Early switch from intravenous to oral antibiotic treatment in bone and joint infections

OBJECTIVES

The timing of the switch from intravenous (i.v.) to oral antibiotic therapy for orthopaedic bone and joint infections (BJIs) is debated. In this narrative article, we discuss the evidence for and against an early switch in BJIs.

DATA SOURCES

We performed a PubMed and internet search investigating the association between the duration of i.v. treatment for BJI and remission of infection among adult orthopaedic patients.

CONTENT

Among eight randomized controlled trials and multiple retrospective studies, we failed to find any minimal duration of postsurgical i.v. therapy associated with clinical outcomes. We did not find scientific data to support the prolonged use of i.v. therapy or to inform a minimal duration of i.v.

THERAPY

Growing evidence supports the safety of an early switch to oral medications once the patient is clinically stable.

IMPLICATIONS

After surgery for BJI, a switch to oral antibiotics within a few days is reasonable in most cases. We recommend making the decision on the time point based on clinical criteria and in an interdisciplinary team at the bedside.

998. Clinical Outcomes and Cost Savings of Dalbavancin Use in OPAT: Focus on Complicated Staphylococcus aureus Infections

Background

The practical and financial benefits of long-acting glycopeptides are increasingly recognized, and their efficacy is becoming better established for a variety of indications. Dalbavancin use as primary therapy for complicated Staphylococcus aureus (cSA) infections, however, has only been described in small case series to this point.

Methods

This retrospective review identified patients prescribed dalbavancin for any indication and followed by the Nebraska Medicine OPAT team since program implementation (4/1/19 - 4/30/22). Patients in the cSA infection subgroup were defined by need for >2 weeks of treatment for a Staphylococcus aureus infection involving bacteremia. Dalbavancin as primary therapy for cSA was defined as initiation of dalbavancin within the first 10 days of antibiotic therapy and continued through the end of treatment. The primary clinical outcome was 30-day readmission rate (both infection-related and not infection-related).

Results

A total of 66 patients were prescribed dalbavancin for treatment of any infection (Table 1), with an all-cause 30-day readmission rate of 13.6% (9 of 66); only two of these were infection-related (3%). Updating a prior institutional analysis, use of dalbavancin led to the avoidance of 506 planned inpatient days per year on average and $1,113,000 in yearly inpatient costs. Dalbavancin was utilized for primary therapy of cSA in 16 patients, of whom only one (6.3%) had a 30-day readmission, due to progression of cSA vertebral osteomyelitis-discitis. Table 1:Characteristics of the Dalbavancin Cohort

Conclusion

In both overall and cSA subgroup analysis, OPAT use of dalbavancin was associated with low readmission rates. This study is the largest to date suggesting favorable clinical outcomes with dalbavancin as primary therapy for cSA infections; others have reported few of these patients or utilized dalbavancin exclusively as consolidation therapy following significant lead-in with other antimicrobials. The enrolling Dalbavancin as an Option for Treatment of Staphylococcus aureus Bacteremia study (DOTS; NCT04775953) is anticipated to provide randomized controlled data evaluating this approach. Discharge facilitation utilizing dalbavancin contributed significantly to OPAT program cost justification and resources to support team expansion.

Disclosures

Bryan T. Alexander, PharmD, BCIDP, AAHIVP, Astellas Pharma: Advisor/Consultant Scott J. Bergman, PharmD, BCIDP, FCCP, FIDSA, Merck & Co., Inc: Advisor/Consultant|Merck & Co., Inc: Grant/Research Support|Merck & Co., Inc: Honoraria|Pfizer: Advisor/Consultant|Pfizer: Honoraria Trevor C. Van Schooneveld, MD, bioMerieux: Advisor/Consultant|bioMerieux: Grant/Research Support|Insmed: Grant/Research Support|Merck: Grant/Research Support|Thermo-Fischer: Advisor/Consultant.

