Human-Derived Bifidobacterium dentium Modulates the Mammalian Serotonergic System and Gut-Brain Axis

BACKGROUND & AIMS

The human gut microbiota can regulate production of serotonin (5-hydroxytryptamine [5-HT]) from enterochromaffin cells. However, the mechanisms underlying microbial-induced serotonin signaling are not well understood.

METHODS

Adult germ-free mice were treated with sterile media, live Bifidobacterium dentium, heat-killed B dentium, or live Bacteroides ovatus. Mouse and human enteroids were used to assess the effects of B dentium metabolites on 5-HT release from enterochromaffin cells. In vitro and in vivo short-chain fatty acids and 5-HT levels were assessed by mass spectrometry. Expression of tryptophan hydroxylase, short-chain fatty acid receptor free fatty acid receptor 2, 5-HT receptors, and the 5-HT re-uptake transporter (serotonin transporter) were assessed by quantitative polymerase chain reaction and immunostaining. RNA in situ hybridization assessed 5-HT-receptor expression in the brain, and 5-HT-receptor-dependent behavior was evaluated using the marble burying test.

RESULTS

B dentium mono-associated mice showed increased fecal acetate. This finding corresponded with increased intestinal 5-HT concentrations and increased expression of 5-HT receptors 2a, 4, and serotonin transporter. These effects were absent in B ovatus-treated mice. Application of acetate and B dentium-secreted products stimulated 5-HT release in mouse and human enteroids. In situ hybridization of brain tissue also showed significantly increased hippocampal expression of 5-HT-receptor 2a in B dentium-treated mice relative to germ-free controls. Functionally, B dentium colonization normalized species-typical repetitive and anxiety-like behaviors previously shown to be linked to 5-HT-receptor 2a.

CONCLUSIONS

These data suggest that B dentium, and the bacterial metabolite acetate, are capable of regulating key components of the serotonergic system in multiple host tissues, and are associated with a functional change in adult behavior.

Clostridioides (Formerly Clostridium) difficile Infection During Hospitalization Increases the Likelihood of Nonhome Patient Discharge

BACKGROUND

Clostridioides (formerly Clostridium) difficile infection (CDI) is associated with significant morbidity and mortality, including frequent hospitalizations. However, the impact of CDI after hospital discharge is poorly understood. The purpose of this study was to assess patient discharge disposition and understand CDI-related risk factors for nonhome discharge.

METHODS

Using a nationally representative database of Veterans Health Administration (VHA) patients (2003-2014) and a validation database from hospitalized non-VHA patients in Houston, Texas, admission and discharge disposition was obtained for patients with CDI and matched controls. Incidence of and clinical/microbiologic risk factors for nonhome discharge were assessed using these databases.

RESULTS

A total of 15173 VHA patients with CDI and 48599 non-CDI control patients originally admitted from the community were included. Significantly more patients with CDI were discharged to a nonhome location compared with controls (18% vs 8%; P < .0001), most commonly hospice/death (12%) or nursing home/long-term care facility (6%). Results were confirmed using a propensity-matched analysis and a validation cohort of 1941 hospitalized patients with CDI in Houston, Texas. Age, comorbidities, severe CDI, and ribotypes F027, F001, and F053-163 were associated with a nonhome discharge (P < .05 for all).

CONCLUSIONS

Hospitalized patients with CDI frequently required a higher level of medical care residence at discharge compared with non-CDI patients. Risk factors for discharge to a higher level of care included CDI disease severity and variables associated with recurrent CDI.

Efficacy of Bezlotoxumab in Participants Receiving Metronidazole, Vancomycin, or Fidaxomicin for Treatment of Clostridioides (Clostridium) difficile Infection

Background

In phase 3 MODIFY I/II trials, bezlotoxumab significantly reduced recurrence of Clostridioides (Clostridium) difficile infection (rCDI) over 12 weeks. Choice of CDI antibacterial treatment may affect CDI-related outcomes; therefore, this prespecified analysis assessed if the magnitude of bezlotoxumab-induced rCDI reduction was influenced by the antibiotic administered.

Methods

In MODIFY I/II (NCT01241552/NCT01513239), participants received a single infusion of bezlotoxumab (10 mg/kg) or placebo during anti-CDI treatment. Using pooled data from MODIFY I/II, initial clinical cure (ICC) and rCDI were assessed in metronidazole-, vancomycin-, and fidaxomicin-treated subgroups.

Results

Of 1554 participants in MODIFY I/II, 753 (48.5%) received metronidazole, 745 (47.9%) vancomycin, and 56 (3.6%) fidaxomicin. Fewer participants receiving metronidazole had a prior CDI episode in the previous 6 months (12.9%) or ≥1 risk factor for rCDI (66.0%) vs participants receiving vancomycin (41.2% and 83.6%, respectively) and fidaxomicin (55.4% and 89.3%, respectively). ICC rates were similar in the bezlotoxumab (metronidazole, 81.0%; vancomycin, 78.5%; fidaxomicin, 86.7%) and placebo groups (metronidazole, 81.3%; vancomycin, 79.6%; fidaxomicin, 76.9%). In placebo-treated participants, the rCDI was lower in the metronidazole subgroup vs the vancomycin and fidaxomicin subgroups (metronidazole, 28.0%; vancomycin, 38.4%; fidaxomicin, 35.0%). When analyzed by subsets based on history of CDI, rCDI rates were similar in the metronidazole and vancomycin groups. rCDI rates were lower in all antibiotic subgroups for bezlotoxumab vs placebo (metronidazole: rate difference [RD], –9.7%; 95% confidence interval [CI], –16.4% to –3.1%; vancomycin: RD, –15.4%; 95% CI, –22.7% to –8.0%; fidaxomicin: RD, –11.9%; 95% CI, –38.1% to 14.3%).

Conclusion

Bezlotoxumab reduces rCDI vs placebo in participants receiving metronidazole and vancomycin, with a similar effect size in participants receiving fidaxomicin.

Human intestinal enteroids as a model of Clostridioides difficile-induced enteritis

Clostridioides difficile is an important nosocomial pathogen that produces toxins to cause life-threatening diarrhea and colitis. Toxins bind to epithelial receptors and promote the collapse of the actin cytoskeleton. C. difficile toxin activity is commonly studied in cancer-derived and immortalized cell lines. However, the biological relevance of these models is limited. Moreover, no model is available for examining C. difficile-induced enteritis, an understudied health problem. We hypothesized that human intestinal enteroids (HIEs) express toxin receptors and provide a new model to dissect C. difficile cytotoxicity in the small intestine. We generated biopsy-derived jejunal HIE and Vero cells, which stably express LifeAct-Ruby, a fluorescent label of F-actin, to monitor actin cytoskeleton rearrangement by live-cell microscopy. Imaging analysis revealed that toxins from pathogenic C. difficile strains elicited cell rounding in a strain-dependent manner, and HIEs were tenfold more sensitive to toxin A (TcdA) than toxin B (TcdB). By quantitative PCR, we paradoxically found that HIEs expressed greater quantities of toxin receptor mRNA and yet exhibited decreased sensitivity to toxins when compared with traditionally used cell lines. We reasoned that these differences may be explained by components, such as mucins, that are present in HIEs cultures, that are absent in immortalized cell lines. Addition of human-derived mucin 2 (MUC2) to Vero cells delayed cell rounding, indicating that mucus serves as a barrier to toxin-receptor binding. This work highlights that investigation of C. difficile infection in that HIEs can provide important insights into the intricate interactions between toxins and the human intestinal epithelium.NEW & NOTEWORTHY In this article, we developed a novel model of Clostridioides difficile-induced enteritis using jejunal-derived human intestinal enteroids (HIEs) transduced with fluorescently tagged F-actin. Using live-imaging, we identified that jejunal HIEs express high levels of TcdA and CDT receptors, are more sensitive to TcdA than TcdB, and secrete mucus, which delays toxin-epithelial interactions. This work also optimizes optically clear C. difficile-conditioned media suitable for live-cell imaging.

Using the Theory of Planned Behavior to Evaluate Factors That Influence PharmD Students' Intention to Attend Lectures

Objective. To use the theory of planned behavior (TPB) to evaluate the contribution of attitude, subjective norm, and perceived behavioral control in predicting students' intention to attend class lectures in a Doctor of Pharmacy (PharmD) curriculum in which lecture recordings were available. Methods. A survey instrument based on the TPB was developed from focus groups with PharmD students. The survey was then distributed to first through third year students at the conclusion of the 2017-2018 academic school year. Respondents were asked to evaluate their beliefs regarding lecture attendance and their intention to attend lectures during the upcoming fall semester. Predictors of intention were evaluated using descriptive statistics and multiple logistic regression analyses. Results. Responses from 198 of 383 students contained usable data (52% effective response rate). The TPB constructs of attitude and subjective norm were predictors of high intention to attend lectures. Students with a positive attitude towards lecture attendance (eg, believed that purposeful active learning is desirable and occurs during class) were nearly 30% more likely to have high intention to attend lectures. Students with a positive subjective norm (ie, perceived social pressure from professors and classmates to attend lectures) were 66% more likely to have high intention to attend lectures. Perceived behavioral control was not associated with high intention to attend lectures. Conclusion. Interventions aimed at improving students' attitudes and subjective norm may be beneficial in improving students' intention to attend class lectures.

Clostridioides difficile ribotype 106: A systematic review of the antimicrobial susceptibility, genetics, and clinical outcomes of this common worldwide strain

Clostridioides difficile typing is invaluable for the investigation of both institution-specific outbreaks as well as national surveillance. While the epidemic ribotype 027 (RT027) has received a significant amount of resources and attention, ribotype 106 (RT106) has become more prevalent throughout the past decade. The purpose of this systematic review was to comprehensively summarize the genetic determinants, antimicrobial susceptibility, epidemiology, and clinical outcomes of infection caused by RT106. A total of 68 articles published between 1999 and 2019 were identified as relevant to this review. Although initially identified in the United Kingdom in 1999, RT106 is now found worldwide and became the most prevalent strain in the United States in 2016. Current data indicate that RT106 harbors the tcdA and tcdB genes, lacks binary toxin genes, and does not contain any deletions in the tcdC gene, which differentiates it from other epidemic strains, including ribotypes 027 and 078. Interestingly, RT106 produces more spores than other strains, including RT027. Overall, RT106 is highly resistant to erythromycin, clindamycin, fluoroquinolones, and third-generation cephalosporins. However, the MIC90 in most studies are one to two fold dilutions below the epidemiologic cut-off values of metronidazole and vancomycin, suggesting both are acceptable treatment options from an in vitro perspective. The few clinical outcomes studies available concluded that RT106 causes less severe disease than RT027, but patients were significantly more likely to experience multiple CDI relapses when infected with a RT106 strain. Specific areas warranting future study include potential survival advantages provided by genetic elements as well as a more robust investigation of clinical outcomes associated with RT106.

