Utilization of broad- versus narrow-spectrum antibiotics for the treatment of outpatient community-acquired pneumonia among adults in the United States

PURPOSE

To characterize antibiotic utilization for outpatient community-acquired pneumonia (CAP) in the United States.

METHODS

We conducted a cohort study among adults 18-64 years diagnosed with outpatient CAP and a same-day guideline-recommended oral antibiotic fill in the MarketScan® Commercial Database (2008-2019). We excluded patients coded for chronic lung disease or immunosuppressive disease; recent hospitalization or frequent healthcare exposure (e.g., home wound care, patients with cancer); recent antibiotics; or recent infection. We characterized utilization of broad-spectrum antibiotics (respiratory fluoroquinolone, β-lactam + macrolide, β-lactam + doxycycline) versus narrow-spectrum antibiotics (macrolide, doxycycline) overall and by patient- and provider-level characteristics. Per 2007 IDSA/ATS guidelines, we stratified analyses by otherwise healthy patients and patients with comorbidities (coded for diabetes; chronic heart, liver, or renal disease; etc.).

RESULTS

Among 263 914 otherwise healthy CAP patients, 35% received broad-spectrum antibiotics (not recommended); among 37 161 CAP patients with comorbidities, 44% received broad-spectrum antibiotics (recommended). Ten-day antibiotic treatment durations were the most common for all antibiotic classes except macrolides. From 2008 to 2019, broad-spectrum antibiotic use substantially decreased from 45% to 19% in otherwise healthy patients (average annual percentage change [AAPC], -7.5% [95% CI -9.2%, -5.9%]), and from 55% to 29% in patients with comorbidities (AAPC, -5.8% [95% CI -8.8%, -2.6%]). In subgroup analyses, broad-spectrum antibiotic use varied by age, geographic region, provider specialty, and provider location.

CONCLUSIONS

Real-world use of broad-spectrum antibiotics for outpatient CAP declined over time but remained common, irrespective of comorbidity status. Prolonged duration of therapy was common. Antimicrobial stewardship is needed to aid selection according to comorbidity status and to promote shorter courses.

Safety and efficacy of weight-based ganciclovir dosing strategies in overweight/obese patients

BACKGROUND

The management of cytomegalovirus (CMV) is particularly challenging as both CMV and its usual first-line treatment, ganciclovir, are associated with neutropenia. Ganciclovir dosing is weight-based, most commonly utilizing total body weight (TBW). The subsequent high doses of ganciclovir in overweight/obese patients may increase the risk of toxicity. Utilizing adjusted body weight (AdjBW) dosing may help mitigate this risk. Therefore, the objective of this study was to evaluate the difference in toxicity and efficacy between TBW and AdjBW ganciclovir dosing strategies in overweight/obese patients.

METHODS

This retrospective study conducted safety and efficacy analyses of ganciclovir courses (≥72 h) used as CMV treatment. The primary safety outcome was the incidence of neutropenia (absolute neutrophil count <1000 cells/μL), and the primary efficacy outcome was a 2-log decrease in CMV polymerase chain reaction within 4 weeks following ganciclovir initiation. In both analyses, courses were excluded in which ganciclovir was dosed outside of specified renal dosing parameters for >20% of the course.

RESULTS

Among the 253 courses in the safety cohort, there was no difference in the incidence of neutropenia (17.4% vs. 13.5%, p = .50) in AdjBW compared to TBW dosing. In the 62 courses evaluating efficacy, there was no statistical difference between AdjBW and TBW dosing (60.0% vs. 45.2%, p = .28). No subgroups were identified in which AdjBW dosing was advantageous.

CONCLUSION

Utilization of AdjBW ganciclovir dosing did not result in decreased neutropenia or treatment efficacy as compared to TBW dosing. Further studies with larger patient populations would be beneficial to confirm these findings.

38. Impact of Antimicrobial Stewardship Interventions on Adherence to Clostridioides difficile Treatment Guidelines

Background

Facility-specific treatment guidelines are a priority intervention recommended in the CDC Core Elements of Hospital Antimicrobial Stewardship Programs (ASPs). Our ASP sought to improve adherence to the facility C. difficile infection (CDI) treatment guideline by implementing prospective audit and feedback of CDI cases, changing fidaxomicin from being restricted to Infectious Diseases consult use, to only requiring prospective audit and feedback, and allowing fidaxomicin and oral vancomycin orders only through the order set. This study reviews the impact of these interventions.