1910. A Highly Effective ID Physician and Infection Preventionist-led Interactive Webinar Series for Infection Prevention and Control Training Among Frontline Healthcare Workers

Background

Nebraska Infection Control Assessment and Promotion Program (ICAP) is funded by Nebraska Department of Health and Human Services through Centers for Disease Control and Prevention (CDC) grants to support Infection Prevention and Control (IPC) activities in the state. In early 2022, ICAP launched COVID-19-specific basic infection prevention and control (IPC) training to frontline healthcare providers (HCPs) through a discussion-based webinar series using curricular materials created by the CDC Project Firstline. Here, we report pre- and post-training survey responses demonstrating improvement in participants' perceived knowledge across a number of IPC domains.

Methods

Training was completed over a 14-week period via a weekly, interactive 30-minute webinars with a new topic covered each week. A survey was administered to participants prior to the webinar series and at the conclusion of training to assess effectiveness. The pre-survey evaluated HCP confidence in their knowledge of each of the 14 topics to be covered in the course. The post-survey evaluated both confidence and perceived value in each of the training topics.

Results

Prior to the training series, a mean 40.3% of participants judge themselves “very confident” in IPC topics, versus 52.7% “somewhat confident” and 7.1% “not confident” (figure 1); by the end of the training, these levels had improved to 85.4%, 14.3%, and 0.4%, respectively (figure 2). The largest gains in the category “very confident” concerned “source control” (+65%) and “COVID-19 variants” (+63%). A majority of participants perceived each topic covered in the series to be “very valuable” (figure 3); 98% of participants indicated interest in a future IPC training series and 95% indicated that they would recommend the training series to a colleague. Figure 1Results of a pre-course survey on knowledge of training topics completed by participants.Figure 2Results of a post-course survey on knowledge of training topics completed by participants.Figure 3Results of a post-course survey on value of the training course completed by participants.

Conclusion

This survey data suggests that a discussion-based webinar using CDC Project Firstline materials is highly effective at conveying fundamental concepts in infection control to frontline HCPs. Moreover, HCPs rated themselves as likely to return, suggesting this format is a promising modality for simple and widespread dissemination of IPC training.

Disclosures

M. Salman Ashraf, MBBS, Merck & Co. Inc: Grant/Research Support.

1003. Curbsiding Twitter: Potential Value and Patient Confidentiality Implications of Infectious Diseases Clinician Peer Consultations via Social Media

Background

Infectious Disease (ID) clinicians increasingly collaborate via social media and have adopted Twitter and the hashtag #IDTwitter for community-wide conversation. We investigated clinicians’ use of #IDTwitter for peer consultation, examining both the utility of responses and how frequently discussions risked compromising patient privacy.

Methods

We reviewed English-language posts on www.twitter.com with the hashtag #IDTwitter over a 6-week period ending August 31^st, 2021. We collected posts that we deemed examples of peer consultation, recording the post’s author, topic, engagement produced, and patient information disclosed. Finally, we recorded whether (by consensus) we judged a question meaningfully answered.

Results

We identified 108 instances of peer consultation; 91 posts (84%) were consultations about a clinical scenario, 17 (16%) included a specific request for medical literature, and seven (6%) included a request for literature interpretation. Twenty-four posts (22%) contained polls, which received a mean 107 (SD 104) votes. We judged 71% of questions meaningfully answered; of these, 68% received responses including explicit justification or reasoning and 35% included citations of supporting literature. Questions were more likely to be meaningfully answered if they included polls (91.7% vs 65.5%; p=0.01). Receipt of a meaningful answer was not predicted by the questioner’s professional role and follower count, the question topic, or the post’s number of likes and shares.

A total 28/108 posts (26%) referenced the care of a specific patient, with details shared including gender (74%), age (26%), radiographic or clinical images (7%), and other potentially identifying data (7%). Patients were stated or implied to be currently under the clinician’s care in 70% of cases, and 61 clinicians (92.4%) had their employer listed in their profile or immediately available via internet search.

