bluuebunny/crossref_metadata_2025 huggingface dataset:
2488. Virologic Failure in ART Naïve Patients Initiating on a Dolutegravir or Elvitegravir-Based Regimen
Authors: Wohlfeiler Michael , Schulman Kathy , Fusco Jennifer S , Punekar Yogesh , Mills Anthony , Priest Julie , Oglesby Alan , Fusco Gregory
Published: October 2019

Background

Robust pharmacoeconomic modeling is dependent on high quality inputs, preferably from randomized clinical trials (RCT), but not all needed head to head comparisons occur in RCTs. We compared virologic outcomes in an antiretroviral (ART) naïve population initiating a dolutegravir (DTG) or elvitegravir (EVG)-based regimen using clinical trial-like criteria.

Methods

ART-naïve adults, initiating a DTG- or EVG-based regimen and meeting all study eligibility criteria (Figure 1) were identified in the OPERA® Observational Database, a collaboration of HIV caregivers following 100,000+ people living with HIV (PLWH) through electronic medical records. PLWH were followed from the date of first prescription until DTG- or EVG discontinuation, death, or study end (July 31, 2018). The primary outcome was verified (2 consecutive viral load (VL) ≥200 copies/mL or 1 VL ≥200 copies + discontinuation) virologic failure (VF), defined as either failure to achieve suppression (<50 copies/mL) prior to 36 weeks or failure to maintain suppression once achieved. Survival analyses were conducted with Kaplan–Meier methods and multivariate Cox Proportional Hazards modeling.

Results

A total of 1,688 (DTG) and 2,537 (EVG) met all eligibility criteria. Median (IQR) length of follow-up in the DTG users was 21 months (14–30), in the EVG users was 20 (14–32) months. Figure 2 characterizes baseline demographic/clinical characteristics. Figures 3 and 4 depict Kaplan–Meier curves and Cox model results, respectively. VF was experienced by 8.2% DTG and 10.9% EVG initiators at a rate (95% CI) per 1,000 person-years of 40.2 (33.8, 47.8) and 51.3 (45.3, 58.1), respectively. Younger age (18–25), being African American, having a baseline CD4 count ≤ 200, or having a government-based payer (ADAP, Ryan White, Medicaid, or Medicare) at baseline were associated with a significant (P < 0.05), increased hazard of VF. Initiating on DTG or initiating therapy with a lower baseline VL was associated with a significant, reduced hazard of VF. Compared with DTG, the adjusted hazard ratio for VF was 1.29 (95% CI: 1.02, 1.63) for EVG.

Conclusion

Among ART-naïve patients, DTG users were significantly less likely to experience virologic failure than EVG users after adjustment for important baseline covariates.

Disclosures

All authors: No reported disclosures.
2493. Real-World Utilization of Ibalizumab (IBA) Without an Optimized Background Regimen (OBT)
Authors: Bouchard Jeannette , Derrick Caroline , Horvath Joseph
Published: October 2019

Background

It is difficult to treat multidrug-resistant (MDR) human immunodeficiency virus (HIV). Trogarzo® (ibalizumab) a novel monoclonal antibody was approved in 2018 for heavily treatment-experienced HIV patients. Data support IBA use with at least one fully active agent, an OBR. Real-world IBA data are lacking. We report a successful case of reaching and maintaining suppression with IBA in a patient without an OBR.

Methods

Mutations were reviewed for the patient, Table 1, and evaluated for treatment. The patient is a 52- year old male, diagnosed in 1994, with MDR HIV secondary to non-adherence. Upon re-presenting to care, the patient was non-compliant with ART. Genotypic interpretation via the Stanford/ANRS algorithm was performed and interpreted, resulting in the addition of IBA intravenous administration every other week. IBA was obtained through patient assistance and costs were covered by the institution for infusion.

Results

Evaluation of the resistance profile indicated varying resistance to all available ART. More specifically, high-level resistance to all FDA-approved INSTIs, PIs, and low to high-level resistance to all NNRTIs and NRTIs. Table 2 outlines the ART history and viral load (VL) trends. The patient was initiated on daruanvir/ritonavir twice daily, etravirine twice daily, emtricitabine/tenofovir alafenamide and did not reach suppression. IBA was added off-label to a failing regimen. The patient reached VS (VL < 200 copies/mL) at Week 4 and has had an undetectable VL for 8 weeks. Notably his CD4 count has risen to 46, first detectable number since re-presenting to care.

Conclusion

We describe a heavily treatment experienced patient with an MDR HIV virus who achieved an undetectable VL without an OBT and the addition of intravenous IBA. Fostemsavir, was utilized in IBA’s phase III trial for similar patients, however, it is not currently FDA-approved nor available. Further data are needed to ensure continued susceptibility to IBA without an OBT. This patient required high-level coordination to reach each visit and receive this therapy alongside his oral agents. We conclude, IBA has allowed this patient to reach and maintain VS.

