bluuebunny/crossref_metadata_2025 huggingface dataset:
192. A Hematology/Oncology Unit-Specific Antibiogram Emphasizes the Need for Intensified Local Stewardship
Authors: Bartash Rachel , McCort Margaret E , Cowman Kelsie , Orner Erika , Szymczak Wendy , Nori Priya , Nori Priya
Published: January 2021

Background

Antibiograms are important stewardship tools for empiric antibiotic prescribing. Appropriate therapy is particularly important in patients with hematologic malignancies and bone marrow transplants being treated for febrile neutropenia. These patients are at high risk for multi-drug resistance based on extensive prior antibiotic and hospital exposures, and therefore, hospital-wide antibiograms may not reliably reflect resistance patterns for this population. We created a unit-specific antibiogram for a closed hematology/oncology unit and hypothesized there would be decreased antibiotic susceptibilities compared to the hospital-wide antibiogram.

Methods

All positive cultures with antimicrobial susceptibilities on a closed 32-bed hematology-oncology unit from 7/2016-6/2019 were obtained from the microbiology laboratory. Based on recommendations by the Clinical and Laboratory Standards Institute (CLSI), only organisms with > 30 isolates were included in antibiogram analysis. Susceptibilities were compared to those reported in our hospital-wide antibiograms from the same time period using Fisher’s exact test.

Results

Two organisms met CLSI criteria: Escherichia coli (n=83) and Klebsiella pneumoniae (n=31). Unit Escherichia coli isolates were significantly more resistant to almost all commonly tested antibiotics (Table 1). Klebsiella pneumoniae unit susceptibilities were significantly lower for many antibiotics, including aztreonam, ceftriaxone, cefepime, levofloxacin, piperacillin-tazobactam and tobramycin (Table 1).

Table 1: Percentage of Escherichia coli and Klebsiella pneumoniae isolates susceptible to reported antibiotic agents

Conclusion

Our hematology-oncology antibiogram showed significantly lower antibiotic susceptibilities in Escherichia Coli and Klebsiella pneumoniae compared with the hospital-wide antibiogram. These findings can help guide prescribers toward appropriate broad-spectrum empiric therapy. Additionally, results suggest a need for intensified stewardship measures to prevent multi-drug resistance in this population.

Disclosures

All Authors: No reported disclosures
204. Post-Liver Transplant Antimicrobial Use after the Expansion of a Pharmacist-Lead Antimicrobial Stewardship Program
Authors: Gales Kee , Wrin Justin E , Pennington Catherine
Published: January 2021

Background

Antimicrobial stewardship programs (ASPs) allow for infectious diseases (ID)-trained practitioners to focus on timely and appropriate antimicrobial use. In December 2016, the ASP at Indiana University (IU) Health expanded from one ID pharmacist to three. The purpose of this study was to assess the impact of an expanding ASP on broad-spectrum antimicrobial use within post-liver transplant patients.

Methods

This was a retrospective, cross-sectional study. Data were collected from patients aged at least 18 years old that received a liver transplant either before or after the ASP expansion. Patients were excluded if they survived less than 72 hours after transplant, if they received a multivisceral transplant, or if there was an active infection prior to transplantation. The hypothesis of this study was that an expanded ASP leads to a reduction in days of therapy (DOT) per 1000 patient-days for a composite of broad-spectrum antimicrobial agents within this patient population.

Results

A total of 268 patients were included in this study. Of the patients that received at least one dose of the studied antimicrobial agents, the median (IQR) DOT per 1000 patient-days in the pre- and post-ASP expansion cohort was 174.4 (117.6 – 333.3) and 142.9 (62.5 – 257.5), respectively. This was statistically significant (difference 48.6, 95% CI 7.5 – 83.3). Specifically, the post-ASP expansion cohort used less meropenem (difference 197.8, 95% CI 66.3 – 451.6) and vancomycin (difference 57.6, 95% CI 2.2 – 132.2). The post-ASP expansion cohort also consulted ID for more patients (2 vs. 12 consults in the pre- and post-expansion group, respectively; p=0.011). Patient and graft survival one year after transplantation were similar between the two cohorts (p=0.540 and p=0.255, respectively).

Conclusion

An expanded ASP contributed to a reduction in broad-spectrum antimicrobial use in post-liver transplant patients without negatively impacting patient and graft survival one year post-transplantation. These data provide further evidence of ASP benefits within immunocompromised populations.

Disclosures

All Authors: No reported disclosures
218. Changes in Dental Antibiotic Prescribing in the United States, 2012–2017
Authors: Ramanathan Swetha , Yan Connie H , Hubbard Colin , Calip Gregory , Sharp Lisa K , Rowan Susan A , McGregor Jessina C , Gross Alan E , Campbell Allen , Evans Charlesnika T , Hershow Ronald , Suda Katie J
Published: January 2021

Background

Data suggest dental antibiotic prescribing is increasing with relatively less documented about prescribing trends in adults and children. Therefore, the aim was to evaluate trends in antibiotic prescribing by US dentists from 2012–2017.

Methods

This was a cross-sectional study of US dental prescribing using IQVIA Longitudinal Prescription Data from 2012 to 2017. Prescribing rates (prescriptions [Rx] per 100,000 dentists), mean days’ supply, and mean quantity dispensed were calculated monthly across eight oral antibiotic groups: amoxicillin, clindamycin, cephalexin, azithromycin, penicillin, doxycycline, fluoroquinolone, and other antibiotics. Descriptive frequencies and multiple linear regressions were performed to obtain trends overall and stratified by adults (≥ 18) and children (< 18).