Conclusion

ID clinicians’ peer consultations via #IDTwitter appeared frequently useful, particularly when questions were accompanied by polls. However, most participants sharing patient data were readily identifiable, and best practices to limit sharing of nonessential data and safeguard patient privacy are needed.

Disclosures

Jasmine R. Marcelin, MD, Pfizer (Grant reviewer): Honoraria.

Excellent Outcomes With the Selective Use of Oral Antibiotic Therapy for Bone and Joint Infections: A Single-Center Experience

Background and objective

Recent studies have challenged the notion that prolonged intravenous (IV) antibiotics are preferable to oral antibiotics for treating musculoskeletal infections. Our institution’s orthopedic surgery and orthopedic infectious disease (ID) groups have established consensus criteria for the use of oral antibiotics in musculoskeletal infections. In this study, we examine one-year and two-year outcomes of the selective use of oral antibiotics for musculoskeletal infections in a real-world setting.

Methods

We conducted a single-center retrospective analysis of adults seen in our orthopedic ID clinic over a six-month period for the first episode of surgically managed osteomyelitis, native joint septic arthritis (NJSA), prosthetic joint infection (PJI), or other musculoskeletal hardware infection with an established microbiologic etiology who received surgical interventions and >2 weeks of antimicrobial treatment. Patients were evaluated for treatment failure at one year and two years following their index surgery, which we defined as death, unplanned surgery, or the initiation of chronic antibiotic suppression.

Results

One-year treatment failure rates were 0/23 (0%) in patients who switched to oral therapy versus 6/17 (35%) in patients who remained on IV treatment. Two-year treatment failure rates were 0/23 (0%) in patients who switched to oral therapy versus 8/17 (47%) in patients who remained on IV treatment.

Conclusions

Our consensus criteria for the switch to oral antibiotics for musculoskeletal infections identified patients who went on to have excellent outcomes at one year and two years, suggesting that these criteria can effectively identify patients at low risk for treatment failure. Collaboration between ID specialists and orthopedic surgeons to select antimicrobial regimens can avoid significant burdens, costs, and complications associated with prolonged IV therapy.

Educational Impact of #IDJClub, a Twitter-Based Infectious Diseases Journal Club

BACKGROUND

Journal clubs have been an enduring mainstay of medical education, and hosting these on social media platforms can expand accessibility and engagement. We describe the creation and impact of #IDJClub, an infectious diseases (ID) Twitter journal club.

METHODS

We launched #IDJClub in October 2019. Using the account @IDJClub, an ID physician leads a 1-hour open-access Twitter discussion of a recent publication. All participants use the hashtag #IDJClub. Sessions started monthly, but increased due to demand during the coronavirus disease 2019 (COVID-19) pandemic. We used Symplur 's Healthcare Hashtag project to track engagement of #IDJClub per 60-minute discussion plus the following 30 minutes to capture ongoing conversations. We also conducted an online anonymous survey using Likert scales and open-ended questions to assess educational impact.

RESULTS

In its first 20 months, 31 journal clubs were held, with medians of 42 (interquartile range [IQR], 28.5-60) participants and 312 (IQR, 205-427.5) tweets per session. 134 participants completed the survey, of whom 39% were ID physicians, 19% pharmacists, 13% ID fellows, and 10% medical residents. Most agreed or strongly agreed that #IDJClub provided clinically useful knowledge (95%), increased personal confidence in independent literature appraisal (72%), and was more educational than traditional journal clubs (72%). The format addressed several barriers to traditional journal club participation such as lack of access, subject experts, and time.

CONCLUSIONS

#IDJClub is an effective virtual journal club, providing an engaging, open-access tool for critical literature appraisal that overcomes several barriers to traditional journal club participations while fostering connectedness within the global ID community.

254. Excellent Outcomes with Oral Versus Intravenous Antibiotics for Bone and Joint Infections: A Single-Center Experience

Background

The OVIVA trial, published in 2019, demonstrated equivalent efficacy of oral (PO) versus intravenous (IV) antibiotics for bone and joint infections. We report our group’s one-year outcomes in a cohort of such patients who received PO or IV antibiotics.