Disclosures

All authors: No reported disclosures.
2502. Impact of Pharmacist-Led Antiretroviral Therapy Simplification Initiative in Heavily Treatment-Experienced Patients on Virologic Control
Authors: Jimenez Humberto R , Natali Kayla M , Suh Jin S
Published: October 2019

Background

It is well established that antiretroviral therapy (ART) with a lower pill burden are associated with better virologic suppression. However, many HIV providers are cautious when considering ART changes in heavily treatment-experienced patients for a variety of reasons: accumulation of complex resistance patterns, intolerance concerns with new agents, drug-interaction concerns, and a paucity of data on ART simplification in this population. The objective of our study was to evaluate the impact of pharmacist-led initiative to simplify ART among heavily treatment-experienced patients with high pill burdens on virologic control.

Methods

This was a prospective, observational cohort at a clinic in Paterson, NJ, USA. Patients were eligible if: heavily treatment experienced (≥10 years on ART with history of failure or resistance), ART with ≥ 4 pills daily, ≥ 48 weeks of data, and at clinic from September 2016 to present. The primary endpoint was to measure the effect of ART simplification (decrease of ≥ 2 pills daily) on virologic response (HIV RNA < 200 copies/mL) compared with continuation of regimens with a high pill burden. Secondary endpoints included difference in antiretroviral pill burden and monthly cost, based on average wholesale price (AWP).

Results

There were 94 patients eligible for the analysis. Most patients were male (65%), and either Black (53%) or Latinx (35%). The simplification and continuation groups had similar baseline characteristics: mean age (50 vs. 50 years old), daily pill burden (4.77 vs. 4.95), virologic response (82% vs. 87%), CD4 count (459 ± 265 vs. 528 ± 273), monthly ART cost ($4,585 vs. $4,159). M184V (50.0%) and K103N (23.4%) were the most commonly documented mutations. Thymidine-analog, atazanavir-associated, and darunavir-associated mutations were documented in 28.7%, 24.5%, and 11.7% of patients, respectively. Patients with ART simplification were more likely to have virologic response than patients continued on the baseline regimen (97% vs. 76%, P = 0.0126), and had a significantly lower daily pill burden (2.05 vs. 4.95, P = 0.001).

Conclusion

Pharmacist-led ART simplification in heavily treatment experienced patients can dramatically reduce pill burden while achieving better virologic success.

Disclosures

All authors: No reported disclosures.
2506. Trends of Transmitted Resistance Mutations to Four Drug Classes, HIV-Subtypes And Herpesviruses Replication Among Subjects Recently Diagnosed as HIV Infected Over 2004–2019
Authors: Basso Monica , Parisatto Beatrice , Stagni Camilla , Zago Daniela , Pozzetto Irene , Scaggiante Renzo , Cruciani Mario , Ferretto Roberto , Manfrin Vinicio , Francavilla Ermenegildo , Panese Sandro , Sarmati Loredana , Dal Bello Federico , Andreoni Massimo , Palù Giorgio , Parisi Saverio G
Published: October 2019

Background

to evaluate circulation of drug resistance mutations (DRMs), sub-types (ST) and Herpesviruses replication among subjects recently diagnosed as HIV infected (pts) in Veneto (Italy), over 16 years, comparing previously reported trends with the most recent one, updated to 2019.

Methods

on plasma from 2919 patients diagnosed from July 2004 to April 2019, protease (PR), reverse transcriptase (RT) and recently Integrase (In) were analyzed for DRMs, susceptibility profile (Stanford db) and ST. Potential low-level resistances were excluded. CMV-DNA and EBV-DNA were evaluated by in-house Real-Time-PCR in PBMCs.

Results

in 5 periods (2004/06, 07/09, 10/12, 13/16, 17–19) 334, 796, 752, 750 and 287 patients were recruited; non-B-ST were 21.9, 29.3, 33, 32.7 and 48.1% (33.5% Italians in 17–19), respectively. A significant increase of non-B-ST (P < 0.0001 for trend) and of the percentage of Italians with non-B-strains (P = 0.029) were observed. Resistance to PR or to multiple classes declined but not to non-nucleoside RT inhibitors (NNRTI) (Fig 1). E138A alone, not included in the previous evaluations, increased from 2.3 to 1.8, to 3.2, to 3.6, to 4.7% in 2017-19. No primary TDRM to In-Inhibitors (InIn) were found in 469 B-ST-Pts enrolled in 2014–19; 16% had major TDRM for RT/PI. Among 231 non-B patients, 12,5% with other TDRMs, only a 143C and a 66I were found. Accessory InIn-TDRMs were detected (Figures 2 and 3). Nevertheless, from 2009 to 2019 in Veneto 114 InIn-failed and potentially transmitters patients with In-DRMs were found. In 2017–19 17,3% of patients had CMV-DNA in PBMCs, with a median CD4 of 55 (8%), HIV-RNA 247251 cps/mL and EBV-DNA of 811 cps/106 PBMCs (3% were neg); Patients CMV-DNA-negative (82,7%) had median CD4 of 334 (18,9%), HIV-RNA 47770 cps/mL and a significantly lower EBV-DNA of 194 cps/106 PBMCs (15% were neg): differences between immuvirological variables were significant.

Conclusion

An increase of non-B strains and a slight increase of TDRMs among B-ST were observed. The persistent circulation of NNRTI-DRMs, the shortage of major In-TDRMs but a circulation of many In-polymorphisms have implications on the screening at baseline and on the selection of the first-line HAART. Many patients with lower CD4 and higher HIV replication has an incomplete control of co-infecting herpesviruses, which contribute to immunoactivation.