Results

220, 325 dentists prescribed 135 million Rx (94.0% in adults). 61.0% were amoxicillin, 14.4% clindamycin, 11.7% penicillin, 4.4% azithromycin, 4.3% cephalexin, 2.0% other antibiotics, 1.4% doxycycline, and 0.7% fluoroquinolones. Prescribing increased by 33 Rx/100,000 dentists (p< 0.0001) each month for all antibiotics. Amoxicillin (p< 0.0001) and clindamycin (p=0.02) prescribing rate increased by 73 and 5 Rx/100,000 dentists, respectively. Prescribing decreased by 8, 12, and 2 Rx/100,000 dentists for cephalexin (p< 0.0001), doxycycline (p< 0.0001), and fluoroquinolones (p=0.008), respectively. Mean days’ supply increased for amoxicillin, penicillin, and clindamycin (p< 0.0001), and decreased for cephalexin (p< 0.0001).Mean quantity dispensed decreased (p< 0.0001) for all groups except azithromycin and doxycycline. Among adults, cephalexin prescribing rates (7 Rx/100,000 dentist; p< 0.0001) and other antibiotics days’ supply (p< 0.0001) decreased. Among children, azithromycin prescribing rates (1 Rx/100,000 dentists, p=0.02), and fluoroquinolone and other antibiotics days’ supply (p< 0.0001) decreased.

Conclusion

These findings support dental antibiotic prescribing is increasing, specifically for amoxicillin and clindamycin. Further, trends differed between adults and children. Understanding what is driving these trends is important to target dental antibiotic stewardship efforts.

Disclosures

All Authors: No reported disclosures
219. Characteristics Associated with Inappropriate Antibiotic Prescribing in Patients with Asymptomatic Bacteriuria (ASB)
Authors: Bixby Morgan L , Raux Brian R , Bhalla Aakansha , McCoy Christopher , Hirsch Elizabeth B
Published: January 2021

Background

Antibiotic treatment of asymptomatic bacteriuria (ASB) is considered inappropriate, does not improve patient outcomes, and may lead to adverse events such as antibiotic resistance and Clostridioides difficile infection. Previous stewardship interventions have focused on reducing unnecessary urine culture collection in individuals without urinary symptoms; however, further interventions to reduce inappropriate prescribing in ASB are warranted. This study sought to identify characteristics associated with treatment of ASB in order to implement future stewardship interventions.

Methods

This two-center, retrospective cohort study included unique emergency department or inpatient adults with consecutive non-duplicate monomicrobial urine isolates of Enterobacterales or Pseudomonas aeruginosa collected between 8/2013 and 1/2014 from two academic hospitals in Boston, Massachusetts. Patients with ASB (without chart-documented urinary-specific symptoms) were identified through chart review and stratified into two groups: those treated with empiric urinary tract infection (UTI) antibiotics and those untreated. Logistic regression analyses were performed to identify variables independently associated with antibiotic treatment of ASB.

Results

During the study, 255 patients were determined to have ASB and a majority (80.8%) were treated with empiric UTI antibiotics. Most patients were female (71.4%) and elderly (mean age 70 years). The most common organisms isolated were Escherichia coli (59.2%), Klebsiella spp. (23.1%), and P. aeruginosa (9.8%). The presence of isolated fever (OR, 7.83 [95% confidence interval, 1.51, 144.20]); p = 0.05), urinalysis positive for pyuria (>10 white blood cells) (OR, 2.52 [95% CI, 1.15, 5.54]; p = 0.02), and Klebsiella spp. urine isolate (OR, 2.99 [95% CI, 1.19, 8.60]; p = 0.02) were independently associated with treatment.

Conclusion

A large proportion of ASB patients were treated with antibiotics despite clinical practice guidelines recommending against this practice. Isolated fever, pyuria, and Klebsiella spp. culture were all significantly associated with the treatment of ASB; targeted review of these patients by stewardship programs may help to reduce inappropriate ASB treatment within these institutions.

Disclosures

Elizabeth B. Hirsch, PharmD, Merck (Grant/Research Support) Nabriva Therapeutics (Advisor or Review Panel member)
231. Impact of DRIP Score Documentation at Time of Physician Order Entry on Combination Antimicrobials in Treatment of Community Acquired Pneumonia
Authors: Herbin Shelbye R , Scipione Marco R , Yost Raymond
Published: January 2021

Background

The Drug Resistance in Pneumonia (DRIP) score is a predictive model for identifying drug-resistant pathogens in community-acquired pneumonia (CAP). The Detroit Medical Center adopted DRIP documentation at time of antimicrobial order entry for CAP in 2017. The purpose of this study was to identify the difference in overall consumption of antibiotics used for the treatment of CAP after the implementation of DRIP documentation.

Methods

A retrospective analysis of adult patients with an antimicrobial order with a documented indication of pneumonia between Jun 1-Oct 31, 2017 and Jun 1-Oct 31, 2018, was conducted. Days of antimicrobial therapy per 1000 adjusted patient days (DOT/1000 pt days) was assessed in patients before and after implementation of DRIP documentation at time of order entry. The percent concordance with institutional guidelines for empiric CAP treatment post-implementation of DRIP documentation was also evaluated.

Results

The DOT/1000 pt days increased in the post-DRIP group for ceftriaxone (36.5 vs. 76.3), doxycycline (22.3 vs. 44.5), and azithromycin (29.5 vs. 53.4). The DOT/1000 pt days decreased for carbapenems in the post-DRIP group (14.0 vs. 8.5). There was no change in vancomycin or linezolid use. Empiric therapy after implementation of DRIP documentation was concordant with institutional guidelines in 34.7% and 11.2% of patients with documented DRIP< 4 and DRIP≥4, respectively. Overall, the most common reason for non-concordance was lack of atypical coverage. Use of expanded Gram-negative coverage (i.e. cefepime) for documented DRIP< 4, and lack of expanded Gram-negative coverage with aminoglycosides in ICU patients with documented DRIP≥4 were also common

Conclusion

An increase in guideline-directed therapy and a decrease in use of carbapenems were seen after implementation of DRIP score documentation at time of order entry. Overall concordance with guidelines was low, and additional review is needed to identify if providers are accurately documenting the DRIP score. Future directions should focus on education of clinicians on the importance of accurate DRIP documentation in order to improve compliance with institutional guidelines.

