Outcomes associated with empiric cefepime for bloodstream infections caused by ceftriaxone-resistant, cefepime-susceptible Escherichia coli and Klebsiella pneumoniae

BACKGROUND

Cefepime is a first-line agent for empiric sepsis therapy; however, cefepime use may be associated with increased mortality for extended-spectrum beta-lactamase-producing Enterobacterales (ESBL-E) in an MIC-dependent manner. This study aimed to compare the efficacy of empiric cefepime versus meropenem for bloodstream infections (BSI) caused by ceftriaxone-resistant Escherichia coli and Klebsiella pneumoniae with cefepime MICs ≤ 2 mg/L.

METHODS

This single-center retrospective cohort study included patients admitted from October 2010 to August 2020 who received cefepime or meropenem empirically for sepsis with a blood culture growing ceftriaxone-resistant Escherichia coli or Klebsiella pneumoniae. The primary outcome was 30-day mortality; secondary endpoints included 14-day mortality, recurrent BSI, readmission and recurrent infection within 90 days, time to clinical resolution of infection, time to clinical stability, and clinical stability at 48 hours.

RESULTS

Fifty-four patients met inclusion criteria: 36 received meropenem and 18 received cefepime. The median (IQR) treatment durations of cefepime and meropenem were 3 (2-6) days and 7 (5-10) days, respectively. Thirty-day and 14-day mortality were similar between cefepime and meropenem (11.1% vs. 2.8%; P = 0.255 and 5.6% vs. 2.8%; P = 1.00, respectively). Cefepime was associated with longer time to clinical stability compared with meropenem (median 38.48 hours vs. 21.26; P = 0.016).

CONCLUSION

Mortality was similar between groups, although most patients who received cefepime empirically were ultimately transitioned to a carbapenem to complete the full treatment course. Empiric cefepime was associated with a delay in achieving clinical stability when compared with meropenem to treat BSI caused by ceftriaxone-resistant Enterobacterales, even when cefepime-susceptible.

Uncomplicated Streptococcal Bacteremia: The Era of Oral Antibiotic Step-down Therapy?

BACKGROUND

The purpose of this study was to compare the clinical outcomes of adults with uncomplicated streptococcal bacteremia who received either oral (PO) step-down or continued intravenous (IV) therapy.

METHODS

This was a retrospective, single-center, cohort study, including adults admitted with Streptococcal bloodstream infection between January 1, 2013, and December 31, 2020. Only patients with uncomplicated Streptococcal bloodstream infections were included. Patients who transitioned to PO therapy within 5 days from bacteremia onset were compared to patients receiving continued IV therapy. The primary outcome was clinical failure, defined by either 90-day hospital readmission or mortality. Secondary outcomes included hospital length of stay (LOS) and antibiotic-related adverse events (AAEs).

RESULTS

Of the 264 patients included, 42% were transitioned to PO therapy. Group B Streptococcus (22.7%) was the most common isolate. The most common sources of infection were skin and soft tissue (35%) and pulmonary (25%). Intensive care unit (ICU) stay was more common in the continued IV therapy group (22.2%) than in the PO step-down group (5.4%). The frequency of clinical failure was similar in the IV and PO groups (24.2% vs. 18.0%, P=0.23). The IV group had longer hospital LOS (median, [interquartile range (IQR)]) compared with the PO group (7 [5-13.5] vs. 4 [3-5] days, P<0.001). The incidence of AAEs was similar in the IV and PO groups (1.3% vs. 1.8%, P=0.74).

CONCLUSION

Oral antibiotic step-down therapy may be appropriate for the treatment of uncomplicated Streptococcal bacteremia, with consideration of factors such as patient comorbidities, type of infection, source control and clinical progress.

168. Closing Time: A Quasi-experiment Comparing Time to Optimal Therapy using Traditional Identification and Susceptibility Methods, Rapid Identification, or Rapid Identification with Phenotype for Gram-negative Bloodstream Infections

Background

Bloodstream infections (BSI) are a major cause of morbidity and mortality. Compared to traditional microbiology methods, rapid diagnostic testing (RDT) provides prompt organism identification and antibiotic susceptibility results. This leads to earlier opportunities to optimize therapy, which may improve patient outcomes.

