bluuebunny/crossref_metadata_2025_split huggingface dataset:
343. Relevance of Use of Anaerobic Blood Culture Bottle for the Diagnosis of Bacteremia
Authors: Noguchi Taro , Shinohara Koh , Tsuchido Yasuhiro , Yukawa Satomi , Yamamoto Masaki , Matsumura Yasufumi , Nagao Miki 
Published: December 2022

Abstract

Background
Blood cultures remain the cornerstone for the diagnosis of bacteremia. Although an anaerobic blood culture bottle can recover facultative and obligate anaerobes, routine use of an anaerobic bottle paired with an aerobic bottle remains controversial. We aimed to evaluate the role of anaerobic bottle for the diagnosis of bacteremia.

Methods
We conducted a retrospective cohort study in a tertial hospital in Japan from January 2019 to September 2021. Blood culture results were collected from microbiology laboratory records. Blood cultures for which simultaneous pairs of aerobic and anaerobic bottles were collected and from which a single organism was recovered were included. Positive blood cultures were considered as a single episode of bacteremia when obtained within 14 consecutive days.

Results
A total of 22677 blood cultures were collected, with 22650 bottles were paired. In 2962 paired blood cultures of which one or both bottles were positive, 1079 episodes of clinically significant monomicrobial bacteremia were observed. In these episodes, 898 had a positive aerobic bottle, while 789 had a positive anaerobic bottle, with 608 had both positive bottles. In 181 episodes (16.8%), clinically significant organisms were isolated in an anaerobic bottle without concomitant positive aerobic bottle. In these anaerobic bottles, 146 facultative and 35 obligate anaerobes were recovered. The most common facultative anaerobe was Escherichia coli (30 isolates), followed by Staphylococcus aureus (27 isolates). Bacteroides fragilis (11 isolates) was the most common obligate anaerobe.

Conclusion
Recovery of clinically significant facultative and obligate anaerobes from anaerobic bottle alone was observed in 17% of episodes, which supports that the routine collection of both aerobic and anaerobic bottles is relevant.

Disclosures
All Authors: No reported disclosures.
350. Clinical impact of positive fungal blood cultures for diagnosis and treatment of fungal infections.
Authors: Chavez Miguel A , Ching Patrick R , Spec Andrej , Hsueh Kevin 
Published: December 2022

Abstract

Background
Fungal blood cultures are usually ordered when sepsis secondary to disseminated fungal infection is suspected. We aimed to analyze whether positive fungal blood cultures had an added clinical impact over other conventional microbiological tests.

Methods
We performed a retrospective study of all patients for whom fungal blood cultures were performed for any indication at our institution from June 2018 to March 2022. We reviewed informatics database and medical records to assess the microbiological and clinical impact of positive fungal blood cultures during the initial admission. Assessment of clinical impact was analyzed using a list of predefined positive, negative, and no impact scenarios (Table 1) based by the treating team’s decisions.

Results
In total, 4447 fungal blood cultures were performed in 3648 admissions during our study period. The overall positivity rate of fungal blood cultures was 6.4% (n=284), of which only 130 (2.9%) were positive for fungi. The most common isolated fungi were Candida spp. (71, 55%), followed by Histoplasma spp. (16, 12%), Cryptococcus spp. (12, 9%), and unidentified mold (9, 7%) (Table 1). The median time to positivity was 106 hours (IQR 79-177). Only 21 (16%) fungal blood cultures resulted in a change in management. Positive fungal blood cultures for fungi led to a positive clinical impact in 17 (13%), negative clinical impact in 4 (3%), and no clinical impact in 109 (84%). Most fungal blood cultures confirmed other conventional microbiological diagnosis (71, 55%) or result was not acted upon (26, 20%). Organisms where fungal blood culture had a positive impact included C. albicans (n=4), and C. parapsilosis (n=3), while Cladosporium spp. (n=2) was the most frequent fungi with a negative clinical impact. Isolated fungi that had no clinical impact because of other confirmatory tests included Candida spp. (n=57), Histoplasma spp. (n=13) and Cryptococcus neoformans (n=10). Table 1.Microbiological characteristics and clinical impact of fungal blood cultures.Abbreviations: h hours; IQR, interquartile range.*Time to positivity was defined as the time from the fungal blood culture collection until growth and preliminary identification of a fungal organism on staining by the microbiology laboratory. **Time to identification was defined as the time from the fungal blood culture collection until identification of the fungal organism by the microbiology laboratory.