Methods

Our orthopedic surgery and orthopedic infectious diseases (ID) groups agreed to employ early switch to PO in patients with a first episode of non-vertebral osteomyelitis (OM), native or prosthetic joint infection (NJA or PJI), or hardware infections when a pathogen susceptible to highly bioavailable antibiotics had been identified and the patient was perceived to be at low risk for medication non-adherence. We reviewed patients 19+ years old seen in the Ortho ID clinic for one of these conditions from July 1st through December 31st, 2019. Data recorded included patient demographics and comorbidities, infection type and site, microbiology, and surgical and antibiotic management. Primary outcome was treatment failure at 1 year, defined as death, unplanned surgery at same site, or chronic antibiotic suppression.

Results

Forty patients (all IV antibiotics, n=17; initial or switch to PO, n=23) were included. Median IV duration was 15 days. PJI was the most common diagnosis (n=22), followed by other hardware infection and OM (n=7 each). Of the PJIs, 13/22 were managed with 2-stage exchange and 11/13 of these received all-IV therapy. Of the hardware infections, 4/7 underwent debridement and retention or single-stage exchange and all of these received initial or switch to PO therapy. Staphylococci (n=14 S. aureus and n=7 coagulase-negative) and streptococci (n=12) were the most common pathogens. Amoxicillin (n=8), trimethoprim-sulfa (n=6), and levofloxacin (n=3) were the most-used PO antibiotics. The PO group received longer treatment (mean 67 vs 48 days). No treatment failures occurred in the patients who started or switch to PO antibiotics, whereas 35% of patients who received all-IV therapy experienced failure.

Conclusion

Adopting known risk factors for poor outcome in bone and joint infection such as prior treatment failure and no identified pathogen as exclusion criteria for early switch to PO antibiotic therapy led to excellent one-year treatment outcomes across a range of musculoskeletal infections.

Disclosures

Angela Hewlett, MD, MS, Mapp Biopharmaceutical (Scientific Research Study Investigator) Angela Hewlett, MD, MS, Mapp Biopharmaceutical, Inc (Individual(s) Involved: Self): Scientific Research Study Investigator Nicolas W. Cortes-Penfield, MD, Nothing to disclose

606. Implementation of a Telehealth-based OPAT Early Post-Discharge Clinic May Reduce Hospital Readmission

Background

Recent studies suggest that early post-discharge follow-up for patients receiving outpatient parenteral antimicrobial therapy (OPAT) reduces readmission rates. We report our experience implementing a telehealth-based clinic to facilitate early (1-2 week) follow-up for selected OPAT patients perceived to be at high risk for readmission.

Methods

We identified patients who met criteria for and completed a supplemental OPAT telehealth visit following the initial seven months after implementation of this clinic (11/1/20 – 5/31/21). Clinical criteria triggering intake of patients for these visits included: endovascular or cardiac device-related infection; treatment with vancomycin, oxacillin/nafcillin, or aminoglycosides; ≥2 prior hospitalizations within past 1 year; treating Infectious Disease or OPAT team’s subjective assessment of high readmission risk. Patients planned for < 14 days of OPAT therapy were excluded. Categorical variables were compared using a Chi-square test at the α=0.05 level of significance.

Results

A total of 49 patients completed a telehealth visit; mean time from discharge to telehealth visit was 12.1 days (SD +/- 3.9). An intervention was made in 27% of these visits (13 of 49 patients), most commonly involving attempted mitigation of an adverse event or line-related complication (7 cases). The all-cause, 30-day readmission rate for this cohort was 6.1% (3 of 49 patients), while the rate for OPAT patients who did not receive an early telehealth visit during the same period was 22.7% (52 of 229 patients) which was statistically significant (p=0.008). This association of benefit was also found when comparing infection-related, 30-day readmission rates (0% vs 7.4%, p=0.049).