Methods

This was a single center quasi-experimental study of hospitalized adults with Gram-negative (GN) BSI, comparing the management and outcomes across three periods: pre-RDT (traditional identification and susceptibilities with BD Phoenix®, December 2014 to September 2016), RDT1 (Nanosphere Verigene®, December 2016 to December 2019), and RDT2 (Accelerate Pheno™, February 2020 to September 2021). The primary outcome was time to optimal therapy (TTOT). Secondary outcomes included time to oral antibiotic step-down, hospital length of stay (LOS), incidence of Clostridioides difficile infection, and 30-day inpatient mortality. Chi-squared and Kruskal-Wallis tests were used to compare categorical and continuous variables. Significance values for the primary endpoint were adjusted with Bonferroni correction to account for multiple pairwise comparisons.

Results

Of 296 included patients, 100 were in the pre-RDT, 98 in the RDT1, and 98 in the RDT2 arms. The most common organisms were Escherichia coli (64.5%) and Klebsiella species (20.3%). The TTOT (median, interquartile range) in the pre-RDT, RDT1, and RDT2 groups were 46 (7-61), 30 (0-53), and 12 (0-28) hours (P< 0.001), respectively. The time to oral antibiotic step-down and hospital LOS was similar between groups. There was no difference in C. difficile infection or 30-day inpatient mortality (Table 1). Table 1.

Prevalence and Predictors of Pseudomonas aeruginosa among Hospitalized Patients with Diabetic Foot Infections

Background

Diabetic foot infections (DFIs) are commonly associated with antibiotic overuse. Empiric DFI treatment often includes coverage for Pseudomonas aeruginosa (PsA), but the frequency of PsA DFIs is poorly understood. The study objectives were to quantify the prevalence of and determine predictors for PsA DFIs.

Methods

This multicenter, retrospective cohort included hospitalized patients with DFI from 2013 through 2020 who were age ≥18 years; diabetes mellitus diagnosis; and DFI based on International Classification of Diseases, Tenth Revision coding, antibiotic treatment, and DFI culture with organism growth. Osteomyelitis was excluded. Patient characteristics were described and compared; the primary outcome was presence of PsA on DFI culture. Predictors of PsA DFI were identified using multivariable logistic regression.

Results

Two hundred ninety-two patients were included. The median age was 61 (interquartile range [IQR], 53–69) years; the majority were men (201 [69%]) and White (163 [56%]). The most commonly isolated organisms were methicillin-susceptible Staphylococcus aureus (35%) and streptococci (32%); 147 (54%) cultures were polymicrobial. Two hundred fifty-seven (88%) patients received empiric antibiotics active against PsA, but only 27 (9%) patients had PsA DFI. Immunocompromised status (adjusted odds ratio [aOR], 4.6 [95% confidence interval {CI}, 1.3–16.7]) and previous outpatient DFI antibiotic treatment failure (aOR, 4.8 [95% CI, 1.9–11.9]) were associated with PsA DFI.

Conclusions

PsA DFI is uncommon, but most patients receive empiric antipseudomonal antibiotics. Empiric broad-spectrum antibiotics are warranted given the frequency of mixed infections, but patient-specific risk factors should be considered before adding antipseudomonal coverage.

Pharmacist-Driven Transitions of Care Practice Model for Prescribing Oral Antimicrobials at Hospital Discharge

IMPORTANCE

Although prescribers face numerous patient-centered challenges during transitions of care (TOC) at hospital discharge, prolonged duration of antimicrobial therapy for common infections remains problematic, and resources are needed for antimicrobial stewardship throughout this period.

OBJECTIVE

To evaluate a pharmacist-driven intervention designed to improve selection and duration of oral antimicrobial therapy prescribed at hospital discharge for common infections.

DESIGN, SETTING, AND PARTICIPANTS

This quality improvement study used a nonrandomized stepped-wedge design with 3 study phases from September 1, 2018, to August 31, 2019. Seventeen distinct medicine, surgery, and specialty units from a health system in Southeast Michigan participated, including 1 academic tertiary hospital and 4 community hospitals. Hospitalized adults who had urinary, respiratory, skin and/or soft tissue, and intra-abdominal infections and were prescribed antimicrobials at discharge were included in the analysis. Data were analyzed from February 18, 2020, to February 28, 2022.

