with FCDI, and presence of both variables was associated with the highest odds of FCDI (OR, 5.73; 95% CI, 2.19-14.9). Using backwards stepwise logistic regression, CDI due to a CDT-producing strain and concomitant hypoalbuminemia was an independent predictor of FCDI (OR, 5.21; 95% CI, 1.97-13.8) after controlling for Charlson Comorbidity Index score >5 (OR, 1.85; 95% CI 0.99-3.48) and admission from a healthcare facility (OR, 1.73; 95% CI 1.02-2.95).

Conclusion

Both clinical and microbiological factors were associated with increased odds of FCDI. Early identification of patients at high-risk for FCDI allows for more timely interventions to help mitigate the risk of disease progression. Future studies incorporating host microbiome features and novel biomarkers into CDI severity predictive models are needed.

Disclosures

Kevin W. Garey, MS;PharmD, Paratek Pharmaceuticals: Grant/Research Support Anne J. Gonzales-Luna, PharmD, BCIDP, Cidara Therapeutics: Grant/Research Support|Ferring Pharmaceuticals: Personal Fees|Paratek Pharmaceuticals: Grant/Research Support|Seres Therapeutics: Grant/Research Support
697. Characteristics of Hospitalized Patients Colonized with Clostridioides difficile at an Academic Medical Center
Authors: Percival Kelly M , Kinn Patrick M , Ford Bradley A , Brust Karen , Ince Dilek
Published: November 2023

Background

Clinical spectrum of C. difficile can range from colonization to fulminant colitis. Patients with toxin antigen negative, C. difficile nucleic acid amplification (NAAT)-positive diarrhea are frequently only colonized and do not suffer consequences of C. difficile associated disease (CDAD) but receive treatment for CDAD due to the perceived low risk of oral vancomycin vs. the risk of developing CDAD.

Methods

We performed a retrospective cohort study of hospitalized adult patients with positive C. difficile NAAT and negative toxin antigen results at University of Iowa Health Care between 9/1/2021 and 9/30/2022. Chart review was conducted to obtain patient age, immunocompromised state, involvement of infectious disease (ID) consultant, prior C. difficile test status and treatment course.

Results

Of the 295 NAAT-positive C. difficile results, 210 (71%) were toxin antigen negative. Patient characteristics and frequency of common risk factors are shown in Table 1. C. difficile colonization was detected ≥4 days after admission in 111 (53%), with internal medicine and stem cell transplant (SCT)/hematologic malignancies (HM) services having the most patients with colonization (31% and 18%, respectively). Antibiotic use in the prior 30 days was reported in 154 (73%). Of 134 (64%) patients on systemic antibiotics at time of C. difficile testing, antibiotics were discontinued in 29 (22%). Only 43 patients (20%) did not receive any treatment for C. difficile. Median treatment duration was 10 days with 133 (80%) being treated for 10-14 days (Table 2). ID consult was obtained in 48 (23%) and recommended no treatment initially in 11 (23%), 4 of whom were started on treatment in subsequent days. Oral twice a day vancomycin for prophylaxis was given to 28 (13%) patients, 19 (68%) of whom were immunocompromised (16 SCT/HM and 3 solid organ transplant).

Conclusion

Patients with C. difficile colonization have similar risk factors as patients with CDAD. Understanding treatment patterns for C. difficile colonization can guide educational activities. Most colonized patients received C. difficile treatment and/or prophylaxis, likely due to ongoing systemic antibiotic use and immunosuppression. Benefit of treatment and prophylaxis in colonized patients remains an unresolved issue.

Disclosures

Kelly M. Percival, PharmD, Gilead Sciences Inc: Advisor/Consultant
700. LOFI: Preliminary Analysis of Intervention Fidelity of a Cluster Randomized Trial Evaluating Universal Gloving to Reduce C. difficile Acquisition within VA Hospitals
Authors: McKinley Linda , Ray Cara , Keating Julie , Dixon Jonah , Moriarty Helene , Zhao Jiwei , Evans Charlesnika T , Foliaki Malini , Gelman Michael , Ndakuya-Fitzgerald Florine , Pfeiffer Christopher D , Sheeti Ahmed , Weintrob Amy , West Katelyn , Williams Maeve , Safdar Nasia
Published: November 2023

Background

Prevention of Clostridioides difficile infection (CDI) is a priority. Infection control measures to prevent CDI target symptomatic (infected) patients. These patients are placed on contact precautions (CP), requiring hand hygiene and use of gloves and gowns. However, asymptomatic (colonized) patients may be a reservoir for cross contamination, and evidence is scarce regarding prevention measures with this population. To address this gap, our study evaluates the effect of universal gloving (UG) for all patient contact to prevent transmission from these patients. However, the gloving intervention involves complex behavioral practices with wide variations in compliance; thus, data on intervention implementation provides critical context. Here we provide a preliminary analysis of intervention fidelity.

Methods

A cluster randomized trial (CRT) is being conducted in ten VA hospital patient units; 5 units randomized to standard of care (CP) and 5 units to the intervention (UG plus CP). A secondary outcome of the study is intervention fidelity (gloving compliance). This analysis includes monthly observation data on hand hygiene (HH) and gloving compliance for UG and HH, gloving, gowning for CP in both groups using a standardized observation tool. Compliance was calculated using the total number of compliant observations divided by the total number of observations.

Results

1012 Observations were conducted between May 2022 and April 2023. HH, gloves and gown compliance for CP did not differ between groups (Table 1). Gloving compliance with UG was lower than expected and significantly lower than gloving compliance for CP in the intervention group (Table 2). Table 3 compares HH and gloving between UG (intervention group) and CP (both groups). Gloving compliance was significantly higher with CP than with UG.

Results Tables

Table 1 - 3

Conclusion

Intervention fidelity is critical to support rigor of the CRT, but our results showed lower than expected compliance for both gloving and HH despite the UG intervention. A pilot interview identified the healthcare worker requirement for practicing both HH and gloving as a barrier. Additional investigation into barriers to gloving and HH compliance within the context of a UG intervention is ongoing.

Disclosures

All Authors: No reported disclosures