Sequential Treatment Failure With Aztreonam-Ceftazidime-Avibactam Followed by Cefiderocol Due to Preexisting and Acquired Mechanisms in a New Delhi Metallo-β-lactamase-Producing Escherichia coli Causing Fatal Bloodstream Infection

We report a fatal case of New Delhi metallo-β-lactamase (NDM)-producing Escherichia coli in a bacteremic patient with sequential failure of aztreonam plus ceftazidime-avibactam followed by cefiderocol. Acquired resistance was documented phenotypically and mediated through preexisting and acquired mutations. This case highlights the need to rethink optimal treatment for NDM-producing organisms.

Informing Building Strategies to Reduce Infectious Aerosol Transmission Risk by Integrating DNA Aerosol Tracers with Quantitative Microbial Risk Assessment

Using aerosol-based tracers to estimate risk of infectious aerosol transmission aids in the design of buildings with adequate protection against aerosol transmissible pathogens, such as SARS-CoV-2 and influenza. We propose a method for scaling a SARS-CoV-2 bulk aerosol quantitative microbial risk assessment (QMRA) model for impulse emissions, coughing or sneezing, with aerosolized synthetic DNA tracer concentration measurements. With point-of-emission ratios describing relationships between tracer and respiratory aerosol emission characteristics (i.e., volume and RNA or DNA concentrations) and accounting for aerosolized pathogen loss of infectivity over time, we scale the inhaled pathogen dose and risk of infection with time-integrated tracer concentrations measured with a filter sampler. This tracer-scaled QMRA model is evaluated through scenario testing, comparing the impact of ventilation, occupancy, masking, and layering interventions on infection risk. We apply the tracer-scaled QMRA model to measurement data from an ambulatory care room to estimate the risk reduction resulting from HEPA air cleaner operation. Using DNA tracer measurements to scale a bulk aerosol QMRA model is a relatively simple method of estimating risk in buildings and can be applied to understand the impact of risk mitigation efforts.

Use of biomarkers to individualize antimicrobial therapy duration: a narrative review

BACKGROUND

Reducing the overuse of antimicrobials is imperative for the sake of minimizing antimicrobial-associated adverse effects, optimizing resource utilization, and curtailing the rise in multidrug-resistant organisms. Biomarkers reflect the host responses to infection and may assist with minimizing unnecessary antimicrobial usage.

OBJECTIVES

To review the literature pertaining to the performance of biomarkers specifically used to guide the duration of antimicrobial therapy (AMT).

SOURCES

Randomized controlled trials, observational studies, and meta-analyses assessing biomarker-guided approaches to AMT decision-making and their impact on the duration of therapy were reviewed.

CONTENT

Several randomized controlled trials and real-world observational studies have shown that a procalcitonin (PCT)-guided strategy can help clinicians individualize the duration of AMT, particularly among non-critically ill patients hospitalized with suspected respiratory tract infections when using a PCT cut-off value of <0.25 μg/L and critically ill patients with respiratory tract infections or undifferentiated sepsis when using a PCT cut-off value of <0.5 μg/L or ≥80% decline in the peak level. C-reactive protein is a non-specific marker of inflammation that may also assist with an early discontinuation of AMT; however, data are limited. Haematological biomarkers are prone to variance between individuals and are often influenced by medications and non-infectious conditions, making them less reliable for the purposes of AMT decision-making. Novel biomarkers such as multi-protein signatures and host gene expression tests have shown promise as tools to better differentiate between bacterial and non-bacterial infections; clinical studies are needed to determine whether they can be used to help optimize the duration of AMT.

IMPLICATIONS

Studies have demonstrated that a PCT-guided strategy, when utilized appropriately, can help guide clinicians to individualize and often reduce the duration of AMT, especially in patients hospitalized with respiratory tract infections and those admitted to the intensive care unit with suspected respiratory tract infections or sepsis. The impact of utilizing other biomarkers is less clear and requires further study.

1863. Treatment and Outcomes of Cefoxitin-Non-Susceptible Serratia marcescens, Klebsiella aerogenes, Citrobacter freundii, Enterobacter cloacae, and Morganella morganii Bacteremia with Piperacillin/Tazobactam Versus Cefepime or Carbapenem in Immunocompromised Patients

Background

A recent guidance suggested “caution if prescribing piperacillin-tazobactam for serious infections caused by organisms at high risk of significant AmpC production” and that the preferred antibiotic choice should be either cefepime or a carbapenem, despite an admitted lack of definitive evidence. Examination of this question in immunocompromised patients may provide such evidence.

