Evaluation of Oral Amoxicillin/Clavulanate for Urinary Tract Infections Caused by Ceftriaxone Non-Susceptible Enterobacterales

Urinary tract infections (UTIs) are one of the most common infections and are frequently caused by Gram-negative organisms. The rise of resistant isolates has prompted evaluation of alternative therapies, including amoxicillin-clavulanate which has potent activity against Ambler class A enzymes. This study sought to evaluate clinical outcomes of patients with ceftriaxone non-susceptible UTIs receiving amoxicillin-clavulanate or standard of care (SOC). This was a single-center, retrospective, cohort study of adult patients with urinary tract infections caused by a ceftriaxone non-susceptible pathogen who received amoxicillin-clavulanate or SOC. The primary outcome was clinical failure at 90 days. Secondary outcomes included time to failure, isolation of a resistant organism, and hospital length of stay. Fifty-nine patients met study inclusion: 26 received amoxicillin/clavulanate and 33 received SOC. Amoxicillin-clavulanate recipients did not have higher failure rates compared to SOC recipients. For patients requiring hospital admission, hospital length of stay was numerically shorter with amoxicillin-clavulanate. The frequency of amoxicillin-clavulanate and carbapenem-resistant organisms did not differ significantly between groups. Amoxicillin-clavulanate may be a useful alternative therapy for the treatment of ceftriaxone non-susceptible Enterobacterales UTIs.

Transitioning young adults with spina bifida: Challenges and paths to success

INTRODUCTION AND BACKGROUND

Recent medical advances, including closure of myelomeningocele defects, shunting of hydrocephalus, and focusing on renal preservation have led to many individuals with spina bifida (SB) living into adulthood. This has led to more individuals with SB transitioning their care from pediatric-based to adult-based care models.

OBJECTIVE

We seek to explore the process of transition, with a focus on difficulties in transitioning individuals with SB. Additionally, we explore new problems that arise during the period of transition related to sexual function and dysfunction. We also discuss some of the difficulties managing neurogenic bladder and the sequalae of their prior urologic surgeries.

STUDY DESIGN

Each of the authors was asked to provide a summary, based on current literature, to highlight the challenges faced in their area of expertise.

CONCLUSIONS

Transitioning care for individuals with SB is especially challenging due to associated neurocognitive deficits and neuropsychological functioning issues. Sexual function is an important component of transition that must be addressed in young adults with SB. Management of neurogenic bladder in adults with SB can be challenging due to the heterogeneity of the population and the sequelae of their prior urologic surgeries. The aim is to ensure that all individuals with SB receive appropriate, evidence-based care throughout their lifetime.

Prospective evaluation of single-dose aminoglycosides for treatment of complicated cystitis in the emergency department

BACKGROUND

Antimicrobial resistance among Enterobacterales continues to be a growing problem, particularly in those with urinary infections. Previous studies have demonstrated safety and efficacy with the use of single-dose aminoglycosides in uncomplicated cystitis. However, data in complicated infections are limited. Single-dose aminoglycosides may provide a convenient alternative for those with or at risk for resistant pathogens causing complicated urinary infections, especially when oral options are unavailable due to resistance, allergy, intolerance, or interactions with other medications. This study evaluated the safety and effectiveness of single-dose aminoglycosides in treatment of complicated cystitis in the emergency department (ED).

METHODS

This was a multicenter, prospective study performed between July 2022 and March 2023 of patients who met criteria for complicated cystitis and were otherwise stable for discharge at an academic ED. Primary outcomes were clinical or microbiologic failure within 14 days of treatment. Safety was assessed by review of adverse events. Descriptive statistics were used.

RESULTS

Thirteen patients were included. Complicating factors were male sex (n = 4), kidney stone (n = 2), urinary catheter (n = 6), recent urologic procedure (n = 1), urinary hardware (n = 1), antibiotic allergy precluding use of alternate oral options (n = 4), immunocompromised status (n = 2), and <1-year history of multidrug-resistant organisms on urine culture (n = 8). Eleven patients (85%) had positive urine cultures in the preceding 12 months with no oral antimicrobial option. Eight patients (62%) received amikacin (median dose 15 mg/kg), four patients (31%) received gentamicin (median dose 5 mg/kg), and one patient (8%) received tobramycin (5 mg/kg) for treatment. Ten patients (77%) reported resolved urinary symptoms after treatment and 11 patients (85%) reported no new urinary symptoms since discharge. No patient required hospital admission for treatment failure, and no adverse events were noted.

CONCLUSIONS

Single-dose aminoglycosides appear to be a reasonably effective and safe treatment for complicated cystitis, which avoided hospital admission in this cohort.

Oritavancin as sequential therapy for Gram-positive bloodstream infections

BACKGROUND

Oritavancin, a long-acting lipoglycopeptide approved for use in acute bacterial skin and skin structure infections, has limited data evaluating use in serious infections due to Gram-positive organisms. We aimed to assess the effectiveness and safety of oritavancin for consolidative treatment of Gram-positive bloodstream infections (BSI), including infective endocarditis (IE).

METHODS

We conducted a retrospective cohort study evaluating adult patients admitted to University of Colorado Hospital from March 2016 to January 2022 who received ≥ 1 oritavancin dose for treatment of Gram-positive BSI. Patients were excluded if the index culture was drawn at an outside facility or were > 89 years of age. The primary outcome was a 90-day composite failure (clinical or microbiological failure) in those with 90-day follow-up. Secondary outcomes included individual components of the primary outcome, acute kidney injury (AKI), infusion-related reactions (IRR), and institutional cost avoidance.

RESULTS

Overall, 72 patients were included. Mean ± SD age was 54 ± 16 years, 61% were male, and 10% had IE. Organisms most commonly causing BSI were Staphylococcus aureus (68%, 17% methicillin-resistant), followed by Streptococcus spp. (26%), and Enterococcus spp. (10%). Patients received standard-of-care antibiotics before oritavancin for a median (IQR) of 11 (5-17) days. Composite failure in the clinically evaluable population (n = 64) at 90-days occurred in 14% and was composed of clinical and microbiological failure, which occurred in 14% and 5% of patients, respectively. Three patients (4%) experienced AKI after oritavancin, and two (3%) experienced an IRR. Oritavancin utilization resulted in earlier discharge for 94% of patients corresponding to an institutional cost-avoidance of $3,055,804 (mean $44,938/patient) from 1,102 hospital days saved (mean 16 days/patient).

CONCLUSIONS

The use of oritavancin may be an effective sequential therapy for Gram-positive BSI to facilitate early discharge resulting in institutional cost avoidance.

Substance use disorder-associated infections' treatment with dalbavancin enabling outpatient transition (SUDDEN OUT) - an investigator-initiated single-arm unblinded prospective cohort study

Background

Severe gram-positive infections are frequent in people who inject drugs, and successful completion of treatment presents unique challenges in this population.

Objectives

We aimed to evaluate the feasibility of a long-acting antibiotic, dalbavancin, as an alternative to standard-of-care antibiotics for severe infections due to vancomycin-susceptible pathogens requiring ⩾2 weeks of therapy.

Design

We designed an investigator-initiated single-arm unblinded prospective cohort study to evaluate the safety and efficacy of an early switch to dalbavancin in two doses administered 1 week apart.

Methods

We screened patients admitted with bloodstream infection, osteomyelitis, septic arthritis, infective endocarditis or deep abscesses, and comorbid substance use disorder (SUD) for eligibility. Consenting patients were switched to dalbavancin within 7 days from their index culture. They were monitored in the hospital for efficacy and safety of the treatment until the second dose of dalbavancin 7 days later and then discharged if stable. Study participants were evaluated with a decision support engine for a hypothetical appropriate level of care regarding their SUD after discharge. Their follow-up was planned for 12 months from the index culture, either in-person or via telehealth/telephone.

Results

The enrollment was terminated early due to significant loss-to-follow-up. In all, 11 patients were enrolled, 4 completed 12 months of follow-up, 2 completed 8 months of follow-up, and 1 was seen once after discharge. The remaining five patients were lost to follow-up immediately after discharge. All 11 patients continued to improve after switching to dalbavancin between the first and second doses. There were two per-protocol failures of treatment. Dalbavancin was well tolerated, though some adverse events were reported.

Conclusion

Dalbavancin may be a safe and effective alternative for an early switch in treating severe gram-positive infections.

Trial registration

The trial was registered as NCT04847921 with clinicaltrials.gov.

Creating and Implementing a Novel Wellness-Inspired Resident Educational RG (WIRE) Curriculum

The Wellness-Inspired Resident Education (WIRE) curriculum is a resident-driven educational program consisting of six formal panels or lectures that are fully incorporated into the yearly resident didactic schedule, in addition to informal events and a resident wellness retreat. The curriculum promotes personal and professional wellness, enhances resident and department camaraderie, and provides opportunities to network with leaders in the field of plastic surgery. This paper provides the context which inspired the development of this curriculum, as well as key steps for successful implementation of wellness educational programming at any institution.