Disclosures

All Authors: No reported disclosures
237. Inpatient and Discharge Antibiotic Use for Hospitalized Patients Growing Multi-Drug Resistant Bacteria in Urine Cultures
Authors: Zou James , Boly Frances , Stwalley Dustin , Olsen Margaret A , Kwon Jennie H , Burnham Jason P
Published: January 2021

Background

Multidrug resistant organism (MDRO) infections are a threat to public health. Urinary tract infections (UTIs) are the most common MDRO infection and are responsible for a significant proportion of antibiotic use. Studies demonstrate both duration and type of antibiotics prescribed to patients with MDRO UTI are inappropriate, and that asymptomatic MDRO bacteriuria is inappropriately treated. In addition, antibiotics prescribed at hospital discharge are inappropriate in ~70% of patients. We sought to characterize inpatient and outpatient antibiotic durations to describe burden of antibiotic use for patients with an MDRO isolated from a urine specimen during a hospitalization.

Methods

This retrospective study was conducted at Barnes-Jewish Hospital, a 1266-bed academic medical center in St. Louis, Missouri from 11/7/12-11/7/17. Patients ≥ 18 years of age were included if they had an MDRO isolated from a urine specimen and no other positive bacterial cultures during their hospitalization. Demographics, comorbidities, cultures, and antibiotics were collected via data pulls and chart review. MDROs were defined according to European and US Center for Disease Control and Prevention guidelines. Antibiotic use was described as percentages of all antibiotics used.

Results

A total of 1052 patients had MDROs in urine cultures. Of these patients, 747 (71.0%) were discharged on oral antibiotics for a mean duration of 6.7 days, while 135 (12.8%) were discharged on IV antibiotics for a mean of 10.9 days. The five most commonly administered inpatient antibiotics after urine culture results were available (% prescribed) were IV ceftriaxone (43.0%), IV vancomycin (26.0%), PO ciprofloxacin (25.6%), IV cefepime (24.5%), and PO trimethoprim-sulfamethoxazole (17.6%). The five most commonly prescribed antibiotics at discharge were PO ciprofloxacin (22.3%), PO trimethoprim-sulfamethoxazole (17.8%), PO nitrofurantoin (8.4%), PO cephalexin (6.2%), and PO doxycycline (5.0%).

Conclusion

Patients with MDROs in urine cultures receive prolonged durations of inpatient and outpatient antibiotics, longer than what is recommended by current evidence and guidelines.

Disclosures

Dustin Stwalley, MA, AbbVie Inc (Shareholder)Bristol-Myers Squibb (Shareholder) Margaret A. Olsen, PhD, MPH, Merck (Grant/Research Support)Pfizer (Consultant, Grant/Research Support)
238. Novel Way to Evaluate Antibiotic Use Appropriateness: Moving Towards the “Never Event” Classification by Electronic Algorithm
Authors: Patel Twisha S , Petty Lindsay A , Liu Jiajun , Scheetz Marc H , Mercuro Nicholas , Davis Susan L , Davis Susan L , Yarnold Paul R , Pais Gwendolyn M , Kaye Keith S
Published: January 2021

Background

Antibiotic use is commonly tracked electronically by antimicrobial stewardship programs (ASPs). Traditionally, evaluating the appropriateness of antibiotic use requires time- and labor-intensive manual review of each drug order. A drug-specific “appropriateness” algorithm applied electronically would improve the efficiency of ASPs. We thus created an antibiotic “never event” (NE) algorithm to evaluate vancomycin use, and sought to determine the performance characteristics of the electronic data capture strategy.

Methods

An antibiotic NE algorithm was developed to characterize vancomycin use (Figure) at a large academic institution (1/2016–8/2019). Patients were electronically classified according to the NE algorithm using data abstracted from their electronic health record. Type 1 NEs, defined as continued use of vancomycin after a vancomycin non-susceptible pathogen was identified, were the focus of this analysis. Type 1 NEs identified by automated data capture were reviewed manually for accuracy by either an infectious diseases (ID) physician or an ID pharmacist. The positive predictive value (PPV) of the electronic data capture was determined.

Antibiotic Never Event (NE) Algorithm to Characterize Vancomycin Use

Results

A total of 38,774 unique cases of vancomycin use were available for screening. Of these, 0.6% (n=225) had a vancomycin non-susceptible pathogen identified, and 12.4% (28/225) were classified as a Type 1 NE by automated data capture. All 28 cases included vancomycin-resistant Enterococcus spp (VRE). Upon manual review, 11 cases were determined to be true positives resulting in a PPV of 39.3%. Reasons for the 17 false positives are given in Table 1. Asymptomatic bacteriuria (ASB) due to VRE in scenarios where vancomycin was being appropriately used to treat a concomitant vancomycin-susceptible infection was the most common reason for false positivity, accounting for 64.7% of false positive cases. After removing urine culture source (n=15) from the algorithm, PPV improved to 53.8%.

Conclusion

An automated vancomycin NE algorithm identified 28 Type 1 NEs with a PPV of 39%. ASB was the most common cause of false positivity and removing urine culture as a source from the algorithm improved PPV. Future directions include evaluating Type 2 NEs (Figure) and prospective, real-time application of the algorithm.

Disclosures

Marc H. Scheetz, PharmD, MSc, Merck and Co. (Grant/Research Support)
242. Seasonality in antibiotic use and resistance across multiple bacterial pathogens and antibiotic classes
Authors: Sun Daphne S , Kissler Stephen M , Kanjilal Sanjat , Olesen Scott , Grad Yonatan H
Published: January 2021

Background

Antibiotic use is an important driver of antibiotic resistance. Previous studies have shown that this relationship is detectable on a seasonal timescale, where seasonally cycling antibiotic prescribing corresponds with cycling levels of resistance. Here, we evaluated the seasonal relationship between antibiotic use and resistance across multiple species and antibiotic classes in Boston, Massachusetts.