Disclosures

All authors: No reported disclosures.
2507. Transmitted and Acquired NNRTI Resistance in the Philippines: Are Newer Generation NNRTIs a Viable Option?
Authors: Theresa Dungca Nina , Schwem Brian , Arevalo Geraldine , Francisco Christian , Penalosa-Ramos Christine , Ching Patrick , Leyritana Katerina , Destura Raul , Lim Jodor , Tactacan-Abrenica Rosario , Telan Elizabeth , Solante Rontgene , Samonte Genesis , Trinidad Lyka , Mendoza Kevin , Alejandria Marissa M , Salvana Edsel Maurice T
Published: October 2019

Background

Doravirine, rilpivirine, and etravirine are newer generation non-nucleoside reverse transcriptase inhibitors (NNRTI) that are intended to be more durable alternatives to efavirenz and nevirapine. We examined transmitted drug resistance (TDR) and acquired drug resistance (ADR) to NNRTIs from recent local TDR and ADR data to determine whether these can be useful as first-line or second-line antiretroviral (ARV) agents.

Methods

We reanalyzed Sanger-Based sequences (SBS) from an ADR surveillance study; and SBS and near-whole-genome next-generation sequences (NGS) from a TDR surveillance study using the Stanford HIV Drug Resistance Database.

Results

ADR: Out of 513 Filipino PLHIV from an ADR surveillance study on one year of ARV treatment, 53 (10.3%) failed (HIV VL >1,000 copies/mL). Among these, 48 had clinically significant mutations. Table 1 shows NNRTI ADR frequencies. There was no significant ADR difference between first-generation and newer generation NNRTIs. TDR: 298 treatment-naïve Filipino PLHIV underwent baselines sequencing. All 298 had SBS. 266 had successful NGS. Table 1 shows SBS and NGS TDR NNRTI resistance at a 5% minor variant cutoff. There was no significant TDR difference between first-generation and newer generation NNRTIs.

Conclusion

ADR and TDR rates to the newer NNRTIs are similar to first-generation NNRTIs. High TDR to doravirine on NGS is concerning, but its clinical significance is unclear. Etravirine had the lowest TDR and ADR and may be the most useful new-generation NNRTI. However, integrase strand transfer inhibitor-based regimens will likely be more durable.

Disclosures

All authors: No reported disclosures.
2527. Improving Care for Adolescents Living with HIV: Evaluating the Impact of Case-Based Education
Authors: Hurst Simi Thomas , Blatherwick Don
Published: October 2019

Background

The CDC estimates that 26% of the approximately 50,000 people newly diagnosed with HIV in 2010 were youth 13 to 24 years of age. Older children and adolescents now comprise the largest population cared for at pediatric HIV clinics.

Methods

To improve HIV/ID specialists’ ability to develop a comprehensive care strategy for adolescents living with HIV, a CME/ABIM MOC/CE certified, case-based, educational program was developed. A series of multiple-choice questions evaluated the application of evidence-based recommendations. A “test then teach” approach elicited cognitive dissonance, with evidence-based feedback provided following each learner response. Educational effectiveness was assessed with a repeated-pairs pre-/post-assessment study design; each individual served as his/her own control. A chi-square test assessed changes pre- to post-assessment. P values < 0.05 are statistically significant. Effect sizes were evaluated using Cramer’s V (< 0.05 modest; 0.06–0.15 noticeable effect; 0.16–0.26 considerable effect; > 0.26 extensive effect). The activity launched on a website dedicated to continuous professional development on November 27, 2018. Data for this initial analysis were collected through February 27, 2019.

Results

To date, 6,755 HCPs (1,714 physicians; 2,795 nurses; 1,076 pharmacists) have participated in the activity. Data from the subset of HIV/ID specialists (n = 87) who answered all pre-/post-assessment questions during the initial study period were analyzed. Following activity participation, significant improvements were observed in the proportion of HIV/ID specialists who answered all assessment questions correctly (5% pre vs. 68% post; P < 0.0001; V = 0.397). Improvements were also observed in several specific areas of assessment (table). Additionally, 43% of HIV/ID specialists indicated they planned to modify their treatment approach among adolescents as a result of participating in the education.

Conclusion

Participation in this online, interactive, case-based, educational intervention significantly improved HIV/ID specialists’ ability to develop individualized strategies for adolescents living with HIV. These findings highlight the positive impact of well-designed online education.

Disclosures

All authors: No reported disclosures.
2541. Impact of a Combined Infectious Disease-Critical Care Medicine (ID-CCM) Track on Fellowship Recruitment
Authors: Bhanot Nitin , Min Zaw , Moffa Matthew , Walsh Thomas L , Como James D
Published: October 2019

Background

There has been a declining national trend in recent years of resident applications to Infectious Disease (ID) fellowship programs. This dearth of interested and available applicants has resulted in many programs failing to fill some or all of their fellowship slots. Our ID fellowship program, founded in 2013 at Allegheny General Hospital, had met with similar difficulty.

Methods

To increase the recruitment pool of candidates and combat the challenge to fill our positions, we incorporated a combined 3 year ID-Critical Care Medicine (CCM) track in 2016, initially with one of our two annual fellowship slots allotted to this track. This entailed a collaborative effort between the ID and CCM divisions, an internal application completion outlining the need and rationale for this combined program, and finally, approval from the institutional as well as the Accreditation Council for Graduate Medical Education (ACGME).

