Infectious Diseases Consultation Research Articles

215b. Real-World Experience of Letermovir Use at an Academic Transplant Center

Abstract Background Letermovir (LMV) is indicated for cytomegalovirus (CMV) prophylaxis in seropositive adults after allogeneic hematopoietic stem cell transplants (alloSCT). LMV is well tolerated compared to its alternatives. Our institution restricts LMV use to high-risk patient groups to maximize the cost/benefit of LMV. Despite these restrictions, LMV was in our institution’s top 50 drug expenditures, prompting a formal evaluation of its use. We describe a real-world experience with LMV at a 576-bed academic transplant center. Methods This was a single center, retrospective, descriptive study of LMV use at a transplant center. Any hospitalized patient who received ≥ 1 dose of LMV between August 2021 and January 2022 was eligible for analysis. Data collection included age, LMV administration data, length of stay, transplant status, Infectious Diseases (ID) consultation, documented rationale for non-criteria uses, and drug cost. The primary outcome was incidence of use not aligning with restriction criteria. The secondary outcome was institutional drug expenditure for non-criteria uses compared to approved uses. Results Over 6 months, 388 doses of LMV were administered to 31 unique patients during 41 admissions. LMV use during 12/41 admissions (31.7%) fell outside the institutional criteria. ID consult occurred in 58.3% (7/12) of cases. 27/31 (87%) were alloSCT patients, including 1 pediatric patient. There was also 1 liver and 1 heart transplant recipient. Reasons for non-criteria use were: primary prophylaxis in the heart transplant patient to avoid ganciclovir toxicity and in 2 alloSCT patients without high risk for CMV, pre-emptive therapy due to CMV reactivation (n=2), and step-down therapy for CMV viremia (n=4). LMV was used for extended periods ( > 100 days from transplant) in 2 cases. Non-criteria use of LMV accounted for $20 414 in drug cost over 6 months, 29% of total expenditure. Conclusion Our data suggest real world use of LMV often differs from the patient types enrolled in the phase 3 trials. Use of LMV as an alternative to available CMV therapies to avoid drug toxicities appears to drive much of this use. In addition, use outside of criteria was frequent and incurred a nontrivial cost. Modification of our criteria, such as requiring an ID consultation for off-label use, should be considered. Disclosures James S. Lewis, PharmD, FIDSA, Cidara: Advisor/Consultant|Merck: Advisor/Consultant|SeLux Diagnostics: Advisor/Consultant.

908. Impact of Antimicrobial Stewardship Protocol Mandating Infectious Diseases Consultation Post 72 Hours of Meropenem Usage

Abstract Background Carbapenem use correlates with the development of carbapenem-resistant organisms, prompting our antimicrobial stewardship program (ASP) to develop a policy mandating infectious diseases (ID) consultation after 72 hours of meropenem use. Our objective was to evaluate the impact of this policy on meropenem utilization and associated clinical outcomes. Methods This quasi-experimental, observational study evaluated the impact of the new ASP policy in adult patients across four campuses. Administered meropenem orders were retrieved retrospectively six months before (11/2020-4/2021) and after (6/2021-11/2021) policy implementation. The primary outcome was meropenem days of therapy per 1000 patient-days (DOTs). Secondary outcomes included DOTs of select broad-spectrum antimicrobials, 30-day all-cause mortality, hospital length of stay (LOS), and Clostridioides difficile (C. difficile) infection incidence. All outcomes were assessed in pre- and post-intervention periods. Results There were 1493 and 1404 meropenem orders in the pre- and post-intervention periods, respectively. Pre-intervention group patients had slightly higher modified Charlson Comorbidity Index scores (2.1 vs 1.9, p=0.02). Pre-intervention group had more patients with penicillin allergies but less patients with sulfa allergies (p=0.007 and p=0.03, respectively). The most common meropenem indications were bloodstream, respiratory, abdominal, and urinary tract infections. The incidence of extended-spectrum beta-lactamase (ESBL)-producing Enterobacterales and cefepime-resistant Pseudomonas spp. was similar in both groups (p=0.7 and p=0.1, respectively). ID consultation increased after policy implementation (44.1% vs 51.7%, p=0.001). Meropenem DOTs decreased significantly after intervention (50.3 vs 35.5, p=0.0003). We observed increases in ceftriaxone and cefepime DOTs (94 vs 103.8, p=0.006 and 39 vs 58.5, p=0.0005, respectively). An increase in C. difficile incidence was seen. Hospital LOS was similar pre- and post-intervention (mean 18.5 days, p=0.9). Conclusion The ASP policy mandating ID consultation after 72 hours of meropenem use helped decrease meropenem DOT and encouraged use of antimicrobial agents with narrower spectrum. Disclosures All Authors: No reported disclosures.