Methods

To conduct our study, we analyzed antibiotic claims data from the Massachusetts All Payers Claims Database for five antibiotic classes, beta-lactams, macrolides, quinolones, tetracyclines, and nitrofurans, which together account for 74% of the total outpatient antibiotic claims in this dataset. In addition, we analyzed antibiotic susceptibility data for clinical isolates collected from two tertiary care hospitals, focusing on three clinically important bacterial pathogens. Our analysis included a total of 131,815 Escherichia coli, 47,208 Staphylococcus aureus, and 27,237 Klebsiella pneumoniae isolates collected over the years 2007–2019, with susceptibility testing data for 5–6 antibiotics per species. To determine the extent of seasonality in use and resistance, we fit the antibiotic claims data for each antibiotic class and the minimum inhibitory concentration (MIC) data for each species-antibiotic combination to a sinusoidal model with either a 6 or 12-month period.

Results

We found that use of all 5 antibiotic classes and resistance in 9 out of 15 species-antibiotic combinations showed a significant amplitude of seasonality (p-value < 0.05). Despite different seasonal peaks in antibiotic use across classes, resistance peaked in the winter for almost all species-antibiotic combinations and was most highly correlated with use of winter-peaking antibiotic classes, beta-lactams and macrolides.

Conclusion

Overall, these results suggest that co-resistance and “bystander” selection – selection for resistance in asymptomatically colonizing and potentially pathogenic bacteria that are not the direct target of treatment – mediate the effects of antibiotic prescribing on the landscape of resistance.

Disclosures

All Authors: No reported disclosures
254. Review of Clinical Outcomes in Patients Treated with Beta-lactam vs Non-beta-lactam Therapy for AmpC Producing Bacterial Bloodstream Infections
Authors: Staicu Mary L , Baumeister Tyler , Laguio-Vila Maryrose R
Published: January 2021

Background

AmpC beta-lactamase producing organisms are traditionally treated with carbapenem or fluoroquinolone antibiotics. Recent studies, however, describe similar clinical outcomes in patients that receive cefepime or piperacillin/tazobactam. We sought to assess outcomes in patients with bloodstream infections caused by AmpC-producing organisms that received beta-lactams compared non-beta-lactam therapy.

Methods

Data was obtained retrospectively from the electronic health record (EHR) from January 2012 to February 2020. The primary objective was 30-day mortality from the day of first positive blood cultures with Enterobacter spp., Citrobacter spp., or Serratia spp. in patients who received non-beta-lactam therapy (carbapenem, fluoroquinolone, trimethoprim/sulfamethoxazole) to those who received beta-lactam therapy (cefepime, piperacillin/tazobactam). Secondary objectives included 30-day recurrence of bacteremia, pathogen isolated, source of bacteremia, hospital length of stay, and duration of antimicrobial therapy.

Results

A total of 90 patients were included, 50 in the non-beta lactam group and 40 in the beta-lactam group. Demographics were similar between groups. Thirty-day mortality was significantly higher in the beta-lactam group (20% vs 2%, p=0.009). Enterobacter spp. was the most frequently identified pathogen (67%), most commonly isolated from a urinary (31%) or intra-abdominal source (22%). The average duration of antibiotic therapy was significantly higher in the non-beta lactam group (18 vs 12 days, p=0.001). In contrast, there was no significant difference found in hospital length of stay, recurrence of bacteremia, pathogen isolated or source of bacteremia between groups.

Conclusion

Beta-lactam therapy for the treatment of bloodstream infections caused by Amp-C producing organisms was associated with significantly greater 30-day mortality compared to patients that received non-beta-lactam therapy.

Disclosures

All Authors: No reported disclosures
265. Blood culture results pre- and post- antimicrobial administration in the Medicine Intensive Care Unit: a retrospective study in South Bronx
Authors: Chiu Chia-Yu , Sarwal Amara , Feinstein Addi
Published: January 2021

Background

It is intuitive that obtaining blood cultures prior to administering antibiotics can increase the likelihood of a positive blood culture result. Surviving Sepsis Campaign Hour-1 bundle stipulates that obtaining a blood culture and administering antibiotics within 1 hour is a critical determinant of survival. However, the diagnostic sensitivity shortly after antibiotic administration remains unknown. In clinical practice, some health care providers delay antibiotic administration in order to first obtain a blood culture.

Methods

Adult patients (> 18 years of age) admitted to the Medicine Intensive Care Unit in Lincoln Medical Center, located in South Bronx, New York City, from 09/2019 to 12/2019. Patients needed to have at least one blood culture obtained within 12 hours of admission and have received intravenous antibiotics during the admission to the Medicine Intensive Care Unit.

Results

Of 327 patients screened, 196 met enrolment criteria and 253 sets of blood cultures underwent analysis. Blood cultures grew bacteria in 21.8% of pre-antimicrobial group whereas 26.9% in post-antimicrobial group (p=0.37). 25.9% of patients received antibiotics within 1 hour before blood culture sampling, while 34.0% of patients received antibiotics >1 hour prior to obtaining blood culture. Blood culture results positive for coagulase-negative staphylococci were more prevalent in the pre-antimicrobial group.

Table 1. Patient Characteristics

Table 2. Number of blood cultures obtained and blood culture result

Table 3. Initial antimicrobial agent and 30-day mortality

Conclusion

In the sequence of blood culture and antibiotic administration, there is no 30-day survival difference in pre-antimicrobial group and post-antimicrobial group (p=0.15), as long as both received antibiotics within 12 hours of coming to the hospital. Coagulase-negative staphylococci were higher in the pre-antimicrobial group which may indicate that the health care provider hastily obtained the blood culture in a non-sterile manner. Antibiotic administration should not be delayed because of pending blood culture collection. In addition, given that more than 70% of patients were ultimately found to have negative blood cultures, it would be useful to develop practical tools to identify low-risk patients that can be treated without obtaining blood culture, as the blood culture would not be likely to provide diagnostic information.