Conclusion

Implementation of OPAT telehealth encounters for high-risk patients resulted in a high rate of intervention to mitigate adverse events of OPAT therapy. Readmission occurred less than one-third as frequently in the telehealth group compared to patients with no early follow-up visit. Telehealth-based encounters appear comparable in effectiveness to those previously reported utilizing in-person visits, introducing efficiencies that may allow for broader implementation of this intervention.

Disclosures

Nicolas W. Cortes-Penfield, MD, Nothing to disclose Bryan Alexander, PharmD, Astellas Pharma (Advisor or Review Panel member)

126. evaluation of Addition of Outpatient Parenteral Antimicrobial Therapy and Orthopedic ID Resources to Transitions-of-care Outcomes

Background

Our large academic medical center initiated both an Outpatient Parenteral Antimicrobial Therapy (OPAT) program supported by an infectious disease trained pharmacist, along with an Orthopedic Infectious Disease (OID) consult service to assist in caring for these specialized populations. We measured the impact of these services.

Methods

Patients discharged on parenteral antimicrobial therapy were divided into two groups. The pre-OPAT cohort included all patient receiving OPAT from 4/1/18 - 10/31/18; the post-OPAT cohort included all patients who received OPAT from 4/1/19 - 10/31/19 with OPAT consult (Fig 1). The OID consult service began in September 2018 prior to initiation of the OPAT program. The primary outcome was 30-day hospital readmission. Secondary outcomes included: length of stay (LOS), 90-day readmission, clinical outcomes, and identification of predictors of hospital readmission. Clinical outcomes included: time from final OR visit to discharge for OID patients and optimal treatment (cefazolin, oxacillin, or nafcillin) for MSSA.

Results

Introduction of these programs was associated with a reduction in all-cause 30-day readmission from 39.3% to 22.9%, and a reduction in 30-day readmission for patients on-treatment from 24.6% to 15.6% (p&lt; 0.01 for both). No difference was seen in hospital LOS (8 days in each cohort). In a subgroup analysis (Fig 2), OID patients in the post-OPAT cohort saw a median reduction of 2 days (7 days to 5 days, p=0.002) in time from final OR visit to discharge. Use of optimal treatments for MSSA increased in the post-OPAT cohort compared to pre-OPAT (65.2% to 80.9%; p=0.06). The 90-day hospital readmission rate were higher in the post-OPAT cohort among patients who lived in metro-area zip codes (p=0.03). Having an established primary care physician was associated with lower 90-day hospital readmission in both the pre-and post-OPAT cohorts (p=0.05 and 0.01, respectively).

Conclusion

Thirty-day readmission rates among patients discharged on OPAT significantly lowered following initiation of a combination of both a pharmacist-led OPAT program and OID consult service. OPAT and OID programs accrue additional efficiencies and clinical benefits to both patients and hospitals, which can be further evaluated and used to justify such service additions.

Disclosures

All Authors: No reported disclosures

624. Significant Institutional Cost Savings from OPAT-Facilitated Discharge for Patients with Challenging Situations

Background

Outpatient parenteral antimicrobial therapy (OPAT) programs are becoming a standard of care, however, program cost justification remains a challenge. One area of focus for institutions is facilitating timely discharge from the inpatient setting, and difficult to discharge patients are a group with which OPAT teams can be particularly impactful.

Methods

This retrospective review identified patients intervened upon by the Nebraska Medicine OPAT team during the initial nine months after program implementation (4/1/19 - 12/31/19) for which routine efforts at discharge by primary teams had failed. Patients were planned for extended inpatient stays to complete the full duration of parenteral antibiotic therapy due to discharge issues given the therapy plan initially recommended by infectious disease consult teams. Outcomes evaluated included inpatient days of therapy avoided, associated financial metrics, and 30-day readmission rates. A matched cohort of patients with similar lengths-of-stay, infectious disease indications, medication use, and lack of major complications was identified to calculate a cost per inpatient day avoided.