Methods

This was a retrospective, single-center study conducted from January 2016 to December 2021. We included immunocompromised patients aged 18 years or older who had a laboratory confirmed blood culture positive for Enterobacterales showing non-susceptibility to cefoxitin and were definitively treated with piperacillin-tazobactam, cefepime, or a carbapenem. The primary endpoint was a composite of clinical or microbiological failure, which was comprised of in-hospital 30-day mortality, white blood count &gt;12 x 109/L or temperature &gt;38°C on days 5-7, microbiological failure on days 3-5, or microbiological recurrence/relapse on days 5-30.

Results

We identified 81 patients who were included for analysis. Baseline characteristics between arms were similar between groups except for more frequent severe neutropenia (p=0.010) and higher Pitt bacteremia scores (p=0.042) in the cefepime/carbapenem group. Within the piperacillin/tazobactam arm, 17 of 35 (48.6%) had clinical or microbiological failure, compared to 17 of 46 (37.0%) patients in the carbapenem/cefepime arm (p=0.294). Microbiological failure occurred in 4 of 35 (11.4%) patients treated with piperacillin/tazobactam compared to 0 of 46 (0%) patients treated with a carbapenem/cefepime (p=0.019). In multivariate analysis, patients treated with a carbapenem/cefepime had a 69% lower odds of clinical or microbiological failure compared to those treated with piperacillin/tazobactam (OR = 0.31; 95% confidence interval, 0.10-0.98).

Conclusion

In immunocompromised patients with bacteremia due to cefoxitin-non-susceptible Serratia marcescens, Klebsiella aerogenes, Citrobacter freundii, Enterobacter cloacae, or Morganella morganii, definitive treatment with piperacillin/tazobactam was associated with a higher likelihood of microbiological failure compared with treatment with a carbapenem or cefepime.

Disclosures

All Authors: No reported disclosures.

Coccidioidal Peritonitis: A Review of 17 cases

Coccidioidomycosis is the second most common endemic fungal infection in the United States. Prior descriptions of coccidioidal peritonitis include only single cases. We describe 17 new cases previously unreported from healthcare institutions in California. The majority of cases presented with nonspecific abdominal complaints. PubMed and Google Scholar were searched for additional case series and only single case reports and reviews of single cases were found.

The diagnosis was confirmed by culture or histopathology and/or serology in each patient. All patients were treated with anti-fungal therapy. This case series demonstrates that coccidioidal peritonitis may be asymptomatic or present with only subtle abdominal symptoms. In a minority of our patients, the diagnosis was established incidentally during surgery. Based on this series, the overall outcome of coccidioidal peritonitis is favorable with long-term triazole treatment. The term cure is not usually used in disseminated coccidioidal disease because of the risk of late relapse.

Effect of rapid methicillin-resistant Staphylococcus aureus nasal polymerase chain reaction screening on vancomycin use in the intensive care unit

PURPOSE

To determine the impact of a pharmacist-driven methicillin-resistant Staphylococcus aureus (MRSA) nasal polymerase chain reaction (PCR) screen on vancomycin duration in critically ill patients with suspected pneumonia.

METHODS

This was a retrospective, quasi-experimental study at a 613-bed academic medical center with 67 intensive care beds. Adult patients admitted to the intensive care unit (ICU) between 2017 and 2019 for 24 hours or longer and empirically started on intravenous vancomycin for pneumonia were included. The primary intervention was the implementation of a MRSA nasal PCR screen protocol. The primary outcome was duration of empiric vancomycin therapy. Secondary outcomes included the rate of acute kidney injury (AKI), the number of vancomycin levels obtained, the rate of resumption of vancomycin for treatment of pneumonia, ICU length of stay, hospital length of stay, the rate of ICU readmission, and the rate of in-hospital mortality.

RESULTS

A total of 418 patients were included in the final analysis. The median vancomycin duration was 2.59 days in the preprotocol group and 1.44 days in the postprotocol group, a reduction of approximately 1.00 day (P < 0.01). There were significantly fewer vancomycin levels measured in the postprotocol group than in the preprotocol group. Secondary outcomes were similar between the 2 groups, except that there was lower AKI and fewer vancomycin levels obtained in the postprotocol group (despite implementation of area under the curve-based vancomycin dosing) as compared to the preprotocol group.

CONCLUSION

The implementation of a pharmacist-driven MRSA nasal PCR screen was associated with a decrease in vancomycin duration and the number of vancomycin levels obtained in critically ill patients with suspected pneumonia.