Results

The number of applicants interviewed from 2013 to 2016 for ID (pre-inception of the ID-CCM track), as well as those for ID, ID-CCM, or those interviewing for both tracks following 2016, were counted. We noted a consistent increasing trend in the numbers interviewed for both the ID (4, 8, and 12 total applicants) and ID-CCM (4, 10, and 12 total applicants) tracks over the three since the inception of our combined fellowship program; 3 additional applicants in years 2017 and 2018, and 5 in 2019, expressed interest in either ID or ID-CCM (Graph 1). This favorably amounted to filling our training positions.

Conclusion

Implementation of a combined ID-CCM fellowship program proved to be a viable strategy to increase the number of applicants at our institution. Given the success of having one dually-accredited slot, we have expanded the combined-track to both positions. As the first fully-integrated ID-CCM fellowship program in the country, we may be pioneering this novel training pathway for future physicians.

Disclosures

All authors: No reported disclosures.
2552. Using a Digital Escape Room as a Framework for Deliberate Practice of ID Fundamentals
Authors: Jeffres Meghan N
Published: October 2019

Background

Deliberate practice is defined as engagement in structured activities created specifically to improve performance in a domain. Deliberate practice is achieved when the following three conditions are met: (1) The student is motivated to practice and exert effort to improve performance, (2) The task takes into account the preexisting knowledge of the learner so the task can be correctly understood after a brief period of instruction, and (3) The learners are given immediate and informative feedback on performance. A digital escape room meets all the conditions for deliberate practice as well as creating a collaborative learning experience.

Methods

Eight puzzles and corresponding digital locks were created using Google Forms and implemented in an infectious diseases (ID) elective offered to third year pharmacy students. The content for escape room puzzles included clinical microbiology, antimicrobial spectrum and pharmacology. Facilitator and classroom logistical data were collected. Student satisfaction was assessed for through an online anonymous survey.

Results

20 small groups received a handout that contained learning objectives, rules, a Google Form link, escape room plot, 8 unique puzzles, and three hint tokens. 3 of 23 (13%) groups completed all 8 puzzles within 2 hours. Groups used 24 of 60 (40%) available hint tokens. The satisfaction survey was completed by 54 students, a 79% response rate. 93% of students indicated they were more engaged with thinking about the content than a typical classroom experience. 68% disagreed that the escape room framework made it difficult to focus on learning due to feeling stressed or overwhelmed. Constructive feedback themes were increasing clarity of puzzle directions and code nuances. Positive feedback themes were related to engagement, collaboration with peers, and variety of puzzles.

Conclusion

The escape room framework provides an engaging opportunity for the deliberate practice of ID fundamentals, a task student often find to be tedious. Using digital instead of physical locks allows the escape room to be deployed in a large classroom setting with one or two facilitators. Since Google Forms provides immediate and informative feedback, the role of the facilitator is respond to hint tokens and remediate the material with students.

Disclosures

All authors: No reported disclosures.
2558. Pharmacy Students’ Perceptions and Confidence to Recommend Appropriate Empiric Antibiotic Therapy in Infective Endocarditis Following Mannequin-Based Simulation
Authors: Kufel Wesley D , Leppien Emily , Lynch Sarah , Seabury Robert
Published: October 2019

Background

Mannequin-based simulation (MBS) has been shown to increase healthcare student confidence. Limited data describes the use of MBS for infectious diseases (ID) education, particularly among pharmacy students. The objectives of this study were to assess the effect of MBS on pharmacy student confidence to recommend appropriate empiric antibiotic therapy for infective endocarditis (IE), and to evaluate students’ perceptions of MBS.

Methods

This single-center, cross-sectional, electronic, anonymous survey was conducted in a second professional year skills education course at a 4-year Doctor of Pharmacy program. Students were provided a pre-survey following IE education via didactic, large classroom instruction, which occurred 2 weeks prior to MBS. The pre-survey asked participants to assess their confidence to recommend appropriate empiric antibiotic therapy for IE on a Likert scale from strongly disagree (1) to strongly agree (5). Participants were provided a post-survey following MBS. The post-survey included the pre-survey questions, as well as questions regarding demographics, and perceptions of MBS. Participation was voluntary.

Results

The survey was distributed to 58 students; 93% (54/58) and 90% (52/58) responded to the pre- and post-survey, respectively. Most were female (29/52, 56%) and 50% (26/52) had a Bachelor’s degree. Half were interested in an ID pharmacy experiential rotation (26/52, 50%), and most were interested in pursuing post-graduate residency training (30/52, 57%). The majority agreed or strongly agreed that MBS was an enjoyable learning experience (48/52, 92%) that improved their knowledge of IE (48/52, 93%). Additionally, most agreed or strongly agreed that MBS improved their learning compared with written case-based instruction (46/52, 89%). Students agreed or strongly agreed that MBS increased their confidence to recommend appropriate empiric antibiotics for IE (pre-survey: 70% vs. post-survey: 87%, P = 0.035).

Conclusion

MBS appeared to increase pharmacy student confidence in their ability to recommend appropriate empiric antibiotics for IE. Pharmacy students agreed that MBS was an enjoyable learning experience that improved their knowledge, and preferred MBS compared with written case-based instruction.