Results

A total of 17 difficult to discharge patients were intervened on by the OPAT team, leading to avoidance of 429 planned inpatient days. Based on calculation from internal matched cohort data, these OPAT interventions avoided an estimated $943,000 in total inpatient costs. All-cause 30-day readmission was 24% (4 of 17 patients). Additionally, 15 of these therapy courses were shifted to hospital-associated outpatient infusion centers. Facilitation of enrollment for 11 of these patients in pharmaceutical manufacturer patient assistance programs resulted in replacement of outpatient medication totaling over $28,000 in value. Reimbursements for two additional patients through either governmental or private insurance generated over $11,000 in margin for the health system.

Conclusion

Attention to complex discharge facilitation by OPAT programs can be a significant contribution to program cost justification, while also transitioning patients to therapy plans that lead to similar clinical outcomes when compared to the overall OPAT population.

Disclosures

All Authors: No reported disclosures

135. Impact of #idjclub, a Synchronous Twitter Journal Club, as a Novel Infectious Disease Education Platform

Background

Journal clubs have been a mainstay of medical education since the days of Osler. Social media platforms allow virtual journal clubs to connect global participants. We describe the creation and impact of #IDJClub, an Infectious Diseases (ID) Twitter journal club.

Methods

We launched #IDJClub in October 2019. The format presents a recent ID publication for a 1-hour synchronous Twitter chat led by an ID physician from @IDJClub. Sessions started monthly, but increased in frequency due to interest during the COVID-19 pandemic. Pre-scripted tweets guide participants through the article description and analysis. We used Symplur’s Healthcare Hashtag project to track the number of impressions, tweets, participants, and the engagement rate (average tweets/participant) of #IDJClub per 60 minute discussion plus the following 30 minutes to capture ongoing conversations. We also conducted an online anonymous survey using Likert scales and open-ended questions to assess educational impact.

Results

As of June 11 2020, @IDJClub garnered 5,338 followers from around the world (Figure 1). In its first 9 months, 12 virtual journal clubs were conducted with a mean of 791,624 impressions, 328 tweets, and 48 participants per session, which steadily increased over time (Figure 2). A total of 134 participants completed the survey, of whom 40% were ID physicians, 19% pharmacists, 13% ID fellows, and 10% medical residents. Most respondents followed 1–2 (38%) or 3–4 (38%) of the discussions, with variable levels of active participation. Majorities agreed that #IDJClub provided clinically useful knowledge, increased personal confidence in review of literature, and compared favorably with in-person journal clubs (Figure 3). The format addressed several barriers such as lack of access to in-person journal clubs or subject experts at one’s own institution and lack of time to read new research or attend traditional journal clubs (Figure 4).

Conclusion

#IDJClub is an effective platform for virtual journal club, providing an engaging, open-access tool for critical appraisal of ID literature. This innovation in medical education overcomes several barriers to traditional journal clubs while fostering professional relationships within the global ID community.

Disclosures

Todd P. McCarty, MD, Amplyx (Scientific Research Study Investigator)Cidara (Scientific Research Study Investigator)

Educational and Personal Opportunity Costs of Medical Student Preparation for the United States Medical Licensing Examination Step 1 Exam: A Single-Center Study

Purpose

To assess the degree to which medical students choose to disengage from their regular preclinical curriculum and extracurricular activities in order to focus on United States Medical Licensing Examination (USMLE) Step 1 exam preparation, as well as learner-perceived effects of Step 1 preparation on their physical, social, and mental health.

Method

Online survey of medical students who have taken the USMLE Step 1 exam at a single large Midwestern academic medical center.