Figure 1: Hours Before and After IV Antibiotic Started

Figure 2: Distribution of Blood Culture Before and After IV Antibiotics

Disclosures

All Authors: No reported disclosures
266. Ceftriaxone Versus Cefazolin for the Treatment of Methicillin-Susceptible Staphylococcus aureus Bacteremia
Authors: Mohamed Adham , Bennett Nick , Ploetz Jeannette , Aragon Laura , Kennedy Kevin , Boyd Sarah E
Published: January 2021

Background

Few studies have evaluated the use of ceftriaxone (CRO) in the treatment of Methicillin-sensitive Staphylococcus aureus (MSSA) infections. Available studies include a small number of patients with MSSA bacteremia, with conflicting results and several limitations. The purpose of this study was to compare the safety and efficacy of CRO versus cefazolin (CFZ) for patients with MSSA bacteremia.

Methods

This was a multi-center, single health-system retrospective cohort study. Patients were included if they were at least 18 years old, had a primary episode of MSSA bacteremia within Saint Luke’s Health System and received CRO or CEFZ as definitive therapy for MSSA bacteremia. Patients were excluded if they had a previous MSSA bacteremia within 6 months, a polymicrobial infection, received combination antimicrobial therapy as definitive therapy, started treatment at outside hospital, treated for less than 72 hours, or deemed palliative or comfort care. The primary endpoint was clinical cure at 7, 10, 14, and 28 days, or discharge, whichever came first. Secondary endpoints included time to clinical cure or discharge, treatment failure at 90 days, time to treatment failure, readmission due to recurrent MSSA bacteremia at 30 and 90 days, duration of bacteremia, discontinuation of definitive treatment due to adverse drug events, incidence of Clostridiodes difficile infection, and hospital length of stay.

Results

A total of 248 patients met inclusion criteria. Among these, 87 (35.1%) received CRO and 161 (64.9%) received CFZ as definitive therapy. Patient baseline and treatment characteristics are shown in Table 1. The primary outcome occurred in 75 (86.2%) patients in the CRO group vs 145 (90.1%) patients in the CFZ group (P= 0.359), even after adjusting for Charlson Comorbidity Index, Pitt bacteremia score and serum creatinine, (aOR=0.74, 95% CI 0.32 – 1.72; p=0.473). There were no differences in time to clinical cure or discharge, treatment failure at 90 days, or safety events between the two groups. Primary and secondary endpoints are included in Table 2.

Table 1

Table 2

Conclusion

Our study suggests that there is no clinical difference between CRO and CFZ for the treatment of MSSA bacteremia. Further studies are needed to confirm these findings.

Disclosures

All Authors: No reported disclosures
277. Comparison of Oral Beta-Lactams and Fluoroquinolones for Step-Down in Uncomplicated Enterobacterales Blood Stream Infections
Authors: Ngo Nichol , Sielatchom-Noubissie Lionel , Molina Kyle , Johnson Tanner M , Huang Misha , Hojat Leila S , Kiser Ty , miller matthew
Published: January 2021

Background

Bloodstream infections (BSI) with Enterobacterales (formerly Enterobacteriaceae) group organisms are a frequently encountered complication, often stemming from urinary tract infections. Recent studies have demonstrated similar outcomes among patients transitioned to oral antibiotics compared to those managed solely with parenteral routes; however, most transitions utilize highly bioavailable agents such as fluoroquinolones (FQ). With limited comparative evidence on oral b-lactams (OBL) and mounting concerns over FQ safety and resistance, we sought to compare outcomes of FQ vs. OBL for Enterobacterales BSI step-down.

Methods

Single-center, retrospective cohort of adults at University of Colorado Hospital from 2015–2017 with uncomplicated Enterobacterales BSI who stepped down to OBL or FQ after initial parenteral therapy. Exclusions were: pregnant or incarcerated, causative organism identified as Salmonella spp., Enterobacter spp., Citrobacter freundii, Serratia spp. and/or Klebsiella aerogenes, parenteral antibiotic duration ≥ 5 days, death before day 5, total antibiotic duration < 5 days or > 21 days. Primary outcome was clinical failure, a composite of any of the following within 30-days of antibiotic completion: death, recurrence or antibiotic change for presumed failure, or readmission for original infection.

Results

Overall, 74 patients were included (n=36 OBL, n=38 FQ). Baseline characteristics were not different between groups, with overall mean age (SD) 60 (17) years and 62% female. E. coli was most commonly identified (65%), with 70% originating from the urinary tract. ICU admission was present in 18%, and median (IQR) Pitt Bacteremia Score was 2 (1–3). Treatment failure occurred in 25% OBL vs. 24% FQ recipients, p=0.55. No deaths were identified in either group within 30-days, and adverse events were rarely reported in either group. Multivariable analysis identified presence of nephrostomy tubes (OR 8.1; 95% CI: 1.1–61) but not OBL (OR 1.5; 95% CI: 0.3–7.2) as associated with clinical failure.

Conclusion

In a cohort of uncomplicated Enterobacterales BSIs there does not appear to be a difference in clinical failure associated with OBLs compared to FQs. Additional studies with a larger cohort, or prospective trials are needed to confirm these findings.

Disclosures

matthew miller, PharmD, Allergan (Speaker’s Bureau)Tetraphase (Speaker’s Bureau)
285. Evaluation of the ePlex® Blood Culture Identification (BCID) Panels for Gram-positive/Gram-negative bacteria and yeasts
Authors: Chapin Kimberle , Tansarli Giannoula
Published: January 2021

Background

Multiple methods used for blood culture identification create inconsistent to reporting of critical results. Study aim was to evaluate performance characteristics of the ePlex BCID panels compared to current standard of care (SOC) methods used in our lab.