Disclosures

All authors: No reported disclosures.
149. Short vs. Long Course of Antibiotics for Uncomplicated Gram-Negative Bacteremia
Authors: Go James , Cotner Sarah , Burgess Donna R , Burgess David , Wallace Katie , VanHoose Jeremy , Arora Vaneet , Li Nannan
Published: October 2019

Background

Bloodstream infections (BSI) continue to be a major cause of morbidity and mortality in the United States; thus, the correct choice of antibiotics for an appropriate duration is imperative. However, there are limited recommendations on adequate duration of treatment of bacteremia caused by Gram-negative organisms. Therefore, treating an infection for an adequate duration to prevent complications while preventing adverse effects from unnecessary antibiotic exposure remains a balancing act. This study aims to compare clinical outcomes between patients treated with a short (7–10 days) vs. long (11–20 days) course of antibiotics for uncomplicated gram-negative bacteremia.

Methods

This single-center retrospective cohort study evaluated adult patients admitted between January 2007 to October 2018 with a blood culture positive for gram-negative bacteria. Data came from the University of Kentucky Microbiological Laboratory and Center for Clinical and Translational Science (CCTS) Data Bank. Patients included must have received appropriate antibiotics for at least 7 days. Appropriate antibiotics were defined as those to which the organism is susceptible with day one of therapy as the first day of appropriate antibiotic therapy. Patients were excluded if they were treated with aminoglycoside monotherapy, had polymicrobial bacteremia, or if treated for longer than 20 days of therapy.

Results

A total of 466 patients were identified (208 in the short-course group and 258 in the long course group). Gender and ethnicity were similar across both groups. The patients in the long course group had more ICU admissions compared with the short-course group (52.7% vs. 43.3%, P = 0.0426), tended to be older (57 ± 16.7 vs. 53 ± 15.9 years, P = 0.0119), had a higher Charlson Comorbidity Index (5.7 ± 3.6 vs. 4.6 ± 3.6, P = 0.0009) and remained admitted to the hospital longer (23.2 ± 25.6 vs. 15.8 ± 17.5 days, P = 0.0002). However, patients treated with a long course had no difference in 30-day mortality compared with the short-course group (3.9% vs. 3.4%, P = 0.7701).

Conclusion

Patients with an uncomplicated gram-negative BSI treated with a short course (7–10 days) of antibiotics do not appear to have a significant difference in 30-day mortality compared with those patients treated with a long course (11–20 days).

Disclosures

All authors: No reported disclosures.
150. Urinary Tract-Associated Gram-Negative Bacteremia: Impact of Treatment Duration
Authors: Badwal Jasmin K , Hand Elizabeth O , Lyons John M , Traugott Kristi A
Published: October 2019

Background

Gram-negative bloodstream infections are one of the leading causes of death in the United States. A select number of studies have been conducted evaluating various treatment durations; however, none have specifically focused on urinary sources. The purpose of this study was to compare the effect of short vs. long course of antimicrobial therapy on clinical and microbiological outcomes for urinary tract-associated gram-negative bacteremia (GNB).

Methods

This was a single-center, retrospective review from January 2016 to October 2018. Subjects were screened using a report of all positive GNB cultures. Hospitalized patients ≥18 years of age were included if they had a bacteremia from a urinary source and received an intravenous or a highly bioavailable oral agent for ≥7 days. Patients were excluded due to pregnancy, incarceration, inappropriate definitive therapy, polymicrobial bacteremia, unaddressed source control issues, or death during the treatment course. Short course (SC) was defined as 7–10 days, while long course (LC) was defined as >10 days. The primary composite outcome of treatment failure included both 30-day all-cause mortality and 90-day recurrence. Secondary outcomes included 30-day re-admission, 90-day mortality, resistance development, and C. difficile infection.

Results

A total of 207 patients were included: 45 patients received SC and 162 received LC. Both groups were similar at baseline in terms of comorbidities, intensive care unit (ICU) admission, and vasopressor initiation. No statistically significant difference in the primary composite endpoint was observed: 2/45 (4.4%) SC vs. LC 10/162 (6.2%), P = 0.66. There was also no difference in other secondary outcomes.

Conclusion

Consistent with prior studies, we were unable to find a significant difference in clinical failure rates between SC vs. LC for treatment of urinary tract-associated GNB. Generalizability to more complicated cases including those with inadequate source control may be limited; however, these data add to the body of literature supporting the use of shorter antibiotic durations.

Disclosures

All authors: No reported disclosures.
2575. Dramatic Time-Dependent Changes of Bacterial and Fungal Taxonomic Signatures in 4 Body Regions of ICU Patients
Authors: Wurm Philipp , Halwachs-Wenzl Bettina , Kashofer Karl , von Lewinski Dirk , Eisner Florian , Krause Robert , Gorkiewicz Gregor , Hoegenauer Christoph
Published: October 2019

Background

It has been hypothesized that intensive care unit (ICU)-related complications like nosocomial pneumonia or gastrointestinal dysfunction are associated with disturbances of normal host microorganisms. However, these alterations are largely unknown in ICU patients. The bacterio- and mycobiota in 4 body regions in 14 ICU patients was investigated after admission until death or discharge to other wards.