Real-world Experience of Bezlotoxumab for Prevention of Clostridioides difficile Infection: A Retrospective Multicenter Cohort Study

Background

Bezlotoxumab is approved for prevention of recurrence of Clostridioides difficile infection (CDI) in adults receiving standard of care (SoC) therapy based on findings from MODIFY clinical trials. However, utilization practices and validation of trial results in the real world are limited.

Methods

Records of patients receiving bezlotoxumab between April 2017 and December 2018 across 34 infusion centers in the United States were retrospectively reviewed. Recurrent CDI (rCDI), defined as diarrhea lasting ≥2 days resulting in treatment, was assessed 90 days postbezlotoxumab.

Results

The study cohort included 200 patients (median age, 70 years; 66% female; median Charlson comorbidity index, 5), of whom 86% (n = 173) had prior CDI episodes and 79% (n = 158) had ≥2 risk factors for rCDI. SoC antibiotics included vancomycin (n = 137, 68%), fidaxomicin (n = 60, 30%), and metronidazole (n = 3, 2%). Median time from C. difficile stool test to bezlotoxumab and initiation of SoC to bezlotoxumab were 15 days and 11 days, respectively. Within 90 days, 31 of 195 patients (15.9%) experienced rCDI, which corresponds to a success rate of 84.1%. Patients with ≥2 CDI recurrences prebezlotoxumab had a higher risk of subsequent rCDI compared with those with 1 recurrence or primary CDI (hazard ratio, 2.77; 95% confidence interval, 1.14–6.76; P = .025).

Conclusions

This real-world multicenter study demonstrated successful prevention of rCDI with bezlotoxumab comparable to clinical trial results regardless of type of SoC and timing of infusion. Multiple prior CDI recurrences were associated with a higher risk of subsequent rCDI, supporting the use of bezlotoxumab earlier in the disease course.

Real-world Multicenter Analysis of Clinical Outcomes and Safety of Meropenem-Vaborbactam in Patients Treated for Serious Gram-Negative Bacterial Infections

Fourty patients were treated with meropenem-vaborbactam (MEV) for serious Gram-negative bacterial (GNB) infections. Carbapenem-resistant Enterobacteriaceae (CRE) comprised 80.0% of all GNB infections. Clinical success occurred in 70.0% of patients. Mortality and recurrence at 30 days were 7.5% and 12.5%, respectively. One patient experienced a probable rash due to MEV.

PCR ribotypes of Clostridioides difficile across Texas from 2011 to 2018 including emergence of ribotype 255

Clostridioides difficile infection (CDI) is the most prevalent healthcare-associated infection in the United States and carries a significant healthcare system burden. As part of an ongoing, active surveillance system of C. difficile throughout Texas, the objective of this study was to assess changes in C. difficile ribotypes of clinical isolates obtained from hospitalized patients in Texas over the past seven years. Fifty hospitals located in Texas, USA sent C. difficile positive stool specimens to a centralized laboratory for PCR ribotyping and toxin characterization between 2011 and 2018. Data collected included specimen collection date, patient age, and sex. Strain genotypes were compiled, and changes in ribotype distribution over time were assessed. Overall, 7796 samples were ribotyped from predominately female patients (58.4%) aged 62 ± 19 years. Samples were obtained from all geographic regions of Texas including Houston/Southwest region (n = 5129; 85%), Dallas/North Texas (n = 579, 9.6%), Central Texas (n = 164; 2.7%), and South Texas (n = 162; 2.6%). The 10 most common ribotypes comprised 73% of all isolates tested during the study period. The most common ribotypes were 027 (17.5%), followed by 014-020 (16.1%), 106 (11.6%), and 002 (9.1%). The prevalence of ribotypes 027, 001, and 078-126 declined significantly over time, while ribotypes 106 and 054 increased in prevalence (P < 0.001). Furthermore, the emergence of a novel ribotype 255 strain was observed. Differences in ribotype distribution were also noted based on age and geographic distribution (P < 0.001, each). This seven-year study demonstrated changing molecular epidemiology of C. difficile in Texas, including the emergence of a novel ribotype 255.

A systematic approach to optimize electronic health record medication alerts in a health system

PURPOSE

The effectiveness of a systematic, streamlined approach to optimize drug-drug interaction alerts in an electronic health record for a health system was studied.

METHODS

An 81-week quasi-experimental study was conducted to evaluate interventions made to medication-related clinical decision-support (CDS) alerts. Medication-related CDS alerts were systematically reduced using a multi disciplinary healthcare committee. The primary endpoint was weekly overall, modification, and acknowledgement rates of medication alerts after drug-drug interaction reclassification. Secondary endpoints included sub analysis of types of medication alerts (drug-drug interaction and duplicate therapy alerts) and alert use by providers (pharmacist and prescribers). Data was analyzed using interrupted time series regression analysis.

RESULTS

After implementation of the new alert system, total number of weekly inpatient alerts decreased from 68,900 (66,300-70,900) and 50,300 (48,600-53,600) in the postintervention period (p < 0.001). The perentage of alerts acknowledged weekly increased from 11.8% (IQR, 11.4-12.1%) in the preintervention period to 13.7% (IQR, 13.3-14.0%) in the postintervention period (p < 0.001). The percentage of alerts that were modified also increased from 5.0% (IQR, 4.9-5.3%) in the preintervention period to 7.3% (IQR, 7.0-7.6%) in the postintervention period (p < 0.001). Both increases were primarily seen with pharmacists versus other healthcare professionals (p < 0.001).

CONCLUSION

A committee-led systematic approach to optimizing drug-drug interactions facilitated a significant decrease in the overall number of alerts and an increase in both medication alert acknowledgement and modification rates.

Eosinopenia and Binary Toxin Increase Mortality in Hospitalized Patients With Clostridioides difficile Infection

Background

Patients with Clostridioides difficile infection (CDI) with either eosinopenia or infected with a binary toxin strain have increased likelihood of mortality. However, the relationship between binary toxin and eosinopenia to synergistically increase mortality has not been studied in humans. We hypothesized that patients with CDI due to binary toxin strains and concomitant peripheral eosinopenia would have a higher likelihood of inpatient mortality.

Methods

This multicenter, retrospective cohort study included adult patients with CDI of known ribotypes stratified by eosinopenia, defined as an absence of eosinophils in the peripheral blood (Houston cohort). The primary outcome was inpatient mortality. Results were supported by a separate national cohort of veterans with CDI (Veterans’ cohort).

Results

In the Houston cohort, a total of 688 patients from 13 institutions in 6 cities were included. Of these, 132 (19%) had an eosinophil count of 0.0 cells/µL (0.0 cells*10⁹/L) and 109 (16%) were infected with a binary toxin strain. After adjusting for covariates, the combination of eosinopenia and infection with a binary toxin strain was an independent predictor of inpatient mortality (odds ratio [OR], 7.8; 95% confidence interval [CI], 1.9–33.2; P = .005). In the separate Veterans’ cohort (n = 790), this combination was also a significant predictor of inpatient mortality (OR, 6.1; 95% CI, 1.5–23.9; P = .009).

Conclusions

In conclusion, the combination of eosinopenia and CDI due to a binary toxin strain was correlated with increased mortality in hospitalized patients from 2 independent cohorts. Prospective studies should further study this important subset of patients at the time of CDI diagnosis.

Practical Guidance for Clinical Microbiology Laboratories: A Comprehensive Update on the Problem of Blood Culture Contamination and a Discussion of Methods for Addressing the Problem

In this review, we present a comprehensive discussion of matters related to the problem of blood culture contamination. Issues addressed include the scope and magnitude of the problem, the bacteria most often recognized as contaminants, the impact of blood culture contamination on clinical microbiology laboratory function, the economic and clinical ramifications of contamination, and, perhaps most importantly, a systematic discussion of solutions to the problem. We conclude by providing a series of unanswered questions that pertain to this important issue.

Clinical Practice Guidelines for Clostridium difficile Infection in Adults and Children: 2017 Update by the Infectious Diseases Society of America (IDSA) and Society for Healthcare Epidemiology of America (SHEA)

A panel of experts was convened by the Infectious Diseases Society of America (IDSA) and Society for Healthcare Epidemiology of America (SHEA) to update the 2010 clinical practice guideline on Clostridium difficile infection (CDI) in adults. The update, which has incorporated recommendations for children (following the adult recommendations for epidemiology, diagnosis, and treatment), includes significant changes in the management of this infection and reflects the evolving controversy over best methods for diagnosis. Clostridium difficile remains the most important cause of healthcare-associated diarrhea and has become the most commonly identified cause of healthcare-associated infection in adults in the United States. Moreover, C. difficile has established itself as an important community pathogen. Although the prevalence of the epidemic and virulent ribotype 027 strain has declined markedly along with overall CDI rates in parts of Europe, it remains one of the most commonly identified strains in the United States where it causes a sizable minority of CDIs, especially healthcare-associated CDIs. This guideline updates recommendations regarding epidemiology, diagnosis, treatment, infection prevention, and environmental management.

Clinical Practice Guidelines for Clostridium difficile Infection in Adults and Children: 2017 Update by the Infectious Diseases Society of America (IDSA) and Society for Healthcare Epidemiology of America (SHEA)

A panel of experts was convened by the Infectious Diseases Society of America (IDSA) and Society for Healthcare Epidemiology of America (SHEA) to update the 2010 clinical practice guideline on Clostridium difficile infection (CDI) in adults. The update, which has incorporated recommendations for children (following the adult recommendations for epidemiology, diagnosis, and treatment), includes significant changes in the management of this infection and reflects the evolving controversy over best methods for diagnosis. Clostridium difficile remains the most important cause of healthcare-associated diarrhea and has become the most commonly identified cause of healthcare-associated infection in adults in the United States. Moreover, C. difficile has established itself as an important community pathogen. Although the prevalence of the epidemic and virulent ribotype 027 strain has declined markedly along with overall CDI rates in parts of Europe, it remains one of the most commonly identified strains in the United States where it causes a sizable minority of CDIs, especially healthcare-associated CDIs. This guideline updates recommendations regarding epidemiology, diagnosis, treatment, infection prevention, and environmental management.

2388. High-risk antibiotics associated with Clostridioides difficile infection: a national, multicenter analysis

Background

Historically, antibiotics with the highest Clostridioides difficile infection (CDI) risk included clindamycin, advanced-spectrum penicillins, and cephalosporins; however, a recent CDI epidemic involving fluoroquinolone (FQ)-resistant ribotype 027-added FQs as a high-risk class. Now that the ribotype 027 strain is part of an endemic population of C. difficile strains, no contemporary analysis of high-risk antibiotics and CDI risk has been conducted. The primary objective of this study was to identify the strongest antibiotic predictors for CDI.