Methods

Identification sensitivity and specificity were assessed across all targets detected by the ePlex as well as time to final identification (from time of bottle positive Gram stain) between ePlex and SOC testing. SOC included Xpert MRSA/SA or latex agglutination for Gram-positive cocci in clusters (GPCC), Vitek MS + Accelerate Pheno for Gram-negative rods (GNRs), serotyping or optochin disk ± Vitek MS for Gram-positive cocci in chains (GPC chains), Vitek MS or Vitek-2 for Gram-positive rods (GPR), and PNA-FISH or Vitek MS for yeasts.

Results

313 unique prospective blood culture specimens were tested with ePlex BCID panels during a 3-month period (January-March 2020). The positive percent agreement was 100% for GNR (n= 98), S. aureus (n= 42), coagulase-negative staphylococci (n= 38), Group A Streptococcus (n= 3), Group B Streptococcus (n= 5), S. pneumoniae (n= 10), GPR (n= 21), and yeasts (n= 20). There was 1 false negative, (S.mutans) which should have been detected. The negative percent agreement was 100% across all targets except for 1 false positive Corynebacterium spp. In total, 6.7% of blood cultures had an off-panel organism which ePlex did not detect. The median time to final identification was 3 (2 – 4) hrs. for ePlex and calculated for all other SOC methods. Compared to SOC molecular methods, the ePlex reduced time to identification 0.5 h compared to Xpert MRSA/SA, 6.7 h compared to Accelerate Pheno for GNR (but Accelerate Pheno provides susceptibilities), and 3 h compared to PNA-FISH for yeasts (p< 0.05). ePlex compared to non-molecular techniques (MALDI-TOF), SOC for Streptococcus spp. and Enteroococcus spp., the time to final identification was reduced by 24 – 30 hours (p< 0.05).

Workflow chart comparison eplex to SOC

Time to results eplex vs SOC

Conclusion

The ePlex BCID system provided highly accurate identification results for GP and GN bacteria as well as for yeasts. Our evaluation showed that this system significantly reduced time to final identification compared to SOC testing methods.

Disclosures

Kimberle Chapin, MD, genmark (Scientific Research Study Investigator) Giannoula Tansarli, MD, GenMark (Grant/Research Support)
286. Exploratory Cost-Effectiveness Analysis for Treatment of Methicillin-Resistant Staphylococcus aureus Bloodstream Infections: Are Daptomycin and Linezolid Favored over Vancomycin and Other Antibiotics?
Authors: Vu Michelle , Smith Kenneth , Aspinall Sherrie L , Clancy Cornelius J , Buehrle Deanna
Published: January 2021

Background

Methicillin-resistant Staphylococcus aureus bloodstream infections (MRSAB) cause significant mortality and often require extended antibiotic therapy. Vancomycin, the most common initial MRSAB treatment, carries significant monitoring burden and nephrotoxicity risks. We compared cost-effectiveness of vancomycin and other antibiotic regimens as MRSAB treatment.

Methods

We estimated cost-effectiveness of intravenous antibiotics (vancomycin, daptomycin, linezolid, ceftaroline/daptomycin, dalbavancin) for Veterans Health Administration (VA) patients with MRSAB using an exploratory decision-tree model. Primary effectiveness outcome was composite of microbiological failure and adverse drug event (ADE)-related discontinuation at 7-days.

Results

In base-case analyses, linezolid and daptomycin were less expensive and had fewer treatment failures than other regimens at 4 and 6-weeks. Compared to linezolid, daptomycin incremental cost-effectiveness ratios were ~$45,000 (4-weeks) and ~$61,000 (6-weeks) per composite failure avoided, respectively. In one-way sensitivity analyses, daptomycin (4-weeks) was favored over linezolid if linezolid microbiological failure or ADE-related discontinuation rates were >14.8% (base case: 14.0%) or >14.3% (base case: 14.0%), respectively, assuming a willingness to pay (WTP) threshold of $40,000/ composite treatment failure avoided. Vancomycin was favored if its microbiological failure risk was < 16.4% (base case: 27.2%). In two-way sensitivity analyses, daptomycin was favored if linezolid microbiological failure and ADE-related discontinuation rates were >19% and > 16%, respectively. Linezolid, daptomycin and vancomycin were favored in 47%, 39%, and 11% of 4-week probabilistic iterations, respectively, at $40,000 WTP.

Conclusion

Daptomycin or linezolid are likely less expensive and more effective than vancomycin or other initial regimens for MRSAB. More data are needed to support safety of linezolid in MRSAB patients.

Disclosures

Cornelius J. Clancy, MD, Astellas (Consultant, Grant/Research Support)Cidara (Consultant, Research Grant or Support)Melinta (Grant/Research Support)Merck (Consultant, Grant/Research Support)Needham Associates (Consultant)Qpex (Consultant)Scynexis (Consultant)Shionogi (Consultant)
290. Impact of follow up blood cultures on outcomes of patients with gram-negative bloodstream infections
Authors: Amipara Rajiv G , Winders Hana R , Justo Julie Ann , Bookstaver P B , Kohn Joseph , Al-hasan Majdi
Published: January 2021

Background

Importance of follow up blood cultures (FUBC) for Staphylococcus aureus bloodstream infections (BSI) is well known, but the role of FUBC in gram-negative BSI remains controversial. This retrospective cohort study examined the association between obtaining FUBC and mortality in patients with gram-negative BSI.