Methods

Medical ICU patients were sampled with pharyngeal swabs, endotracheal aspirates, gastric secretions and stools or rectal swabs (in constipated patients). V1-V2 (16S rRNA gene) and eukaryoitic ITS sequencing was performed as previously described as well as denoizing, transformation into amplicon sequence variants and analysis using qiime2 and LEfSe (LDA Score > 3.0, P-value < 0.05). For sequence classification databases SILVA 132 (16S) and UNITE version 7.2 (ITS) were used.

Results

Samples were obtained at multiple time points from day 1 up to day 47 with a median of 11 samples per patient (range 2 to 17). In 11 patients all intended body regions were sampled (stool was missing in two patients and gastric secretion in two patients). The length of ICU stay and number of antibiotics administered during ICU stay was associated with loss of diversity in all investigated body sites. Taxonomic profiling showed a significant reduction of physiological members from the oral and fecal microbial community (e.g., Clostridiales, Bacteroidales, Faecalibacterium spp. etc.) after 2 weeks at the ICU. In contrast, Enterococcus spp. and Staphylococcus spp. were enriched in the gastric and fecal microbiota. Candida spp. dominated fungal communities of all body sites investigated. Staphylococcus aureus was associated with ITS positive, Candida spp. dominated samples throughout all body sites, while Pseudomonas aeruginosa was associated with ITS-negative samples.

Conclusion

The length of the ICU stay and the number of different antibiotics administered during the stay at the ICU are associated with severe intestinal dysbiosis, determined by loss of physiological microbes, decreased bacterial richness and domination of low-diversity fecal microbiota. Early colonization of Candida spp. might favor a co-existance of a Staphylococcus spp.-dominated microbiota in the ICU.

Disclosures

All authors: No reported disclosures.
2581. An Invertebrate Model to Study Gut Microbiome Dysbiosis
Authors: Alnezary Faris S , Rashid Tasnuva , Begum Khurshida , Carlson Travis J , Gonzales-Luna Anne J , Alam M Jahangir , Garey Kevin W
Published: October 2019

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.
2587. Etiology and Outcome of Acute Neonatal Infectious Encephalitis
Authors: Frankel Craig , Whyte Hilary , Chau Vann , MacGregor Daune , Mahant Sanjay , Branson Helen , Campigotto Aaron , Bitnun Ari
Published: October 2019

Background

There are very few studies on acute encephalitis with onset during the neonatal period. The objectives of this study were to investigate the etiology and salient clinical features of neonatal encephalitis.

Methods

Neonates with possible infectious encephalitis (IE) were prospectively enrolled. Inclusion criteria included encephalopathy (altered/fluctuating level of consciousness ≥24 hours) plus ≥2 of: fever/temperature instability; seizure(s); focal neurologic findings; CSF pleocytosis; EEG abnormalities consistent with encephalitis; neuroimaging abnormalities consistent with encephalitis. Neonates with a clear diagnosis of post-perinatal asphyxial encephalopathy or culture proven bacterial meningitis were excluded. Results shown as absolute numbers, proportions or medians [interquartile range] as appropriate.

Results

Fifty-nine neonates fulfilled the inclusion/exclusion criteria (June 2013–November 2018). Empiric acyclovir was initiated in 49 (83.1%) cases. An infectious etiology was identified in 25 (42.4%): enteroviruses (n = 15), HSV (n = 5), HHV6 (n = 2), parainfluenza 3 (n = 1), influenza A (n = 1), CMV (n = 1). A noninfectious cause was confirmed in 20 (33.9%): missed hypoxic-ischemic encephalopathy (n = 10), genetic/metabolic disorders (n = 7), ischemic/hemorrhagic stroke (n = 3). No specific etiology was identified in 14 (23.7%). Thirteen (52%) neonates with IE either died (n = 7) or suffered neurologic sequelae (n = 6). Deaths were attributable to HSV (n = 4), enteroviruses (n = 2) and HHV6 (n = 1). Neurocognitive sequelae were documented in one case each of enterovirus, HSV2, HHV6, CMV, parainfluenza 3 and influenza A. Differences between neonates with and without IE, respectively, included age in days of symptom onset (7 [6, 10] vs. 1 [0, 3]; P < 0.001), gestational age (37.0 [36.0, 39.0] vs. 38.6 [37.6, 40.0]; P = 0.045), peripheral leukocyte count (10.5 [IQR 5.9, 14.6] vs. 14.3 [IQR 10.7, 21.7]; P = 0.008) and CSF glucose (2.80 [IQR 2.3, 3.2] vs. 3.10 [2.8, 3.8]; P = 0.003).

Conclusion

Enteroviruses and HSV are the predominant causes of neonatal IE. Outcome of neonatal IE is poor with approximately half dying or suffering neurologic sequelae.

Disclosures

All authors: No reported disclosures.
152. Brevibacterium species: Case Series and Literature Review of an Emerging Opportunistic Cause of Bloodstream Infections
Authors: Shweta F N U , Gurram Pooja , Khalil Sarwat , Rodino Kyle , O’Horo John C
Published: October 2019

Background

Brevibacterium species are non-motile, catalase-positive, obligate aerobic gram-positive bacilli. Colonies are yellow to gray-white, non-hemolytic, smooth, 6.5% sodium chloride tolerant. B. fermentans post neurosurgical meningitis was first described in 1969 in an infant. B. casei remains the most commonly isolated species (Table 4). The most commonly reported syndromes are bloodstream infections (BSIs) and endocarditis. Despite these reports, this organism continues to be listed on CDC’s NHSN commensal database.