INTERVENTIONS

Clinical pharmacists engaged in a new standard of care for antimicrobial stewardship practices during TOC by identifying patients to be discharged with a prescription for oral antimicrobials and collaborating with primary teams to prescribe optimal therapy. Academic and community hospitals used both antimicrobial stewardship and clinical pharmacists in a multidisciplinary rounding model to discuss, document, and facilitate order entry of the antimicrobial prescription at discharge.

MAIN OUTCOMES AND MEASURES

The primary end point was frequency of optimized antimicrobial prescription at discharge. Health system guidelines developed from national guidelines and best practices for short-course therapies were used to evaluate optimal therapy.

RESULTS

A total of 800 patients prescribed oral antimicrobials at hospital discharge were included in the analysis (441 women [55.1%]; mean [SD] age, 66.8 [17.3] years): 400 in the preintervention period and 400 in the postintervention period. The most common diagnoses were pneumonia (264 [33.0%]), upper respiratory tract infection and/or acute exacerbation of chronic obstructive pulmonary disease (214 [26.8%]), and urinary tract infection (203 [25.4%]). Patients in the postintervention group were more likely to have an optimal antimicrobial prescription (time-adjusted generalized estimating equation odds ratio, 5.63 [95% CI, 3.69-8.60]). The absolute increase in optimal prescribing in the postintervention group was consistent in both academic (37.4% [95% CI, 27.5%-46.7%]) and community (43.2% [95% CI, 32.4%-52.8%]) TOC models. There were no differences in clinical resolution or mortality. Fewer severe antimicrobial-related adverse effects (time-adjusted generalized estimating equation odds ratio, 0.40 [95% CI, 0.18-0.88]) were identified in the postintervention (13 [3.2%]) compared with the preintervention (36 [9.0%]) groups.

CONCLUSIONS AND RELEVANCE

The findings of this quality improvement study suggest that targeted antimicrobial stewardship interventions during TOC were associated with increased optimal, guideline-concordant antimicrobial prescriptions at discharge.

1228. Outcomes Associated with Empiric Cefepime or Meropenem for Bloodstream Infections Caused by Ceftriaxone-Resistant, Cefepime-Susceptible Escherichia coli and Klebsiella pneumoniae

Background

Cefepime is a 4^th generation cephalosporin frequently used for empiric sepsis therapy. Dose- and MIC-dependent efficacy of cefepime is supported by the Clinical & Laboratory Standards Institute, however its use in infections due to extended-spectrum beta-lactamase-producing Enterobacterales is controversial. This study aims to compare outcomes in patients given empiric meropenem or cefepime for bloodstream infections (BSI) caused by ceftriaxone-resistant E. coli and K. pneumoniae.

Methods

This single-center retrospective cohort included adults hospitalized from 2010 - 2020 and received empiric cefepime or meropenem for BSI caused by ceftriaxone-resistant E. coli or K. pneumoniae. In the cefepime group, only organisms with MIC ≤ 2 mg/L were included. Patients who received the empiric agent for < 48 hours, or received an additional active agent within 48 hours were excluded. The primary outcome was 30-day mortality; secondary outcomes were recurrent infection, readmission, and time to clinical stability. Chi-squared or Fisher’s exact was used for categorical variables and Mann-Whitney-U for continuous variables. Inverse probability treatment weighing was used to determine the impact of empirical therapy on clinical stability at 48 hours.

Results

Fifty-four patients were included: 36 received empiric meropenem, 18 received cefepime. There were no significant differences in baseline severity of illness or comorbid conditions. Urinary source was less common in the meropenem group compared to cefepime (52.8 vs 83.8%, p=0.028) (Table 1). There was no difference in 30-day mortality between meropenem and cefepime (2.8 vs 11.1%, p = 0.255). More patients achieved clinical stability at 48 hours on empiric meropenem compared to cefepime (75 vs 44.4%, p = 0.027), and time to clinical stability was significantly shorter (median 21.3 vs 38.5 hours, p = 0.016). Most patients in the meropenem and cefepime groups completed definitive treatment with a carbapenem (88.9 vs 72.2%, p=0.142).

Table 1: Results

Summary of primary and secondary outcomes

Conclusion

There was no difference in mortality between patients receiving empiric cefepime for BSI due to ceftriaxone-resistant Enterobacterales, with cefepime MIC ≤ 2 mg/L, compared to meropenem; however, time to clinical stability was significantly delayed.