1784. Appropriateness of Intravenous Vancomycin in a Canadian Acute Care Hospital

Abstract Background Intravenous (IV) vancomycin is a commonly prescribed antimicrobial. However, there is limited literature assessing IV vancomycin appropriateness. The objective of the study was to assess the appropriateness of IV vancomycin prescriptions in a Canadian acute care hospital. Methods Prospective audit and feedback (PAF) was conducted on all new IV vancomycin prescriptions in hospitalized adults (age ≥ 18 years) at the University of Alberta Hospital from January 17 to February 11, 2022. Appropriateness was assessed against institutional prescribing guidelines (Bugs & Drugs® and Alberta Health Services Formulary Prescribing Guidelines). Verbal and written feedback were provided to the attending teams. Results A total of 109 prescriptions were audited. Median age was 57 (IQR 43-72) years and 42% were female. 65 (60%) were admitted to Medicine, 18 (17%) to Surgery, and 26 (24%) to Intensive Care units. MRSA colonization was present in 32 (29%) patients, β-lactam allergy recorded in 21 (19%), and acute kidney injury (AKI) in 21 (19%). Infectious Diseases consultation (IDC) occurred in 29 (27%). The top indications were skin and soft tissue, pulmonary, and bloodstream infections (Table 1); 70% of prescriptions were empiric in nature. Overall, 43 (39%) prescriptions were assessed to be suboptimal. Antimicrobial Stewardship program (ASP) recommendations were made in 56 prescriptions, totaling 63 unique recommendations. Vancomycin was recommended to be discontinued in 24 (43%) cases or changed to a different agent in 15 (27%). Regimen optimization (duration or frequency change) was recommended in 4 (7%). ASP recommended investigations in 8 cases and IDC in 12. Full or partial acceptance was achieved in 49 cases (88%). IDC was associated with greater appropriateness (83% vs 53%, p=0.004) as was MRSA colonization (75% vs 55%, p=0.047), but AKI was not (62% vs 60%, p=0.888). Adjusting for age, AKI, and MRSA colonization, IDC remained a significant predictor of vancomycin appropriateness (OR=4.27, [95%CI 1.44-12.70]; p=0.009). Conclusion IV vancomycin prescriptions were suboptimal in 39% of cases. IDC was associated with increased appropriateness. This pilot informs the need for antimicrobial stewardship intervention and the importance of IDC at our center. Disclosures Dima Kabbani, MD, MSc, AVIR Pharma: Grant/Research Support|AVIR Pharma: Honoraria|GSK: Honoraria|Merck: Grant/Research Support.

1782. Antimicrobial Stewardship Opportunities in Gram-Negative Bacteremia Treatment at a Community Teaching Hospital

Abstract Background Gram Negative Bacteremia (GNB) is frequently encountered among hospitalized patients. In contrast to traditional 14-day lengths of treatment (LOT), recent literature supports a shorter (7-day) LOT for uncomplicated GNB with adequate source control, and the effectiveness of oral antibiotics. The goal of the following is to outline current practices of GNB treatment and identify opportunities for antibiotic stewardship (AS). Methods This study retrospectively reviewed all cases of uncomplicated GNB at a 528-bed community teaching hospital in Rochester, NY from January 2021 through March 2022. Demographic, laboratory, microbiologic, antibiotic therapy data, results of follow-up blood cultures (FUBC), hospital length of stay and 30-day readmission were collected. Exclusions were complicated or polymicrobial bacteremia, deaths during treatment, or prolonged hospitalization due to other medical factors. Influences of Infectious diseases (ID) or AS consult on treatment and outcomes were compared to cases with no consult. Continuous variables were analyzed using unpaired t-tests; categorical variables were analyzed using Fischer’s exact test and Chi-square as appropriate. Results 133 cases met inclusion criteria. Demographic and laboratory data are in Table 1. The frequency of bacteria isolated and source of infection are in Figure 1 and Figure 2. ID was significantly more often consulted for central line infections (17% vs 3%, p=0.01), and significantly less frequently involved in urinary tract infections (39% vs 69%, p=0.009). While total LOT were similarly longer than current literature supports (11.7 vs 12.5 days, p=0.2644), cases without ID consultation received significantly more days of oral treatment (4.7 vs 7.1 days, p=0.0275). There were no significant differences between receipt and no receipt of AS recommendations. Conclusion GNB continued to receive longer LOTs than current literature recommends, with longer IV durations recommended by ID consultants compared to those without ID consult. Educational initiatives regarding the safety of shorter LOT for GNB, including the efficacy of oral antibiotics, are needed and should include ID specialists. Disclosures All Authors: No reported disclosures.