Burn Injury and Augmented Renal Clearance: A Case for Optimized Piperacillin-Tazobactam Dosing

Patients with burn injuries are at high risk for infection as well as altered antimicrobial pharmacokinetics. Patients suffering from a burn injury, generally encompassing a total body surface area (TBSA) ≥ 20%, have been cited as at risk for augmented renal clearance (ARC). Our case report describes an obese patient with 3.2% TBSA partial thickness burns who suffered from burn wound cellulitis with Pseudomonas aeruginosa. Measured CLcr documented the presence of ARC, and 22.5 grams daily continuous infusion of piperacillin-tazobactam was initiated. Therapeutic monitoring of piperacillin at steady state was 78 mcg/mL, achieving the prespecified goal piperacillin concentration of 100% 4-times the minimum inhibitory concentration assuming MIC for susceptible P. aeruginosa at 16/4 mcg/mL per Clinical Laboratory Standards Institute. Available literature suggests younger critically ill patients with lower organ failure scores, and for a burn injury, a higher percentage of TBSA, are most likely to exhibit ARC which does not entirely align with the characteristics of our patient. In addition, piperacillin-tazobactam has been associated with altered pharmacokinetics in ARC, burn, and obese populations, demonstrating failure to meet target attainment with standard doses. We suggest a continuous infusion of piperacillin-tazobactam be used when ARC is identified. This case report describes the unique findings of ARC in a non-critically ill burn patient and rationalizes the need for further prospective research to classify incidence, risk factors, and appropriate antimicrobial regimens for burn patients with ARC.

1986. Multicenter evaluation of Staphylococcus aureus prosthetic valve infective endocarditis with and without gentamicin treatment: Is it time to revisit?

Background

Staphylococcus aureus prosthetic valve infective endocarditis (SA-PVIE) is associated with high mortality. Gentamicin (GEN) with anti-staphylococcal antibiotics and rifampin are guideline recommendations for SA-PVIE extrapolated from in vitro data. GEN can lead to acute kidney injury (AKI), meanwhile, the clinical benefit on infection-related outcomes remains unclear. Therefore, we evaluated the impact of GEN on outcomes in SA-PVIE.

Methods

This is a multicenter, retrospective cohort conducted at HonorHealth and UCHealth systems. Adults admitted between January 2014-2022 with definite/possible SA-PVIE by Duke Criteria were included if they received ≥2 days of treatment within 2 days of index culture. Cohorts were stratified by GEN receipt. The primary outcome was 90-day all-cause mortality. The secondary outcomes were treatment failure (change in antimicrobials, abscess development, new indication for cardiac surgery), 30-day all-cause mortality, and incidence of AKI by KDIGO Criteria.

Results

Overall, 38 patients with definite (40%) and possible SA-PVIE (60%) met inclusion (13 GEN, 25 without GEN [no-GEN]). At baseline, 15 (40%) patients were in an ICU, median Pitt bacteremia score was 2, and methicillin-susceptible S. aureus predominated (71%). A total of 10 (26%) patients had valve surgery; median bacteremia duration was similar between GEN and no-GEN (4 vs 3 days, p = 0.26). Common antibiotics were vancomycin (95%), cefazolin (63%), and nafcillin (21%); rifampin was more common in GEN than no-GEN (20% vs 77%, p < 0.001). Baseline AKI (44% vs 46%) and renal impairment (8% vs 0%) were not different between GEN and no-GEN, respectively. GEN was initiated a median 3 days after index culture, most commonly as intermittent strategy (69%) with 3 mg/kg daily equivalent (84.6%). There was no statistical difference in treatment failure (23% vs 24%, p=0.17), 30-day mortality (20% vs 39%, p=0.22), or 90-day mortality (28% vs 43%, p=0.263) between GEN and no-GEN, respectively. Three in the (23%) GEN group experienced AKI, compared to 10 (40%) in no-GEN.

Conclusion

We did not find that the addition of GEN to SA-PVIE therapy enhanced mortality benefit, yet patients without GEN may live to experience adverse events. Further studies were warranted.

Disclosures

All Authors: No reported disclosures.

Comparison of Sequential Dalbavancin to Standard-of-Care Treatment for Staphylococcus aureus Bloodstream Infections

Background

Dalbavancin (DAL) is a long-acting lipoglycopeptide with activity against Staphylococcus aureus, including methicillin-resistant S. aureus (MRSA). This study investigates DAL as sequential therapy in S. aureus bloodstream infections (BSIs).

Methods

We conducted a retrospective cohort study from 2014 to 2021 comparing sequential DAL with standard-of-care therapy (SoC) for S. aureus BSI. The primary outcome was 90-day clinical failure (90-day all-cause mortality or 90-day recurrence). Secondary outcomes were incidence of acute kidney injury, creatinine phosphokinase elevations, catheter-related thrombosis, and hospital-acquired infections. Analyses were adjusted using inverse probability of treatment weighting (IPTW).

Results

Overall, 225 patients (45 DAL, 180 SoC) were included. DAL patients had a higher incidence of community-acquired infection and persons who use drugs; SoC patients had more comorbidities and a longer duration of bacteremia. MRSA incidence was similar between the DAL and SoC groups. The median length of stay was 16 days among DAL recipients compared with 24 days among SoC recipients. Central catheter placement was 17.8% compared with 57.2% in the SoC group. Ninety-day clinical failure occurred in 13.3% and 18.3% of participants in the DAL and SOC groups, respectively. In IPTW-adjusted analysis, sequential DAL was not associated with 90-day clinical failure (adjusted odds ratio, 0.94; 95% CI, 0.333–2.32).

Conclusions

This study provides preliminary evidence that select patients with S. aureus BSI treated with sequential DAL have similar clinical failure rates, with significant reductions in catheter placement and hospital length of stay compared with SoC. Further prospective evaluation is needed.

Deep modeling of plasma and neutral fluctuations from gas puff turbulence imaging

The role of turbulence in setting boundary plasma conditions is presently a key uncertainty in projecting to fusion energy reactors. To robustly diagnose edge turbulence, we develop and demonstrate a technique to translate brightness measurements of HeI line radiation into local plasma fluctuations via a novel integrated deep learning framework that combines neutral transport physics and collisional radiative theory for the 3³D - 2³P transition in atomic helium with unbounded correlation constraints between the electron density and temperature. The tenets for experimental validity are reviewed, illustrating that this turbulence analysis for ionized gases is transferable to both magnetized and unmagnetized environments with arbitrary geometries. Based on fast camera data on the Alcator C-Mod tokamak, we present the first two-dimensional time-dependent experimental measurements of the turbulent electron density, electron temperature, and neutral density, revealing shadowing effects in a fusion plasma using a single spectral line.

Real-World Use of Tedizolid Phosphate for 28 Days or More: A Case Series Describing Tolerability and Clinical Success

Tedizolid has activity against Gram-positive pathogens as well as Mycobacterium spp and Nocardia spp. Real-world evidence supporting long-term tolerability and clinical success of tedizolid is lacking. Prolonged tedizolid therapy (median, 188 days; interquartile range, 62-493 days) appeared to be well tolerated in 37 patients (8.1% experienced adverse effect leading to discontinuation). Clinical success was 81.3% in those evaluated.

Clinical Pharmacokinetics and Pharmacodynamics of Dalbavancin

Dalbavancin is a synthetic lipoglycopeptide that exerts its antimicrobial activity through two distinct modes of action, inhibition of cell wall synthesis and an anchoring mechanism. Compared with previous glycopeptide antibiotics, dalbavancin demonstrates improved antibacterial potency against Gram-positive organisms and a long half-life of approximately 1 week, which is longer in tissues (e.g., skin, bone) than plasma. These factors facilitated the development of single-dose or once-weekly dosing regimens to treat acute bacterial skin and skin structure infections (ABSSSI). Dalbavancin exhibits dose-proportional pharmacokinetics and is highly protein bound (93%). Despite being highly protein bound, it has a steady-state volume of distribution >10 L and distributes widely into the skin, bone, peritoneal space, and epithelial lining fluid, but not cerebrospinal fluid. Dalbavancin elimination occurs via a combination of renal (approximately 45%) and non-renal clearance, with dose adjustments recommended only in patients with a creatinine clearance <30 mL/min not receiving any form of dialysis. The established pharmacokinetic/pharmacodynamic index associated with bacterial kill is free area under the concentration-time curve over the minimum inhibitory concentration (fAUC/MIC), with a goal 24-h fAUC/MIC of at least 27.1 for Staphylococcus aureus infections. Recent data suggest usefulness in the treatment of infections beyond ABSSSI, with convenient dosing and redosing strategies for complicated infections requiring extended treatment durations. Additional studies are needed to confirm these preliminary findings.