Methods

Adults with first episodes of community-onset monomicrobial BSI due to gram-negative bacilli hospitalized at Prisma Health-Midlands hospitals in Columbia, South Carolina, USA from January 1, 2010 to June 30, 2015 were identified. Patients who died or were discharged from hospital within 72 hours of collection of index blood culture were excluded to minimize impact of survival and selection biases on results, respectively. FUBC were defined as repeat blood cultures obtained between 24 and 96 hours from initial positive blood culture. Cox proportional hazards regression model was used to examine association between obtaining FUBC and 28-day all-cause mortality.

Results

Among 766 patients with gram-negative BSI, 219 (28.6%) had FUBC obtained and 15 of 219 (6.8%) FUBC were persistently positive. Overall, median age was 67 years, 438 (57%) were women, 457 (60%) had urinary source of infection, and 426 (56%) had BSI due to Escherichia coli. Mortality was significantly lower in patients who had FUBC obtained than in those who did not have FUBC (6.3% vs. 11.7%, log-rank p=0.03). Obtaining FUBC was independently associated with reduced mortality (hazards ratio [HR] 0.49, 95%CI: 0.25–0.90) after adjustments for age (HR 1.35 per decade, 95% CI: 1.13–1.61), cancer (HR 5.90, 95% CI: 3.53–9.84), Pitt bacteremia score (HR 1.38 per point, 95% CI: 1.26–1.50), and inappropriate empirical antimicrobial therapy (HR 2.37, 95% CI: 1.17–4.39).

Conclusion

Obtaining FUBC was associated with improved survival in hospitalized patients with gram-negative BSI. These observations are consistent with the results of recent publications from Italy and North Carolina supporting utilization of FUBC in the management of gram-negative BSI.

Disclosures

Julie Ann Justo, PharmD, MS, BCPS-AQ ID, bioMerieux (Speaker’s Bureau)TRC Healthcare (Speaker’s Bureau)
294. Interim Analysis of an Evidence-Based Bundle Intervention for Uncomplicated Enterobacterales Bacteremia
Authors: Stallsmith Jena , Won Regina , Lopez Christopher M , Orme Forrest , Turner R Brigg , Chan Dominic
Published: January 2021

Background

Use of evidence-based process bundles for Staphylococcus aureus bacteremia benefit patient outcomes. No studies exist assessing the value of an evidence-based bundle (EBB) in Enterobacterales bacteremia. Recent studies show shorter durations of therapy (DOT) (~ 7 days) result in similar outcomes as longer DOT when treating uncomplicated gram-negative bacteremia. An internal study showed 87% of treatment course durations were > 7 days. This study seeks to determine the impact of an education-based EBB for uncomplicated Enterobacterales bacteremia on patient length of stay (LOS) and DOT.

Methods

This is a quasi-experimental pre- post- analysis conducted across six medical centers. The pre-intervention cohort (n=546) consisted of patients treated for uncomplicated Enterobacterales bacteremia between Jan 1 2016 and Dec 31 2017. The post-EBB education cohort (n=49) consisted of patients treated with the bundle from Jan 1 2020 through Apr 4 2020. Exclusion criteria included immunocompromised state, multiple infection sites, lack of source control, polymicrobial bacteremia, death within 48 hours of treatment, receiving end of life care, < 6 days or > 16 days of therapy, and failure to receive at least one antibiotic with in vitro activity against the organism. The primary outcome was the proportion of patients receiving 6–10 days of therapy. Secondary outcomes included LOS, 30-day readmission rate, 30-day all-cause mortality, time to intravenous to oral conversion, and EBB adherence. Descriptive statistics were used for the baseline characteristics and primary and secondary outcomes. Multiple regression analysis was performed to assess patient covariates.

Results

There was no difference in the proportion of patients receiving 6–10 days of therapy between the pre- and the post-EBB groups (43.4% vs 53.1%; p = 0.19). There was no association between DOT and covariates. The pre- and post-intervention group had average total DOT of 11.7 ± 2.6 days and 10.6 ± 2.7 days (p = 0.0047), respectively.

Conclusion

This interim analysis suggests an education-based EBB for Enterobacterales does not increase the proportion of patients receiving DOT of 6–10 days. Education alone may be insufficient.

Disclosures

All Authors: No reported disclosures
297. Lactobacillus: Friend or Foe
Authors: Nwanyanwu Chiemeziem , Shobayo Anuoluwapo , Ghitan Monica , Chapnick Edward , Kuhn-Basti Margaret , Lin Yu Shia , Simon Samuel , Li Rosanna
Published: January 2021

Background

Lactobacillus are low virulence commensal organisms which are commonly found in the human oral cavity, gastrointestinal and genitourinary tracts. Although Lactobacillus bacteremia (LB) is rare, evidence aggregating from case reports has implicated LB in several medical conditions. As such, there is reason to suggest that the presence of these organisms in blood cultures may not be due to spurious contamination, but rather, indicative of clinically meaningful events capable of inducing serious illnesses. The purpose of this study is to characterize the risk factors, clinical significance and outcomes of patients with LB.

Methods

We retrospectively reviewed the medical records of patients presenting to a large urban teaching hospital between January 1, 2017 and December 31, 2018, who were found to have LB. Identified individuals were grouped into two mutually exclusive case categories: true LB cases or non-true cases (i.e., contamination). Individuals with ≥1 positive blood and were started on appropriate antibiotics were considered true cases. Those with positive cultures not started on appropriate antibiotics were considered contaminants.

Results

A total of 14 patients were identified during our study period, with majority considered true LB cases [71.4%; n = 10]. These 14 individuals were mostly males [64.2%; n = 9] and reported no use of Lactobacilli probiotics [78.6%; n = 11] or antacids [57.1%; n = 8]. On average, true LB cases were older (mean [SD]): 80.1 [±10.9]vs. 54.0 [±19.1] years) and required longer hospitalization (38.5 [(±27.6] vs. 8.0 [(±6.2] days) compared to non-LB cases, respectively. Among the 10 true LB cases, the suspected source of infection included gastrointestinal system [50%; n = 5], infective endocarditis [10%; n = 1], genitourinary system [10%; n = 1]; and could not be determined in 3 [30%] cases. Concurrent infection with candida and gastrointestinal microbes were noted in four (40%) of the true LB cases, respectively. Overall, five deaths were observed, with 4 [80%] occurring in true LB cases and one in a non-LB case.