1429. Epidemiology, Clinical Characteristics, and Outcomes of Extra-Pulmonary Non-Tuberculous Mycobacterial Infections from a Single Center over a 10-Year Period

Abstract Background Non-tuberculous mycobacteria (NTM) cause a wide variety of clinical syndromes, including extra-pulmonary infections. Skin and soft tissue infections (SSTI) and bone infections caused by NTM are often associated with traumatic inoculation and data to guide diagnosis and treatment is limited. We sought to better understand skin and soft tissue infections (SSTI) and bone infections caused by NTM. Methods All NTM clinical isolates recovered at Brooke Army Medical Center from 2012-2022 were initially screened and SSTI and bone isolates were included. Corresponding electronic health records were reviewed for epidemiologic, microbiologic, and clinical data. Infections were defined as recovery of ≥ 1 NTM isolate from skin, soft tissue, or bone cultures with a corresponding clinical syndrome. Results Forty isolates from 27 corresponding patients were analyzed with a median of 1 isolate [IQR 1-1] per patient. Two-thirds (18, N = 27) were female with a median age of 51 years (IQR 33-66, Table 1). A total of 21 (78%) patients had infecting isolates, most commonly secondary to surgery (28.6%) or trauma (33%). Six of 21 (29%) had bone infections, 5 (83%, N = 6) were secondary to trauma, and 2 (33%, N=6) had both bone and SSTI isolates recovered. The majority were rapid growers (81%), most frequently M. abscessus. In infected patients, 8 (38%) had combined medical/surgical therapy, 8 (38%) had surgery alone, 4 (19%) had medical therapy alone, and 1 (5%) patient received no treatment. No infectious disease consultation was sought for 7 (87.5%) patients who received only surgery nor for the patient who received no treatment. Time from symptom onset to isolate recovery was a median of 64 days (IQR 48-108), with a median of 33 days (IQR 6-60) from isolate recovery to directed medical therapy. At the end of the study period 2 of 21 patients had died. Conclusion Data supporting diagnosis and treatment decisions in SSTI and bone NTM infections is sparse. In this study the majority of NTM isolated were determined to be the cause of true infections. We confirm that surgery and trauma are the most common mechanisms of exposure. The delay between symptom onset and directed therapy demonstrates a need for additional studies delineating specific criteria for diagnosis and treatment. Disclosures All Authors: No reported disclosures.

1815. Assessment of Therapy Duration for Non-Staphylococcal Gram-Positive Bloodstream Infections

Abstract Background The optimal duration of antimicrobial therapy for non-staphylococcal Gram-positive (GP) bloodstream infections (BSIs) remains unknown. The purpose of this study was to evaluate clinical outcomes in patients with short (6-10 days) vs. long (11-21 days) duration of therapy (DOT) for non-staphylococcal GP BSIs. Methods Adult patients with BSI due to Streptococcus or Enterococcus spp. admitted to a community health system from January 2016 to December 2021 were included in this retrospective chart review. Patients were excluded for polymicrobial BSI, positive culture deemed contamination, infectious source requiring prolonged treatment, DOT < 6 or > 21 days, or transfer, hospice, or death prior to therapy completion. The primary endpoint was 90-day all-cause mortality. Descriptive statistics, chi-square or Fisher’s exact test, and the student t-test were used for data analysis. Results Of 3,544 patients identified, 384 were screened and 86 included. There were 71 patients in the long DOT group and 15 patients in the short DOT group. All included patients were on active therapy for the entire DOT. Baseline characteristics were similar except patients in the long DOT group were more likely to have an infectious diseases consultation and a non-pulmonary source of infection (Table 1). All-cause mortality at 90 days was similar between short vs. long DOT groups (0% vs. 3%, p=0.51) (Table 2). The secondary endpoints of 30-day all-cause mortality, 30-day and 90-day BSI recurrence due to the same organism, 30-day readmission, and hospital length of stay were not statistically different between groups (Table 2). The most common pathogen identified in the short DOT group was Streptococcus pneumoniae (n=8), and the most common identified pathogens identified in the long DOT group was Streptococcus agalactiae (n=22), Enterococcus faecalis (n=14), and S. pneumoniae (n=13) (Table 3). Conclusion In this retrospective review of non-staphylococcal GP BSIs, there was no statistical difference in clinical outcomes between the short and long DOT arms. Additional research is needed to identify the optimal duration of antimicrobial therapy for non-staphylococcal GP BSIs. Disclosures All Authors: No reported disclosures.