Disclosures

James Kirby, MD, D(ABMM), First Light Biosciences (Board Member)TECAN, Inc. (Research Grant or Support)

228. Fluoroquinolone Prescribing for Diabetic Foot Infections following an FDA Drug Safety Communication for Aortic Aneurysm Risk

Background

Fluoroquinolones were commonly prescribed for hospitalized patients with diabetic foot infection (DFI) at our institution, included in 69% of empiric antibiotic regimens from 2011–2014. On December 20, 2018, the U.S. Food and Drug Administration (FDA) issued a Drug Safety Communication regarding the risk of aortic aneurysm with fluoroquinolones. The objective of this study was to assess the impact of the FDA Communication on antibiotic prescribing for DFI.

Methods

This was a single-center quasi-experimental study of hospitalized patients initiated on antibiotics for DFI before (February-December 2018) and after (February-December 2019) the 2018 FDA Communication. Patients with concomitant infections or documented beta-lactam or fluoroquinolone allergies were excluded. The primary outcome was inpatient days of fluoroquinolone therapy. Secondary outcomes included days of beta-lactam therapy and Outpatient Parenteral Antibiotic Therapy (OPAT) enrollment. Variables were compared using the Pearson’s chi square, Fisher’s exact, and Mann Whitney U tests, as appropriate. A logistic regression was performed to identify predictors for inpatient receipt of fluoroquinolones.

Results

A total of 198 patients were included. Baseline characteristics were similar between groups (Table 1). After the FDA Communication, the median duration of inpatient fluoroquinolones decreased from 3 [0–5.5] to 0 [0–1] days (p< 0.001). The duration of antipseudomonal beta-lactams increased from 0 [0–2] to 2 [0–6] days (p< 0.001). OPAT enrollment increased from 16.5% to 29.7% (p=0.028), with a corresponding increase in peripherally inserted central catheter placement (15.5% to 25.7%, p=0.074). There was no difference in outpatient fluoroquinolone prescribing over time. Incidence of re-infection, readmission for DFI, and antibiotic adverse events were similar between groups (Table 2).

Table 1

Table 2

Conclusion

Inpatient fluoroquinolone prescribing for DFI decreased significantly following the 2018 FDA Communication, followed by an increase in antipseudomonal beta-lactam use and OPAT enrollment. FDA statements can influence institutional antibiotic prescribing and transitions of care decisions, representing an opportunity for education by Antimicrobial Stewardship programs.

Disclosures

All Authors: No reported disclosures

1329. Vancomycin Therapeutic Drug Monitoring: How to hit the Curve

Background

For the management of serious S. aureus infections, area-under-the curve to minimum inhibitory concentration (AUC/MIC) applied dosing is recommended as the preferred method to goal trough-based monitoring. This pharmacodynamic dosing demonstrates efficacy with optimized exposure and decreased nephrotoxicity. While two levels are ideal for estimating AUC/MIC mathematically, the logistics and costs may outweigh the benefits of this approach. This study will compare AUC/MIC estimates using two single-level pharmacokinetic calculators (C2 and C3) and a Bayesian dosing calculator (C1) versus steady-state troughs.

Methods

A retrospective cohort study using a data repository to identify patients from 2019 included patients on intravenous vancomycin for greater than 48 hours with a steady state trough. Patients on dialysis or with unstable renal function were excluded. Vancomycin AUC/MIC and peak levels were estimated using C1, C2, and C3. The objective was to assess correlation of trough levels of 10-20mcg/ml to an AUC/MIC of 400-600 mg∙h/L. Secondary outcomes included examining the difference in R-squared values of the three calculators, and the percentage of patients with dose adjustments.

Results

55 patients met inclusion criteria. Of 55 troughs, 78% were 10-20mcg/ml and 5% were >20mcg/ml. On average, the three calculators found 85% of all initial troughs and 93% of therapeutic troughs correlated to an AUC >400. However, less than half of therapeutic troughs corresponded to an AUC of 400-600 mg∙h/L. Nearly 70% of patients had one or more dose adjustments often for unclear reasons as the AUC/MIC target of 400-600 mg∙h/L was met in 29-63% of initial adjustments. The three different calculators showed noticeable variability in calculating AUC/MIC.