In Vitro Human Skin Absorption of Solvent-deposited Solids: Niacinamide and Methyl Nicotinate

A quantitative understanding of the dose dependence of topical delivery is important to cosmetic and dermatological product development and to risk assessment for hazardous chemicals contacting the skin. Despite considerable research, predictive capability in this area remains limited. To this end we conducted an experimental skin absorption study of two closely related skin care agents, niacinamide (nicotinamide, NA) and methyl nicotinate (MN), and analyzed the results quantitatively using a transient diffusion model described separately (Yu et al. submitted for publication). Radiolabeled test compounds were solvent-deposited onto ex vivo human skin mounted in Franz diffusion cells over a dose range exceeding 4.5 orders of magnitude, and permeation was measured over a 1-4 day period. At low doses, the permeation rate of NA was approximately 60-fold lower than that of its lower melting, more lipophilic analog, MN; at high doses an even greater difference was observed. The difference can be qualitatively explained based on higher lipid solubility and lower crystallinity of MN relative to NA. Dissolution-limited mass transfer through a lipid layer at the SC surface is suggested. Relevance of the results to practical skin care formulations was confirmed by a parallel study of NA in an o/w emulsion.

Real-World Comparison of Bezlotoxumab to Standard of Care Therapy for Prevention of Recurrent Clostridioides difficile Infection in Patients at High Risk for Recurrence

BACKGROUND

Bezlotoxumab (BEZ) is a monoclonal antibody used to prevent recurrent Clostridioides difficile infection (rCDI). This study investigates BEZ effectiveness in relation to rCDI and patient-specific risk factors in a real-world setting.

METHODS

A matched, retrospective cohort study was conducted from 2015 to 2019 to compare BEZ to historical standard of care (SoC) therapy with vancomycin or fidaxomicin. The primary outcome was incidence of 90-day rCDI. Secondary outcomes were incidence of all-cause hospital readmission and all-cause mortality at 90 days, infusion-related reactions, and incidence of heart failure exacerbation. Baseline confounding was addressed using inverse probability of treatment weighting (IPTW).

RESULTS

Overall, 107 participants were included (54 BEZ and 53 SoC). Mean number of prior CDI episodes was 2, median number of risk factors for rCDI was 4, and 28% of participants had severe CDI. Incidence of 90-day rCDI was 11% BEZ vs 43% SoC (P = < .001) and 90-day all-cause readmission was 40% BEZ vs 64% SoC (P = .011). In IPTW-adjusted analyses, BEZ was associated with significantly reduced odds of rCDI (odds ratio [OR], 0.14 [95% confidence interval {CI}: .05-.41]) and all-cause readmission (OR, 0.36 [95% CI: .16-.81]). No safety signals were detected with BEZ use.

CONCLUSIONS

BEZ is effective for the prevention of rCDI and reduction in all-cause hospital readmission for patients at high risk for recurrence, supporting current guideline recommendations.

Effectiveness of Bezlotoxumab for Prevention of Recurrent Clostridioides difficile Infection Among Transplant Recipients

Background

Bezlotoxumab significantly reduces the incidence of recurrent Clostridioides difficile infection (CDI); however, limited data are available in solid organ transplant (SOT) and hematopoietic cell transplant (HCT) recipients.

Methods

We conducted a single-center retrospective analysis comparing recurrent CDI in SOT and HCT recipients receiving standard of care alone (oral vancomycin, fidaxomicin, or metronidazole) or bezlotoxumab plus standard of care. The primary outcome was 90-day incidence of recurrent CDI, and secondary outcomes included 90-day hospital readmission, mortality, and incidence of heart failure exacerbation.

Results

Overall, 94 patients received bezlotoxumab plus standard of care (n = 38) or standard of care alone (n = 56). The mean age was 53 years; patients had a median of 3 prior Clostridioides difficile episodes and 4 risk factors for recurrent infection. Most patients were SOT recipients (76%), with median time to index CDI occurring 2.7 years after transplantation. Ninety-day recurrent CDI occurred in 16% (6/38) in the bezlotoxumab cohort compared to 29% (16/56) in the standard of care cohort (P = .13). Multivariable regression revealed that bezlotoxumab was associated with significantly lower odds of 90-day recurrent CDI (odds ratio, 0.28 [95% confidence interval, .08–.91]). There were no differences in secondary outcomes, and no heart failure exacerbations were observed.

Conclusions

In a cohort of primarily SOT recipients, bezlotoxumab was well tolerated and associated with lower odds of recurrent CDI at 90 days. Larger, prospective trials are needed to confirm these findings among SOT and HCT populations.

Effectiveness of Shorter Versus Longer Durations of Therapy for Common Inpatient Infections Associated With Bacteremia: A Multicenter, Propensity-Weighted Cohort Study

BACKGROUND

National guidelines for pneumonia (PNA), urinary tract infection (UTI), and acute bacterial skin and skin structure infection (ABSSSI) do not address treatment duration for infections associated with bacteremia. We evaluated clinical outcomes of patients receiving shorter (5-9 days) versus longer (10-15 days) duration of antibiotics.

METHODS

This was a multicenter retrospective cohort study of inpatients with uncomplicated PNA, UTI, or ABSSSI and associated bacteremia. The primary outcome was clinical failure, a composite of rehospitalization, reinitiation of antibiotics, or all-cause mortality within 30 days of antibiotic completion. Secondary outcomes included individual components of the primary outcome, Clostridioides difficile infection, and antibiotic-related adverse effects necessitating change in therapy. A propensity score-weighted logistic regression model was used to mitigate potential bias associated with nonrandom assignment of treatment duration.

RESULTS

Of 408 patients included, 123 received a shorter treatment duration (median 8 days) and 285 received a longer duration (median 13 days). In the propensity-weighted analysis, the probability of the primary outcome was 13.5% in the shorter group and 11.1% in the longer group (average treatment effect, 2.4%; odds ratio [OR], 1.25; 95% confidence interval [CI], .65-2.40; P = .505). However, shorter courses were associated with higher probability of restarting antibiotics (OR, 1.62; 95% CI, 1.01-2.61; P = .046) and C. difficile infection (OR, 4.01; 95% CI, 2.21-7.59; P < .0001).

CONCLUSIONS

Shorter courses of antibiotic treatment for PNA, UTI, and ABSSSI with bacteremia were not associated with increased overall risk of clinical failure; however, prospective studies are needed to further evaluate the effectiveness of shorter treatment durations.

An overview of current and emerging antifungal pharmacotherapy for invasive fungal infections

Introduction: Invasive fungal infections (IFIs) remain a significant cause of morbidity and mortality despite significant advancements in currently available therapy. With a flush pipeline of investigational antifungals, the clinician must identify appropriate roles of currently available therapies, potential advantages of emerging antifungals, and shortcomings in the evolving clinical evidence.Areas covered: Standard and developing treatment approaches for IFIs with currently available antifungals are summarized with a focus on invasive candidiasis and invasive aspergillosis. Emerging investigational antifungals are discussed in depth, including mechanisms of action, fungal activity, clinical evidence, and ongoing research. An opinion on the impact and potential role of therapy for emerging antifungals of interest is also provided.Expert opinion: Despite advances and clinical studies optimizing antifungal use, current therapies fall short in preventing IFI morbidity and mortality. Further optimization of currently available antifungals may improve outcomes; however, novel agents are required for historically difficult-to-treat infections, transitions to oral treatment, minimizing adverse drug effects, decreasing drug interactions, and ultimately improving patient quality of life. Emerging antifungals may positively revolutionize the treatment of IFIs.

Combination ceftaroline and daptomycin salvage therapy for complicated methicillin-resistant Staphylococcus aureus bacteraemia compared with standard of care

Complicated methicillin-resistant Staphylococcus aureus bloodstream infections (MRSA-BSIs), particularly those with delayed culture clearance, are associated with high mortality. Combination therapy with daptomycin and ceftaroline (DAP+CPT) represents a novel therapeutic approach to MRSA-BSI owing to synergistic bactericidal activity. This study aimed to compare DAP+CPT with historical standard of care (SoC) for treatment of complicated MRSA-BSI. This single-centre retrospective cohort study included patients with complicated MRSA-BSI at University of Colorado Hospital. Patients receiving DAP+CPT for ≥48 h between November 2013 and March 2020 or SoC with vancomycin or DAP ± gentamicin and/or rifampicin from November 2011 to December 2013 were compared. The primary outcome was clinical failure defined as a composite of MRSA-related mortality and recurrent infection at 60 days. A total of 60 patients received DAP+CPT (n = 30) or SoC (n = 30). Median age was 56 years and median Pitt bacteremia score was 3. Common infectious sites were endovascular (63%) and musculoskeletal (40%). DAP+CPT was associated with a numerically lower incidence of clinical failure compared with SoC (20% vs. 43%; P = 0.052). Multivariable analysis controlling for immunocompromised status (OR, 6.90, 95% CI 1.08-44.15), Charlson comorbidity index (OR, 1.12, 95% CI 0.90-1.39) and source control (OR, 0.35, 95% CI 0.08-1.46) associated DAP+CPT with 77% lower odds of clinical failure (OR, 0.23, 95% CI 0.06-0.89). In patients with complicated MRSA-BSI with delayed clearance, DAP+CPT trended towards lower rates of clinical failure than SoC and was significantly associated with decreased clinical failure after adjustment for baseline differences.