Methods

This was a case–control study in the national United States Veterans Health Administration (VHA). The study included patients 18–89 years old with an ICD-9-CM code for CDI (008.45), a positive stool test, and active CDI therapy between 2002 and 2014. A random sample of VHA patients without a CDI ICD-9-CM code served as the control cohort. Antibiotic use was defined as any use in the 90 days prior to inclusion. Antibiotic risk factors for CDI were evaluated in a multivariable logistic regression model that included 33 covariates. Results were validated in non-VA patients at a quaternary care medical center in Houston, TX.

Results

A total of 85,451 VHA patients were included (26,149 CDI patients and 59,302 controls). FQs were most commonly prescribed: 24.9% (CDI group) and 7.3% (controls). Strongest predictors of CDI included carbapenems (OR 54.39, 95% CI 25.42–116.36), advanced-spectrum penicillins (OR 41.54; 95% CI 31.49–54.78), third/fourth-generation cephalosporins (OR 17.35; 95% CI 14.49–20.77), clindamycin (OR 3.63; 95% CI 3.26–4.02), and FQs (OR 1.48; 95% CI 1.40–1.57). Macrolides (OR 0.83; 95% CI 0.77–0.91) and tetracyclines (OR 0.58; 95 CI 0.51–0.66) were negatively associated with CDI risk. In a validation cohort of 68,795 patients, carbapenems (OR 2.19; 95% CI 1.86–2.57), third/fourth-generation cephalosporins (OR 1.70; 95% CI 1.50–1.93), and advanced-spectrum penicillins (OR 1.64; 95% CI 1.42–1.89) were also the strongest predictors for CDI. FQs were not significantly associated with CDI.

Conclusion

Although FQs were the most prescribed antibiotic class, carbapenems were the strongest predictor of CDI development in a national cohort of veterans and a validation cohort.

Disclosures

All authors: No reported disclosures.

688. In Vitro Activity of Eravacycline, a New Tetracycline Analog, and Comparators Against the Six Most Commonly Isolated Ribotypes of Clostridioides difficile

Background

Eravacycline is a novel, tetracycline class antibacterial indicated for the treatment of complicated intra-abdominal infections in adults. In clinical trials, patients given eravacycline had a low likelihood of developing Clostridioides difficile infection (CDI). We hypothesized this was likely due, in part, to the in vitro susceptibility of eravacycline to C. difficile. The purpose of this study was to test the in vitro susceptibility of eravacycline vs. comparators on contemporary clinical isolates representing common ribotypes, including isolates with decreased susceptibility to metronidazole and vancomycin.

Methods

Two hundred and thirty-four isolates from our biobank were selected from the six most common ribotypes (F001, F002, F014-020, F027, F106, and F255). Minimum inhibitory concentrations (MIC) at 24 hours were measured according to CLSI guidelines for eravacycline, vancomycin, metronidazole and fidaxomicin. MICs results were tabulated and are presented as the geometric mean by ribotype.

Results

Geometric MIC results are shown in Table 1. Eravacycline was the most potent antimicrobial tested followed by fidaxomicin, metronidazole, and vancomycin. Results were consistent amongst all ribotypes, including isolates with reduced susceptibility to vancomycin and metronidazole.

Conclusion

Eravacycline displayed potent in vitro activity against a large collection of clinical C. difficile isolates. These data provide insight into why patients given eravacycline had a low likelihood of developing CDI and support further research to better understand the use of eravacycline to prevent or potentially treat patients with CDI.

Disclosures

All authors: No reported disclosures.

668. Quality of Life Changes in Patients with Clostridium difficile Infection (CDI): A Randomized, Double-Blind Trial of Ridinilazole (RDZ) Compared with Vancomycin (VAN)

Background

C. difficile is the most frequent hospital-acquired bacteria in the United States. CDI is associated with significant morbidity and mortality, and a 46% lower mean EQ-5D index of Health-Related Quality of Life (HRQoL) compared with the general population. However, data on the impact of antibiotic treatment for CDI on HRQoL are lacking.

Methods

RDZ is a novel, narrow-spectrum antibiotic with targeted activity against C. difficile, under development for the treatment of CDI and prevention of recurrence. We evaluated HRQoL prospectively with the EQ-5D-3L in 69 patients enrolled in a Phase 2 randomized, double-blind trial comparing RDZ (n = 36) with VAN (n = 33). EQ-5D-3L was obtained at five time points (baseline, days 5, 10, 12, and 40) with summary index values calculated using US weights (Shaw 2005) evaluating raw scores for mobility, self-care, usual activities, pain/discomfort, and anxiety/depression, and visual analog scale (VAS) scores.

Results

As early as Day 5, CDI patients on RDZ had significant improvements in mean change from baseline in index scores (P = 0.008) and VAS scores (P = 0.01) but no significant improvements were seen in patients on VAN. Time to resolution of diarrhea also occurred sooner with RDZ with a hazard ratio 1.19 in favor of RDZ (90% CI: 0.76, 1.87). Mean changes in index scores in the VAN group took longer to improve significantly compared with baseline and became higher on VAN on Day 12 and Day 40. Treatment-related improvements in pain/discomfort and anxiety/depression are shown in Figures 1 and 2. The mean change from baseline in EQ-5D-3L domains showed the highest (significant) improvements in the pain/discomfort domain for both treatment groups across all time points. However, by Day 40, anxiety/depression improved significantly more with RDZ than with VAN (P = 0.039).

Conclusion

We believe this is the first study to document improvements in HRQoL after antimicrobial treatment for CDI. Patients receiving ridinilazole experienced greater improvements in HRQoL sooner than those on VAN. Anxiety/depression and pain/discomfort improved significantly with treatment. HRQoL should be evaluated in Phase 3 interventional studies for CDI. These results will need to be validated in the ongoing Phase 3 randomized, double-blind, global trials comparing RDZ to VAN for the treatment of CDI.

Disclosures

All authors: No reported disclosures.

2380. Fecal Collinsella Abundance is Negatively Associated with Toxin A/B Production in Cancer Patients with Clostridioides difficile

Background

The detection of C. difficile (CDI) by nucleic acid amplification test (NAAT) with negative toxin enzyme immunoassay (EIA-) is difficult to interpret in cancer patients. Markers that differentiate true infection from colonization, and are associated with clinical outcomes are needed. We hypothesized that the microbiome composition and inflammatory fecal markers in EIA- patients differed from those who are EIA+ and were associated with disease severity and recurrence.

Methods

We studied the fecal microbiome composition (16s rRNA, V3) of 147 cancer patients with CDI diagnosed by a two-step testing algorithm. Clinical data, CDI bacterial quantity (BQ) by qPCR and markers of intestinal inflammation (calprotectin, lactoferrin, IL-1β and IL-8) were analyzed. Data were stratified according to cancer type [hematologic (H) n = 49, solid tumor (ST) n = 66, or stem cell transplant (SCT) n = 32].

Results

Demographic characteristics and symptoms were similar between the three groups. At baseline, species diversity by Shannon index was similar in all three groups regardless of EIA detection and did not correlate with clinical presentation, response to therapy or recurrence. Microbiome composition did not correlate with inflammatory response except in H in whom a higher diversity correlated with increased IL-8 (P = 0.021) and calprotectin (P = 0.01) levels. At the genus level across all strata and when compared with EIA- cases, EIA+ cases presented with a higher abundance of Peptoclostridium (P = 0.0008) which correlated with CDI BQ qPCR (log of BQ/mg 2.38 ± 1.49 vs 0.92 ± 1.28, P < 0.001). In contrast, EIA- cases had a higher abundance of Collinsella (P = 0.001). SCT patients carried fewer Peptoclostridium when compared with other groups, whereas all three patient groups carried similar amounts of Collinsella. The relative abundance of Peptoclostridium and Collinsella was not associated with response to therapy, or fecal markers of inflammation. Principal component analysis did not demonstrate differences between the three groups studied.

Conclusion

In this study, the presence of Collinsella, a known butyrate and bile salt hydrolase producer, was associated with the lack of CDI toxin A/B production. Loss of Collinsella may represent a novel risk factor for active CDI.

Disclosures

All authors: No reported disclosures.

1720. Isolation and Characterization of Candida auris From an Active Surveillance System in Texas

Background

Candida auris is an emerging new multi-drug-resistant fungal pathogen spreading globally. C. auris is associated with outbreaks due to the bloodstream, ear, and wound infections with a high mortality rate (30 to 60%). As part of our multi-pathogen surveillance system, we began screening for C. auris to understand the ecology, sources, and epidemiology of this important pathogen from leftover stool samples collected from hospitalized patients.

Methods

Four hundred and seventeen stool samples were collected, enriched in brain heart infusion broth for 2–3 days at 37°C, and sub-cultured onto selective Candida agar plates. Agar plates were incubated at 37°C for another 2–3 days and suspected Candida colonies were stocked for DNA extraction, PCR identification, and whole-genome sequencing. PCR amplicons were sequenced to confirm the identification C. auris. Enrichment samples were also screened by PCR to directly detect C. auris. Minimum inhibitory concentration (MIC) of various anti-fungal drugs was determined by the micro-dilution method using a commercial MIC plate (Sensititre “YeastOne”).

Results

Three C. auris samples were identified by PCR (0.7%; 3/417) of which one was able to be cultured. The isolated strain was resistant to fluconazole, itraconazole, voriconazole, posaconazole, and caspofungin. WGS data analysis demonstrates our isolate has high similarity with the Pakistani strains.

Conclusion

We have detected C. auris from stool samples of hospitalized patients in Texas for the first time. WGS data indicate our isolate has high similarity with South Asian patient strains. Long-term surveillance of C. auris is essential to understand the infection or colonization sources and epidemiology of this newly emerging fungal pathogen.

Disclosures

All authors: No reported disclosures.

2391. Increased Risk of Systemic Infections with Multidrug-Resistant Organisms in Patients with Severe Clostridioides difficile Infection

Background

The gut microbiota is a defense mechanism against colonization of multidrug-resistant organisms (MDROs), including carbapenem-resistant Enterobacteriacae (CRE). Gut dysbiosis caused by broad-spectrum antibiotics favors MDRO colonization and increased susceptibility of intestinal infections, including C. difficile infection (CDI). Increased CDI severity may increase the risk of bacterial translocation due to damage to colonic epithelial layer. The aim of this study was to assess CDI disease severity and subsequent risk for MDRO systemic infection.