2194. Epidemiology, Clinical Features and Outcomes of Hospitalized Adult Patients with Respiratory Syncytial Virus Infections

Abstract Background Respiratory Syncytial Virus (RSV) is a common cause of respiratory tract infection (RTI) in all age groups. In general, RSV causes more severe disease in the elderly and adults with underlying comorbidities. There are limited studies evaluating RSV disease among inpatient adults. Our study objective was to assess the epidemiology, clinical features and outcomes of RSV RTIs among hospitalized adults. Methods A multicenter retrospective cohort study was conducted on adult patients hospitalized for RSV RTIs in southeast Michigan from 1/1/19-12/31/21. Hospitalized patients were identified using ICD 10 codes for RSV related diseases. Electronic medical records were reviewed. We collected the following data: demographics, comorbid conditions, laboratory and radiology results, treatment received and outcomes (death, discharge, 30 day readmission). Results A total of 102 patients were identified and included for analysis. The mean (SD) age of the cohort was 68.8 ± 14.2 yrs, 61 (60%) were female and 60 (59%) were white. The mean body mass index of the cohort was 31 ± 9.5 kg/m2. The common comorbidities were chronic lung disease (75%), hypertension (69%), obesity (38%) and congestive heart failure (30%). The mean Charlson weighted index of comorbidity was 2.28 ± 2. Fever and hypotension were noted in 13% and 15% on admission respectively. Admission CXR were abnormal in 47% cases. RSV upper and lower RTI were present in 23 (22.5%) and 79 (77.5%) respectively. Antibiotics were given in 63% of patients. Infectious diseases consultation was obtained in 41% cases. Mechanical ventilation was required in 11%, intensive care in 23.5% patients and length of stay was 6.5 + 5.6 days. Other complications were encephalopathy in 17%, acute kidney injury in 21% and liver injury in 5%. Seven (6.8%) patients died. Conclusion Our study found that adults admitted with RSV tended to be elderly, have multiple comorbid conditions and a high incidence of lower RTIs. Admissions were frequently complicated by need for ICU stay, mechanical ventilation and death. Our study supports a need for RSV immunizations once available for this high risk population. Disclosures All Authors: No reported disclosures.

1795. Evaluation of Appropriate Daptomycin Usage in an Academic Medical Center

Abstract Background The usage of daptomycin at our institution has steadily increased, with a threefold increase from Jan 2020 to Jan 2022 according to Days of Therapy Data. The increased usage prompted this study to determine whether daptomycin use at our institution is appropriately indicated and supervised by the infection disease service. Methods We conducted a retrospective descriptive study on 74 patients who were selected randomly from a total of 234 pts who received daptomycin at our facility in Northwest Louisiana over the past two years. We studied the patient's age and gender, type of infection, indications, empiric versus targeted therapy, culture results, infectious disease consultation, and reason for early discontinuation. Results Seventy-four pts were included in the analysis. The median age was 53.50 (22-90 yrs), and 47 pts (63.5%) were male. The most common infections were bone and joint (37, 50.7%), followed by bacteremia (22, 30.1%), followed by infective endocarditis (4, 5.5%). The infectious disease service was consulted before administration of daptomycin in 87.3% (62 patients). In 70.3% (52 patients), daptomycin was used as targeted therapy. MRSA was the most common bacteria for which daptomycin was used (29, 42.6%), followed by Enterococcus faecalis (10, 14.7%) and Coagulase-negative staphylococcus (8, 11.8%). Fifty-five pts (74.3%) received vancomycin before switching to daptomycin. The most common indications was MRSA with vancomycin MIC ≥ 2 mcg/ml (25, 33.8%), followed by as an alternative to vancomycin in acute renal failure (14, 18.9%), followed by clinical or/and microbiological failure on the previous antibiotic regimen (10, 13.5%). Thirty-six pts (48.6%) completed their course, 20 (27%) pts had early discontinuation, 11 pts (14.9%) were lost to follow-up, 4 pts (5.4%) were still on daptomycin at the time of data collection, and 3 pts (4.1%) died during hospitalization. The most common cause of early discontinuation was the culture growing pathogen necessitating discontinuation of daptomycin (7 patients, 35%), followed by insurance issues that account for 15%. Conclusion Most daptomycin usage in our institution was wisely indicated under the supervision of the infectious disease service and was primarily used as targeted therapy. Disclosures All Authors: No reported disclosures.