Plasma Microbial Cell-free DNA Next Generation Sequencing in the Diagnosis and Management of Febrile Neutropenia

Background

Standard testing fails to identify a pathogen in most patients with febrile neutropenia (FN). We evaluated the ability of the Karius microbial cell-free DNA sequencing test (KT) to identify infectious etiologies of FN and its impact on antimicrobial management.

Methods

This prospective study (ClinicalTrials.gov; NCT02912117) enrolled and analyzed 55 patients with FN. Up to 5 blood samples were collected per subject within 24 hours of fever onset (T1) and every 2 to 3 days. KT results were compared with blood culture (BC) and standard microbiological testing (SMT) results.

Results

Positive agreement was defined as KT identification of ≥1 isolate also detected by BC. At T1, positive and negative agreement were 90% (9/10) and 31% (14/45), respectively; 61% of KT detections were polymicrobial. Clinical adjudication by 3 independent infectious diseases specialists categorized Karius results as: unlikely to cause FN (N = 0); definite (N = 12): KT identified ≥1 organism also found by SMT within 7 days; probable (N = 19): KT result was compatible with a clinical diagnosis; possible (N = 10): KT result was consistent with infection but not considered a common cause of FN. Definite, probable, and possible cases were deemed true positives. Following adjudication, KT sensitivity and specificity were 85% (41/48) and 100% (14/14), respectively. Calculated time to diagnosis was generally shorter with KT (87%). Adjudicators determined real-time KT results could have allowed early optimization of antimicrobials in 47% of patients, by addition of antibacterials (20%) (mostly against anaerobes [12.7%]), antivirals (14.5%), and/or antifungals (3.6%); and antimicrobial narrowing in 27.3% of cases.

Clinical Trials Registration

NCT02912117

Conclusion

KT shows promise in the diagnosis and treatment optimization of FN.

Discontinuation Patterns and Cost Avoidance of a Pharmacist-Driven Methicillin-Resistant Staphylococcus aureus Nasal Polymerase Chain Reaction Testing Protocol for De-escalation of Empiric Vancomycin for Suspected Pneumonia

A pharmacist-driven methicillin-resistant Staphylococcus aureus (MRSA) nasal polymerase chain reaction (PCR)-based testing protocol with a 70% acceptance rate for vancomycin discontinuation within 24 hours of negative results significantly reduced unnecessary vancomycin use with an estimated cost avoidance of $40 per vancomycin course. We found high concordance (141 of 147, 96%) of culture-based versus PCR-based MRSA nasal screening.

Reactivation of Chagas Disease in a Patient With an Autoimmune Rheumatic Disease: Case Report and Review of the Literature

Reactivation of Chagas disease has been described in immunosuppressed patients, but there is a paucity of literature describing reactivation in patients on immunosuppressive therapies for the treatment of autoimmune rheumatic diseases. We describe a case of Chagas disease reactivation in a woman taking azathioprine and prednisone for limited cutaneous systemic sclerosis (lcSSc). Reactivation manifested as indurated and erythematous cutaneous nodules. Sequencing of a skin biopsy specimen confirmed the diagnosis of Chagas disease. She was treated with benznidazole with clinical improvement in the cutaneous lesions. However, her clinical course was complicated and included disseminated CMV disease and subsequent septic shock due to bacteremia. Our case and review of the literature highlight that screening for Chagas disease should be strongly considered for patients who will undergo immunosuppression for treatment of autoimmune disease if epidemiologically indicated.

1489. Safety and Performance of a Pharmacist-Driven Nasal MRSA PCR Protocol for De-escalation of Empiric Vancomycin for Suspected Pneumonia at an Academic Medical Center

Background

Limited published data supports the de-escalation of empiric anti-methicillin resistant Staphylococcus aureus (MRSA) antibiotics for suspected pneumonia upon negative nasal MRSA screening. Besides limited sample sizes, special populations, such as those who are immunocompromised and/or critically ill, have been underrepresented in these reports. We describe real-world efficacy and safety of a pharmacist-driven nasal MRSA PCR testing protocol implemented at Stanford Health Care in May 2018 across a diverse patient population.

Methods

This was an observational cohort study of adult patients who received vancomycin for empiric pneumonia before (PRE) vs after (POST) implementation of a pharmacist-driven nasal MRSA PCR testing protocol (between 05/01/2017 - 08/31/2017 (PRE) and 5/7/2018 - 12/31/2019 (POST). The primary outcome measure was duration of vancomycin administration. Secondary outcomes included time to vancomycin discontinuation, frequency of restarting vancomycin for empiric pneumonia within 7 days, acute kidney injury (defined as “risk” by RIFLE criteria), and MRSA respiratory cultures. Statistical methods are described in Figure A.