Methods

This was a prospective, observational study of adult hospitalized patients tested for CDI at a large, university-affiliated tertiary care hospital. Patients with a history of systemic MDRO infection in the past 90-days of stool testing were excluded. Patients were stratified by test positivity (CDI vs. antibiotic-associated diarrhea (AAD)), as well as, CDI disease severity and followed for 30-days for subsequent MDRO infections defined as presence of MDRO cultures from systemic, normally sterile sites (blood, urine, cerebrospinal fluid). Stool samples were collected and grown for MDRO colonization.

Results

A total of 335 CDI-positive and 135 antibiotic-associated diarrhea (AAD) hospitalized patients were included. No differences were found in rates of MDRO colonization by test positivity or disease severity (overall 68% VRE, 53% Candida spp., 30.4% MRSA, and 1.8% CRE). Significantly more patients with severe CDI had higher rates of developing systemic MDROs compared with mild-moderate CDI and AAD (23.2%, n = 112 vs. 8.1%, n = 223 P < 0.001; vs. 11.9%, p = 0.018). Severe CDI was found to be an independent risk factor for subsequent systemic MDRO infection via logistic regression.

Conclusion

Severe CDI disease is associated with an increased risk of systemic MDRO infections.

Disclosures

All authors: No reported disclosures.

1038. Impact of an Electronic Antibiotic Timeout on the Utilization of Frequently Prescribed Antibiotics in Hospitalized Patients

Background

Methods to operationalize antibiotic timeouts (ATO) among hospitalized patients are often constrained by the high volume of antibiotic orders that surpass the capabilities of the antimicrobial stewardship program (ASP) to intervene. Houston Methodist Hospital implemented a streamlined electronic ATO process that alerted providers to evaluate the need for continued antibiotics on day 4 of predefined anti-infective therapy. Unresolved alerts were reviewed by clinical pharmacists the following day. The objective of this study was to determine the impact of this electronic ATO on frequently prescribed antibiotics.

Methods

This was a quasi-experimental study in a 924-bed quaternary care hospital comparing days of therapy (DOT) in patients admitted prior to (February 2017 – January 2018) and after implementing an ATO process (March 2018 – February 2019). Antibiotics evaluated included vancomycin, cefepime, piperacillin/tazobactam, and meropenem. ATO alert logic was simulated retrospectively to capture the pre-ATO cohort. The primary outcome was mean composite DOT per patient admission. Secondary outcomes included total hospitalization cost, Clostridioides difficile infection (CDI) and multidrug-resistant organism (MDRO) rates.

Results

A total of 8,458 patients met ATO alert criteria for inclusion in the pre-ATO timeframe and 6,901 patients with an ATO alert in the post-ATO group; 2,642 (38%) prompted a pharmacists’ review. The average composite DOT was 11.5 per admission in the pre-ATO cohort compared with 11.1 in the post-ATO cohort (P = 0.02). After multivariate linear regression, the ATO was significantly associated with a decrease of 0.5 DOT per patient admission (P < 0.001). Other factors associated with a reduction in DOT included age (P < 0.001), service line (P = 0.003), and admission source (P = 0.031). Mean hospital costs per admission were significantly reduced in the post-ATO group: $67,613 vs. $66,615 (P = 0.01). There was no difference in rates of CDI and MDRO.

Conclusion

Implementation of our electronic ATO process demonstrated significant reductions in overall DOT for frequently prescribed antibiotics and decreased total hospital costs across a diverse patient population. This process provides a real-world strategy to operationalize a large-scale ATO as an adjunct to an ASP.

Disclosures

All authors: No reported disclosures.

2682. Prophylaxis-Driven Molecular Epidemiology of Pseudomonas aeruginosa Bloodstream Infections in Adults With Leukemia

Background

Fluoroquinolones (FQs) are routinely used as antimicrobial prophylaxis in leukemia patients receiving chemotherapy to prevent Pseudomonas aeruginosa infections. Patients who are intolerant to FQs may receive cefpodoxime (CPD) or other agents. How FQ use affects the resistance profile and epidemiology of breakthrough P. aeruginosa infections is unknown. To determine this, we performed a whole-genome sequencing (WGS)-driven epidemiologic study of leukemia patients with P. aeruginosa bloodstream infections.

Methods

All adult (age > 17 years) inpatients with leukemia and a first episode of monomicrobial P. aeruginosa bloodstream infection were included. Clinical data were extracted from the electronic medical record. Isolates were sequenced using an Illumina NextSeq and phylogenomics was performed using an in-house analysis pipeline consisting of Bowtie2, SAMtools and bcftools.

Results

110 patients were included and most had a diagnosis of acute myeloid leukemia (n = 66). Twenty (18%) patients received FQ prophylaxis, 56 (54%) received CPD, and the remaining 34 (31%) received other agents. 9 (8%) isolates were multidrug-resistant (MDR). MDR was more common in those receiving FQ prophylaxis (20% vs 6%, P = 0.06). 76 sequence types (STs) were represented with ST235 (n = 8) being most common followed by ST244 (n = 7). ST235 strains were genetically distinct, but closely related (>10 but < 250 SNPs) in comparison to other STs. 2 ST244 strains were genetically identical despite being isolated 4 months apart, suggesting horizontal transmission. MDR was more common among ST235 isolates compared with other STs (38% vs 6%, P = 0.02). ST235 strains were more common in patients receiving FQ vs other prophylaxis (20% vs 4%, P = 0.04). 1 ST244 isolate harbored a VIM-2 β-lactamase. In 20 FQ-resistant isolates, 80% had mutations in either parC (S87L) or gyrA (T83I) and 50% had both. FQ-resistance mutations were more common in FQ recipients (50% vs 8%, P < 0.01).

Conclusion

Most P. aeruginosa infections occurred in non-FQ recipients, while MDR P. aeruginosa infections were more common in FQ recipients. These data suggest that decisions on empiric treatment of patients with P. aeruginosa bacteremia must take antimicrobial prophylaxis history into account.

Disclosures

Samuel L. Aitken, PharmD, Melinta Therapeutoics: Grant/Research Support, Research Grant; Merck, Sharpe, and Dohme: Advisory Board; Shionogi: Advisory Board.

840. Clinical Failure Rates Associated with Hemin-induced Metronidazole Resistance in Clostridioides difficile

Background

Current guidelines suggest limiting metronidazole (MTZ) use due to increased treatment failures in patients with Clostridioides difficile infections (CDI). We hypothesized that an increase in the minimum inhibitory concentration (MIC) of MTZ to C. difficile may contribute to these poor response rates. The objective of this study was to examine clinical response rates in patients with CDI based on MTZ MIC and stratified by receipt of MTZ treatment.

Methods

Clostridioides difficile-positive stool samples collected from 2017 to 2018 as part of routine care at two hospital systems in Houston, Texas were collected for MIC determination at 24 h to MTZ by broth microdilution following incorporation of 5 mg/L of hemin. The primary outcome was initial clinical success by Day 7 of treatment in those with MICs ≥1 vs. <1. Results were stratified based on receipt of MTZ within 48 hours of diagnosis. Study objectives were tested using χ 2 and multivariable logistic regression analyses.

Results

A total of 235 C. difficile samples were included, of which 73 (31%) had an MTZ MIC ≥1. Overall, 72% received MTZ within the first 48 hours. Clinical success rates differed based on disease severity (77% in nonsevere, 64% in severe/fulminant; P = 0.03) and infecting ribotype (52% in RT 027, 75% in non-RT 027; P = 0.014). In patients with MTZ receipt, clinical success rates were higher in patients infected with strains with an MTZ MIC < 1 (76%) compared with those with an MIC ≥1 (60%; P = 0.031). The difference in initial clinical success was not different in those that did not receive MTZ (78% for MIC <1 vs. 65% for MIC ≥1, P = 0.28). After controlling for disease severity, treatment failure was higher in patients infected with strains with an MTZ MIC ≥1 and treated with MTZ (OR 2.1; 95% CI, 1.01–4.35; P = 0.048) but not for those with an MIC ≥1 treated with other therapies (OR 1.9; 95% CI, 0.62–5.6; P = 0.27).

Conclusion

This study provides the first preliminary evidence of an association between reduced metronidazole susceptibility and decreased clinical success rates. Larger studies are warranted to validate these findings.

Disclosures

All Authors: No reported Disclosures.

2398. Effect of Eosinopenia and Binary Toxin on Clostridioides difficile Infection Clinical Outcomes

Background

The ability of Clostridioides difficile to cause clinical disease in humans is dependent on toxin production. Significantly fewer eosinophils are seen in the peripheral blood of mice infected with a binary toxin positive (CDT+) C. difficile strain. Furthermore, the presence of CDT and eosinopenia have separately been associated with increased mortality in humans with C. difficile infection (CDI). We hypothesized that CDI due to a CDT+ C. difficile strain accompanied by peripheral eosinopenia would be associated with higher odds of inpatient mortality.

Methods

This multicenter, retrospective cohort study included all patients ≥ 18 years of age with toxigenic CDI in which specimen ribotype data were available as part of our ongoing surveillance study. The cohort was stratified by eosinophil count (0.0 cells/μL vs. > 0.0 cells/μL). The primary outcome was inpatient mortality. A logistic regression model was developed modeling inpatient mortality as a function of the available patient covariates. All P-values were from 2-sided tests, and results were deemed statistically significant at P < 0.05.

Results

A total of 688 patients from 13 institutions in six cities were included. Of those, 132 had a baseline eosinophil count of 0.0 cells/µL and 556 had a baseline eosinophil count > 0.0 cells/µL. While the odds of inpatient mortality were higher among patients with eosinopenia and those infected with a CDT+ ribotype, the combination of these variables remained an independent predictor of inpatient mortality after adjusting for CCI score, WBC count, and serum albumin level (OR, 7.84; 95% CI, 1.85–33.20; P = 0.005).

Conclusion

This is the first attempt to study the in vivo relationship between CDT presence, human immune response, and CDI clinical outcome. We identified an association between CDT presence with concomitant eosinopenia and worsened CDI outcomes. Healthcare facilities should consider identifying this important subset of patients at the time of CDI diagnosis. Future CDI drug development might benefit from targeting C. difficile properties that impair host immune response, which may in turn decrease adverse clinical outcomes associated with this disease.

Disclosures

All authors: No reported disclosures.