The effects of air stress during storage and low packing density on the fermentation and aerobic stability of corn silage inoculated with Lactobacillus buchneri 40788

We determined if a microbial inoculant could improve the fermentation and aerobic stability of corn silage subjected to various challenges during storage that included an air stress challenge and low packing density. In Experiment 1, whole-plant corn was untreated (CTR) or treated (INO, Lactobacillus buchneri 40788 and Pediococcus pentosaceus 12455. Five individually replicated 7.5-L silos, at a density of 240 kg of dry matter (DM)/m³, for each treatment were kept sealed (NAS) for 19 wk, air stressed early (ES, 3 h/wk for wk 1-9), or air stressed late during storage (LS, 3 h/wk for wk 10-19). Inoculation increased the number of agar-culturable lactic acid bacteria regardless of air stress status, but it did not affect the relative abundance of Lactobacillus. Early, but not late air stress, resulted in silages with a higher relative abundance of Acetobacter when compared with NAS. Silages treated with INO had greater concentrations of acetic acid than CTR. Numbers of yeasts were lowest for INO regardless of air stress and CTR-LS had the most yeasts among all treatments. Silages that were not air stressed had a higher relative abundance of Candida tropicalis than air stressed silages. Monascus purpureus was detected in ES and LS but not in NAS, and its relative abundance was numerically higher in CTR-ES than in INO-ES and statistically higher in CTR-LS compared with INO-LS. Early air stress numerically reduced aerobic stability compared with NAS, and there was a statistical tendency for lower stability in LS compared with NAS. Inoculation improved aerobic stability regardless of when the air stress occurred. In Experiment 2, corn silage was prepared with the same primary treatments of CTR and INO but was packed at a low (LD; 180 kg of DM/m³) or a normal (ND; 240 kg of DM/m³) density and sealed (NAS) or air stressed (AS; 24 h on d 28, 42, and 89) for 92 d of storage. The concentration of acetic acid was greater in INO compared with CTR and in AS compared with NAS. Numbers of yeasts were lower in NAS compared with AS regardless of inoculation and they were lower in INO-AS compared with CTR-AS. Treatment with INO improved aerobic stability but the improvement was better in NAS versus AS and better in ND versus LD. Overall, our experiments corroborate past findings showing that INO markedly improves the aerobic stability of corn silage but they are the first to show that improvement can be sustained even when the silage was exposed to regular air stresses and when packed at a low density.

Evaluating the effects of Lactobacillus animalis and Propionibacterium freudenreichii on performance and rumen and fecal measures in lactating dairy cows

Two experiments evaluated the effect of supplementation with a bacterial direct-fed microbial on performance and apparent total-tract nutrient digestion of dairy cows. In experiment 1, 30 multiparous cows (75 ± 32 d in milk) were randomly assigned to 1 of 2 treatments fed for 10 wk. All cows were fed a diet containing 23.8% starch. Treatments were top dressed to rations twice daily and consisted of a combination of Lactobacillus animalis (1 × 10⁹ cfu/d) and Propionibacterium freudenreichii (2 × 10⁹ cfu/d; LAPF) or carrier alone (CON). In experiment 2, 6 ruminally cannulated cows (123 ± 129 d in milk) were randomly assigned to a crossover design with two 6-wk periods. Cows received the same CON or LAPF treatment as in experiment 1. Cows were fed the same 23.8% starch diet as experiment 1 during wk 1 through 5 of each period, and then cows were abruptly switched to a 31.1% starch diet for wk 6. For both experiments, intake and milk yield were measured daily, and milk samples were collected weekly. In experiment 1, fecal grab samples were collected every 6 h on d 7 of experimental wk 1, 2, 4, 6, 8, and 10. Fecal consistency was scored, and fecal starch was measured in daily composite samples. Fecal composites from a subset of 7 cows per treatment were used to measure apparent total-tract nutrient digestion. In experiment 2, rumen pH was continuously recorded during wk 5 and 6. On d 7 of wk 5 (the final day of feeding the 23.8% starch ration), d 1 of wk 6 (the day of diet transition), and d 7 of wk 6 (the final day of feeding the 31.1% starch ration), rumen in situ digestion was determined. Samples of rumen fluid and feces were collected every 6 h on those days for measurement of fecal starch (composited by cow within day), rumen volatile fatty acids, and fecal pH. Rumen and fecal samples were collected at one time point on those days for microbiota assessment. In experiment 1, treatment did not affect intake, milk yield, milk composition, or fecal score. The LAPF treatment decreased fecal starch percentage and tended to increase starch digestion compared with CON, but the differences were very small (0.59 vs. 0.78% and 98.74 vs. 98.46%, respectively). Digestion of other nutrients was unaffected. In experiment 2, LAPF increased rumen pH following the abrupt switch to the high-starch diet, but milk yield was lower for LAPF compared with CON (35.7 vs. 33.2 kg/d). Contrary to the decrease in fecal starch with LAPF observed in experiment 1, fecal starch tended to be increased by LAPF following the abrupt ration change in experiment 2 (2.97 vs. 2.15%). Few effects of treatment on rumen and fecal microbial populations were detectable. Under the conditions used in our experiments, addition of the bacterial direct-fed microbials did not have a marked effect on animal performance, ruminal measures, or total-tract nutrient digestion.

Evaluation of immunologic parameters in canine glioma patients treated with an oncolytic herpes virus

AIM

To molecularly characterize the tumor microenvironment and evaluate immunologic parameters in canine glioma patients before and after treatment with oncolytic human IL-12-expressing herpes simplex virus (M032) and in treatment naïve canine gliomas.

METHODS

We assessed pet dogs with sporadically occurring gliomas enrolled in Stage 1 of a veterinary clinical trial that was designed to establish the safety of intratumoral oncoviral therapy with M032, a genetically modified oncolytic herpes simplex virus. Specimens from dogs in the trial and dogs not enrolled in the trial were evaluated with immunohistochemistry, NanoString, Luminex cytokine profiling, and multi-parameter flow cytometry.

RESULTS

Treatment-naive canine glioma microenvironment had enrichment of Iba1 positive macrophages and minimal numbers of T and B cells, consistent with previous studies identifying these tumors as immunologically "cold". NanoString mRNA profiling revealed enrichment for tumor intrinsic pathways consistent with suppression of tumor-specific immunity and support of tumor progression. Oncolytic viral treatment induced an intratumoral mRNA transcription signature of tumor-specific immune responses in 83% (5/6) of canine glioma patients. Changes included mRNA signatures corresponding with interferon signaling, lymphoid and myeloid cell activation, recruitment, and T and B cell immunity. Multiplexed protein analysis identified a subset of oligodendroglioma subjects with increased concentrations of IL-2, IL-7, IL-6, IL-10, IL-15, TNFα, GM-CSF between 14 and 28 days after treatment, with evidence of CD4⁺ T cell activation and modulation of IL-4 and IFNγ production in CD4⁺ and CD8⁺ T cells isolated from peripheral blood.

CONCLUSION

These findings indicate that M032 modulates the tumor-immune microenvironment in the canine glioma model.

Mucormycosis in Hematopoietic Cell Transplant Recipients and in Patients With Hematological Malignancies in the Era of New Antifungal Agents

Background

The survival benefit of combination antifungal therapy for invasive mucormycosis (IM) in patients with hematologic malignancy (HM) and hematopoietic cell transplant (HCT) is not well defined.

Methods

This multicenter, retrospective study included HM and HCT recipients with proven or probable IM between January 1, 2007 and December 31, 2017 from 10 transplant centers across North America.