Methods

This single-center retrospective quasi-experimental study evaluated inpatient CDI lab events 3 months pre-intervention (10/1/2019-12/31/2019) and post-intervention (10/14/2020-1/14/2021). Patient and treatment data was evaluated via chart review. The primary outcome was adherence to CDI treatment guideline. ASP intervention types were categorized. Statistical analyses were performed using Chi-squared or Fischer’s exact, where appropriate.

Results

Baseline characteristics were well matched between the 58 and 70 patients pre and post intervention respectively (Table 1). ASP interventions resulting from the prospective audit and feedback are described in Table 2 and overall acceptance rates were high (88%). Guideline adherence improved significantly from 71% pre to 90% post-intervention (p=0.005). Reasons for non-adherence included vancomycin dose incorrect for the severity of illness (9 pre vs 2 post), inappropriate duration (4 pre vs 0 post), use of combination therapy in non-fulminant disease (5 pre vs 3 post), and not using fidaxomicin for recurrent disease (3 pre vs 2 post). Clinical outcomes pre and post intervention were not different in this small sample size: colectomy 1 (2%) vs 1 (1%) p=1, 60 day all- cause mortality 15 (26%) vs 14 (20%) p=0.43, and CDI recurrence at day 60 9/43 (21%) vs 5/56 (9%) p=0.131.

Conclusion

A bundle of ASP interventions including prospective audit and feedback of CDI cases improved adherence to facility-specific CDI treatment guidelines.

Disclosures

Tamara Krekel, PharmD, BCPS, BCIDP, Merck (Speaker’s Bureau) Erik R. Dubberke, MD, MSPH, Ferring (Grant/Research Support)Merck (Consultant)Pfizer (Consultant, Grant/Research Support)Seres (Consultant)Summit (Consultant)

1319. Assessment of Spectrum Score-Based Antibiotic De-Escalation in Patients with Nosocomial Pneumonia

Background

Hospital-acquired and ventilator-associated pneumonia (HAP/VAP) cause significant morbidity and mortality. Guidelines recommend broad-spectrum empiric antibiotic therapy, including treatment for Pseudomonas aeruginosa (PSAR) and methicillin-resistant Staphylococcus aureus (MRSA), followed by de-escalation (DE). This study sought to assess the impact of DE on treatment failure.

Methods

This single-center retrospective cohort study screened all adult patients with a discharge diagnosis code for pneumonia from 2016–2019. Patients were enrolled if they met pre-defined criteria for HAP/VAP ≥48 hours after admission. Date of pneumonia diagnosis was defined as day 0. Spectrum scores were calculated, and DE was defined as a score reduction on day 3 versus day 1. Patients with DE were compared to patients with no de-escalation (NDE). Data were compared using chi-square, Mann-Whitney U, or T-tests. The primary outcome was composite treatment failure, defined as all-cause mortality or re-admission for pneumonia within 30 days of diagnosis, analyzed using a Cox proportional hazards analysis to control for confounding variables.

Figure 1. Study Schematic

Table 1. Spectrum Score Assignment

Results

Of 11860 admissions screened, 1812 unique patient-admissions were included (1102 HAP, 710 VAP). Fewer patients received DE (876 DE vs. 1026 NDE). Groups were well-matched at baseline, although more patients receiving DE had respiratory cultures ordered (56.6% vs. 50.6%, P=0.011). Patients receiving DE experienced a 65% and 44% reduction in anti-MRSA and anti-PSAR therapies by day 3, respectively. There was no difference in composite treatment failure (35.0% DE vs. 33.8% NDE, P=0.604). DE was not associated with treatment failure on Cox multivariate regression analysis (HR 1.13, 95% CI 0.97-1.33, P=0.149). Patients receiving DE had fewer antimicrobial days (median 9 vs. 11, P< 0.0001), episodes of Clostridioides difficile (2.2% vs. 3.8%, P=0.046), and days of hospitalization (median 20 vs. 22 days, P=0.006).

Figure 2: Median Spectrum Scores (SS) Days 0 to 28

Table 2: Cox Regression Analysis

Conclusion

DE and NDE resulted in similar rates of composite treatment failure at 30 days; however, DE was associated with fewer antimicrobial days, episodes of C. difficile, and days of hospitalization. Spectrum scores can objectively identify DE, but further studies are needed to fully understand their utility in this context.

Disclosures

Tamara Krekel, PharmD, BCPS, BCIDP, Merck (Speaker’s Bureau) David J. Ritchie, PharmD, BCPS (AQ-ID), AbbVie (Speaker’s Bureau)Merck (Speaker’s Bureau)

A pharmacist-driven antimicrobial stewardship intervention targeting cytomegalovirus viremia in ambulatory solid organ transplant recipients

BACKGROUND

There is a growing need for robust antimicrobial stewardship interventions in both ambulatory and solid organ transplant (SOT) populations.