LB7. A Randomized, Blinded, Placebo- and Vancomycin-Controlled, First-In-Human (FIH) Study of the Safety, Pharmacokinetics (PK), and Fecal Microbiome Effects of ACX-362E, a Novel Anti-Clostridial DNA Polymerase IIIC (polIIIC) Inhibitor

Background

ACX-362E, a novel DNA polIIIC inhibitor, is a narrow-spectrum antibacterial selectively active against certain Gram-positive bacteria, including Clostridioides difficile (MIC90 = 4 µg/mL). The objectives of this phase I study was to assess the safety, pharmacokinetics, and fecal microbiome effects of ACX-362E

Methods

This three-part FIH phase 1, double-blind, randomized healthy volunteer trial determined the safety profile, food effect, and systemic/stool pharmacokinetics of escalating single (150, 300, 600, and 900 mg) and multiple (300 and 450 mg) doses of oral ACX-362E vs. placebo (PBO). Fecal microbiome effects (metagenomic sequencing and qPCR) of multiple-dose ACX-362E were compared with 6 subjects receiving concomitant open-label vancomycin 125 mg four times daily. Dose escalation to each new cohort occurred following review of safety and PK data by a safety oversight committee.

Results

Forty-four subjects received ACX-362E (single dose = 24, multiple doses = 12, food effect = 8) and 12 PBO. Overall, ACX-362E was well tolerated at all dose levels. Adverse events were generally mild and transitory, and no moderate, severe, cumulative, or dose-limiting drug-related adverse events leading to discontinuation were observed. Mean plasma half-life was approximately 2 hours and no accumulation occurred with repeated dosing (Figure 1). Systemic exposure was less than 1 μg/mL and decreased with food. Fecal concentrations during multiple dosing exceeded the C. difficile MIC by multiples of up to ~2,500. ACX-362E had minimal effect on Bacteroidetes phylum and caused significantly less dysbiosis than vancomycin (Figure 2).

Conclusion

This FIH clinical trial with ACX-362E demonstrated a favorable safety profile, low systemic and high fecal concentrations, and favorable gut microbiome changes compared with vancomycin. These results shows promise for further clinical development to treat C. difficile infections.

Disclosures

Kevin W. Garey, MS, PharmD, Acurx (Grant/Research Support), Martin Kankam, MD, PhD, MPH, Acurx Pharmaceuticals, LLC (Research Grant or Support), Julie Mercier, BS, Acurx Pharmaceuticals, LLC (Research Grant or Support), Corinne Seng Yue, BPharm, MSc, PhD, Acurx Pharmaceuticals, LLC (Grant/Research Support), Murray Ducharme, PharmD, Acurx Pharmaceuticals, LLC (Grant/Research Support), Anne J. Gonzales-Luna, PharmD, no financial relationships or conflicts of interest, M Jahangir Alam, PhD, No financial relationships or conflicts of interest, Khurshida Begum, PhD, No financial relationships or conflicts of interest, Michael Silverman, MD, Acurx Pharmaceuticals, LLC (Consultant, Employee, Shareholder).

2382. Recurrent Clostridioides difficile Infection (CDI) Worsens Anxiety-Related Patient-Reported Quality of Life

Background

The Health-Related Quality of life (HR-QOL) instrument, the Cdiff32, allows studies on QOL changes associated with recurrent CDI. An ongoing real-world study of bezlotoxumab (BEZ) provided a unique opportunity to study anxiety-related HR-QOL in patients at high risk for recurrent CDI using the anxiety sub-domain of Cdiff32. The aims of this study were to assess baseline anxiety-related HR-QOL based on the number of prior episodes of CDI and to evaluate changes in patients with or without recurrence.

Methods

Patients at high risk for recurrent CDI given BEZ were administered the anxiety sub-domain questions of the Cdiff32 prior to infusion and at approximately 90 days after administration (0 = worst anxiety; 100 = no anxiety). The number of prior episodes of CDI were collected, along with demographics and co-morbid conditions. Patients were followed for 90 days for CDI recurrence, which was defined as new onset of diarrhea requiring CDI-active antibiotics.

Results

There were 107 patients evaluated, aged 68 ± 14 years (mean ± SD) with multiple co-morbid conditions (mean Charlson: 4 ± 3) and multiple previous CDI episodes (3 ± 1 episodes). Fourteen patients (13%) experienced a further CDI recurrence within 90 days following BEZ. Overall, baseline anxiety HR-QOL was 29 ± 22. Risk factors for lower baseline anxiety-related HR-QOL included immunocompromised conditions (P < 0.046) and receipt of a proton pump inhibitor (P < 0.018). Compared with patients with primary CDI disease (Score: 35 ± 20), baseline anxiety HR-QOL was worse with subsequent prior recurrences (Score: 26 ± 23) for CDI episodes 2–4, and then improved for subsequent episodes (Score: 38 ± 22). Anxiety-related HR-QOL improved by a mean of 32 ± 25 points compared with patients that experienced a further recurrence where HR-QOL declined (P < 0.0001). Results were confirmed in a multivariate model controlling for Charlson score and chronic renal failure.

Conclusion

Poor anxiety-related HR-QOL was observed at baseline in all patients regardless of number of prior episodes. QOL improved 90 days after BEZ infusion in patients without further recurrences of CDIs and worsened in patients with a subsequent recurrence.

Disclosures

All authors: No reported disclosures.

2235. Fecal Biomarkers for Clostridioides difficile Infection in Cancer Patients

Background

The diagnosis of C. difficile infection (CDI) relies on using a nucleic acid amplification test (NAAT) followed by confirmatory toxin enzyme immunoassay (EIA). This study examined the utility of fecal biomarkers and C. difficile bacterial quantity (BQ) in differentiating patients with true infection (NAAT+/EIA+) from patients with colonization (NAAT+/EIA-) in the context of C. difficile ribotypes.

Methods

We studied 136 patients with diarrhea and CDI identified by NAAT in stools for which a confirmatory toxin A, B, EIA was performed. Fecal IL-8, IL-1β, calprotectin, and lactoferrin were studied by ELISA. C. difficile BQ was determined by 16S rRNA qPCR. Data were stratified according to cancer diagnosis into three groups [hematologic (H) n = 43, solid tumor (ST) n = 62, or stem cell transplant (SCT) n = 31].

Results

Stools were EIA+ in 36/136 (26%) of the cohort. Although ST patients had a higher Charlson co-morbidity index when compared with the other two groups (P < 0.002), demographic characteristics and symptoms at the time of presentation were similar between groups regardless of EIA status. Most common ribotypes identified included F106 and F014-020. Ribotype distribution differed according to oncologic diagnosis as determined by the Shannon diversity index. There were fewer distinct C. difficile ribotypes in the SCT (n = 8) vs. ST (n = 15) and H (n = 15) groups (P < 0.001 and P < 0.002, respectively). BQ were higher in EIA+ than EIA- across all strata (log of BQ/mg 2.38 ± 1.49 vs. 0.92 ± 1.28, P > 0.001). Similarly, higher levels of fecal IL-8 (1.72 ± 1.9 vs. 0.83 ± 1.6 ng/mL), IL-1β (3.74 ± 13.7 vs.. 1.21 ± 4.6) and calprotectin (14.9 ± 27 vs. 6 ±1.8 ug/mL) levels were seen in EIA+ patients. While IL-8, IL-1β, and calprotectin were increased in EIA+ ST and H, no differences were seen in the SCT group. A sensitivity analysis using ROC curves, revealed that BQ resulted in a greater area under the curve than fecal markers of inflammation (A = 0.77, P < 0.001, 95% CI [0.67–0.86]).

Conclusion

In this study in cancer and immunocompromised patients, C. difficile bacterial burden regardless of infecting ribotype and fecal cytokines showed to be a helpful assay in distinguishing true CDI from colonization.

Disclosures

All authors: No reported disclosures.

2580. Serial Microbiome Analysis in a Patient with Multiple Failed Fecal Microbiome Transplantations

Background

Fecal microbiota transplantation (FMT) is recommended to treat refractory or recurrent cases of Clostridioides difficile infection (CDI) through restoration of a healthy intestinal microbiome. The procedure has reported success rates of 90% or higher for CDI, but several risk factors for FMT failure have been identified. Here we present a case of a patient failing four FMT procedures over a 2-year period, with accompanying microbiome and metagenomic analyses.

Methods

Seven serial C. difficile-positive stool samples were collected as part of an ongoing surveillance system in Texas. Samples, including the index case, represented independent CDI episodes interspersed between four separate FMT procedures between 2016 and 2018. PCR ribotype (RT) testing, 16S rRNA gene sequencing, MIC testing, multidrug-resistant organism (MDRO) screening, and shotgun metagenome sequencing were conducted for each of the samples.

Results

The patient was a 42-year-old female with various comorbidities, including systemic lupus erythematosus. She received continuous non-CDI antibiotic courses throughout her CDI therapy for a variety of infections. The vancomycin MICs in infecting C. difficile strains increased with cumulative vancomycin exposure. Multidrug-resistant organisms were detected in stool, including Enterococcus spp., MRSA, and Candida glabrata. The first five of the seven strains were RT 078–126, one was mixed RT 002 and RT 054, and one was RT 002. The analysis of 16S rRNA gene sequences demonstrated that microbial diversity was never restored after FMT procedures. A strong correlation between microbial and functional gene compositions suggests that fecal samples share many microbial species with associated functional genes.

Conclusion

A number of systems biology changes were observed in a patient with persistent CDI despite multiple FMTs. The lack of FMT engraftment was most likely due to continuous broad-spectrum antibiotic exposure in an immunocompromised patient.

Disclosures

All authors: No reported disclosures.

2410. Molecular Characteristics of Environmental Clostridioides difficile From a Large Texas Hospital

Background

Clostridioides difficile is an anaerobic spore-forming, toxin-producing Gram-positive bacillus listed by the CDC as an “urgent threat” pathogen. Epidemiologic studies using whole-genome sequencing (WGS) have found that genetically distinct lineages infections occur in hospitalized patients, in addition to the fact that C. difficile spores persist on hospital surfaces after disinfection. The purposes of this study were to isolate and characterize C. difficile from the environment of a large Texas hospital.

Methods

We collected 330 swab samples of hospital environmental surfaces using sterile cotton gauze. The samples were then anaerobically enriched in brain heart infusion broth for 48–72 hours and plated onto cycloserine–cefoxitin fructose agar (CCFA). Suspected colonies were then genetically characterized using PCR (for tcdA, tcdB, cdtA, cdtB and tpi genes) and genotyped using fluorescent PCR ribotyping techniques.

Results

A total of 90/330 (27.3%) environmental samples were culture positive for C. difficile, of which 75/90 (82.1%) tested were toxigenic C. difficile by the presence of tcdA, tcdB, cdtA or cdtB. A total of 16 distinct ribotypes were identified from 41 C. difficile isolates tested using a fluorescent-ribotyping method. The predominant ribotypes isolated were F078–126 (8/41), F002 (5/41), F106 (4/41), F255 (4/41), and F014-020 (3/41).