Conclusion
Most of positive fungal blood cultures for fungi resulted in no immediate clinical impact due to other microbiological tests available sooner or isolates thought to be non-clinically significant. Further studies should evaluate the long-term impact of fungemia and identify stewardship interventions to optimize clinical utility of fungal blood cultures.

Disclosures
All Authors: No reported disclosures.
369. Tissue Based Species Level Molecular Identification of Schistosoma haematobium in Appendiceal Tissue
Authors: Haddad Fadi A , Nutman Thomas , Feldman Daniela Osowiecki , Correa Manuela , Armas Octavio , Haddad Victoria , Klion Amy , Issa Yazan Al 
Published: December 2022

Abstract

Background
Appendiceal involvement in schistosomiasis is rare, but it has been reported for the 3 major species commonly infecting humans (S. haematobium, S. mansoni, and S. japonicum). Often the diagnosis is made histologically following appendectomy. However, many times the eggs found in the appendiceal tissue are calcified or degraded to a degree that a species level diagnosis cannot be made morphologically.
Case presentation: A 37-year-old Somali female patient presented with chronic abdominal pain. An appendectomy was performed due to the finding of appendicitis on an abdominal CT. A biopsy sent to pathology showed calcified eggs consistent with Schistosoma (Figure 1), but a species could not be defined. Serum Schistosoma IgG was negative.
Eggs of Schistosoma Species Figure 1:Miscroscopy of degraded eggs of Schistosoma species.

Methods
The biopsy was then sent to the Laboratory of Parasitic Diseases at the National Institutes of Health (NIH) for qPCR and molecular indentification. DNA was extracted from two unstained biopsy slides using standard techniques for formalin-fixed, paraffin embedded tissue and subjected to qPCR using S. heaematobium- or S.mansoni-specific primers/probes.

Results
The patient sample only amplified (Ct value -32) with the S. haematobium-specific primers/probes and not with the S. mansoni-specific primers/probes (no amplification). For both qPCR reactions, positive controls were positive and negative controls showed no amplification.

Conclusion
Tissue-based parasite identification of S. haematobium DNA provides a definitive species assignment for the causative agent presumably driving the appendiceal inflammation. This technique further allows species-based therapeutics, should it be necessary.

Disclosures
All Authors: No reported disclosures.
373. Development of multiplex loop-mediated isothermal amplification (LAMP) based on a microfluidic chip for detection of HSV-1 and 2 and VZV.
Authors: Ihira Masaru , Natsuhara Daigo , Enya Yasuko , Higashimoto Yuki , Kozawa Kei , Kawamura Yoshiki , Sugiura Kazumitsu , Shibata Takayuki , Yoshikawa Tetsushi 
Published: December 2022

Abstract

Background
In the era of universal varicella vaccination, point-of-care testing for herpes simplex viruses 1 and 2 (HSV-1, HSV-2) and varicella-zoster virus (VZV) is becoming more important because of the increase in the number of breakthrough varicella cases. The Loop-mediated isothermal amplification (LAMP) method is a reliable method for rapid diagnostic tests for infectious diseases. Meanwhile, microfluidics technology is revolutionary in total system miniaturization, including facile parallelization through multiplexing and process-reduced reagent volumes. It is easy to create miniaturized chips containing multiple chambers according to the needs. In this study, we sought to develop multiplex LAMP for the detection of HSV-1, HSV-2, and VZV DNA using in-house microfluidic chips.

Methods
The polydimethylsiloxane-based chip consists of microfluidic channels and 5 reaction chambers. The specific primers were pre-spotted and dried in each chamber. The condition of LAMPs and each specific primer were described previously. The sensitivity of microfluidic LAMPs was confirmed using plasmids that contain the target sequences. In order to assess the reliability of clinical use, 35 swab samples (without DNA extraction) collected from patients with vesicular skin lesions were used. The result of microfluidic multiplex LAMP was compared with conventional LAMPs and real-time PCRs.

