204. Clinical Outcomes with Ceftaroline Monotherapy versus Daptomycin-Ceftaroline Combination Therapy in the Treatment of Methicillin-Resistant Staphylococcus aureus Bacteremia

Background

Methicillin-resistant Staphylococcus aureus (MRSA) bacteremia is associated with poor outcomes and increased mortality. Daptomycin (DAP) and ceftaroline (CPT) in combination has been explored as a potential treatment option and showed improved outcomes compared to vancomycin/standard therapy. CPT monotherapy has been evaluated as salvage therapy for MRSA bacteremia but, to our knowledge, not as a comparator to DAP-CPT combination therapy. The purpose of this study is to compare the clinical outcomes of DAP and CPT combination therapy to CPT monotherapy in the setting of MRSA bacteremia.

Methods

A retrospective chart review of adult patients (≥ 18 years of age) admitted to University Health from January 2017 to December 2020 with a diagnosis of MRSA bacteremia was performed. Patients received either CPT monotherapy or DAP-CPT combination therapy for a minimum of 48 hours during their course of therapy.

Results

Thirty-two patients met inclusion criteria and were evaluated. Primary source of infection was pulmonary in the CPT monotherapy group (n=7/24; 29.2%) and osteomyelitis in the DAP-CPT combination group (n= 4/8; 50.0%). Median duration of bacteremia was 8 days and 9 days in the CPT monotherapy and DAP-CPT combination group, respectively. Microbiological cure was achieved in 95.8% (n=23/24) of patients in the CPT monotherapy and 100% (n=8/8) of patients in the DAP-CPT combination group. Bacteremia relapse (30 day, p=0.62; 60 day, p=0.63), readmission rates (30 day, p=0.62; 60 day, p=0.63), and mortality rates (30 day, p=0.70; 90 day, p=0.85) were similar in both groups. There was no statistically significant difference in safety parameters, including incidence of acute kidney injury (p=1.00) and creatine kinase elevations (p=1.00). Bone marrow suppression after at least 72 hours of therapy, including anemia, leukopenia, and thrombocytopenia, was also not statistically significant between groups.

Conclusion

This study was unable to find a statistically significant difference in clinical outcomes between patients receiving CPT monotherapy or DAP-CPT combination therapy. A large prospective, randomized controlled trial to assess CPT monotherapy and DAP-CPT combination therapy for the treatment of persistent MRSA bacteremia is warranted.

Disclosures

All Authors: No reported disclosures

608. Impact of Implementing Pharmacist Review and Monitoring of Outpatient Parenteral Antimicrobial Therapy

Background

Given current efforts to increase the safety of outpatient parenteral antimicrobial therapy (OPAT) programs nationwide, this project sought to determine whether pharmacist managed OPAT review and monitoring improves adherence to standard of care laboratory monitoring recommendations.

Methods

A single-center, retrospective review of patients > 18 years of age who received OPAT from University Health System was conducted. Patients who received OPAT between October 2018 and December 2018 served as the historical control group. After a pharmacist transitions of care program was implemented, patients who received OPAT between October 2019 and December 2019 were included in the intervention group. Patients were excluded if they received less than 7 days of OPAT, completed therapy prior to discharge, or died while inpatient. The primary endpoint was adherence to laboratory monitoring recommendations > 75% of the duration of planned OPAT. Only patients followed by the OPAT clinic were included in this analysis. Recommendations provided in the 2018 Infectious Diseases Society of America OPAT guidelines were used to define appropriate lab monitoring. Secondary endpoints included 30-day readmissions.

Results

A total of 409 patients were included in this study: 198 patients in the pre-implementation group and 211 patients in the post-implementation group. In patients with OPAT clinic follow-up, the post-implementation group was significantly more likely to receive monitoring adherent to standard of care laboratory monitoring recommendations > 75% of the duration of planned OPAT: 42/161 (26.1%) vs. 98/176 (55.7%), OR 3.6 (95% CI 2.2-5.6, p = 0.0001). There was no difference in 30-day readmission rates between groups in the overall population. Patients in the post-implementation group with OPAT clinic follow up had lower 30-day infectious disease-attributed readmissions: 18/161 (11.2%) vs. 14/176 (8.0%), p = 0.31.

Conclusion

Implementation of a transitions of care pharmacist significantly improved adherence to laboratory monitoring recommendations for patients receiving OPAT and numerically reduced 30-day infectious disease-attributed readmissions.

Disclosures

All Authors: No reported disclosures

150. Urinary Tract-Associated Gram-Negative Bacteremia: Impact of Treatment Duration

Background

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

Methods

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

Results

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

Conclusion

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

Disclosures

All authors: No reported disclosures.