Conclusion

We found a diversity of C. difficile strain types in various hospital high-touch surface environment in addition to ribotype F027 and F078, suggesting the hospital environment a reservoir and significant source C. difficile infections.

Disclosures

All authors: No reported disclosures.

2378. Corticosteroid Use Prevents Primary Clostridioides difficile Infection in the Setting of Broad-Spectrum Antibiotic Use Among Hospitalized Patients

Background

Clostridioides difficile is the most common pathogen causing healthcare-associated infections in the United States and a Centers for Disease Control and Prevention urgent threat-level pathogen. The pathophysiology of C. difficile infection (CDI) involves neutrophil invasion of the colon associated with an inflammatory response. Previous case–control studies investigating an anti-inflammatory corticosteroid (CS) effect on CDI risk demonstrated conflicting results but were unable to control for antibiotic use. We hypothesized that CS use would decrease the risk of CDI in a well-matched, high-risk population.

Methods

This nested case–control study included hospitalized patients admitted to a single quaternary care hospital in the Texas Medical Center. The case population included adults who were diagnosed with CDI and received at least one dose of an antibiotic of interest (piperacillin–tazobactam, cefepime, or meropenem) in the 90 days prior to CDI diagnosis. The control population included hospitalized adults who received one of the same antibiotics during their hospital stay but did not develop CDI in the 90 days following their first dose. Patients were excluded if they had a documented history of CDI. CS use was defined as ≥ 20 mg prednisone or equivalent administered in the 48 hours prior to CDI diagnosis (cases) or antibiotic start (controls). The primary study outcome was the development of CDI. A logistic regression model was developed modeling CDI diagnosis as a function of available patient covariates.

Results

A total of 321 patients met the inclusion criteria; 56 patients had a history of CDI, leaving a final study cohort of 265 patients (104 cases and 161 controls). Antibiotic days of therapy were significantly higher in the control group (8 vs. 6 days; P = 0.02). The odds of CDI diagnosis were lower among patients administered CS (OR, 0.17; 95% CI, 0.08–0.38; P < 0.001), which remained protective in the multivariable model after adjusting for age, gender, and invasive GI surgery within 6 months.

Conclusion

We observed an association between CS use and decreased risk of developing primary CDI in hospitalized patients receiving broad-spectrum antibiotics. Future studies are needed to delineate the dose and duration of CS needed to realize this effect.

Disclosures

All authors: No reported disclosures.

2402. Clinical Outcomes Associated with an Emerging Clostridioides difficile Ribotype 255 in Texas

Background

PCR ribotyping of Clostridioides difficile strains is commonly used to describe the epidemiology of C. difficile infection (CDI). Certain ribotypes (RT) have been associated with more severe disease and clinical outcomes, such as RT 027, while others are considered less virulent, such as RT 014-020. Texas statewide surveillance identified the emergence of a rarely-described RT 255 beginning in 2015, which now represents the fifth most common ribotype across the state. Here we describe clinical outcomes associated with an emergent RT 255 in Texas.

Methods

A retrospective cohort study was conducted including patients from two tertiary care centers in Houston, Texas. Patients infected with C. difficile strains of either RT 255, 014-020, or 027 between 2016–18 were included. The primary outcome was disease severity as classified by the 2017 IDSA guidelines. Multivariable logistic regression analysis was done to control for other patient factors. Results were significant at P < 0.05, and all statistical analyses were completed using SPSS, version 25.

Results

A total of 150 patients were included (50 patients infected with each RT). Overall, 53% of the patients had severe or fulminant disease most commonly due to RT 027 (80%) followed by RT 014-020 (40%) and RT 255 (38%). Patients infected with RT 255 or 014-020 had a 75% relative reduction in the odds of severe disease compared with RT 027 after controlling for patient age and serum albumin level (OR, 0.25; 95% CI, 0.86–0.74; P = 0.12;). No differences were seen in the rates of 30- or 90-day recurrence between RTs.

Conclusion

Although RT 255 is becoming increasingly common across Texas, it does not appear to be associated with more severe disease when compared with other common ribotypes. Further studies are warranted to determine contributing factors for its increasing prevalence.

Disclosures

All authors: No reported disclosures.

2581. An Invertebrate Model to Study Gut Microbiome Dysbiosis

Background

Antimicrobials disrupt the gut microbiota by reducing gut microbiome diversity and quantity. Galleria mellonella provides an invertebrate model that is inexpensive, easy to maintain, and does not require specialized equipment. This study investigated the feasibility of using G. mellonella as an in vivo model to evaluate the effect of different antimicrobials on gut microbiota.

Methods

To determine baseline gut microbiota composition, the gut contents of G. mellonella were extracted and genomic DNA underwent shotgun meta-genomic sequencing. To determine the effect of infection and antibiotic use, 30 larvae were injected (left proleg) with ~1 × 105 colony-forming unit (cfu) of methicillin-resistant Staphylococcus aureus (MRSA) and were randomized 1:1:1 to treatment with vancomycin (20 mg/kg) or a natural antimicrobial (Nigella sativa seed oil, 70 mg/kg; NS oil), or a combination. The larvae were kept at 37°C post-infection and monitored daily for 72 hours for activity, extent of cocoon formation/growth, melanization, and survival. Two larvae from each group were randomly selected and homogenized with PBS as controls. After 24 hours of incubation, gut contents were extracted and plated for MRSA and Enterococcus cfu counts.

Results

Metagenomics analysis showed the gut microbiota composition of G. mellonella larvae was dominated by a subset of closely-related Enterococcus species. After 24 hours of exposure, mean Enterococcus counts were 4 × 103 cfu in the vancomycin arm and 6.2 × 104 cfu in the NS oil arm. Mean MRSA counts were 3.3 × 105 cfu in vancomycin arm and 1.5 × 104 cfu in NS oil arm. The combination of vancomycin and NS oil had higher Enterococcus counts than the vancomycin alone arm (6.3 × 104 cfu vs. 4 × 103 cfu, respectively), suggesting that NS oil may have a role in protecting the gut microbiota.

Conclusion

This study provides preliminary evidence to support the potential use of G. mellonella to assess the in vivo effect of a natural and synthetic antimicrobial on the gut microbiota.

Disclosures

All authors: No reported disclosures.

2248. Clinical and Microbiological Outcomes Associated with Real-World Use of Ceftolozane/Tazobactam

Background

Ceftolozane/tazobactam (C/T) is a novel cephalosporin/β-lactamase inhibitor combination for treating Gram-negative infections, particularly Pseudomonas aeruginosa (PA). C/T has been FDA-approved for complicated intra-abdominal and urinary tract infections and has just completed a trial in ventilator nosocomial pneumonia, but real-world outcome data are still emerging.

Methods

Demographic, microbiologic, treatment and outcome data of patients who received C/T for ≥48 hours from January 2016 to August 2018 at multiple centers within a single hospital system were retrospectively collected. Available isolates were analyzed for C/T susceptibility (by Etest) and whole-genome sequencing (WGS). Spades v.3.11.1 was used for assembly, multi-locus sequence typing v2.10 performed for in silico MLST with the PubMLST database and Abricate v0.7 was used for resistance gene screening with the CARD database.

Results

Among 45 patients, 58% were non-white, 53% were female and 13% were immunocompromised. The median age was 64 years (IQR, 50 to 69). At the time of the index event, a high proportion of patients required ICU care (42%) and pressor support (13%) as well as had invasive devices in place (64%). A minority (2.4%) had prior exposure to C/T. Respiratory infections were most common (38%) followed by urinary tract (20%). Concomitant Gram-negative agents were used in 18%. 69% achieved clinical success (i.e., recovery from infection-related signs and symptoms). The in-hospital mortality rate was 16% of which 5 out of 7 were attributed to infection. Microbiology was available for 91% of patients; 84% had PA isolates resistant to at least 3 antipseudomonal classes (Figures 1 and 2). Ten PA isolates were analyzed with WGS (Table 1). C/T resistance arose during therapy in one patient (MIC increase from 1 to 128 µg/mL). WGS showed a substitution in AmpC β-lactamase (A46D) and presence of bla_CARB-2.

Conclusion

Although C/T was used in a critically ill population with highly resistant organisms, cure rates were high and mortality was low. Acquired β-lactamases were not frequently seen among the PA isolates. C/T is a vital therapeutic option, particularly on MDR isolates for which options are limited.

Disclosures

Samuel L. Aitken, PharmD, Melinta Therapeutoics: Grant/Research Support, Research Grant; Merck, Sharpe, and Dohme: Advisory Board; Shionogi: Advisory Board.

Combating resistance while maintaining innovation: the future of antimicrobial stewardship

Antimicrobial resistance represents a significant global health threat. However, a commercial model that does not offer a return on investment resulting in a lack of investment in antibiotic R&D, means that the current pipeline of antibiotics lacks sufficient innovation to meet this challenge. Those responsible for defining, promoting and monitoring the rationale use of antibiotics (the antimicrobial stewardship programme) are key to addressing current shortcomings. In this personal perspective, we discuss the future role stewardship can play in stimulating innovation, a need to move away from a pharmacy budget dominated view of antibiotic use, and the impact of the ever-increasing sophistication and interdisciplinary nature of antimicrobial control programs. Changes are needed to optimize clinical outcomes for patients.

Economic health care costs of blood culture contamination: A systematic review

BACKGROUND

Blood culture contamination with gram-positive organisms is a common occurrence in patients suspected of bloodstream infections, especially in emergency departments. Although numerous research studies have investigated the cost implications of blood culture contamination, a contemporary systematic review of the literature has not been performed. The aim of this project was to perform a systematic review of the published literature on the economic costs of blood culture contamination.

METHODS

PubMed was searched (January 1, 1978, to July 15, 2018) using the search terms "blood culture contamination" or "false-positive blood cultures." Articles were title searched and abstracts were reviewed for eligible articles that reported immediate or downstream economic costs of blood culture contamination.

RESULTS AND DISCUSSION

The PubMed search identified 151 relevant articles by title search, with 49 articles included after abstract review. From the studies included, overall blood culture contamination rates ranged from 0.9%-41%. Up to 59% of patients received unnecessary treatment with parenteral vancomycin as a result of blood culture contamination, resulting in increased pharmacy charges between $210 and $12,611 per patient. Increases in total laboratory charges between $2,397 and $11,152 per patient were reported. Attributable hospital length of stay increases due to blood culture contamination ranged from 1-22 days.

CONCLUSIONS

This systematic review of the literature identified several areas of health care expenditure associated with blood culture contamination. Interventions to reduce the risk of blood culture contamination would avoid downstream economic costs.