Results

The response rate was 54%. Students often reported absenteeism from a variety of preclinical curricular activities, including lectures (44%) and didactics focusing on medical ethics (37%), clinical skills (28%), and encounters with actual and standardized patients (9%) in order to study for USMLE Step 1. Many students also forewent extracurricular opportunities including research (53%), elective patient care opportunities (45%), community service (39%), and healthcare advocacy experiences (38%) in order to study for USMLE Step 1. Majorities of students identified Step 1 preparation as a cause of burnout (79%) or significant anxiety or depression (61%), for which nearly a third sought mental healthcare; students also reported Step 1 preparation as a cause of engaging in dangerous behaviors such as illicit prescription stimulant use as well as driving or providing patient care while impaired by fatigue. In narrative comments, students frequently described Step 1 to be a barrier to their development into effective clinicians, the traditional medical school curriculum to be a barrier to performance on Step 1, or both.

Conclusions

Medical students often prioritize Step 1 exam preparation over engaging with the standard preclinical curriculum, extracurricular opportunities, and activities to promote wellbeing. These findings have implications for the emphasis residency program directors place on single high-stakes standardized exams in the resident recruitment process.

2650. Evaluating Antiviral Agents for Human Noroviruses Using a Human Intestinal Enteroid Model

Background

Norovirus can cause chronic infections with serious morbidity and mortality in immunocompromised patients. While there are no FDA-approved medications for these infections, nitazoxanide, ribavirin, and enterally administered pooled immunoglobulin (IVIG) are used off-label on the basis of expert opinion. Nitazoxanide and ribavirin show antiviral activity in a murine norovirus infection model and an in vitro replicon model of genotype GI.I human norovirus RNA expression, respectively. However, these drugs have not been evaluated in in vitro infections with GII.4 human noroviruses, responsible for most human norovirus disease. We used the stem cell-derived nontransformed human intestinal enteroid (HIE) system, which supports GII.4 human norovirus replication, to evaluate the antiviral activities of nitazoxanide, ribavirin, and IVIG.

Methods

We inoculated HIEs with GII.4 human norovirus in the presence of half-log dilutions of nitazoxanide (3 µM to 100 µM), ribavirin (10 µM to 10 mM), or IVIG (1:100 to 1:3,000) and a media control. One and 48 hours after inoculation, we extracted and quantified GII.4 norovirus RNA from the HIEs. To demonstrate that replication inhibition was not due to cytotoxicity, we performed quantitative lactate dehydrogenase release assays on the HIEs across the therapeutic range of each compound.

Results

Nitazoxanide reduced GII.4 replication at 48 hours in a dose-dependent manner, achieving a >90% reduction in viral replication at 10 µM without cytotoxicity. These findings were confirmed in multiple HIE lines representing different intestinal segments and established from different donors. IVIG completely inhibited GII.4 replication at up to a 1:1,000 dilution and was not cytotoxic at therapeutic concentrations. Ribavirin did not reduce GII.4 replication at concentrations up to 10 mMµM, well in excess of levels achieved in human sera with standard doses.

Conclusion

Nitazoxanide and IVIG, but not ribavirin, potently inhibit GII.4 human norovirus replication in a biologically relevant in vitro model of human norovirus infection. These data highlight the use of HIEs as a new pre-clinical model for developing therapeutics for human norovirus disease.

Disclosures

All authors: No reported disclosures.

2564. What Predicts Journal Publication Tier and Audience Engagement in the Infectious Diseases Literature? A Review of 146 Publications

Background

As part of an online medical education project (www.idjournal.club), we surveilled the infectious diseases (ID) literature, selecting subsets of what we deemed the most clinically impactful articles on a monthly basis using a prespecified search algorithm. We used this resource to perform a broad overview of articles published in the field and examine factors associated with publication in higher tier journals and higher rates of public and ID community engagement.

Methods

We examined articles reviewed on www.idjournal.club between June and September 2018. For each article, we recorded the publishing journal, subfield of ID, study type, nation and degree of the lead author, and sample size, and we assigned the paper up to three topic keywords. Our outcomes of interest were the publishing journal’s Scimago Journal Rank (SJR), a surrogate for journal tier, and the article’s Altmetric score, a surrogate for audience engagement.