Methods

Isolates of Brevibacterium from clinical samples at Mayo Clinic, Rochester from January 1, 2014 to December 31, 2018 were identified. Charts were reviewed to determine patient demographics, immune status, source of culture, comorbidities, antibiotic susceptibility test (AST), length of stay (LOS) in hospital and intensive care unit (ICU), and mortality. Likelihood ratio (L-R) and Pearson correlation coefficient (PCC) of nominal data were calculated using the Chi-square test and Fischer exact test (FET). We defined statistical significance as P ≤ 0.05.

Results

We identified 48 isolates from 45 unique patients, 46% were females. Distribution of age, hospital and ICU LOS, and time to culture growth, and AST data are shown in Table 1. 15.5% patients received allogeneic or autologous stem cell (SCT), or solid-organ transplant (SOT) recipients. 89% cultures were from sterile sources and 68.75% were blood cultures. Of these, 63.64% were monomicrobial. 62% of isolates identified to species level were B. casei. 5 patients were treated; an additional 10 received active antibiotics for other indications. Statistically significant variables are reported in Tables 2 and 3. Thirty-day mortality was 13%. This was higher in patients with bacteremia (L-R: 5.3 [P = 0.02]) but FET was not statistically significance (P = 0.15).

Conclusion

Accurate diagnosis of Brevibacterium may require molecular techniques. At our center, SCT or SOT recipient status and recent chemotherapy were associated with bacteremia. In these patients, this organism could represent an opportunistic cause of BSI. AST data suggest that Vancomycin offers a reasonable empiric treatment option. Additional data are needed to further define host populations in whom this organism presents pathogenicity.

Disclosures

All authors: No reported disclosures.
2592. Lung Function as an Indicator of Vaccine Enhanced RSV Disease in Cotton Rats
Authors: Jones Crystal , Shen Xiaolan , Ping Xiaoli , Gallagher Catherine , Beech Jeremy , Douglas Cameron M , Citron Michael , Espeseth Amy
Published: October 2019

Background

Respiratory syncytial virus (RSV) infection is the leading cause of lower respiratory tract infections in infants and young children. Seronegative children previously vaccinated with formalin-inactivated live RSV formulated with aluminum (FIRSV) developed vaccine enhanced RSV disease (VERD), which is characterized by fever, wheezing, bronchopneumonia, and airway hyperresponsiveness (AHR). We investigated whether impaired lung function can serve as a marker for VERD in an animal model of RSV infection.

Methods

Uninfected and RSV-infected cotton rats intranasally challenged with 106 pfu of RSV A2 were anesthetized with pentobarbital and tracheostomized. A cannula was placed in the trachea and animals were connected to flexiVent™ (Scireq), which is a computer-controlled piston ventilator that analyzes pressure and volume signals in response to an oscillatory waveform applied at the animal’s airways. Vecuronium bromide was administered to ventilated animals to prevent independent breathing. To measure AHR, animals were exposed to increasing doses of inhaled methacholine, and methacholine-induced bronchoconstriction was measured.

Results

Two independent studies showed that RSV-infected cotton rats (n = 4) exhibited increased total respiratory system resistance (Rrs) and airway resistance (Rn) following methacholine challenge on days 4 and 6 post-infection compared with uninfected cotton rats (n = 4).

Conclusion

RSV-induced impairment in lung function can be exploited for the development of a more robust and objective method for assessing vaccine safety in a cotton rat model of respiratory disease compared with traditional histopathological analysis.

Disclosures

All authors: No reported disclosures.
2594. Biofilm-Dispersed Staphylococcus aureus Exhibits a Distinct agr-Independent Host Interaction
Authors: Chang Spencer , Fowler Vance G , Sharma-Kuinkel Batu K , Medie Felix , Park Larry , Zheng Yue , Otto Michael , Horswill Alexander
Published: October 2019

Background

Staphylococcus aureus biofilms are a common cause of persistent, life-threatening infections. Dispersal of S. aureus cells from established biofilm-based infections is crucial for dissemination within the host, but is poorly understood. We tested the hypothesis that biofilm dispersed S. aureus cells have distinct physiology from planktonic cells and are better equipped to evade host immunity in an agr-dependent manner.

Methods

Primary murine bone marrow-derived macrophages (BMDMs) were infected with planktonic and biofilm dispersed cells from S. aureus USA300 LAC wild type (WT) and USA300 LAC-agr knockout (KO). Biofilm dispersed cells were collected via glucose deprivation. Gentamicin protection assays were used to enumerate phagocytosed bacteria and fluorescence microscopy to quantify macrophage viability. A 26-plex immunoassay was used to screen for cytokines and chemokines. Reversed phase high-performance liquid chromatography was used to measure relative phenol-soluble modulin (PSM) levels from macrophage co-cultures.