Results

Sixty-four patients with proven (n = 47) or probable (n = 17) IM defined by 2008 European Organization for Research and Treatment of Cancer/Mycoses Study Group (EORTC/MSG) consensus definitions were included. Thirty-nine (61%) were HCT recipients (95% allogeneic). Sites of infection included rhino-orbital-cerebral (33), pulmonary (30%), disseminated (19%), gastrointestinal (3%), and cutaneous (3%). Surgical debridement was performed in 66%. Initial antifungal treatment consisted of the following: lipid formulation of amphotericin B (AmB) alone (44%), AmB + posaconazole (25%), AmB + echinocandin (13%), AmB + isavuconazole (8%), posaconazole alone (5%), and isavuconazole alone (3%). All-cause mortality at 30 days and 1 year were 38% and 66%, respectively. Initial treatment with AmB plus posaconazole or isavuconazole (n = 28) was associated with a trend toward lower treatment failure compared with AmB (n = 21) (42% vs 64%, P = .136).

Conclusions

Long-term survival with IM among HM and HCT populations remains poor. However, initial use of AmB + azole in conjunction with surgery may result in less treatment failure. More evidence from prospective controlled studies is needed to confirm this observation.

A Comparison Between the Clinical Features of Pseudotumor Cerebri Secondary to Tetracyclines and Idiopathic Intracranial Hypertension

PURPOSE

Comparisons between clinical features of tetracycline-induced pseudotumor cerebri (PTC-T) and those of idiopathic intracranial hypertension (IIH) are absent in the literature. We hypothesized that significant clinical differences between these etiologies exist and could be better understood by retrospective analysis.

DESIGN

Retrospective cohort study.

METHODS

We reviewed patients diagnosed with pseudotumor cerebri syndrome (PTCS) at our center and identified those who developed PTC-T after treatment with a tetracycline-class antibiotic and those with IIH. Groups were compared by demographics, body mass index, ophthalmic examination, treatment, clinical course, and visual outcomes.

RESULTS

We identified 52 cases of PTC-T and 302 cases of IIH. Obesity rates were significantly different (43.8% for PTC-T vs 79.2% for IIH, P < .001). The mean age at diagnosis was younger for PTC-T (19.8 years vs 28.1 years for IIH, P < .001). Diplopia was more common with PTC-T (40.4% vs 20.1% for IIH, P = .001). The mean illness duration was shorter for PTC-T (18.3 weeks vs 62.9 weeks for IIH, P <.0001). Recurrence rates were significantly different (4.0% for PTC-T vs 16.5% for IIH, P <.001). The frequency of surgical intervention was similar. Vision loss was uncommon but occurred with similar frequency.

CONCLUSION

We identified significant clinical differences but also identified important similarities between the 2 groups. There appear to be nonobese patients who develop PTC-T, discontinue the antibiotic, and never develop PTCS again. There are other patients who develop PTC-T, discontinue the antibiotic, and later develop IIH. We conclude that PTC-T represents a spectrum of disease in susceptible individuals.

Addressing Suicide in the Veteran Population: Engaging a Public Health Approach

Suicide is a national public health issue in America, and it disproportionately affects those who are serving or who have served in the United States military. The US Department of Veterans Affairs (VA) has made suicide prevention its number one clinical priority. VA is committed to prevent suicide among the entire population of those who have served our country in the military, regardless of whether they make use of any VA services or benefits. Suicide can be prevented through the application of a public health strategy embracing partners at all levels. Following a national strategy, VA has embarked on an effort involving the application of a public health strategy combining both clinically-based and community-focused interventions. This paper describes several examples of these efforts and steps forward.

On- and off-label utilization of dalbavancin and oritavancin for Gram-positive infections

BACKGROUND

Long-acting lipoglycopeptides (laLGPs) are FDA approved only for acute bacterial skin and skin structure infections (ABSSSIs). However, these antibiotics show promise for off-label use, reductions in hospital length of stay (LOS) and healthcare cost savings.

OBJECTIVES

To assess the effectiveness, safety, impact on LOS and estimated cost savings from laLGP treatment for Gram-positive infections.

METHODS

Retrospective cohort of adult patients who received at least one dose of laLGPs at the University of Colorado Health system. Descriptive statistics were utilized for analysis.

RESULTS

Of 59 patients screened, 56 were included: mean age 47 years, 59% male and 30% injection drug users/polysubstance abusers (dalbavancin, 71%; oritavancin, 25%; both, 4%). Most common indications for laLGP: ABSSSIs (36%), osteomyelitis (27%) and endocarditis (9%). Most common isolated pathogens: MSSA and MRSA (25% and 19%, respectively), Enterococcus faecalis (11%) and CoNS (11%). Previous antibiotics were administered for a median of 13 days (IQR = 7.0-24.5 days) and laLGPs for a median of one dose (IQR = 1-2 doses). Ten (18%) patients were lost to follow-up. Clinical failure was found in 7/47 (15%) cases with adequate follow-up. Mild adverse effects occurred in six (11%) patients. Projected reduction in hospital LOS and health-system costs were 514 days (9.18 days/person average) and $963456.72 ($17204.58/person average), respectively.

CONCLUSIONS

Prospective trials are needed to validate the use of these antibiotics for Gram-positive infections in practice, with the hope that they will reduce hospital LOS and the need for daily antibiotic infusions to provide alternative options for patients not qualifying for outpatient parenteral antimicrobial therapy.

Severe acute Q fever pneumonia complicated by presumed persistent localized Q fever endocarditis in a renal transplant recipient: A case report and review of the literature

Q fever in solid organ transplant (SOT) recipients is rarely described in the medical literature. We present a case of severe acute Q fever pneumonia that evolved into persistent localized Q fever endocarditis in a renal transplant recipient.

218. Evaluation of Clinical Outcomes with Shorter Vs. Longer Duration of Treatment for Common Inpatient Bacterial Infections Associated with Bacteremia

Background

Pneumonia (PNA), urinary tract infection (UTI), and acute bacterial skin and skin structure infection (ABSSSI) are the most common infections treated in the inpatient setting and often are associated with bacteremia. Though short courses of treatment are advocated for these infections in general, no established guidelines exist for cases involving bacteremia. We evaluated the clinical outcomes of patients receiving short (5–9 days) vs. long (10–15 days) duration of antibiotic treatment.

Methods

A retrospective study was conducted at 3 area hospitals comprising a university-based tertiary center, a public safety net hospital, and a Veterans’ Affairs hospital. We included hospitalized adult patients with transient bacteremia associated with uncomplicated cases of PNA, UTI, or ABSSSI. The primary outcome consisted of a composite of rehospitalization or resumption of antibiotic treatment attributed to the original infection or death due to any cause within 30 days of the antibiotic start date. Secondary outcomes included the individual composite components, Clostridioides difficile infection, and antibiotic-related adverse effects leading to change in antibiotic therapy. A propensity score weighted logistic regression model was used to mitigate factors which could bias a patient toward receiving a shorter or longer treatment duration.

Results

Of 411 patients included in the study, 123 (29.9%) received a short duration of therapy and 288 (70.1%) received a long duration of therapy. The median duration of treatment was 8 days in the short group and 13 days in the long group. In the propensity-weighted analysis, the probability of meeting the composite primary outcome was not statistically different between the short and long groups (Table 1). However, receiving a short course was associated with a higher probability of restarting antibiotics and Clostridioides difficile infection.

Conclusion

Shorter vs. longer courses of antibiotic treatment for bacteremia associated with PNA, UTI, and ABSSSI were not significantly different in a composite of readmission, restart of antibiotics, and mortality; however, further study is needed to evaluate the safety and effectiveness of short-course therapy.

Disclosures

All authors: No reported disclosures.

1021. Accuracy of Provider-Selected Antibiotic Indications at Point of Order Entry Compared with Electronic Health Record Documentation

Background

The Centers for Medicaid and Medicare Services (CMS) state that hospital antimicrobial stewardship (AMS) policies require indications be documented for all orders. This may be included in the electronic medical record (EMR) or during order entry per CMS. Reliance solely on EMR documentation may be inconsistent or absent at times. In an effort to optimize compliance to this new measure and improve antibiotic use tracking, the University of Colorado AMS committee implemented required indications for all systemic antimicrobial orders. To follow up on this intervention we sought to determine the accuracy of ordered indication based on EMR documentation.

Methods

Retrospective review of antibiotics ordered between May 2, 2017 and December 1, 2017 among hospitalized patients aged 18–89 years. The primary objective was the accuracy of provider-selected indications (PSI) compared with EMR documented-clinical indication (DCI). Secondary objectives included accuracy comparison between check-box and free-text PSI format, and adherence to institutional antibiotic use guidelines. Differences between proportions of antibiotic orders with certain variables were assessed with Pearson’s chi-square and Fisher’s exact as appropriate.