Results
Detection limits of HSV-1 and 2 and VZV LAMP-based on a microfluidic chip were 500 copies per reaction. Among 35 swab samples, HSV-1, HSV-2, and VZV DNA were detected in 10 (28.6%), 4 (11.4%), and 12 (34.3%) samples, respectively. The results of microfluidic LAMPs were completely consistent with the results of conventional LAMPs. HSV-1 DNA was detected in one LAMP negative sample by real-time PCR. One HSV-1 LAMP positive sample was negative in real-time PCR. If real-time PCR was used as a standard, sensitivity of HSV-1, HSV-2, and VZV LAMPs based on microfluidic chip were 90%, 100%, and 100%, and the specificity of three methods were 96%, 100% and 100%, respectively.

Conclusion
Multiplex LAMP, based on a microfluidic chip that detects three alpha herpesviruses, may be useful in laboratory diagnosis of patients with vesicular skin lesions.

Disclosures
All Authors: No reported disclosures.
376. Testing for Cytomegalovirus Viremia in People with HIV/AIDS- An Opportunity for Diagnostic Stewardship
Authors: Savenka Tatsiana , Saccente Michael 
Published: December 2022

Abstract

Background
Guidelines recommend against testing for cytomegalovirus (CMV) viremia as a screening tool for CMV end-organ disease (EOD) in people with HIV/AIDS (PWHA) due to low positive predictive value. Additionally, a negative result does not exclude EOD. In this study, we aim to assess the clinical utility of plasma CMV quantitative PCR (qPCR) for the diagnosis of CMV EOD and to determine if positive results lead to further testing for EOD or earlier initiation of anti-CMV therapy.

Methods
We retrospectively identified PWHA who had a plasma CMV qPCR result or who were diagnosed with CMV EOD between 2014-2021. qPCR results that were undetectable or less than the minimum quantifiable value (300 IU/mL) were considered negative and results &gt;300 IU/mL were considered positive. EOD was confirmed via tissue biopsy, ophthalmic exam, or cerebrospinal fluid analysis. We compared CMV qPCR results for participants with proven EOD and those without proven EOD. For participants diagnosed with CMV EOD, we evaluated if a positive qPCR prompted further workup for EOD diagnosis or triggered anti-CMV therapy.

Results
We identified 138 PWHA with a CMV qPCR result and 17 PWHA with CMV EOD. Participant characteristics are shown in Table 1. Among participants with a qPCR result, 27 (19.6%) were positive; 13 (9.42%) of those with a qPCR results had EOD. 4 participants with EOD did not have qPCR. Participants with a positive qPCR were 4.55 (95% CI 2.63-7.90) times more likely to have EOD than those with a negative result. Table 2 shows qPCR results among participants with and without EOD. Table 3 shows the performance of qPCR for the diagnosis of EOD. 9 (69.2%) of 13 participants with EOD had a positive qPCR. 7 of them were diagnosed with EOD and started on treatment before the qPCR resulted. In 1 case, the qPCR resulted as positive on the same day ophthalmology diagnosed CMV retinitis. In only 1 case did a positive qPCR result and initiation of therapy precede the diagnosis of EOD.

Conclusion
Contrary to guidelines, clinicians often order plasma CMV qPCR on PWHA. Although PWHA who have CMV EOD are more likely to a have a positive qPCR than those without EOD, our data confirm CMV qPCR should not be used as a screening tool for EOD. Instead, clinical assessment should guide diagnostic investigation.

Disclosures
All Authors: No reported disclosures.
381. Antibiotic Spectrum Index and Risk of Clostridioides difficile Infection
Authors: Ray Michael J , Tucker Kendall J , Furuno Jon P , Lofgren Eric , Strnad Luke , Gerber Jeffrey S , McGregor Jessina C 
Published: December 2022

Abstract

Background
Antibiotic therapy is a known risk factor for Clostridioides difficile infection (CDI) and evidence suggests the magnitude of risk varies by spectrum of antibiotic activity and days of therapy (DOT). We quantified the risk of hospital-associated (HA) CDI associated with antibiotic therapy considering spectrum of activity and DOT.

Methods
We performed a retrospective cohort study of adult (≥18 years) inpatient encounters at a 576-bed academic medical center in Portland, OR between January 2018 and February 2020. We excluded patients with hospital stays under 4 days and those known to have recurrent (CDI in the previous 12 weeks) or community-acquired (CDI diagnosis within first 3 days of hospitalization) CDI. The primary exposure of antibiotic utilization was measured using the Antibiotic Spectrum Index (ASI), where spectrum-based weights are applied to each agent and DOT over the time at risk, summed over the encounter, and divided by the number of antibiotic days. The primary outcome was HA-CDI. We estimated the independent association between aggregate ASI and HA-CDI using multivariable logistic regression.