Figure 1

Figure 2

Figure 3

Conclusion

A weak relationship between AUC/MIC and steady state troughs was found. Excess vancomycin exposure was demonstrated in 39% of therapeutic troughs. Over 25% of dose adjustments were deemed unnecessary. Utilizing AUC/MIC estimates for vancomycin may limit excess exposure while reducing the overall number of drug levels. Selecting a single-level calculator is problematic with the high degree of variation between calculators.

Figure 4

Disclosures

All Authors: No reported disclosures

54. Microbiologic Characterization and Antibacterial Use in Hospitalized Adults with covid-19 Infection

Background

Coronavirus disease 2019 (CoVID-19) admissions, oft complicated by an uncertain trajectory, lent to treatment influenced by supposition. Respiratory bacterial co-infection frequently was invoked. The purpose of this study was to determine the respiratory pathogen distribution and antibiotic prescribing patterns in hospitalized patients with CoVID-19.

Methods

Patients with a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) ICD-10 code and/or positive polymerase chain reaction (PCR) hospitalized between March 1 and May 31, 2020 were included. Antibiotic utilization (patient days of therapy-pDOT) was collected for the institution during this period and two years prior. Respiratory microbiologic cultures were reviewed to examine the frequency of co-infection on presentation, categorized as within 3 calendar days from admission or afterward. The relationship of antibiotic utilization to positive cultures was also categorized.

Results

Of the 7,969 encounters, 829 were ICD-10 coded and/or confirmed SARS-CoV-2 PCR positive and 196 (23.6%) had positive respiratory cultures. 89.8% of patients had endotracheal samples, the rest were isolated from sputum or bronchoalveolar lavage (17.4% and 6.6%, respectively). Patients were more likely to isolate commensal respiratory flora (108 versus 78 patients within the first 3 days of presentation. Notable isolates such as Staphylococcus aureus and Pseudomonas aeruginosa, were more often isolated after 3 days of hospitalization. While the CoVID-19 average hospital census was only 14.7% of the total, antibiotic utilization, (pDOT/1000) was 2.3 times higher, 831.9 versus 368.3 across the institution. During similar periods in 2018 and 2019, days of therapy overall were lower. For CoVID-19 infected patients, the frequency of antibiotic initiation was 73.2%. The length of therapy was on average 8 days with a high rate of observed restarts.

Table 1: Patient characteristics for CoVID-19 infected patients admitted during March 1 to May 31, 2020

Figure 1: Positive respiratory pathogen culture results for CoVID-19 encounters (March 1-May 31, 2020)

Table 2: Prevalence and select types of antibiotics administered to CoVID-19 patients. (March 1-May 31, 2020)

Conclusion

Bacterial co-infection in an acute viral process is generally low. In this examination of CoVID-19 infected patients, the rate of any positive respiratory culture was 23.6%. A disproportionate effect on the volume of antibiotics and total days of therapy prompted an interest in early stewardship efforts and education.

Table 3: Antibiotic consumption (patient days of therapy) for CoVID-19 encounters (March 1-May 31, 2020) compared to total consumption during identical time periods in 2018, 2019, and 2020

Disclosures

All Authors: No reported disclosures

Risk of QT Interval Prolongation Associated With Use of Hydroxychloroquine With or Without Concomitant Azithromycin Among Hospitalized Patients Testing Positive for Coronavirus Disease 2019 (COVID-19)

IMPORTANCE

Administration of hydroxychloroquine with or without azithromycin for the treatment of coronavirus disease 2019 (COVID-19)-associated pneumonia carries increased risk of corrected QT (QTc) prolongation and cardiac arrhythmias.

OBJECTIVE

To characterize the risk and degree of QT prolongation in patients with COVID-19 in association with their use of hydroxychloroquine with or without concomitant azithromycin.

DESIGN, SETTING, AND PARTICIPANTS

This was a cohort study performed at an academic tertiary care center in Boston, Massachusetts, of patients hospitalized with at least 1 positive COVID-19 nasopharyngeal polymerase chain reaction test result and clinical findings consistent with pneumonia who received at least 1 day of hydroxychloroquine from March 1, 2020, through April 7, 2020.

MAIN OUTCOMES AND MEASURES

Change in QT interval after receiving hydroxychloroquine with or without azithromycin; occurrence of other potential adverse drug events.