Results

A total of 304 patients were evaluated with a median age of 56 years, 49% male, and 31% identified as immunocompromised. Check-box was most utilized in 81%, with 93% having a single indication selected. Most orders were classified as empiric (63%), followed by prophylaxis (23%) and definitive (15%). Frequent indications chosen were pneumonia (17%), bacteremia (13%), skin and soft tissue (10%), urinary tract infection (9%), and intra-abdominal infections (5%). Accuracy by PSI/DCI match was 78%, which was not different by a method of indication entry. Only indication type (P = 0.023) and care team specialty (P = 0.009) were shown to significantly impact accuracy. Nonadherence to institutional guidelines was 19%.

Conclusion

Antibiotic indications on order entry are an effective strategy to improve documentation and meet compliance around new CMS standards. Ordering by surgical services and prophylactic indications had lower PSI/DCI match, mostly resulting from absent EMR indication documentation.

Disclosures

All authors: No reported disclosures.

2287. Real-world Use of Tedizolid Phosphate: A Case Series of Long-Term Tolerability

Background

Tedizolid is an oxazolidinone antibiotic with broad-spectrum Gram-positive activity approved for the treatment of skin and skin structure infections with a 6-day course. Oxazolidinone antibiotics represent appealing options for prolonged antimicrobial therapy due to their available oral formulations with excellent bioavailability and potent in vitro activity against various multidrug-resistant Gram-positive organisms, Mycobacterium spp., and Nocardia spp. Although tedizolid and linezolid offer a similar clinical spectrum based on antimicrobial activity alone, long-term use of linezolid is often limited by serious adverse effects. Preliminary assessments have suggested better tolerability with tedizolid; however, these are limited by shorter exposure duration. The objective of this study was to evaluate the long-term safety and tolerability of tedizolid.

Methods

Retrospective cohort of adult patients receiving tedizolid for ≥ 28 days, with baseline complete blood cell (CBC) indices available, and CBC indices drawn ≥ 14 days into tedizolid course. The primary objective was to evaluate the long-term tolerability of tedizolid.

Results

13 patients met inclusion criteria: median age 61 years (IQR, 51–64 years), 69% male, 85% Caucasian. The majority of patients utilized tedizolid for suppression (85%), and the median duration of tedizolid was 113 days (IQR, 71–204 days). There were no differences in CBC indices when comparing baseline to last laboratory draw throughout tedizolid exposure: platelets (baseline: 203 x 10⁹/L (IQR, 186–283 x 10⁹/L) vs. last: 196 x 10⁹/L (IQR, 161–303 x 10⁹/L; p = 0.65), hemoglobin (baseline: 9.8 g/dL (IQR, 8.8–11.1 g/dL) vs. last: 11.7 g/dL (IQR, 11.0–13.1 g/dL; p = 0.10), and white blood cells (baseline: 6.2 x 10⁹/L (IQR, 5.6–7.6 x 10⁹/L) vs. last: 6.5 x 10⁹/L (IQR, 6.3–7.3 x 10⁹/L; p = 0.45). The final laboratory draws were obtained a median of 78 days (IQR, 44–119 days) into therapy. No patients experienced peripheral neuropathy, optic neuritis/visual changes, or serotonin syndrome during treatment/suppression with tedizolid during the period evaluated.

Conclusion

Long-term therapy with tedizolid appears to be well-tolerated. Treatment and suppression with tedizolid seems to be a safe alternative to linezolid.

Disclosures

All authors: No reported disclosures.

1116. Impact of Antimicrobial Stewardship Incentive Goals for Pharmacists on Overall Antibiotic Use and Appropriate Duration of Therapy in Urinary Tract Infections

Background

Urinary tract (UTI), skin and soft tissue, and respiratory infections are among the most frequently reported indications for antibiotics, such that focusing stewardship efforts here would expectedly have dramatic effects. Antimicrobial stewardship (AMS) programs vary in structure and available resources. At the University of Colorado Hospital, a 740-bed academic medical center, dedicated resources for AMS are limited to a pharmacist, pharmacy resident, and physician; however, there is a large clinical pharmacist group. For the past 2 years, pharmacy management incorporated AMS targets as group goals tied to performance bonuses.

Methods

This is a descriptive report utilizing incentives to achieve AMS goals. The first goal (July 1, 2016 to June 30, 2017) set out to reduce inpatient antibiotic use by 10%. The second goal (July 1, 2018 to June 30, 2018) was a 10% reduction in median antibiotic duration for UTIs. The AMS team provided guidelines, education, and oversight throughout target periods. Antibiotic use was calculated as days of therapy (DOT) per 1000 patient-days. Data related to UTI treatment was collected retrospectively on a quarterly basis. This was compared with baseline data previously collected during a statewide hospital stewardship collaborative project.

Results

During the first period, overall antibiotic use declined from 497 to 403 DOT per 1000 patient-days (18.9%), and broad-spectrum antibiotic use declined 22%. During the second period, 30 patient charts were reviewed quarterly, and the median UTI duration declined from 10 to 7 days (P = 0.002). The most common UTI diagnoses were similar between periods with complicated cystitis and pyelonephritis comprising 60–70% of cases. The 30-day readmission rate was not different between the baseline and goal period, 11% vs. 6% respectively (P = 0.18).

Conclusion

The use of group pharmacist goals tied to annual performance bonuses was effective in achieving AMS goals at our institution. In larger facilities with fewer dedicated AMS personnel, clinical pharmacists covering ward and intensive care units are an essential resource to achieving AMS goals. Group performance incentives may be a feasible strategy to generate interest and motivation to achieve AMS program goals.

Disclosures

All authors: No reported disclosures.

1535. Pharmacokinetic (PK) and Pharmacodynamic (PD) Evaluation of Cefepime (CPM) in Obese and Non-Obese Patients

Background

Appropriate application of antimicrobial PK/PD properties is crucial to optimizing patient outcomes. Although β-lactams are among the most utilized and effective antibiotics, optimal dosing strategies in obese populations are largely unknown. The objective of this study was to compare PK/PD of CPM in non-obese (NO, weight 80–100 kg) and obese (O, weight > 100 kg) patients.

Methods

A prospective comparative PK/PD analysis was conducted in NO and O patients receiving CPM. Blood samples were obtained at 30, 60, 120, 240, 360, and 480 minutes after CPM infusion. CPM concentrations were determined by reversed-phase high-performance liquid chromatography. Non-compartmental PK analyses were performed, followed by Monte Carlo simulations (Oracle Crystal Ball®, 5,000 simulated patients) to estimate probability of target attainment (PTA) against common Gram-negative pathogens. The desired PD target for CPM was % time above MIC of unbound drug (%fT > MIC) ≥ 60%. Chi-squared and Mann–Whitney U tests were used for analysis.

Results

Seventeen patients were enrolled and most (94%) received CPM 2 g q8h. A significant difference in actual body weight and body mass index was observed (P < 0.001). There were no differences in other baseline or PK characteristics between the two groups. Utilizing CPM 2 g q8h, PTA ≥ 90% was not observed for organisms with an MIC of 8 μg/mL, the current CLSI breakpoint for P. aeruginosa and A. baumannii (PTA = 88% vs. 81% in NO and O groups, respectively). With a 6 g continuous infusion (CI), however, ≥ 90% PTA was achieved in both groups (PTA = 100%) for organisms with an MIC of 8 μg/mL, while a regimen of 2 g q8h (infused over 3 hours [EI]) also provided PTA of ≥ 90% in both groups (PTA = 98% vs. 92% in NO and O groups, respectively). Goal PTA was not obtained in either group for organisms with an MIC of 4 μg/mL with CPM 1 g q8h or 2 g q12h (i.e., CLSI recommended dosing for organisms with MICs of 4 μg/mL).

Conclusion

Optimizing PK/PD parameters through novel dosing strategies are essential in both the NO and O populations for optimal CPM exposure in susceptible pathogens with higher MICs. CPM 6 grams/day by either CI or EI provides more optimal PK/PD characteristics in obese patients for pathogens with MICs at or near the current CLSI-recommended breakpoint.

Disclosures

All authors: No reported disclosures.