Results
Among 37,629 inpatient encounters, 68% patients received at least one antibiotic. We identified 159 cases of non-recurrent HA-CDI, which corresponds to 4.8 cases per 10,000 patient-days. Compared to those without HA-CDI, those with HA-CDI had a greater median number of distinct antibiotics prescribed (4 vs 1), greater median days of antibiotic therapy (22 vs 2), a greater median time at-risk (9 vs 6 days), and greater median Elixhauser Comorbidity Index (9 vs 4) (Kruskal-Wallis p-value &lt; 0.0001 for all comparisons). There were no significant differences by age or sex. Patients with HA-CDI had a greater mean ASI per antibiotic day than those without (5.2 vs 3.2, Student’s t-test p &lt; 0.0001). After adjusting for time at-risk and Elixhauser Comorbidity Index, each one-unit of ASI per antibiotic day was associated with 1.29 times increased odds of developing HA-CDI (Odds Ratio = 1.29, 95% Confidence Interval: 1.21 to 1.37).

Conclusion
The Antibiotic Spectrum Index was strongly associated with HA-CDI. ASI may be a useful tool for quantifying the risk of CDI according to the specific antibiotic therapy received among hospitalized patients.

Disclosures
All Authors: No reported disclosures.
390. Eravacycline combination therapy for severe, recurrent, or fulminant Clostridioides difficile infection
Authors: Morrison Austin R , Kwiatkowski Shaina , Ramesh Mayur , Kenney Rachel M 
Published: December 2022

Abstract

Background
Eravacycline (ERV) is a fluorocycline with in vitro activity against Clostridioides difficile infection (CDI). The purpose of this study was to evaluate the usage of ERV in the management of CDI.

Methods
IRB-approved, retrospective case series in a health system that added ERV to formulary in 9/2019. All patients between 9/2019 and 2/2020 treated with adjunctive ERV for &gt; 24 hours for severe, recurrent, or fulminant CDI were included. Exclusion criteria: pregnant, age &lt; 18 years. Primary outcome: all-cause mortality at 30 days (d) from start of ERV. Secondary outcomes: clinical cure, colectomy, and recurrence within 30 d. Data was reported using descriptive statistics and measures of central tendency.

Results
14 patients included: severe (4, 29%), recurrent (4, 29%), and fulminant CDI (6, 43%) (table 1). Infectious diseases consult: 14/14, median time to consult 1 (1, 2) d. Surgery consult: 1 severe and 5 fulminant CDI cases, median time to consult 1 (1, 3) d. Prior to ERV initiation, 10 patients were on oral vancomycin (PO VAN) and intravenous metronidazole (IV MTZ), one was on PO VAN, two were on IV MTZ, and one was on no CDI therapy. After ERV was initiated, six patients were on ERV, PO VAN, and IV MTZ combination and eight patients were on ERV and PO VAN concurrently. The reason for using ERV was fulminant CDI (6, 42.8%), severe CDI (4, 29%), unable to tolerate other CDI medications (3, 21%), refractory CDI (3, 21%), and recurrent CDI (1, 7%). Time to eravacycline initiation 1.5 d (1, 3.75) with median duration of 6 d (4.5, 7.75). 30-day all-cause mortality 2 (14%), all were in-hospital; 1 (7%) hospice. Clinical cure occurred in 12 (86%). Two (14%) required colectomy; one received surgery on the same day of CDI diagnosis and ERV initiation and the other had surgery 4 days before ERV initiation. Two patients with recurrent CDI received fecal microbiota transplant outpatient, one of which also received bezlotoxumab. Zero recurrences and one readmission within 30 d. Table 1.Patient demographics, severity, and clinical outcomes

Conclusion
ERV appears to be a potential adjunctive therapy for severe, recurrent, or fulminant CDI. Prospective studies are needed to further investigate the safety and efficacy of ERV in serious CDI.