RESULTS

Among 90 patients given hydroxychloroquine, 53 received concomitant azithromycin; 44 (48.9%) were female, and the mean (SD) body mass index was 31.5 (6.6). Hypertension (in 48 patients [53.3%]) and diabetes mellitus (in 26 patients [28.9%]) were the most common comorbid conditions. The overall median (interquartile range) baseline QTc was 455 (430-474) milliseconds (hydroxychloroquine, 473 [454-487] milliseconds vs hydroxychloroquine and azithromycin, 442 [427-461] milliseconds; P < .001). Those receiving concomitant azithromycin had a greater median (interquartile range) change in QT interval (23 [10-40] milliseconds) compared with those receiving hydroxychloroquine alone (5.5 [-15.5 to 34.25] milliseconds; P = .03). Seven patients (19%) who received hydroxychloroquine monotherapy developed prolonged QTc of 500 milliseconds or more, and 3 patients (8%) had a change in QTc of 60 milliseconds or more. Of those who received concomitant azithromycin, 11 of 53 (21%) had prolonged QTc of 500 milliseconds or more and 7 of 53 (13 %) had a change in QTc of 60 milliseconds or more. The likelihood of prolonged QTc was greater in those who received concomitant loop diuretics (adjusted odds ratio, 3.38 [95% CI, 1.03-11.08]) or had a baseline QTc of 450 milliseconds or more (adjusted odds ratio, 7.11 [95% CI, 1.75-28.87]). Ten patients had hydroxychloroquine discontinued early because of potential adverse drug events, including intractable nausea, hypoglycemia, and 1 case of torsades de pointes.

CONCLUSIONS AND RELEVANCE

In this cohort study, patients who received hydroxychloroquine for the treatment of pneumonia associated with COVID-19 were at high risk of QTc prolongation, and concurrent treatment with azithromycin was associated with greater changes in QTc. Clinicians should carefully weigh risks and benefits if considering hydroxychloroquine and azithromycin, with close monitoring of QTc and concomitant medication usage.

Clinical Utility of Lefamulin: If Not Now, When?

Purpose of Review

The looming threat of antimicrobial resistance requires robust stewardship and new developments in infectious diseases pharmacotherapy. This review discusses the pertinent spectrum and clinical data of lefamulin (Xenleta®), with a focus on potential real-world use.

Recent Findings

Lefamulin is a novel pleuromutilin antibiotic that obtained Food and Drug Administration labeling for community-acquired bacterial pneumonia (CABP) in 2019. Lefamulin is available in both intravenous and oral formulations, and it inhibits bacterial protein synthesis inhibition through interactive binding to unique sites of the peptidyl transferase center of the 50s bacterial ribosome subunit. Resistance, including cross-resistance with other antibiotics, is infrequent. Lefamulin demonstrates activity against most Gram-positive pathogens and other organisms commonly associated with CABP, i.e., Streptococcus pneumoniae, Haemophilus influenzae, Mycoplasma pneumoniae, Legionella pneumophila, and Chlamydophila pneumoniae. Lefamulin may also be an option for serious public health threats like methicillin-resistant Staphylococcus aureus, vancomycin-resistant Enterococcus faecium, and multi-drug-resistant organisms associated with sexually transmitted infections, e.g., Neisseria gonorrhoeae, Mycoplasma genitalium. Lefamulin lacks activity against Pseudomonas aeruginosa, Acinetobacter baumannii, Enterobacterales, most anaerobes, and E. faecalis. In Phase III trials, lefamulin monotherapy was non-inferior to moxifloxacin with or without linezolid for CABP.

Summary

Lefamulin is a well-tolerated agent with a unique mechanism, availability in both IV and PO formulations, and it has been rigorously studied for safety and efficacy for CABP.

Treatment and outcomes of Enterococcus faecium bloodstream infections in solid organ transplant recipients