Results

Of 146 articles included in the analysis, the most common study types were retrospective observational (n = 47), randomized controlled trial (n = 23), in vitro (n = 20), and prospective observational (n = 19). The median sample size was 238; median sample sizes were higher for randomized controlled trials (n = 400) and lower for in vitro and pharmacokinetic/pharmacokinetic studies (n = 53 and n = 44). Lead authors were based in the United States in 38% of cases and in North America or Europe in 86% of cases. Physicians accounted for 65% of lead authors, PhDs 23%, and PharmDs 10%. The most commonly referenced pathogens were HIV, MDR Gram-negative bacteria, S. aureus, and C. difficile; the most commonly referenced disease states were bacteremia, sexually transmitted infection, respiratory tract infection, and UTI. The mean SJR was 3.5 (SD 3.1) and the mean Altmetric score was 54.5 (SD 143). SJR and Altmetric score were associated with study type, sample size, and key topics; Altmetric score was also associated with publishing journal. In multivariate analysis, SJR was associated with study type and sample size, and Altmetric score was associated with ID subfield, journal, and sample size.

Conclusion

We present a descriptive overview of the ID literature and identify article factors associated with journal tier and audience engagement after publication.

Disclosures

All authors: No reported disclosures.

Human Norovirus Cultivation in Nontransformed Stem Cell-Derived Human Intestinal Enteroid Cultures: Success and Challenges

Noroviruses, in the genus Norovirus, are a significant cause of viral gastroenteritis in humans and animals. For almost 50 years, the lack of a cultivation system for human noroviruses (HuNoVs) was a major barrier to understanding virus biology and the development of effective antiviral strategies. This review presents a historical perspective of the development of a cultivation system for HuNoVs in human intestinal epithelial cell cultures. Successful cultivation was based on the discovery of genetically-encoded host factors required for infection, knowledge of the site of infection in humans, and advances in the cultivation of human intestinal epithelial cells achieved by developmental and stem cell biologists. The human stem cell-derived enteroid cultivation system recapitulates the multicellular, physiologically active human intestinal epithelium, and allows studies of virus-specific replication requirements, evaluation of human host-pathogen interactions, and supports the pre-clinical assessment of methods to prevent and treat HuNoV infections.

Cell attachment protein VP8* of a human rotavirus specifically interacts with A-type histo-blood group antigen

As with many other viruses, the initial cell attachment of rotaviruses, major causative agent of infantile gastroenteritis, is mediated by interactions with specific cellular glycans^1–4. The distally located VP8* domain of the rotavirus spike protein VP4⁵ mediates such interactions. The existing paradigm is that ‘sialidase-sensitive’ animal rotavirus strains bind to glycans with terminal sialic acid (Sia), whereas ‘sialidase-insensitive’ human rotavirus (HR) strains bind to glycans with internal Sia such as GM1³. Although the involvement of Sia in the animal strains is firmly supported by crystallographic studies^1,3,6,7, it is not yet known how VP8* of HRs interacts with Sia and whether their cell attachment necessarily involves sialoglycans. We found that VP8* of a HR strain specifically recognizes A-type histo-blood group antigen (HBGA) using a glycan array screen comprised of 511 glycans, and that virus infectivity in HT-29 cells is abrogated by anti-Atype antibodies as well as significantly enhanced in CHO cells genetically modified to express the A-type HBGA, providing a novel paradigm for initial cell attachment of HR. HBGAs are genetically determined glycoconjugates present in mucosal secretions, epithelial and on red blood cells⁸, and are recognized as susceptibility and cell attachment factors for gastric pathogens like H. pylori⁹ and noroviruses¹⁰. Our crystallographic studies show that the A-type HBGA binds to the HR VP8* at the same location as the Sia in the VP8* of animal rotavirus, and suggest how subtle changes within the same structural framework allow for such receptor switching. These results raise the possibility that host susceptibility to specific HR strains and pathogenesis are influenced by genetically controlled expression of different HBGAs among the world’s population.