β-Lactam Therapy for Methicillin-Susceptible Staphylococcus aureus Bacteremia: A Comparative Review of Cefazolin versus Antistaphylococcal Penicillins

Methicillin-susceptible Staphylococcus aureus (MSSA) bacteremia is associated with high morbidity and mortality. Traditionally, antistaphylococcal penicillins (ASPs) have been considered the agents of choice for the treatment of MSSA bacteremia. Vancomycin has been demonstrated to have poorer outcomes in several studies and is only recommended for patients with severe penicillin allergies. Although cefazolin is considered as an alternative to the ASPs for patients with nonsevere penicillin allergies, cefazolin offers several pharmacologic advantages over ASPs, such as more convenient dosing regimens, and antimicrobial stewardship programs are increasingly using cefazolin as the preferential agent for MSSA infections as part of cost-saving initiatives. Concerns about susceptibility to hydrolysis by type A β-lactamases, particularly at high inocula seen in deep-seated infections such as endocarditis; selective pressures from unnecessary gram-negative coverage; and lack of comparative clinical data have precluded recommending cefazolin as a first-line therapy for MSSA bacteremia. Recent clinical studies, however, have suggested similar clinical efficacy but better tolerability, with lower rates of discontinuation due to adverse drug reactions, of cefazolin compared with ASPs. Other variables, such as adequate source control (e.g., intravascular catheter removal, debridement, or drainage) and enhanced pharmacodynamics through aggressive cefazolin dosing, may mitigate the role of cefazolin inoculum effect and factor into determining improved clinical outcomes. In this review, we highlight the utility of cefazolin versus ASPs in the treatment of MSSA bacteremia with a focus on clinical efficacy and safety.

Ceftaroline as Salvage Monotherapy for Persistent MRSA Bacteremia

OBJECTIVE

To summarize published data regarding the use of ceftaroline as salvage monotherapy for persistent methicillin-resistant Staphylococcus aureus (MRSA) bacteremia.

DATA SOURCES

PubMed (January 1980-June 2016) was searched using combinations of the search terms methicillin-resistant Staphylococcus aureus, MRSA, bacteremia, ceftaroline, refractory, and persistent Supplemental references were generated through review of identified literature citations.

STUDY SELECTION AND DATA EXTRACTION

Available English-language, full-text articles pertaining to the use of ceftaroline for persistent MRSA bacteremia (MRSAB) were included.

DATA SYNTHESIS

The PubMed search yielded 23 articles for evaluation. There are no randomized controlled trials to date-only case series and reports. Four retrospective case series detailing the use of ceftaroline as monotherapy for persistent MRSAB were included. Most patients received at least 4 days of an appropriate anti-MRSA antimicrobial prior to ceftaroline and were able to clear bacteremia within 3 days. The most common rationales for ceftaroline use were progression of disease or nonresponse to current therapy. Higher off-label dosing of ceftaroline is often utilized to achieve optimal pharmacokinetic/pharmacodynamic parameters. Adverse events are not well described due to lack of follow-up; however, neutropenia has been associated with prolonged use.

CONCLUSIONS

Treatment options for persistent MRSAB remain few and far between. Ceftaroline is an effective agent for the salvage treatment of MRSAB. Off-label doses up to 600 mg every 8 hours are often used to achieve optimal pharmacokinetic/pharmacodynamic parameters. Because of lack of follow-up in these reports, the incidence of adverse effects of prolonged use of ceftaroline is not well defined.

A clinical pathway for community-acquired pneumonia: an observational cohort study

BACKGROUND

Six hospitals instituted a voluntary, system-wide, pathway for community acquired pneumonia (CAP). We proposed this study to determine the impact of pathway antibiotics on patient survival, hospital length of stay (LOS), and total hospital cost.

METHODS

Data were collected for adults from six U.S. hospitals with a principal CAP discharge diagnosis code, a chest infiltrate, and medical notes indicative of CAP from 2005-2007. Pathway and non-pathway cohorts were assigned according to antibiotics received within 48 hours of admission. Pathway antibiotics included levofloxacin 750 mg monotherapy or ceftriaxone 1000 mg plus azithromycin 500 mg daily. Multivariable regression models assessed 90-day mortality, hospital LOS, total hospital cost, and total pharmacy cost.

RESULTS

Overall, 792 patients met study criteria. Of these, 505 (64%) received pathway antibiotics and 287 (36%) received non-pathway antibiotics. Adjusted means and p-values were derived from Least Squares regression models that included Pneumonia Severity Index risk class, patient age, heart failure, chronic obstructive pulmonary disease, and admitting hospital as covariates. After adjustment, patients who received pathway antibiotics experienced lower adjusted 90-day mortality (p = 0.02), shorter mean hospital LOS (3.9 vs. 5.0 days, p < 0.01), lower mean hospital costs ($2,485 vs. $3,281, p = 0.02), and similar mean pharmacy costs ($356 vs. $442, p = 0.11).

CONCLUSIONS

Pathway antibiotics were associated with improved patient survival, hospital LOS, and total hospital cost for patients admitted to the hospital with CAP.