METHODS

A retrospective quasi-experiment was conducted to evaluate the impact of a pharmacist-driven antimicrobial stewardship intervention targeting cytomegalovirus (CMV) viremia in ambulatory SOT recipients. The intervention consisted of (a) real-time CMV DNA surveillance and result notification conducted by the pharmacist and (b) recommendations for the optimization of drug therapy provided at the time of result notification. The intervention period was compared to a pre-intervention period of usual care. Of 431 adult SOT recipients who had an initial quantifiable CMV viral load in the ambulatory setting, 185 received antiviral induction therapy and were included for analysis.

RESULTS

Significantly fewer patients in the intervention period reached a CMV viral load >10 000 IU/mL immediately prior to treatment (10.6% vs 27.3%; P = 0.004), and a significantly greater proportion of patients in the intervention period achieved CMV eradication at 21 days (84.5% vs 71.7%; P = 0.038). Additional differences favoring the intervention period were antiviral initiation within 5 days of the first quantifiable CMV DNA (62.4% vs 55.0%; P = 0.02) and time-to-CMV eradication (25.5 vs 28.9 days; P = 0.003). Although not significant, there were also numerical reductions in CMV-related hospital admissions (11.9% vs 19.0%; P = 0.188) and CMV disease (5.9% vs 12.0%; P = 0.151) during the intervention period, as well as fewer episodes of CMV resistance at 1-year (2.3% vs 4.0%; P = 0.689).

CONCLUSION

Together, these findings suggest a potential role for pharmacist involvement in CMV surveillance and treatment optimization in ambulatory SOT recipients.

1810. Therapeutic Drug Monitoring of Azole Antifungals at an Academic Medical Center: Opportunities and Lessons Learned

Background

Methods

Results

Conclusion

Disclosures

233. Evaluation of an Antimicrobial Time-Out on Antimicrobial Utilization at a Large Health System

Background

Infectious Diseases Society of America and Society for Healthcare Epidemiology Guidelines for Implementing an Antibiotic Stewardship Program (ASP) and the CDC Core Elements of Hospital ASP include antimicrobial time-outs (ATO) as an example of a recommended action. There are limited data evaluating the impact of ATOs on antimicrobial use. Cleveland Clinic Health-System (CCHS) implemented a 72-hour ATO for antimicrobials with an empiric indication and no stop date within the electronic health record. This study aimed to assess the effect of an ATO on antimicrobial utilization.

Methods

Retrospective, quasi-experimental study of patients between October 1–December 31, 2016 and 2017 who received at least one systemic antimicrobial agent while admitted to a US-based CCHS hospital. Primary objective was to compare the days of therapy (DOT) per 1,000 patient-days of broad-spectrum agents before and after ATO implementation. Secondary objectives included comparing indications for use, actions taken as a result of the ATO, and rate of Clostridium difficile. Antimicrobial groupings per National Healthcare Safety Network AUR Module.

Results

In 4Q2016, there were 75,982 antimicrobial orders in 31,945 encounters, of which 5,029 encounters had an empiric antimicrobial active at 72 hours. In 4Q2017, there were 78,418 antimicrobial orders in 33,378 encounters, which led to 38,129 ATOs in 6,138 encounters. Mean duration of therapy was 71 hours in 4Q2016 vs. 62 hours in 4Q2017, P < 0.05 (Figure 1). DOT/1,000 patient-days did not differ (Figure 2). Orders with the indication of pathogen directed did not change (14.1% vs. 14.4%; P = 0.11). Of 16,009 ATOs acknowledged by clinicians, 2,195 (14%) prompted antimicrobial discontinuation, while 684 alerts (4%) prompted de-escalation. There was no difference in encounters with positive C. difficile PCR, 123 (2.4%) vs. 152 (2.5%).

Conclusion

Implementation of an ATO for all antimicrobials within an electronic health record decreased duration of therapy but not DOT/1,000 patient-days. Further study is needed to define optimal ATO characteristics (targeted vs. all antimicrobials, 48 vs. 72 hours, etc.) and potential impact on utilization and appropriate antimicrobial usage.

Disclosures

All authors: No reported disclosures.