Results

Compared with planktonic cells, biofilm-dispersed cells in both S. aureus WT and KO backgrounds exhibited: (1) ~10-fold less phagocytosis by BMDMs (p = 0.0003; Figure 1); (2) increased macrophage killing (23% vs. 8%; p = 0.0038; Figure 2); (3) stronger pro- (e.g., IFN-y, IL-2, IL-6, IL-17; Figure 3A) and anti- (e.g., IL-10, IL-4, IL-22; Figure 3B) inflammatory cytokine responses from macrophages (P < 0.05 for all); (4) significantly higher δ toxin PSM production (P = 0.0090; Figure 4) in WT background only.

Conclusion

S. aureus biofilm dispersed cells are physiologically distinct from planktonic cells and have a unique interaction with the host immune system. Dispersed cells are more resistant to phagocytosis, have a greater propensity to kill macrophages, and mount stronger pro- and anti-inflammatory responses in an agr-independent manner. Dispersed cells also have the ability to produce more δ toxin PSM via well-known agr-dependent pathways.

Disclosures

All authors: No reported disclosures.
2601. Identification of Staphylococcus aureus Genetic Factors Associatiated with the Subversion of Macrophage Phagosomal Acidification
Authors: Morris Paul E R , Renshaw Stephen , Foster Simon J , Peden Andrew , Dockrell David
Published: October 2019

Background

S. aureus is a major medical pathogen contributing to healthcare-associated costs and mortality. Metastatic S. aureus infection is commonly associated with skin and soft-tissue infections. Macrophages as resident tissue phagocytes are essential for bacterial clearance and effectively phagocytose and kill S. aureus at low inocula. Formation of an intracellular reservoir develops when the capacity for macrophages to eradicate S. aureus is overwhelmed at increased inocula. Phagosomal maturation after bacterial ingestion involves sequential fusion with endosomes and lysosomes, reducing luminal pH, facilitating bacterial degradation. In the context of intracellular S. aureus, incomplete phagosomal maturation is demonstrable with impaired acidification and failure of lysosome fusion. Inhibition of phagosomal maturation is dependent upon bacterial factors as it is reversed in heat-killed bacteria. Intracellular survival of S. aureus is associated with reduced antimicrobial effectivity and increased complications. Within the intracellular environment, persistence of S. aureus is associated with adaptation of gene expression which confers greater resistance to antimicrobial effector mechanisms.

Methods

An ordered mutant library of S. aureus provides the opportunity to give a comprehensive evaluation of gene function. The Nebraska transposon (Tn) mutant library contains 1952 sequence-defined Tn insertion mutants derivative of USA300 LAC S. aureus, each with a single non-essential gene deletion. The mutants were labeled with a fluorescent stain activated at pH < 6 and challenged against differentiated human monocyte-derived macrophages for 4 hours. A high-content microscopy screen was developed to identify the bacterial genes associated with impairment of phagosomal acidification.

Results

The results of the high-throughput screen indicate the global regulators agr and saeR, hemolysin A and catalase are associated with the inhibition of phagosomal acidification.

Conclusion

The burden of S. aureus bacteremia and metastatic disease makes the targeting of intracellular S. aureus essential. Identification of bacterial factors associated with impaired phagosomal acidification and maturation offers targets to limit S. aureus infections.

Disclosures

All authors: No reported disclosures.
2615. Increased Severity of Lower Respiratory Tract Infection Among Native American Compared with Non-Native American Children
Authors: Cayetano. Lopez Santiago Manuel , Weber Zachary , Palmer Geralyn , Kooima Travis , Bula-Rudas Fernando , Chatterjee Archana , Chatterjee Archana
Published: October 2019

Background

Lower respiratory tract infection (LRTI) is the leading cause of pediatric hospitalizations in the United States, with significant morbidity and mortality. Native American children are at increased risk for severe illness during LRTI. Yet, the reasons for this increased risk are poorly understood. Socio-economic status and/or a genetic predisposition have been postulated as possible causes. In addition, the spectrum of LRTI presentations has not been adequately described in this patient population. The objective of this study was to define the clinical presentations of LRTI and highlight the differences between Native American and non-native American previously healthy patients under the age of 24 months.

Methods

We performed a retrospective chart review during the 2017–2018 respiratory season. We reviewed 357 medical records, and included 192 patients in the analysis that were full term, previously healthy, and met our inclusion criteria. We recorded demographic information, clinical and laboratory data, and outcomes.

Results

Of 192 patients, 39 were Native American and 153 were non-native American. We found no differences in gestational age, gender or age (median age was 5 and 7 months, respectively) between groups. We found no difference in rates of vaccination, upper respiratory symptoms, cough, wheezing, crackles, increased work of breathing or peripheral white blood cell count at presentation. In addition, we found no differences in antibacterial use or length of antimicrobial therapy during hospitalization. Native American children had a statistically significant higher length of hospitalization (P = 0.01) as well as days of oxygen supplementation (mean 4.9 vs. 3 days; P = 0.006) compared with non-native Americans. Furthermore, Native American children had a significantly higher percentage of PICU admissions (28% vs. 10.4%; P = 0.008) as well as intubation rate (26% vs. 8%; P = 0.04) compared with non-native Americans.

Conclusion

Native American children had increased length of hospitalization associated with severe illness including longer oxygen supplementation, higher PICU admission rate and need for mechanical ventilatory support.

Disclosures

All authors: No reported disclosures.