Optimal antimicrobial therapy for Enterococcus faecium bloodstream infection (EFBSI) in the solid organ transplant (SOT) population is not well defined. The purpose of this study was to describe the pharmacotherapy and outcomes of EFBSI in SOT patients. This was a single-center retrospective cohort of SOT patients with EFBSI from 2013 to 2019. Susceptibility testing was performed with Vitek^® 2 or Etest. Estimates of optimal DAP pharmacokinetic/pharmacodynamic exposures (dose <10 mg/kg, fAUC/MIC >27.4) were made from previously established literature and equations. Fifty-one unique cases were included in the analysis. The median age was 61 years and liver (64%), intestinal (19%), and kidney (12%) were the most common organs transplanted. Most patients had indwelling central lines (75%) at the time of bacteremia; intra-abdominal abscesses/fluid collections were present in 44% of patients and 8% had endocarditis. Nineteen (37%) patients had polymicrobial infections. The most common definitive antimicrobial regimens were as follows: DAP plus beta-lactam (46%), DAP monotherapy (18%), and LZD (25%). Of the 33 patients that received DAP, 21% of E faecium isolates developed DAP resistance. 30-day mortality was 25% overall but higher in patients who received an initial DAP dose <10 mg/kg (43% vs 13%). Vancomycin-resistance, severity of illness, neutropenia, and source control were also associated with mortality. Inadequate DAP dosing for EFBSI may be associated with mortality in the SOT population. Larger, controlled analyses are necessary to determine the impact of optimized pharmacodynamics in this population.

Improving care for critically ill patients with community-acquired pneumonia

PURPOSE

The purpose of this study was to improve antimicrobial management and outcomes of critically ill patients with community-acquired pneumonia (CAP) through implementation of a pharmacist-driven bundle for ordering evidence-based diagnostic tests in a medical intensive care unit (MICU).

METHODS

An inpatient collaborative practice agreement (CPA) was established for MICU pharmacists to order criteria-driven diagnostic testing for CAP from November 2017-March 2018. Adults admitted to the MICU and started on empiric antibiotics for CAP were included. The intervention arm was compared with a standard of care (SOC) group from November 2016-March 2017.

RESULTS

Ninety-one patients were included in each group. There was no difference in the median antibiotic duration between SOC and CPA, at 7 days (interquartile range [IQR], 6-10) versus 7 days (IQR, 6-8), respectively. The overall use of evidence-based diagnostic tests increased in the CPA group. Patients in the CPA group had more frequent pathogen identification (SOC and CPA, respectively: 31 [34%] versus 46 [51%], p = 0.035) and antimicrobial deescalation (24 [26%] versus 53 [58%], p < 0.001). There was no significant difference in length of intensive care unit stay, at 4 days for SOC (IQR, 2-10) versus 6 days for CPA (IQR, 3-10), and no significant difference in inpatient all-cause mortality (13 [14%] versus 7 [8%]), retreatment 14 [15%] versus 11 [12%]), or 30-day readmission 16 ([18%] versus 13 [14%]) for SOC and CPA, respectively. The CPA was the only variable that was independently associated with antimicrobial deescalation (odds ratio, 4.030; 95% confidence interval, 2.101-7.731) in a multiple logistic regression.

CONCLUSION

Implementation of a pharmacy-driven pneumonia diagnostic stewardship bundle improved the use of evidence-based diagnostics and increased the frequency of pathogen identification. This intervention was associated with increased antimicrobial deescalation without a negative impact on patient safety outcomes.

1019. Treatment Outcomes for Enterococcus faecium Bacteremia in Solid-Organ Transplant Patients: Implications for Daptomycin

Background

Optimal antimicrobial therapy for Enterococcus faecium (EFM) bacteremia in the solid-organ transplant (SOT) population is not well defined. Antimicrobial resistance, immunosuppression, and high mortality associated with EFM infections all pose serious threats. The purpose of this study was to describe the pharmacotherapy and outcomes of EFM bacteremia in SOT patients.

Methods

This was a single-center retrospective cohort of SOT patients with EFM bloodstream infection from 2013 to 2018. Susceptibility of ampicillin (AMP), vancomycin (VAN), linezolid (LZD), and daptomycin (DAP) against EFM were reported as MIC90 when available. The primary outcome, 30-day all-cause mortality, was assessed in bivariate analysis to identify potential risk factors. Secondary outcomes included inpatient mortality and development of DAP nonsusceptibility (DNS).