Figure A. Statistical methods

Results

Total of 610 patients were included in this study with 116 in the PRE group and 494 in the POST group. Over 40% were critically ill and approximately 37% were immunocompromised in both groups (Table 1). For the primary outcome, median vancomycin duration was significantly shorter in the POST group (1.29 days; 95% CI 1.13-1.45) vs. PRE group (1.98 days; 95% CI 1.49-2.46) (p < 0.0005), a 34.8% reduction (Figure 1). Median vancomycin duration was lower in patients with a negative vs positive nasal MRSA PCR (1.20 days [95% CI 1.08-1.33] vs 2.53 days [95% CI 1.77-3.29], p < 0.0005), a 52.6% reduction (Figure 2). MRSA was recovered in respiratory cultures in 1.7% vs 1.4% in the PRE vs POST groups. One (0.002%) patient had a negative nasal MRSA PCR but culture-confirmed MRSA pneumonia and recovered after completing a treatment course. Secondary safety outcomes were similar between groups (Table 2).

Tables 1 and 2: Baseline Characteristics and Secondary Outcomes

Figure 1. Primary Outcome: Kaplan–Meier Estimates of Cumulative Active Vancomycin Therapy Before and After Implementation of Nasal MRSA PCR protocol

Figure 2. Secondary Outcome: Figure 2. Kaplan–Meier Estimates of Cumulative Active Vancomycin Therapy in Patients with Negative vs Positive Nasal MRSA PCR

Conclusion

Pharmacist-driven nasal MRSA PCR testing is effective and safe in early de-escalation of empiric vancomycin used for pneumonia treatment in a diverse population including critically ill and immunocompromised patients.

Disclosures

All Authors: No reported disclosures

Bacteremia due to Methicillin-Resistant Staphylococcus aureus: An Update on New Therapeutic Approaches

Vancomycin and daptomycin are options for the initial treatment of patients with methicillin-resistant Staphylococcus aureus (MRSA) bacteremia. Treatment options for persistent MRSA bacteremia or bacteremia due to vancomycin-intermediate or vancomycin-resistant strains include daptomycin, ceftaroline, and combination therapies. There is a critical need for high-level evidence from clinical trials to allow optimally informed decisions in the treatment of MRSA bacteremia.

Omadacycline: A Novel Tetracycline Derivative With Oral and Intravenous Formulations

Omadacycline, an aminomethylcycline, is a novel member of the tetracycline class of antibiotics. It has received approval by the US Food and Drug Administration for the treatment of community-acquired bacterial pneumonia and acute bacterial skin and skin structure infections, and is available in both oral and intravenous formulations. It is also being evaluated in clinical trials for the treatment of cystitis and pyelonephritis. The omadacycline molecule was designed to overcome tetracycline resistance and has broad-spectrum activity that includes gram-positive bacteria, gram-negative bacteria, anaerobes, atypicals, and other drug-resistant strains, like methicillin-resistant Staphylococcus aureus, as well as Yersinia pestis and Bacillus anthracis, organisms of biodefense interest. Omadacycline has minimal drug-drug pharmacokinetic interactions and a favorable safety profile, with the most common adverse events being gastrointestinal symptoms.

Building antimicrobial stewardship through massive open online courses: a pilot study in Macedonia

Background

The global struggle against antibiotic resistance requires antimicrobial stewardship (AMS). Massive open online courses (MOOCs) offer health professionals unprecedented access to high-quality instructional material on AMS; the question is how apprehensible it is to non-native English speakers. Furthermore, to better understand how education interventions promote change towards rational antibiotic prescribing, leading institutions call for studies integrating behavioural science. Research from lower- and middle-income countries is particularly needed.

Objectives

To measure the knowledge improvement from an AMS MOOC, the influence of language, course satisfaction and subsequent effect on intention to change antibiotic prescribing behaviour.

Methods

Fifty-five physicians from Macedonia completed the MOOC. Pre- and post-course knowledge test scores were compared using a one-sample t-test. The effect of a language barrier was assessed using self-reported English level. Scores were compared with participants’ intention to change behaviour in clinical practice.

Results

Scores significantly improved from 77.8% to 82.2%. Participants with a higher English level improved most, while the low-level group showed no significant improvement. Physicians reported a high or very high intention to change behaviour. This was independent of knowledge improvements.