Oral Vancomycin Prophylaxis as Secondary Prevention Against Clostridioides difficile Infection in the Hematopoietic Stem Cell Transplantation and Hematologic Malignancy Population

Clostridioides difficile infection (CDI) is a common complication in the hematopoietic stem cell transplantation (HSCT) and hematologic malignancy (HM) population. CDI is associated with increased hospital length of stay, health care and societal costs, morbidity, and mortality. Identifying strategies for secondary prevention of CDI is of extreme importance in the HSCT/HM population. In this study, our primary objective was to evaluate the effectiveness and safety of an oral vancomycin prophylaxis (OVP) protocol for secondary prevention of CDI in a retrospective cohort of adult autologous/allogeneic HSCT recipients and patients with HM who did not undergo HSCT with a first CDI episode treated with concomitant broad-spectrum antibiotics (BSA). Patients were diagnosed and treated for CDI as inpatients and/or outpatients and were divided into 2 groups based on a preprotocol versus postprotocol analysis: the OVP group, comprising patients who received planned monotherapy with oral vancomycin 125 mg every 6 hours for 14 days for a first episode of CDI and subsequently received OVP posttreatment and a no OVP (NOVP) group, comprising patients who received planned monotherapy with oral vancomycin 125 mg every 6 hours for 14 days for a first episode of CDI and subsequently did not receive OVP posttreatment. OVP was defined as vancomycin 125 mg every 12 hours for up to 7 days after BSA discontinuation. The primary endpoint was recurrent CDI (rCDI), defined as symptoms of loose stools/diarrhea with high clinical suspicion for CDI prompting empiric therapy within 60 days of completion of treatment/prophylaxis for the first CDI episode. The incidence of vancomycin-resistant enterococcal (VRE) infection and 60-day mortality were also compared between the 2 groups. Multivariate logistic regression was created from associated variables to identify independent associations with rCDI. A total of 50 patients were included, 21 in the OVP group (42%) and 29 in the NOVP group (58%). The mean patient age was 58 years, and the cohort was 60% male and 86% Caucasian. HSCT was performed in 60% of the patients, and 76% of CDI cases were diagnosed during hospitalization. The rate of rCDI was significantly lower in the OVP group compared with the NOVP group (5% [1 of 21] versus 35% [10 of 29]; P= .016), with no subsequent increase in VRE infection rate (14% [3 of 21] versus 10% [3 of 29]; P = .686). By multivariable logistic regression, rCDI was inversely associated with OVP (odds ratio [OR], .14; 95% confidence interval [CI], .007 to .994; P = .049) and directly associated with outpatient CDI diagnosis (OR, 8.72; 95% CI, 1.816 to 49.158; P = .007). No between-group differences were found in 60-day mortality (10% [2 of 21] for OVP versus 7% [2 of 29] for NOVP; P > 0.999). OVP appears to be safe and effective for secondary prevention of CDI in the HSCT/HM population. Prospective trials are needed to validate the effectiveness of OVP in this vulnerable population to prevent rCDI.

Long-Acting Lipoglycopeptides: "Lineless Antibiotics" for Serious Infections in Persons Who Use Drugs

Background

Injection drug use is associated with serious infections. Due to challenges with medical management of addiction, relapses and additional infections are common. Persons who use drugs (PWUD) are more likely to leave against medical advice before completing treatment, which could result in treatment failure. Prolonged intravenous (IV) antimicrobial therapy in PWUD may be complicated by concern for IV catheter misuse, sometimes requiring prolonged hospitalization. Ideal alternatives would provide the following: (1) high success rate; (2) reduced rate of medical complications; (3) improved safety profiles; and (4) improved cost-effectiveness. Long-acting lipoglycopeptides present such opportunity for treatment of serious Gram-positive infections.

Methods

We performed a system-wide, retrospective analysis of adults admitted to University of Colorado Health from September 2015 to June 2018 and treated with dalbavancin or oritavancin based on clinical judgment of their treating physicians.

Results

Fifty-six patients met inclusion criteria (17 PWUD vs 39 non-PWUD). The PWUD group were younger, healthier by Charlson comorbidity index, more likely insured by Medicaid, and admitted for conditions requiring longer treatment. Ten patients were lost to follow-up. Of the patients with follow-up, clinical failure was met in 1 PWUD patient (6%) and 6 non-PWUD patients (15%) (P = .413). The median hospital length-of-stay reduction was 20 days (interquartile range [IQR], 10–30 days) in PWUD vs 11 days (IQR, 9–14 days) in non-PWUD; P = .133. Estimated median savings were $40 455.08 (IQR, $20 900.00–$62 700.00) in PWUD vs $19 555.08 (IQR, $15 375.08–$23 735.08) in non-PWUD; P = .065.

Conclusions

Long-acting lipoglycopeptides may be equally effective as standard-of-care, present a safety advantage, and secure earlier discharge and significant cost-savings.

MetaUniDec: High-Throughput Deconvolution of Native Mass Spectra

The expansion of native mass spectrometry (MS) methods for both academic and industrial applications has created a substantial need for analysis of large native MS datasets. Existing software tools are poorly suited for high-throughput deconvolution of native electrospray mass spectra from intact proteins and protein complexes. The UniDec Bayesian deconvolution algorithm is uniquely well suited for high-throughput analysis due to its speed and robustness but was previously tailored towards individual spectra. Here, we optimized UniDec for deconvolution, analysis, and visualization of large data sets. This new module, MetaUniDec, centers around a hierarchical data format 5 (HDF5) format for storing datasets that significantly improves speed, portability, and file size. It also includes code optimizations to improve speed and a new graphical user interface for visualization, interaction, and analysis of data. To demonstrate the utility of MetaUniDec, we applied the software to analyze automated collision voltage ramps with a small bacterial heme protein and large lipoprotein nanodiscs. Upon increasing collisional activation, bacterial heme-nitric oxide/oxygen binding (H-NOX) protein shows a discrete loss of bound heme, and nanodiscs show a continuous loss of lipids and charge. By using MetaUniDec to track changes in peak area or mass as a function of collision voltage, we explore the energetic profile of collisional activation in an ultra-high mass range Orbitrap mass spectrometer. Graphical abstract ᅟ.

Comparing Surfactant Penetration into Human Skin and Resulting Skin Dryness Using In Vivo and Ex Vivo Methods

Numerous tests have been developed to estimate a surfactant's mildness in rinse-off formulations. In this study, mixed surfactant systems were examined for their impact on surfactant penetration into the skin and skin hydration using in vivo and ex vivo methods. A forearm controlled application test (FCAT) was conducted, and skin hydration was evaluated using corneometry and visual dryness grading. Tape strip and cup scrub extractions were completed within the FCAT to examine the penetration of five individual surfactants into the skin in vivo. The ratio of surfactant mass extracted by five pooled tape strips to surfactant mass extracted by cup scrubs was found to be in the range of 40-59%. Furthermore, cup scrub collection and analysis was less time-consuming and less expensive to conduct than tape stripping. Thus, we recommend cup scrub extraction as a suitable substitute for tape stripping in future surfactant skin penetration analyses. In vivo results were compared with ex vivo ¹⁴C-sodium dodecyl sulfate (¹⁴C-SDS) penetration into human cadaver skin from the same surfactant systems. In vivo measurements conducted in the FCAT, including corneometer reading, visual dryness score, and individual surfactant (sodium laureth (1) ether sulfate and cocamidopropyl betaine) extracted from the skin, were found to correlate well with ¹⁴C-SDS penetration into the skin ex vivo for anion-based surfactant systems. Thus, ¹⁴C-SDS skin penetration may be a useful preclinical test for skin dryness induced by rinse-off products containing anionic surfactants.

Applications of Immunopharmacogenomics: Predicting, Preventing, and Understanding Immune-Mediated Adverse Drug Reactions

Adverse drug reactions (ADRs) are a significant health care burden. Immune-mediated adverse drug reactions (IM-ADRs) are responsible for one-fifth of ADRs but contribute a disproportionately high amount of that burden due to their severity. Variation in human leukocyte antigen ( HLA) genes has emerged as a potential preprescription screening strategy for the prevention of previously unpredictable IM-ADRs. Immunopharmacogenomics combines the disciplines of immunogenomics and pharmacogenomics and focuses on the effects of immune-specific variation on drug disposition and IM-ADRs. In this review, we present the latest evidence for HLA associations with IM-ADRs, ongoing research into biological mechanisms of IM-ADRs, and the translation of clinical actionable biomarkers for IM-ADRs, with a focus on T cell-mediated ADRs.

A comparison of safety and outcomes with cefazolin versus nafcillin for methicillin-susceptible Staphylococcus aureus bloodstream infections

BACKGROUND

Methicillin-susceptible Staphylococcus aureus (MSSA) is a frequent cause of bloodstream infections (BSI). Treatment with nafcillin (NAF) has been preferred to cefazolin (CFZ). However, comparable outcomes have been found with CFZ with possibly lower risk for side-effects. This study compared safety and effectiveness of NAF versus CFZ for MSSA BSI.

METHODS

This single center retrospective study evaluated adults admitted with MSSA BSI who received NAF or CFZ. Patients receiving ≥24 h of antibiotics were included for safety analyses. Patients receiving NAF or CFZ for ≥75% of a 14 day minimum treatment course were assessed for clinical effectiveness. The primary safety outcome was incidence of renal toxicity with multiple secondary safety endpoints. Clinical success was defined as symptom resolution, repeat negative cultures, lack of additional therapy for presumed failure, and lack of recurrence within 30 days.