Disclosures
All Authors: No reported disclosures.
398. Post-Infectious Irritable Bowel Syndrome in Patients Referred to a Complicated Clostridioides difficile Clinic
Authors: Pham Natalie , Jones Marieke , Costa Deiziane , Shin Jae , Behm Brian , Warren Cirle A 
Published: December 2022

Abstract

Background
Recurrence of Clostridioides difficile infection (CDI) occurs in up to 20-30% after an initial episode and up to more than half of patients with previous infection. C. difficile has also been associated with post-infectious irritable bowel syndrome (PI-IBS) following the resolution of an acute infection, complicating assessment of gastrointestinal symptoms post-CDI. The prevalence and risk factors for post-CDI IBS are not as well-defined as PI-IBS secondary to other pathogens.

Methods
In this study, we examined the electronic medical record of 67 consecutive patients referred to a Complicated C. Difficile Clinic from March 2020 to July 2021 for consideration of fecal microbiota transplantation.

Results
Patients were referred by primary care providers (54%), gastroenterologists (16%), hospital admitting team (19%) or others (10%). Mean age was 64 (21-93) and 51 patients (76%) were female. In 25 out of the 67 patients (37%), treatment was prescribed without documentation of a positive C. difficile assay. We found that 32.8% of patients referred to the clinic for recurrent CDI had symptoms consistent with post-CDI IBS. Patients with post-CDI IBS were generally younger in age (P = 0.03), had fewer medical comorbidities (P = &lt; 0.001), and more often had history of anxiety (P = 0.03) than patients with a diagnosis of CDI.

Conclusion
Our findings suggest that post-CDI IBS is prevalent, can be misdiagnosed as CDI recurrence, and may lead to inappropriate use of anti-C. difficile agents or interventions.

Disclosures
All Authors: No reported disclosures.
406. Vancomycin Activity against Clostridioides difficile Over Three Decades in Chicago
Authors: Skinner Andrew M , Petrella Laurica A , Young Kim Do , Serna-Perez Fidel , Johnson Stuart 
Published: December 2022

Abstract

Background
In 2017, the Infectious Diseases Society of America (IDSA) and Society for Healthcare Epidemiologist of America (SHEA) updated the C. difficile (CD) treatment guidelines recommending vancomycin as the preferred therapy for C. difficile infections (CDI). We assessed the in vitro vancomycin minimum inhibitory concentration (MIC) against CD across three decades to determine if the vancomycin MIC had increased since these guidelines were published.

Methods
We performed antimicrobial agar dilution susceptibility testing on 89 clinically relevant CD isolates collected within Chicagoland area. These isolates were selected from 3 separate timeframes: 2005 – 2007, 2013 – 2015, and 2021. Isolates were selected based on the prevalence of restriction endonuclease analysis (REA) strain types within each time cohort. Treatment response to vancomycin was reviewed for patients from the 2021 cohort if CD isolates had a vancomycin MIC of ≥ 16 μg/ml.

Results
The in vitro vancomycin geometric mean MIC against all 89 CD isolates was 2.53 μg/ml with a MIC50 of 2 μg/ml and MIC90 of 4 μg/ml. Comparing the 3 timeframes, the geometric mean vancomycin MICs from 2005-2007, 2013-2015, and 2021 were 2.35, 2.27, and 2.91, respectively (p=0.11). Comparison of the isolates collected from 2005 – 2015 to 2021, the in vitro vancomycin geometric mean MICs were 2.31 and 2.91, respectively (p = 0.037). REA group BI was the most common strain group to have an increased in vitro vancomycin MIC within the 2021 cohort as 4 of the 5 isolates tested had a MIC of 16 μg/ml. All 4 of the patients infected with these strains with an elevated vancomycin MICs were treated vancomycin. All 4 patients had a resolution of symptoms on vancomycin and 2 suffered from a recurrent infection within ≤4 weeks of completing vancomycin.

Conclusion
The vancomycin MIC against CD has trended upwards slightly over the past 20 years. The most notable change occurred between 2015 and 2021. We hypothesize that this increase is due to increased use of oral vancomycin for the treatment of CDI. However, these data indicate that most isolates still have a MIC of ≤4 μg/ml and an elevated MIC does not appear to impact clinical outcomes. Further study is required to determine if this upward trend in vancomycin MIC continues and if this could have any potential clinical implications.

Disclosures
Stuart Johnson, M.D., Ferring Pharmaceuticals: Membership on Ferring Publication Steering Committee|Ferring Pharmaceuticals: Employee|Summit Plc: Advisor/Consultant.