Conclusions

First, lower self-reported English proficiency hindered knowledge acquisition from a MOOC platform. AMS programmes should commit to bridge this barrier so as to enable a global spread of education in AMS. Second, factors underlying the physicians’ intentions to engage in AMS appear to be more complex than simple knowledge improvements. This suggests that less time-consuming interventions could be as effective.

Application of pharmacoeconomics to formulary management in a health system setting

PURPOSE

A novel value-based approach to evaluate costly specialty drugs for formulary addition was developed.

SUMMARY

In February 2016, Stanford Health Care launched the specialty drug subcommittee (SDSC), a subcommittee of the pharmacy and therapeutics committee, responsible for the formulary review of specialty pharmaceuticals. A process was developed for value-based review that includes not only consideration of clinical trial data and institutional acquisition costs but also internal patient outcomes and a cost-effectiveness model using internal financial data. A Markov model was developed to assess the value of trabectedin, which was approved for formulary addition in April 2016, relative to the addition of dacarbazine. The economic model and internal patient outcome analysis were presented to the prescribing oncologist and the SDSC for review. Internal data revealed that fewer patients than had been estimated received trabectedin, with outcomes significantly worse than those observed in the clinical trial leading to Food and Drug Administration approval. In the cost-effectiveness model, trabectedin had higher costs and poorer outcomes compared with dacarbazine. Based on the economic model, low utilization, and real-world outcomes, trabectedin was removed from formulary and a restrictive treatment pathway for nonformulary use, developed by the primary prescriber, was implemented. This process has since been applied to 11 more specialty drugs.

CONCLUSION

Internal cost-effectiveness models in combination with real-world patient outcomes data can be effective formulary management tools. Engagement and collaboration with the requesting provider are key to developing thoughtful treatment pathways.

2640. Aerosol vs. Oral Ribavirin for the Treatment of Community-Acquired Respiratory Virus Infections in Lung Transplant Recipients

Background

Community-acquired respiratory virus (CARV) infections are associated with an increased risk of chronic lung allograft dysfunction (CLAD) and graft loss in lung transplant recipients (LTR). Administration of ribavirin by aerosol was the standard of care at Stanford Health Care in the management of CARV infections. Given the sparse evidence of benefit with aerosol ribavirin (AR) and its increasing cost and teratogenic risk for exposed healthcare personnel, AR was restricted to the treatment of respiratory syncytial virus (RSV) in 2016 and was ultimately removed from formulary in 2017. Oral (PO) ribavirin was used at the discretion of the transplant team. The objective of this study was to evaluate the clinical outcomes of AR compared with PO ribavirin in lung transplant recipients.

Methods

We performed a retrospective cohort analysis of adult lung transplant recipients diagnosed with CARV (metapneumovirus, parainfluenza virus, and RSV) infections treated with either AR or PO ribavirin. The analysis included the first treatment course of ribavirin by either route and patients were excluded if they received ribavirin in the prior 12 months. The primary outcome was the development/progression of CLAD, acute organ rejection, and overall mortality.

Results

Of 85 patients, 41 received AR and 44 received PO ribavirin. There was no significant difference in the following clinical outcomes with AR and oral ribavirin, respectively: development or progression of CLAD (30 days: 9.7% vs. 4.5%, P = 0.4227; 90 days: 14.6% vs. 6.8%, P = 0.303; 6 months: 17% vs. 9%, P = 0.3413; 12 months: 24% vs. 15.9%, P = 0.4188), acute organ rejection (90 days: 7.3% vs. 4.5%, P = 0.6689; 6 months: 12.1% vs. 9%, P = 0.7329; 12 months: 19.5% vs. 13.6%, P = 0.5635), and overall mortality (30 days: 0% vs. 4.5%, P = 0.4947; 90 days: 7.3% vs. 4.5%, P = 0.6689; 6 months: 7.3% vs. 9%, P = 1.0; 12 months: 7.3% vs. 13.6%, P = 0.4858). There was no observable difference in reported adverse effects between AR and PO ribavirin.

Conclusion

Lung transplant recipients with CARV infections had similar outcomes when treated with AR or PO ribavirin. Oral ribavirin is a less costly treatment than AR, but the efficacy of ribavirin by any route remains questionable.

Disclosures

All authors: No reported disclosures.