Impact of antimicrobial stewardship and rapid microarray testing on patients with Gram-negative bacteremia

A rapid microarray assay, Nanosphere Verigene® Gram-negative blood culture test (BC-GN), detects four Gram-negative species, four Gram-negative genera, and six resistance genes directly from positive blood culture samples, shortening the time from Gram stain to pathogen and resistance-gene identification. The purpose of this study was to determine the impact of the BC-GN paired with an antimicrobial stewardship intervention on antimicrobial and clinical outcomes. Patients with Gram-negative bacteremia were compared before (n = 456) and after (n = 421) BC-GN implementation. The primary objective was to compare time from Gram stain to antimicrobial switch pre- and post-implementation. Time from Gram stain to effective treatment, in-hospital mortality, and hospital length of stay were also compared. The number and type of antimicrobial switches were similar between groups. Median (IQR) time from Gram stain to antimicrobial switch was significantly decreased in the post group, 28.6 (8.6-56.9) h vs 44.1 (18.9-64.6) h, p = 0.004. In patients on ineffective antimicrobial therapy at the time of result, median time to effective therapy was lower in the post group, 8.8 (5.5-18.4) h vs 24.5 (4.9-44.3) h, p = 0.034. Median (IQR) hospital length of stay was also decreased in the post group, 7 (5-15) days vs 9 (4.5-21) days, p = 0.001. The rate of in-hospital mortality was similar between groups, 11.6% (pre) vs 11.4% (post), p = 0.87. Rapid microarray testing on blood cultures combined with active antimicrobial stewardship intervention was associated with decreased time to antimicrobial switch, time to effective therapy, and hospital length of stay.

Comparison of serum concentrations between different dosing strategies of posaconazole delayed-release tablet at a large academic medical centre

It is unclear if the prophylaxis dose of 300 mg/day is sufficient for achieving serum concentrations targeting the treatment of invasive fungal infections. To evaluate differences between PCZ serum concentrations in patients receiving the DRT vs the OS and in patients receiving higher doses than 300 mg/day of the DRT, a retrospective review was conducted on inpatients who received PCZ for either treatment or prophylaxis. Baseline demographics including comorbid conditions, indication and dose of therapy were collected. Serum trough concentrations were collected at steady state. Fifty-seven patients received PCZ during the study period. A total of 35 levels were collected (DRT n = 18, OS n = 17). Patients receiving the DRT had levels >0.7 mcg/mL 100% of the time compared to 58.8% in those receiving the OS. No significant difference was seen in serum concentrations at 300 mg/day (n = 14) vs 400 mg/day (n = 8) of the DRT (1.55 mcg/mL (1.08-2.50) vs 2.5 mcg/mL (1.85-2.70), P = .19). The DRT leads to more consistent levels in the therapeutic range than the OS. Standard dosing of 300 mg/day with DRT achieves adequate concentrations for prophylaxis and treatment of IFIs, although further data are needed to determine optimal serum concentrations for treatment.

Ceftaroline fosamil: A super-cephalosporin?

Ceftaroline is a broad-spectrum cephalosporin used to treat infections caused by a variety of microorganisms, including methicillin-resistant Staphylococcus aureus (MRSA) and multidrug-resistant Streptococcus pneumoniae. However, it is not active against Pseudomonas aeruginosa, Bacteroides fragilis, and carbapenem-resistant Enterobacteriaceae. Its approved indications include community-acquired bacterial pneumonia and bacterial infections of skin and skin structures. It has also been used off-label to treat osteomyelitis, endocarditis, and meningitis caused by ceftaroline-susceptible organisms.

Antimicrobial stewardship program to reduce antiretroviral medication errors in hospitalized patients with human immunodeficiency virus infection

OBJECTIVE

Evaluate antimicrobial stewardship interventions targeted to reduce highly active antiretroviral therapy (HAART)- or opportunistic infection (OI)-related medication errors and increase error resolution.

DESIGN

Retrospective before-after study.

SETTING

Academic medical center.

PATIENTS

Inpatients who were prescribed antiretroviral therapy before the intervention (January 1, 2011, to October 31, 2011) and after the intervention (July 1, 2012, to December 31, 2012). Patients treated with lamivudine or tenofovir monotherapy for hepatitis B were excluded.

METHODS

Antimicrobial stewardship interventions included education, modification of electronic medication records, collaboration with the infectious diseases (ID) department, and prospective audit and review of HAART and OI regimens by an ID clinical pharmacist.