Conclusion

LB should not be dismissed as contaminants particularly in at-risk patients for LB, such as the elderly or immunocompromised individuals.

Disclosures

All Authors: No reported disclosures
304. Predictors of mortality in carbapenem-resistant Enterobacteriales bacteremia
Authors: Hovan Michael R , Cedarbaum Vanessa , Kirn Thomas , Kirn Thomas
Published: January 2021

Background

Carbapenem-Resistant Enterobacteriales (CRE) bacteremia is associated with significant morbidity and mortality. CRE were assigned a threat level of “urgent” in the 2019 CDC report on antibiotic resistance in the United States. We attempted to identify predictors of 30-day mortality in patients with CRE bacteremia.

Methods

We performed a chart review of 146 patients with CRE bacteremia from January 2010 - July 2019. CRE was defined using the current CDC definition. Electronic medical records were reviewed to obtain clinical characteristics and outcomes including prior antibiotic use, comorbidities, prior location, treatment, hospital course, microbiological data and outcomes including in-hospital mortality.

Results

Of 146 patients included for analysis, the overall 30-day mortality rate was 36.3%. Patients admitted from a healthcare facility including outside hospitals, rehab, nursing homes, and LTACs had a 49.1% (29/59) 30-day mortality rate compared to 27.5% (24/87) for those admitted from home (RR=1.78, 95% CI 1.16–2.73, p=.0082). Patients with a Pitt bacteremia score ≥ 4 had a greater 30-day mortality rate (42.6%, 26/61) compared to those with a Pitt bacteremia score < 4 (17.6%, 15/85) (RR=2.92, 95% CI 1.40–4.16, p=.0015). Patients that received inactive empiric therapy had a 30-day mortality rate of 36% (36/100) compared to 36.9% (17/46) in those that received active empiric therapy (RR=.9741, 95% CI .6155-1.59, p=.9109). Patients with isolates determined to have a meropenem MIC ≥ 4 had a 30-day mortality rate of 40.2% (37/92) while those with an MIC < 4 had a 30-day mortality rate of 30.2% (16/53) (RR=1.33, 95% CI .8250–2.1513, p=.2408). A pulmonary source of bacteremia was associated with an increased risk of 30-day mortality (64.3%, 9/14) compared to all other sources of bacteremia (34.8%, 31/89) (RR=1.85, 95% CI 1.39–2.99, p=.0129). No other infection source was associated with an increased 30-day mortality rate.

Conclusion

Admission from a healthcare facility, Pitt bacteremia score ≥ 4, and pulmonary source of bacteremia were associated with increased risk of 30-day mortality. Interestingly, administration of active empiric therapy was not associated with a decreased mortality risk. Meropenem MIC was not predictive of 30-day mortality.

Disclosures

All Authors: No reported disclosures
310. The Impact of Microscan versus Vitek-2 for Automated Susceptibility Testing on the Utilization of Vancomycin Alternatives for the Treatment of Methicillin-Resistant Staphylococcus aureus Bacteremia
Authors: Moskhos Alexander , Wibisono Arya , Reveles Kelly R , Rose Dusten T
Published: January 2021

Background

Automated susceptibility testing (AST) provides minimum inhibitory concentrations (MIC) to guide effective antibiotic therapy. AST is critical for methicillin-resistant Staphylococcus aureus (MRSA) bacteremia, as susceptible MIC values ≥ 1.5 µg/mL are associated with vancomycin (VAN) failure. The Microscan (MS) instrument may report elevated MIC values compared to Vitek-2 (VTK), thus impacting treatment. This study aimed to evaluate the impact of MS versus VTK on VAN alternative use in the treatment of MRSA bacteremia in a Texas health system.

Methods

This was a retrospective cohort study of patients admitted to the Ascension Seton health system in Austin, TX. Patient eligibility included: age ≥18 years, ≥1 positive MRSA blood culture, ≥72 hours of MRSA therapy, and VAN use within 48 hours of positive culture. Patients were stratified into the MS group (May 2013-Dec 2016) and VTK group (Jun 2017-Mar 2020). The primary outcome was therapy switch from VAN to VAN alternatives. Secondary endpoints include S. aureus MIC, 30-day all-cause mortality, 30 and 90-day readmission, and length of hospital stay (LOS). Outcomes were compared between groups using appropriate bivariable comparisons, as well as multivariable logistic regression and propensity score-adjusted logistic regression.

Results

A total of 199 patients were included: 91 in the MS group and 108 in the VTK group. Switch to VAN alternative was 56% vs. 19% (p< 0.0001) for MS and VTK, respectively. The median (interquartile range) MIC value reported was 2 μg/mL (2 – 2) and 1 μg/mL (0.5 – 1) for MS and VTK, respectively (p< 0.0001). Thirty-day readmission (19% vs. 20%, p=0.7647) and 30-day mortality (10% vs. 9%, p=0.5262) were comparable between MS and VTK groups, respectively. Hospital LOS significantly decreased in the VTK period (16 days vs. 12 days, p=0.0153). The MS group was the only independent positive predictor of VAN alternative therapy: logistic regression, OR 5.64 (95% CI 1.67–18.99) and propensity score adjusted, OR 4.21 (95% CI 1.32–13.48).

Conclusion

Since implementation of VTK from MS, Ascension Seton hospitals experienced a decreased median VAN MIC for MRSA bacteremia as well as therapy switches from VAN to VAN alternatives without affecting other patient health outcomes.

Disclosures

All Authors: No reported disclosures