210. Step-down from IV to oral therapy in patients with bacteremia due to Enterobacteriaceae: fluoroquinolones (FQ) vs. ß-lactams (BL) or trimethoprim-sulfamethoxazole (TMP-SMX)

Background

Methods

Results

Conclusion

Disclosures

1984. A Multi-Disciplinary Team-based Quality Improvement Initiative to Reduce Clostridioides difficile Rates and Promote Antimicrobial Stewardship in Targeted Surgical Wards

Background

At Stanford, two surgical wards, E3 and F3, were responsible for 1/5 of hospital-acquired Clostridioides difficile infection (HO CDI) cases in the fiscal year 2018 (FY2018). We used a quality improvement framework with a goal to reduce yearly HO CDI episodes by 1/2 on these wards.

Methods

A multidisciplinary quality improvement team was created with frontline nursing leaders and representatives from colorectal surgery, gynecology oncology, antimicrobial stewardship (ASP), infection prevention, and pharmacy. Coaching and instruction on quality improvement were provided as part of Stanford’s “Realizing Improvement through Team Empowerment” (RITE) program. Using A3 problem solving, root cause analysis identified key drivers, and interventions were performed. Cumulative HO CDI cases in FY2019 and weekly antibiotic days of therapy (DOT) on E3/F3 were monitored.

Results

Review of FY2018 HO CDI cases (n = 14) revealed the most common key driver as inappropriate antibiotic prescribing (8 cases, 57%). Multiple interventions were instituted (Figure 1). Three ASP interventions began February 2019: nursing questioned antibiotic choice/duration on daily interdisciplinary rounds (Figure 2), automatic infectious disease consultation for > 72 hours of piperacillin/tazobactam on gynecology/oncology patients, and twice-weekly rounds between ASP and a colorectal attending. Data from ASP/colorectal rounds from March 19, 2019 to April 16, 2019 showed means of 18.2 minutes taken for chart review and 4.4 minutes for discussion. 25 charts reviewed led to 16 (64%) ASP recommendations and 14/16 (87.5%) of recommendations accepted. Common interventions included: appropriate duration of antibiotics, clarification of the team’s planned duration, and review of microbiology data to narrow therapy. Mean DOT decreased from 35.28 to 21.61 (39%) since July 2018 (Figure 3). Patient volume and case mix index remained stable throughout, suggesting no impact on DOT. Though CDI cases did not decrease, interventions were in place for only 2 months (Figure 4).

Conclusion

While too early to determine its impact on HO CDI rates, a multi-disciplinary team approach utilizing A3 problem solving was successful in implementing effective ASP measures including nursing-led ASP and structured antibiotic timeouts.

Disclosures

All authors: No reported disclosures.

2532. Identifying Educational Needs and Improving Provider Knowledge Regarding the Management of Febrile Neutropenia

Background

In a retrospective chart review of 211 first episodes of febrile neutropenia (FN) in in-patients with acute myelogenous leukemia evaluating rates of appropriate vs. inappropriate management, we identified frequent noncompliance with national guidelines for the management of FN. We utilized these data to develop an educational intervention targeting front-line providers.

Methods

Based on findings from our chart review, we developed and implemented an interactive, case-based didactic session for advanced practice providers (APPs) and medical students/residents rotating on hematology, targeting inappropriate antibiotic use. Pretest questions were embedded into the lecture, preceding content related to each learning objective. Lecture material included content from national guidelines, literature addressing misconceptions (e.g., vancomycin usage for persistent fever), and data from our institutional antibiogram (Figure 1). A post-test was given directly after the lecture to evaluate knowledge gained.

Results

Five inappropriate behaviors were identified (Figure 2): (1) changing empiric therapy despite clinical stability, (2) misunderstanding piperacillin/tazobactam’s spectrum of activity, (3) inappropriate initiation of antibiotics active against resistant Gram-positive organisms; (4) failure to de-escalate therapy at 72 hours and (5) failure to add Gram-positive coverage when using aztreonam. Lectures were provided to 13 APPs and 17 medical students/residents over 6 sessions. An improvement in knowledge was noted for most learning objectives except for the third, for which misconceptions remained, especially regarding need for vancomycin in the setting of mucositis (Figures 3 and 4). Higher baseline knowledge was noted for medical students/residents than APPs. 93% of learners rated the lecture very/extremely helpful. Learners recommended future content focus on antifungal therapy.

Conclusion

We utilized local practice data to develop educational content for front-line providers. We will convert this lecture into a video-format to be incorporated into hematology rotations to reinforce key concepts. A prospective cohort study to evaluate the impact on prescribing behavior is underway.

Disclosures

All authors: No reported disclosures.