RESULTS

A total of 130 patients receiving NAF (n = 79) or CFZ (n = 51) were included for safety analysis. Of those, 90 met criteria for effectiveness assessment (NAF n = 40, CFZ n = 50). Baseline characteristics were well matched. NAF was associated with a higher incidence of nephrotoxicity compared to CFZ (25% vs. 2%, RR 1.31, 95% CI 1.15-1.5, p < 0.001), allergic reactions (p = 0.01) and a trend for hepatotoxicity (p = 0.08). Clinical success was achieved in 82% NAF and 94% CFZ treated patients (p = 0.1).

CONCLUSION

CFZ was associated with less nephrotoxicity and no difference in clinical success compared to NAF for MSSA BSI. A prospective study comparing NAF to CFZ for MSSA BSI should be conducted to elucidate differences in therapies.

Abrupt cloud clearing of marine stratocumulus in the subtropical southeast Atlantic

We document rapid and abrupt clearings of large portions of the subtropical marine low cloud deck that have implications for the global radiation balance and climate sensitivity. Over the southeast Atlantic, large areas of stratocumulus are quickly eroded, yielding partial or complete clearing along sharp transitions hundreds to thousands of kilometers in length that move westward at 8 to 12 meters per second and travel as far as 1000+ kilometers from the African coast. The westward-moving cloudiness reductions have an annual peak in occurrence in the period from April through June. The cloud erosion boundaries reduce cloud at ≈10-kilometer scale in less than 15 minutes, move approximately perpendicular to the mean flow, and are often accompanied by small-scale wave features. Observations suggest that the cloud erosion is caused by atmospheric gravity waves.

The Lupus Inhibitor: A Study of Its Heterogeneity

The plasmas of six patients with prolonged activated partial thromboplastin times were studied in detail. In five of the six, the Russell’s viper venom and prothrombin times were likewise prolonged. Five of the patients had documented systemic lupus erythematosus; one lacked the necessary criteria for this diagnosis. On quantitation, factor XI was decreased in all six; factors X and XII were diminished in five of the six. When tested for inhibitory activity, plasma from each of the patients prolonged the celite eluate inhibition test for factor XII and/or XI inhibition. In the formation of the Xa-V-phospholipid-Ca2+ complex (prothrombinase), factors X and Xa were inhibited to a greater degree than factor V or the phospholipid. Finally, each plasma was isofocused, the inhibitory fractions were identified and the clotting factor specificity of each inhibitory peak was determined.Fractions inhibitory against factors XI and XII isofocused with the IgG in each patient’s plasma. Based on the data presented from these six patients, the “lupus inhibitor” is in fact a heterogeneous collection of inhibitors directed against factors XII, XI and X rather than a homogeneous entity.

Antigen-specific interferon-gamma release is decreased following the single intradermal comparative cervical skin test in African buffaloes (Syncerus caffer)

Effective disease management of wildlife relies on the strategic application of ante-mortem diagnostic tests for early identification and removal of M. bovis-infected animals. To improve diagnostic performance, interferon-gamma release assays (IGRAs) are often used in conjunction with the tuberculin skin test (TST). Since buffaloes are major maintenance hosts of M. bovis, optimal application of bovine TB diagnostic tests are especially important. We aimed to determine whether the timing of blood collection relative to the TST has an influence on IFN-γ production and diagnostic outcome in African buffaloes. Release of IFN-γ in response to bovine purified protein derivative (PPD), avian PPD and PC-HP^® and PC-EC^® peptides was measured by Bovigam^® and an in-house IGRA in a group of Bovigam^®-positive and - negative buffaloes at the time the TST was performed and three days later. There was significantly lower IFN-γ release in response to these antigens post-TST in Bovigam^®-positive buffaloes, but no significant changes in Bovigam^®-negative buffaloes. Also, a significantly greater proportion of buffaloes were Bovigam^®-positive prior to the TST than three days later. We therefore recommend that blood samples for use in IGRAs be collected prior to or at the time the TST is performed to facilitate the correct identification of greater numbers of IGRA-positive buffaloes.

Seroprevalence of Mycobacterium bovis infection in warthogs (Phacochoerus africanus) in bovine tuberculosis-endemic regions of South Africa

Bovine tuberculosis (bTB), caused by Mycobacterium bovis (M. bovis), has been reported in many species including suids. Wild boar are important maintenance hosts of the infection with other suids, that is domestic and feral pigs, being important spillover hosts in the Eurasian ecosystem and in South Africa, warthogs (Phacochoerus africanus) may play a similar role in M. bovis-endemic areas. However, novel diagnostic tests for warthogs are required to investigate the epidemiology of bTB in this species. Recent studies have demonstrated that serological assays are capable of discriminating between M. bovis-infected and uninfected warthogs (Roos et al., ). In this study, an indirect ELISA utilizing M. bovis purified protein derivative (PPD) as a test antigen was used to measure the prevalence and investigate risk factors associated with infection in warthogs from uMhkuze Nature Reserve and the southern region of the Greater Kruger National Park (GKNP). There was a high overall seroprevalence of 38%, with adult warthogs having a higher risk of infection (46%). Seroprevalence also varied by geographic location with warthogs from Marloth Park in the GKNP having the greatest percentage of positive animals (63%). This study indicates that warthogs in M. bovis-endemic areas are at high risk of becoming infected with mycobacteria. Warthogs might present an under-recognized disease threat in multi-species systems. They might also serve as convenient sentinels for M. bovis in endemic areas. These findings highlight the importance of epidemiological studies in wildlife to understand the role each species plays in disease ecology.

Stability of the Syndesmosis After Posterior Malleolar Fracture Fixation

BACKGROUND

We sought to define the rate of syndesmotic instability after anatomic reduction of the posterior malleolus when posterior stabilization of a trimalleolar or trimalleolar equivalent ankle fracture was chosen vs when a supine position and initially conservative management of the posterior elements was chosen.

METHODS

The types of syndesmotic and posterior malleolar fixation used to treat adult patients with ankle fractures involving the posterior malleolus at our level I trauma center were retrospectively assessed (N = 198). Specifically, both bimalleolar and trimalleolar fractures were included. Exclusion criteria included pilon fractures, trimalleolar fractures with Chaput fragments, and neurologic injury. Demographics, fracture classification, initial operative position, medial clear space, and posterior malleolar fragment size were recorded for each fracture.

RESULTS

In total, 151 patients (76.3%) were initially positioned supine, 27.2% of whom had syndesmotic instability requiring operative stabilization. Almost 25% of supine patients also underwent posterior malleolar stabilization for posterior instability. Overall, 73 (48.3%) patients who were initially treated in the supine position needed some form of additional stabilization. Forty-seven patients (23.7%) were initially positioned prone. Syndesmotic stability was restored in 97.9% of these patients. This 2.1% rate of instability vastly differs from the 13-fold higher syndesmotic instability rate observed in the supine group ( P < .001).

CONCLUSION

Our data demonstrate that the rate of syndesmotic instability was reduced in trimalleolar and trimalleolar equivalent fractures when prone positioning and direct fixation of the posterior malleolus were first performed. Using traditional preoperative estimates of posterior stability to determine the need for posterior malleolar fixation may be inadequate since almost a quarter of patients treated supine received posterior stabilization.

LEVEL OF EVIDENCE

Level III, retrospective comparative series.

Tuberculosis serosurveillance and management practices of captive African elephants (Loxodonta africana) in the Kavango-Zambezi Transfrontier Conservation Area

Transfrontier conservation areas represent an international effort to encourage conservation and sustainable development. Their success faces a number of challenges, including disease management in wildlife, livestock and humans. Tuberculosis (TB) affects humans and a multitude of non-human animal species and is of particular concern in sub-Saharan Africa. The Kavango-Zambezi Transfrontier Conservation Area encompasses five countries, including Zimbabwe, and is home to the largest contiguous population of free-ranging elephants in Africa. Elephants are known to be susceptible to TB; thus, understanding TB status, exposure and transmission risks to and from elephants in this area is of interest for both conservation and human health. To assess risk factors for TB seroprevalence, a questionnaire was used to collect data regarding elephant management at four ecotourism facilities offering elephant-back tourist rides in the Victoria Falls area of Zimbabwe. Thirty-five working African elephants were screened for Mycobacterium tuberculosis complex antibodies using the ElephantTB Stat-Pak and the DPP VetTB Assay for elephants. Six of 35 elephants (17.1%) were seropositive. The risk factor most important for seropositive status was time in captivity. This is the first study to assess TB seroprevalence and risk factors in working African elephants in their home range. Our findings will provide a foundation to develop guidelines to protect the health of captive and free-ranging elephants in the southern African context, as well as elephant handlers through simple interventions. Minimizing exposure through shared feed with other wildlife, routine TB testing of elephant handlers and regular serological screening of elephants are recommended as preventive measures.