RESULTS

Data for 162 admissions from the preintervention period and 110 admissions from the postintervention period were included. The number of admissions with a medication error was significantly reduced after the intervention (81 [50%] of 162 admissions vs 37 (34%) of 110 admissions; P < .00)1. A total of 124 errors occurred in the preintervention group (mean no. of errors, 1.5 per admission), and 43 errors occurred in the postintervention group (mean no. of errors, 1.2 per admission). The most common error types were major drug interactions and dosing in the preintervention group and renal adjustment and OI-related errors in the postintervention group. A significantly higher error resolution rate was observed in the postintervention group (36% vs 74%; P < .001). After adjustment for potential confounders with logistic regression, admission in the postintervention group was independently associated with fewer medication errors (odds ratio, 0.4 [95% confidence interval, 0.24-0.77]; P = .005). Overall, presence of an ID consultant demonstrated a higher error resolution rate (32% without a consultation vs 68% with a consultation; P = .002).

CONCLUSIONS

Multifaceted, multidisciplinary stewardship efforts reduced the rate and increased the overall resolution of HAART-related medication errors.

Studies on canine bone marrow long-term culture: effect of stem cell factor

Long-term culture of canine marrow cells allows in vitro studies of the hematopoietic system of the dog and characterization of early progenitor cells. Colonies of fresh marrow cells grew equally good in both agar or methylcellulose supplemented with fetal calf serum, while colonies of long-term cultures required agar-based medium containing human serum. Optimum colony growth was obtained when stem cell factor (SCF) and granulocyte-macrophage-colony-stimulating factor (GM-CSF) were used as growth stimuli of colony forming units (CFU). Similar results were achieved with several cell culture media. Addition of hydrocortisone to long-term cultures improved clonogenic growth of cultured cells. Addition of 2-mercaptoethanol had no effect. Strong differences were observed in long-term culture with different horse serum lots and the addition of fetal calf serum to long-term culture suppressed CFU growth of cultured cells. Recharging of cultures with fresh marrow cells on day 7 of culture improved CFU growth only in the following week but had little effect on the outcome. Adding SCF to long-term cultures led to differentiation of more primitive cells and destruction of the stromal layer. Investigation of purified and cultured cell populations was possible when preestablished long-term cultures as stromal layers were used. Loss of long-term culture-initiating ability could be demonstrated in this system with lineage negative marrow cells expanded ex vivo with SCF and GM-CSF.

Immune phenotype of canine hematopoietic progenitor cells

The immune phenotype of canine hematopoietic progenitor cells was studied by immunoseparation and culturing of separated cells. Two separation methods were used, the magnetic cell sorting system (MACS) and the fluorescence activated cell sorter (FACS). For separation rat anti dog antibodies Dog 13 and Dog 14 directed against Thy-1, and Dog 26 as well as cross-reactive mouse anti human antibodies IOT2a and 7.2 directed against MHC class II were used. Separated cell populations were cultured in semisolid agar before and after long-term culture on a pre-established irradiated stromal cell layer. After 28 days, adherent and nonadherent cells were harvested from long-term culture. The MACS system allowed separation of cells into positive and negative fractions. Long-term culture-initiating cells (LTC-IC) were found in both the Thy-1+ and the Thy-1- fraction, but the content of LTC-IC was higher in the Thy-1+ fraction. The MACS system did not allow separation of progenitor cells according to the expression of MHC class II antigen detected by Dog 26 and the cross-reactive antibodies IOT2a and 7.2. In contrast to the MACS system the FACS allowed separation of negative, low-positive and high-positive cell populations. Low-positive fractions were well defined for Thy-1 and less well defined for MHC class II. CFU before and after long-term culture were exclusively observed in the low positive fraction (Thy-1(lo+)). Using MHC class II antibody Dog 26 LTC-IC were found mainly in the negative and low positive fraction, and CFU were observed mainly in the low and high positive fraction. In conclusion pluripotent canine hematopoietic precursor cells are low positive for Thy-1 and for MHC class II. In this respect canine hematopoietic progenitor cells are comparable to those of mouse and man.

Characterization of the F9 antigen(s) isolated from teratocarcinoma cell culture medium

Anti-F9 is a syngeneic antiserum directed against mouse teratocarcinoma cells which also reacts, by complement-mediated cytotoxicity, with early mouse embryos and male germ cells. A molecule (or molecules) which specifically inhibits anti-F9, cytotoxicity can be recovered from the culture medium of undifferentiated teratocarcinoma cells. The inhibitory component is not present in the culture medium of differentiated teratocarcinoma cells or embryonic fibroblasts. The inhibitory material binds to Ricinus communis I affinity columns indicating that it contains terminal non-reducing beta-galactosyl residues. The antigenicity of the molecule does not require protein, since the inhibitory activity is completely protease-resistant. Gel filtration indicates that the protease digested inhibitory material has a molecular weight of more than 80,000.