Oral Fluoroquinolone or Trimethoprim-sulfamethoxazole vs. ß-lactams as Step-Down Therapy for Enterobacteriaceae Bacteremia: Systematic Review and Meta-analysis

BACKGROUND

Using published data, we sought to compare outcomes in patients transitioned to either oral fluoroquinolones (FQ) or trimethoprim-sulfamethoxazole (TMP-SMX) versus ß-lactams (BL's) after an initial intravenous (IV) course for gram-negative rod (GNR) bacteremia.

METHODS

We conducted a systematic review of PubMed and EMBASE and published IDWeek abstracts. We included studies that reported all-cause mortality and/or infection recurrence in patients transitioned to oral FQ/TMP-SMX and BL's.

RESULTS

Eight retrospective studies met inclusion criteria with data for 2,289 patients, of whom 65% were transitioned to oral FQ, 7.7% to TMP-SMX, and 27.2% to BL's. Follow up periods ranged from 21 to 90 days. All-cause mortality was not significantly different between patients transitioned to either FQ/TMP-SMX or BL's (OR 1.13; 95%CI, 0.69-1.87). Overall recurrence of infection, either bacteremia or the primary site, occurred more frequently in patients transitioned to oral BL's vs. FQ's (OR 2.05, 95% CI 1.17 to 3.61). Analysis limited to recurrent bacteremia was similarly suggestive although limited by small numbers (OR 2.32, 95% CI 0.99 to 5.44). However, based on known pharmacokinetics/pharmacodynamics, prescribed ß-lactam dosing regimens were frequently suboptimal.

CONCLUSIONS

In the step-down IV to oral treatment of GNR bacteremia, we found insufficient data regarding outcomes after oral TMP-SMX; however, selection of a FQ over commonly utilized ß-lactam regimens may reduce chances of infection recurrence. While this may be a class effect, it may simply be the result of inadequate dosing of ß-lactams. Additional investigations are warranted to determine outcomes with TMP-SMX and optimized oral ß-lactam dosing regimens.

Coccidioidomycosis: What a long strange trip it's been

The recorded history of coccidioidomycosis began in 1892 with the report of the illness of Domingo Escurra by Alejandro Posadas followed by a description of the first North American cases by Rixford and Gilchrist. Originally considered a protozoan, William Ophüls determined that Coccidioides was a fungus and that the lungs were the apparent initial site of infection. During the 1930s, both Gifford and Dickson determined that a self-limited illness, Valley Fever, was caused by the same fungus that caused the often fatal coccidioidal granuloma. Charles Smith, over a period of approximately 2 decades, comprehensively described the clinical and geographic epidemiology of coccidioidomycosis in California. Demosthenes Pappagianis continued this work after Smith's death. In 1957, one year before Marshall Fiese published his masterful monograph on coccidioidomycosis, the use of the first effective agent for the therapy of coccidioidomycosis, amphotericin B, was reported. This was followed by descriptions of its appropriate clinical use by William Winn and by Hans Einstein, among others. The development of the much less toxic azole antifungal agents greatly simplified therapy in many cases, but much of the management of patients with coccidioidomycosis still relies more on art than science. The search for the “Holy Grail” - a vaccine capable of preventing this disease-continues.

Conversion from Vancomycin Trough Concentration-Guided Dosing to Area Under the Curve-Guided Dosing Using Two Sample Measurements in Adults: Implementation at an Academic Medical Center

STUDY OBJECTIVE

The optimal pharmacodynamic parameter for the prediction of efficacy of vancomycin is the area under the concentration-time curve (AUC), and current published data indicate that dosing based on vancomycin trough concentrations is an inaccurate substitute. In this study, our objective was to compare the achievement of therapeutic target attainment after switching from a trough-based to an AUC-based dosing strategy as a part of our institution's vancomycin-per-pharmacy protocol.

DESIGN

Prospective observational quality assurance study.

SETTING

Academic medical center.

PATIENTS

A total of 296 hospitalized adults who received vancomycin and monitoring under our institution's vancomycin-per-pharmacy protocol were included in the analysis. The preimplementation retrospective comparison group consisted of 179 patients in whom vancomycin was initiated using a trough-based dosing strategy between November 22, 2017, and January 22, 2018. The postimplementation group included 117 patients in whom vancomycin was initiated using an AUC-based dosing strategy using two-point sampling between June 19, 2018, and July 19, 2018, after hospital-wide implementation of this protocol on June 19, 2018.