Molecular epidemiology of toxigenic Clostridioides difficile isolates from hospitalized patients and the hospital environment in Dhaka, Bangladesh

Epidemiology of Clostridioides difficile (syn. Clostridium difficile) infection (CDI) in Bangladesh is poorly understood. This study assessed the epidemiology of CDI in hospitalized patients and hospital environmental contamination of toxigenic C. difficile at two large urban Bangladesh hospitals. This 12-month prospective observational cohort study collected stool samples from adults with diarrhea and recent antimicrobial exposure during 2017. Environmental samples were collected by swabbing surfaces of hospital common areas. Samples underwent toxigenic culture. C. difficile isolates were tested for toxins A and B and PCR-ribotyped. Of 208 stool samples, 18 (8.7%) were positive for toxigenic C. difficile. Of 400 environmental samples, 45 (11%) were positive for toxigenic C. difficile. Ribotypes present in ≥10% of stool isolates were 017 (38%), 053-163 (13%), and a novel ribotype (FP435 [13%]). Common ribotypes in environmental isolates were 017 (22%), 053-163 (11%), 106 (24%). This is the first report describing current epidemiology of CDI in at risk hospitalized adult patients in Bangladesh.

Bifidobacterium dentium Fortifies the Intestinal Mucus Layer via Autophagy and Calcium Signaling Pathways

Much remains unknown about how the intestinal microbiome interfaces with the protective intestinal mucus layer. Bifidobacterium species colonize the intestinal mucus layer and can modulate mucus production by goblet cells. However, select Bifidobacterium strains can also degrade protective glycans on mucin proteins. We hypothesized that the human-derived species Bifidobacterium dentium would increase intestinal mucus synthesis and expulsion, without extensive degradation of mucin glycans. In silico data revealed that B. dentium lacked the enzymes necessary to extensively degrade mucin glycans. This finding was confirmed by demonstrating that B. dentium could not use naive mucin glycans as primary carbon sources in vitro To examine B. dentium mucus modulation in vivo, Swiss Webster germfree mice were monoassociated with live or heat-killed B. dentium Live B. dentium-monoassociated mice exhibited increased colonic expression of goblet cell markers Krüppel-like factor 4 (Klf4), Trefoil factor 3 (Tff3), Relm-β, Muc2, and several glycosyltransferases compared to both heat-killed B. dentium and germfree counterparts. Likewise, live B. dentium-monoassociated colon had increased acidic mucin-filled goblet cells, as denoted by Periodic Acid-Schiff-Alcian Blue (PAS-AB) staining and MUC2 immunostaining. In vitro, B. dentium-secreted products, including acetate, were able to increase MUC2 levels in T84 cells. We also identified that B. dentium-secreted products, such as γ-aminobutyric acid (GABA), stimulated autophagy-mediated calcium signaling and MUC2 release. This work illustrates that B. dentium is capable of enhancing the intestinal mucus layer and goblet cell function via upregulation of gene expression and autophagy signaling pathways, with a net increase in mucin production.IMPORTANCE Microbe-host interactions in the intestine occur along the mucus-covered epithelium. In the gastrointestinal tract, mucus is composed of glycan-covered proteins, or mucins, which are secreted by goblet cells to form a protective gel-like structure above the epithelium. Low levels of mucin or alterations in mucin glycans are associated with inflammation and colitis in mice and humans. Although current literature links microbes to the modulation of goblet cells and mucins, the molecular pathways involved are not yet fully understood. Using a combination of gnotobiotic mice and mucus-secreting cell lines, we have identified a human-derived microbe, Bifidobacterium dentium, which adheres to intestinal mucus and secretes metabolites that upregulate the major mucin MUC2 and modulate goblet cell function. Unlike other Bifidobacterium species, B. dentium does not extensively degrade mucin glycans and cannot grow on mucin alone. This work points to the potential of using B. dentium and similar mucin-friendly microbes as therapeutic agents for intestinal disorders with disruptions in the mucus barrier.

Characterization of Clostridioides difficile ribotypes in domestic dogs in Rio de Janeiro, Brazil

Clostridioides difficile is the major etiologic agent of nosocomial bacterial diarrhoea and pseudomembranous colitis. The pathogenesis of C. difficile infection (CDI)involves two cytotoxic enzymes (TcdA, TcdB) that cause colonic epithelial damage, fluid accumulation and enteritis. CDI has been demonstrated in a variety of animal species and some reports have recently raised the importance of wild animals as a reservoir of this pathogen and possible transmission to humans and domestic animals. The aim of this study was to characterize C. difficile isolates obtained from pet dogs in Rio de Janeiro, Brazil. A total of 50 faecal samples were obtained from healthy and diarrheic dogs. Five of fifty samples (10%) grew C. difficile. Of those, three belonged to the PCR ribotype 106 (ST 42) and were toxigenic (A⁺B⁺). The other two strains belonged to the PCR ribotype 010 (ST 15) and were not toxin producers (A^-B^-). None of the isolates tested positive for the binary toxin genes. Considering the antimicrobial resistance patterns of all isolates using EUCAST breakpoints, all strains were sensitive to metronidazole and vancomycin. However, two strains (ribotype 106 and ribotype 010), were resistant to clindamycin (≤256 μg/mL). All strains were strong biofilm producers. Our study provides evidence that dogs can act as reservoirs for C. difficile epidemic ribotypes.

Molecular epidemiology of Clostridioides difficile in domestic dogs and zoo animals

Animals such as domestic dogs and zoo animals reside in close proximity to humans and could contribute to the dissemination of Clostridioides difficile spores which are common in the community environment. The purpose of this study was to assess C. difficile colonization in domestic dogs attending a day boarding facility and zoo animals receiving systemic antibiotics. Stool samples and paw swabs were collected from dogs who attended a day boarding facility. Stool samples were also collected from zoo animals starting systemic antibiotics. Finally, environmental samples were collected from nearby public parks. Stool samples and swabs were incubated anaerobically in enrichment broth for C. difficile growth, PCR was done to confirm presence of toxin genes, and PCR ribotyping was performed for strain characterization. During the study period, 136 dog stool samples were obtained, the paws of 16 dogs were swabbed, and 250 environmental swabs from surrounding public parks were obtained. Twenty-three of 136 dog stool samples (17%) and 9 of 16 dog paws sampled (56%) grew toxigenic C. difficile. One hundred and four stool samples from 49 zoo animals were collected of which 19 (18%) grew toxigenic C. difficile. Rates of toxigenic C. difficile colonization increased significantly during antibiotic therapy (33%) and then returned to baseline during the follow-up (11%) period (p = 0.019). Fifty-five of 250 environmental swabs from public parks (22%) grew toxigenic C. difficile. Ribotypes associated with human disease including 106 and 014-020 were isolated from all sources. This study demonstrated a high rate of toxigenic C. difficile colonization in domestic dogs and zoo animals with ribotypes similar to those causing human disease. These results demonstrate the relationship between humans, animals, and the environment in the dissemination of spores.

Ridinilazole for the treatment of Clostridioides difficile infection

INTRODUCTION

Ridinilazole is a novel antibiotic being developed for the treatment of Clostridioides difficile infection (CDI). Ridinilazole has completed two phase II trials and phase III trials which are denoted Ri-CoDIFy 1 and 2, are planned (ClinicalTrials.gov identifiers: NCT03595553 and NCT03595566). Areas covered: This article covers the chemistry, mechanism of action, in vitro microbiology versus C. difficile and host microbiota, pre-clinical and clinical efficacy, pharmacokinetics, pharmacodynamics and safety and tolerability of ridinilazole. Expert opinion: Ridinilazole is a novel antibiotic with ideal properties for the treatment of CDI. Given the promising results from the phase II clinical trial, ridinilazole may have the capability to lower the risk for CDI recurrence thus improving sustained clinical response rates - a current unmet medical need. Assuming a positive phase III trial, ridinilazole will enter a market with heightened awareness on the importance of prevention of CDI. This along with further research into the economic consequences and decreased patient quality of life associated with recurrent CDI, should provide clinicians with further evidence for the need for therapy that limits CDI recurrence and improves sustained clinical cure.

Epidemic Clostridioides difficile Ribotype 027 Lineages: Comparisons of Texas Versus Worldwide Strains

Background

The epidemic Clostridioides difficile ribotype 027 strain resulted from the dissemination of 2 separate fluoroquinolone-resistant lineages: FQR1 and FQR2. Both lineages were reported to originate in North America; however, confirmatory large-scale investigations of C difficile ribotype 027 epidemiology using whole genome sequencing has not been undertaken in the United States.

Methods

Whole genome sequencing and single-nucleotide polymorphism (SNP) analysis was performed on 76 clinical ribotype 027 isolates obtained from hospitalized patients in Texas with C difficile infection and compared with 32 previously sequenced worldwide strains. Maximum-likelihood phylogeny based on a set of core genome SNPs was used to construct phylogenetic trees investigating strain macro- and microevolution. Bayesian phylogenetic and phylogeographic analyses were used to incorporate temporal and geographic variables with the SNP strain analysis.

Results

Whole genome sequence analysis identified 2841 SNPs including 900 nonsynonymous mutations, 1404 synonymous substitutions, and 537 intergenic changes. Phylogenetic analysis separated the strains into 2 prominent groups, which grossly differed by 28 SNPs: the FQR1 and FQR2 lineages. Five isolates were identified as pre-epidemic strains. Phylogeny demonstrated unique clustering and resistance genes in Texas strains indicating that spatiotemporal bias has defined the microevolution of ribotype 027 genetics.

Conclusions

Clostridioides difficile ribotype 027 lineages emerged earlier than previously reported, coinciding with increased use of fluoroquinolones. Both FQR1 and FQR2 ribotype 027 epidemic lineages are present in Texas, but they have evolved geographically to represent region-specific public health threats.

Estimated Clinical and Economic Impact through Use of a Novel Blood Collection Device To Reduce Blood Culture Contamination in the Emergency Department: a Cost-Benefit Analysis

Blood culture contamination results in increased hospital costs and exposure to antimicrobials. We evaluated the potential clinical and economic benefits of an initial specimen diversion device (ISDD) when routinely utilized for blood culture collection in the emergency department (ED) of a quaternary care medical center. A decision analysis model was created to identify the cost benefit of the use of the ISDD device in the ED. Probabilistic costs were determined from the published literature and the direct observation of pharmacy/microbiology staff. The primary outcome was the expected per-patient cost savings (microbiology, pharmacy, and indirect hospital costs) with the routine use of an ISDD from a hospital perspective. The indirect costs included those related to an increased hospital length of stay, additional procedures, adverse drug reactions, and hospital-acquired infections. Models were created to represent hospitals that routinely or do not routinely use rapid diagnostic tests (RDT) on positive blood cultures. The routine implementation of ISDD for blood culture collection in the ED was cost beneficial compared to conventional blood culture collection methods. When implemented in a hospital utilizing RDT with a baseline contamination rate of 6%, ISDD use was associated with a cost savings of $272 (3%) per blood culture in terms of overall hospital costs and $28 (5.4%) in direct-only costs. The main drivers of cost were baseline contamination rates and the duration of antibiotics given to patients with negative blood cultures. These findings support the routine use of ISDD during blood culture collection in the ED as a cost-beneficial strategy to reduce the clinical and economic impact of blood culture contamination in terms of microbiology, pharmacy, and wider indirect hospital impacts.