Results

Forty-four unique cases representing 40 patients were included in the analysis. The median age was 62.5 years and liver (65.9%), intestine (20.5%), and kidney (11.4%) were the most common organs transplanted. The MIC90 of VAN, DAP, and LZD of initial isolates collected were &gt;32 mg/L, 4 mg/L, and 2 mg/L, respectively; all were AMP resistant. The median durations of hospitalization and intensive care stay were 29 days and 17.5 days, respectively. Most patients had indwelling central lines (81.8%) at the time of bacteremia; intra-abdominal abscesses/fluid collections were present in 45.5% of patients and 9.1% had endocarditis. The most common definitive antimicrobial regimens were DAP plus β-lactam (45.5%), DAP monotherapy (18.2%), and LZD 600 mg Q12H (25.0%). The mean initial and definitive DAP doses were 8.1 ± 1.6 and 8.9 ± 1.7 mg/kg actual body weight, respectively. Among subjects that received DAP, 21.9% developed DNS. Inpatient mortality was 39.5% and 30-day mortality was 27.3%. Mortality at 30-days was greater in patients with high-grade bacteremia (40.7 vs. 5.9%, P = 0.01) and receipt of DAP &lt;10 mg/kg as the first active antibiotic (42.9 vs. 13.0%, P = 0.03).

Conclusion

Inadequate DAP dosing for EFM bacteremia may be associated with mortality in the SOT population. Larger, matched analyses are necessary to determine the impact of optimized pharmacodynamics.

Disclosures

S. L. Davis, Achaogen: Scientific Advisor, Consulting fee. Allergan: Scientific Advisor, Consulting fee. Melinta: Scientific Advisor, Consulting fee. Nabriva: Scientific Advisor, Consulting fee. Zavante: Scientific Advisor, Consulting fee.

1884. Assessment of Potential Antimicrobial-Related Harms in Hospitalized Adults With Common Infections

Background

Methods

Results

Conclusion

Disclosures

238. Sharing Unit-Specific Stewardship Metrics With Front-line Providers to Improve Antibiotic Prescribing

Background

Methods

Results

Conclusion

Disclosures

Combatting resistant enterococcal infections: a pharmacotherapy review

INTRODUCTION

The role of enterococci in infectious diseases has evolved from a gut and urinary commensal to a major pathogen of concern. Few options exist for resistant enterococci, and appropriate use of the available agents is crucial.

AREAS COVERED

Herein, the authors discuss antibiotics with clinically useful activity against Enterococcus faecalis and E. faecium. The article specifically discusses: antibiotics active against enterococci and their mechanism of resistance, pharmacokinetic and pharmacodynamic principles, in vitro combinations, and clinical studies which focus on urinary tract, intra-abdominal, central nervous system, and bloodstream infections due to enterococci.

EXPERT OPINION

Aminopenicillins are preferred over all other agents when enterococci are susceptible and patients can tolerate them. Daptomycin and linezolid have demonstrated clinical efficacy against vancomycin-resistant enterococci (VRE). Synergistic combinations are often warranted in complex infections of high inoculum and biofilms while monotherapies are generally appropriate for uncomplicated infections. Although active against resistant enterococci, the pharmacokinetics, efficacy and safety of tigecycline and quinupristin/dalfopristin can problematical for severe infections. For cystitis, amoxicillin, nitrofurantoin, or fosfomycin are ideal. Recently, approved agents such as tedizolid and oritavancin have good in vitro activity against VRE but clinical studies against other resistant enterococci are lacking.

Stewardship opportunities in viral pneumonia: Why not the immunocompromised?

Antimicrobial management of viral pneumonia has proven to be a challenge in hospitalized immunocompromised patients. A host of factors contribute to the dilemma, such as diagnostic uncertainty, lack of organism identification, and clinical status of the patient. Respiratory virus panel (RVP) use was compared between 131 immunocompromised patients who received send‐out (n = 56) vs in‐house (n = 75) testing. Antimicrobial optimization interventions consisted of antiviral addition/discontinuation, antibiotic discontinuation/de‐escalation, or modification of immunosuppressive regimen. After implementation of an in‐house test with audit and feedback, turnaround time of the RVP was reduced from 46.7 to 5.5 hours (P < .001) and time to intervention was reduced from 52.1 to 13.9 hours (P < .001), yet the frequency of antimicrobial optimization interventions was unchanged (30.7% vs 35.7%). Differences were not observed in duration of empiric antibiotic therapy or length of stay. The overall discontinuation rate for patients tested with a RVP was low (4.6%), and those with positive RVP (n = 43) had antibiotics stopped in 14% of cases. Bacterial pneumonia coinfection was confirmed in 2 patients. Further systematic efforts should be taken to reduce antibiotic use in viral pneumonia and identify the major barriers in the immunocompromised population.