MEASUREMENTS AND MAIN RESULTS

AUC values were calculated from two vancomycin concentrations (peak and trough). The primary outcome was achievement of therapeutic AUC values (400-800 mg·hr/L) in the postimplementation group or therapeutic trough level values (10-20 mg/L) in the preimplementation group. Only 98 (55%) of 179 initial trough values were therapeutic in the preimplementation group (trough-only dosing method) versus 86 (73.5%) of 117 initial AUC values in the postimplementation group (AUC-based dosing method) (p=0.0014). A lower proportion of supratherapeutic AUC values was observed in the postimplementation group compared with supratherapeutic trough concentrations in the preimplementation group (1.7% vs 18%, p<0.0001). Overall, 62% of patients with initially therapeutic AUC values had subsequent trough value increases of 25% or greater, occurring at a median of 6 days of vancomycin therapy. Nephrotoxicity occurred in 11% of patients in the preimplementation versus 9.4% in the postimplementation group (p=0.70).

CONCLUSION

Compared with a trough concentration-based dosing strategy, AUC-based dosing using two-point sampling improved therapeutic target attainment. Implementation is feasible at any hospital that performs vancomycin peak concentration testing and is a workable alternative to using Bayesian software for estimating AUC. This approach should also be directly compared with AUC-based dosing using Bayesian software.

Infectious Complications of Multiple Sclerosis Therapies: Implications for Screening, Prophylaxis, and Management

Multiple sclerosis therapies include interferons, glatiramer, and multiple immunosuppressive drugs. Discerning infectious risks of immunosuppressive drugs requires understanding their mechanisms of action and analyzing interventional studies and postmarketing observational data. Though identical immunosuppressive therapies are sometimes used in non-neurologic conditions, infectious risks may differ in this population. Screening for and treatment of latent tuberculosis (TB) infection should be prioritized for patients receiving alemtuzumab; ocrelizumab is likely not associated with an increased risk of TB. Hepatitis B virus (HBV) reactivation can be devastating for patients treated with ocrelizumab and alemtuzumab, whereas the small molecule oral agents do not likely pose substantial risk of HBV. Progressive multifocal leukoencephalopathy is a particular concern with natalizumab. Alemtuzumab, and possibly natalizumab and fingolimod, risks herpes virus reactivation and may warrant prophylaxis. Unusual opportunistic infections have been described. Vaccination is an important tool in preventing infections, though vaccine timing and contraindications can be complex.

Histoplasmosis in transplant recipients

Histoplasma capsulatum is a dimorphic fungus that most often causes asymptomatic infection in the immunocompetent population. In immunocompromised patients, including solid organ transplant (SOT) and hematopoietic cell transplant (HCT) recipients, however, it is likely to cause severe life-threatening infection. Post-transplant histoplasmosis (PTH) in SOT is uncommon with an incidence of ≤1% and is even rarer in HCT patients. The majority of PTH in SOT is diagnosed in the first 2 years following transplantation. Histoplasmosis may result from endogenous reactivation of latent infection, de novo post-transplant acquisition, and donor-derived infection. Disseminated infection is common. Fever is the most common symptom and clinical features are often nonspecific, but patients with disseminated infection may present with a septic picture. Other features, including pancytopenia and hepatosplenomegaly, may not be prominent early in the course of illness. Contemporary histoplasma antigen assays are the most sensitive tests but cross-reactivity with antigens of other fungi, including with Aspergillus galactomannan, is not uncommon. Treatment should be continued for at least a year. Histoplasma antigen levels have prognostic value and can be used to monitor the response to therapy. The attributable mortality is approximately 10%. Routine screening of donors and recipients is not currently recommended.

Leishmaniasis in solid organ and hematopoietic stem cell transplant recipients

Leishmaniasis occurs in <1% of solid organ and hematopoietic stem cell transplant recipients in endemic countries in which transplants are performed. Visceral leishmaniasis (VL) makes up the bulk of reported cases. The onset generally occurs months after transplantation and the mode of acquisition is often impossible to determine, but de novo vector-borne infection and reactivation of inapparent infection are thought to be the principal means. The potential role of clinically inapparent donor infection is uncertain and screening is not currently recommended, nor is it recommended for recipients from endemic areas, some of whom may have detectable circulating protozoan nucleic acid. While transplant recipients with VL often present with the non-specific findings of fever and cytopenia, the additional presence of hepatosplenomegaly in patients from endemic areas should lead to a directed diagnostic evaluation with bone marrow examination and PCR testing of marrow and peripheral blood having a high yield. Management may often be complicated by the presence of concomitant infections. A lipid formulation of amphotericin B is the preferred treatment, especially for VL, but the relapse rate in transplant recipients is approximately 25%. PCR monitoring of blood for either secondary prophylaxis or preemptive therapy requires further study.