471. Prevalence and Characteristics of Clostridioides difficile Infection in Bangladesh

Background

The estimated prevalence of Clostridioides difficile infection (CDI) in several South Asian countries is 10.5%, similar to that in North America and Europe. However, the epidemiology of CDI in Bangladesh is unknown. We aimed to assess the prevalence of CDI and assess hospital environmental contamination of toxigenic C. difficile in Bangladesh.

Methods

This was a prospective observational cohort study at two large tertiary care centers in Dhaka, Bangladesh, conducted from January 2017 to December 2017. Stool samples were collected from hospitalized adults with diarrhea (≥3 loose stools in a 24-hour period) and antimicrobial exposure within the past 30 days. Hospital environmental samples were collected by swabbing surfaces of common areas in the hospital. All samples underwent toxigenic culture. C. difficile isolates were tested for toxins A and B and PCR-ribotyped.

Results

Of 204 stool samples collected, 16 (7.8%) were positive for toxigenic C. difficile. Patients with CDI shared a room with significantly more patients (Table 1). Of 392 environmental samples, 48 (12.2%) were positive for toxigenic C. difficile, which was more common in patient care vs. nonpatient care areas (14.4% vs. 7.8%, P = 0.057). Twelve clinical stool isolates and 42 environmental isolates were ribotyped. Ribotypes identified in stool isolates were F017 (50%), FP053-163 (17%), FP435 (17%), F106 (8%), and F014-020 (8%). With the exception of FP435, these were also the most common ribotypes in environmental isolates: F017 (24%), FP053-163 (12%), F106 (26%), and F014-020 (10%).

Conclusion

For the first time, we report the prevalence of CDI and ribotypes in at risk patients in Bangladesh. Rates and ribotypes are similar to other resource-rich or resource-limited countries.

Disclosures

K. W. Garey, Merck & Co.: Grant Investigator, Grant recipient.

510. First Environmental Investigation of Toxigenic Clostridium difficile Strains in Texas Hospitals

Background

Clostridium difficile is the most common cause of infectious diarrhea in hospitalized patients in the developed world and an emerging pathogen in developing countries due to increased use of broad-spectrum antibiotics worldwide. Spores of toxigenic C. difficile can survive and disseminate in any environs and act as sources for human colonization or infections. Although likely ubiquitous in any environs, the prevalence of C. difficile spores in the hospital environment of Texas hospitals is poorly understood. The objectives of the study are to isolate and characterize C. difficile from the hospital environs of three hospitals in three cities in Texas.

Methods

As part of a Texas hospital-wide surveillance effort, we collected shoe-bottom swabs samples from hospital employees, patients, and visitors inside three large hospital from three cities. Samples were analyzed for C. difficile using anaerobic enrichment culture and molecular methods. Suspected colonies from cycloserine cefoxitin fructose agar (CCFA) plates were identified by PCR (tcdA, tcdB, cdtA, cdtB, tpi) and genotyped using fluorescent PCR ribotyping.

Results

A total 229 of 1079 (21.2%) surface swab and 81 of 121 (66.9%) shoe swab samples were culture positive for toxigenic C. difficile (tcdA and tcdB). A total of 29 distinct ribotypes were identified from 166 C. difficile isolates tested. Predominant ribotypes were F106, F019, F014-020, F002, and F255. Interestingly, ribotype F027 was not a predominant strain among the swab samples. Each hospital had widely diverse strains. Shoes were the most contaminated item in all the hospitals.

Conclusion

We identified a high prevalence of toxigenic C. difficile with diverse ribotypes from hospital environmental shoe-bottom swabs and high touch surface swabs in hospitals in three cities of Texas. Our findings suggest that patients might be at higher risk for C. difficile colonization or infection in these hospitals.

Disclosures

K. W. Garey, Merck & Co.: Grant Investigator, Grant recipient.

501. Evaluation of Bezlotoxumab in Prevention of Recurrent C. difficile Infection: A Multicenter Single-Arm Study in Outpatient Infusion Centers

Background

Bezlotoxumab (BEZ) was approved in October 2016 for the prevention of recurrent C. difficile (rCDI) infection in patients receiving standard-of-care (SoC) antibiotic therapy for active CDI who are at high risk for CDI recurrence. Presently, there are little real-world data on recurrence rates and factors associated with recurrence in patients receiving BEZ. This study describes characteristics of patients receiving BEZ in US Outpatient Infusion Centers (OICs) and analyzes subsequent CDI recurrences.

Methods

Medical records from 24 OICs were retrospectively reviewed of all patients treated with BEZ through December 2017. Data collected included demographics, comorbidities, and all therapy parameters, including SoC antibiotic therapy. Risk factors for rCDI were assessed and included age, immunocompromised status, prior number of CDI episodes, use of gastric acid suppressants, inflammatory bowel disease (IBD), and history of fecal microbiota transplant (FMT). rCDI, defined as diarrhea lasting ≥2 days with treatment for CDI with or without a positive stool test for toxigenic C. difficile, was assessed through a follow-up visit or phone call 90 days post BEZ administration. Risk factors for rCDI were evaluated using Student’s t-test and Pearson χ² test.

Results

Eighty patients received BEZ (10 mg/kg) with 78 available for follow-up evaluation for rCDI ≥90 days post treatment. Mean age was 65 ± 16 years with 51% female. Mean number of CDI episodes were 3 ± 1 with a mean Charlson score of 4 ± 3. SoC antibiotics included vancomycin (66% of patients) with 41% on long-term taper, fidaxomicin (33% of patients), and metronidazole (25% of patients). Nineteen (24%) patients received more than one SoC antibiotic during their treatment course, most commonly with metronidazole and another SoC antibiotic. Of the 78 patients with follow-up data, 17 (22%) developed rCDI with a mean time to recurrence of 33 ± 22 days. Risk factors for rCDI are shown in the table. The use of BEZ earlier in the disease course (first or second CDI episode) was associated with a decreased risk of rCDI (OR: 0.21 95% CI: 0.04–0.98; P = 0.033).

Conclusion

In highly comorbid patients with recurrent C. difficile infection, bezlotoxumab use was effective in prevention of recurrence at 90 days and consistent with that of the randomized trials.

Disclosures

R. L. Hengel, Merck & Co.: Scientific Advisor, Consulting fee. T. E. Ritter, Merck & Co.: Scientific Advisor, Consulting fee. R. V. Nathan, Merck & Co.: Scientific Advisor and Speaker’s Bureau, Consulting fee and Speaker honorarium. The Medicines Company: Speaker’s Bureau, Speaker honorarium. Allergan: Speaker’s Bureau, Speaker honorarium. L. J. Van Anglen, Merck & Co.: Grant Investigator, Research grant. S. Marcella, Merck & Co.: Employee and Shareholder, Salary. K. W. Garey, Merck & Co.: Grant Investigator, Grant recipient.

240. Estimated Clinical and Economic Impact Through Use of an Initial Specimen Diversion Device to Reduce Blood Culture Contamination: A Cost–benefit Analysis

Background

Methods

Results

Conclusion

Disclosures

Outcomes associated with Clostridium difficile infection in patients with chronic liver disease

Patients with chronic liver disease (CLD) have frequent exposure to Clostridium difficile infection (CDI) risk factors but the incidence and aetiology of CDI on this population is poorly understood. The aim of this study was to assess the incidence, disease presentation and outcomes of CDI in patients with underlying CLD. The Health Care and Utilization Project National Inpatient Sample (HCUP-NIS) 2009 dataset was used to identify patients with CLD who developed CDI along with matched non-CLD patients with CDI. Using the NIS dataset, the incidence rate of CDI was 189.4/10 000 discharges in CLD patients vs. 83.7/10 000 discharges in the non-CLD matched cohort (P < 0.001). Compared with non-CLD, comorbidity-matched controls with CDI, CLD patients with CDI had higher likelihood of in-hospital mortality (8.8% vs. 18.6%, P < 0.001), increased length of stay by 1.19 days (P < 0.001) and increased total costs by $8632 (P < 0.001). In separate analyses using a tertiary case database of hospitalised patients in Houston, Texas (2006-2016) with CLD and CDI (n = 41) compared with patients with CDI but not CLD (n = 111), CLD patients had significantly higher Charlson comorbidity index (P < 0.0001) but similar risk factors for CDI and CDI-related disease presentation compared with non-CLD patients. In conclusion, CDI-related risk factors were almost universally present in the CLD population. CDI resulted in worse outcomes in this population.

Implementation and evaluation of a sterile compounding robot in a satellite oncology pharmacy

PURPOSE

The purpose of this study was to quantify the impact of robotic technology on efficiency, accuracy, and cost in a satellite oncology pharmacy.

METHODS

A 33-week quasi-experimental study was conducted at an academic, quaternary care institution with 1,119 licensed beds from June 2016 to February 2017 to evaluate the turnaround time (TAT) for preparations compounded by automated robotic compounding technology (ARCT) versus historical procedures. Secondary endpoints included mean preparation time and percentage of doses with a TAT of <30 minutes before and after the implementation of ARCT and were evaluated using time-segmented regression analysis. The cost savings in the satellite oncology pharmacy was determined by comparing usage of closed-system transfer devices (CSTDs) and labor costs between study phases. Accuracy of the intervention was expressed through a descriptive analysis of mean ARCT dose preparation deviations and preparation failures.

RESULTS

Data for 1,453 preparations were included for analysis. The mean ± S.D. preimplementation TAT was 64.1 ± 27.9 minutes, which decreased to 53.2 ± 32.2 minutes after ARCT implementation (p < 0.01). Financial benefit was demonstrated through supply cost savings. Breakeven was estimated at 8.6 years after capital expenditure, with an annualized projected savings of $129,477. The mean ± S.D. deviation of the doses compounded using ARCT was -0.58% ± 0.01% from the ordered dosage.

CONCLUSION

Adoption of ARCT for compounding of admixtures containing 4 oncology agents reduced TAT and preparation time and led to lower expenditures for CSTDs.