876. Suggested Empiric Therapy for CoNS Identified by BioFire BCID2 – Making Mountains Out of Molehills?

Abstract Background Coagulase-negative Staphylococci (CoNS), including mecA-positive Staphylococcus epidermidis (MRSE), are among the bacteria identified by BioFire blood culture identification (BCID2). After transition to BCID2 on 31 March 2021, our institution began providing a suggested empiric antimicrobial therapy (EAT) comment with rapid diagnostic results, whereas no suggestions were given with the prior platform. Limited data exist on the impact of EAT suggestions on antibiotic use when likely contaminants such as CoNS are identified. Methods This was a single center, observational, pre- and post-intervention study of patients aged ≥ 18 years with CoNS in the blood between 1 April 2020 and 30 September 2021. Patients with compromised immunity, intravenous drug use, polymicrobial cultures, or MRSE-active therapy use for a documented infection were excluded. Primary outcome was the rate of initiation or discontinuation of MRSE-active agent in response to the rapid diagnostic result. Secondary outcome was healthcare resource utilization such as Infectious Diseases consultation and delayed discharge. Results A total of 174 patients were included (pre-BCID2, n=93; post-BCID2, n=81). For all CoNS rapid diagnostic results, no significant difference was noted in MRSE-active agent initiation (33.3% vs. 37.0%, p=.90) and discontinuation (61.3% vs. 48.4%, p=.31). A subgroup analysis of S. epidermidis was performed with 64 and 46 patients in pre- and post-BCID2 groups, respectively; in the latter, BCID2 identified 31/46 (67.4%) as MRSE. In this subgroup, empiric MRSE-active agent was significantly less likely to be discontinued if EAT suggestion was reported with results (68.4% vs. 31.2%, p=.03). This change was not seen if Staphylococcus species were identified as the suggestion was to withhold EAT. There was no difference in healthcare resource utilization. Conclusion Providing EAT suggestion with BCID2 result for S. epidermidis unexpectedly encouraged continuing empiric MRSE-active agent for likely contaminants. In contrast, suggestion to withhold treatment had no impact on EAT use for other CoNS. The reason for this difference is unclear, but may be a result of the highlighted methicillin resistance in the BCID2 result reporting which is specific to S. epidermidis. Disclosures James S. Lewis, PharmD, FIDSA, Cidara: Advisor/Consultant|Merck: Advisor/Consultant|SeLux Diagnostics: Advisor/Consultant.

320. Clinical Impact of Metagenomic Next Generation Sequencing in a Large Pediatric and Adult Cohort

Abstract Background Plasma metagenomic next-generation sequencing (mNGS) is an emerging diagnostic tool. As the clinical use of mNGS increases, efforts to better understand the role of mNGS in diagnosis and management of infectious diseases are essential. Current literature is limited to small retrospective reviewers and a prospective study therefore subject to institutional variability. Here, we aim to describe the use, sensitivity, time to diagnosis, clinical impact, and cost effectiveness of mNGS in the largest patient cohort to date. Methods We included pediatric and adult patients who had plasma mNGS testing as part of care from December 2017 through December 2021 at University of Minnesota (UMN). Patients were identified using the Karius database. Electronic medical records were reviewed for every mNGS test, recording patient demographics, underlying conditions, indications, and results within 30 days of mNGS. All cases were assessed by 2 reviewers including one board-certified infectious diseases doctor. Sensitivity of mNGS was determined relative to conventional tests. The primary end point was change in clinical management. Secondary end points included accuracy, time to diagnosis, and infectious disease consultation. UMN IRB approved this study as non human subjects research. Results 584 mNGS tests were ordered in the study period, with 203 reviews completed to date. Solid organ transplantation (SOT) (32%) was the most common underlying condition, followed by hemopoietic stem cell transplantation (HSCT) (28%). Fever (45.8%), then pulmonary findings (26%) were the most common indications for ordering mNGS. Conventional and mNGS tests identified an infectious cause of the clinical syndrome in 49% of cases, while a contaminant was found in 52% of cases. The sensitivity of mNGS in identification of infectious cause was 47%, approximately 7% more sensitive than conventional testing. Despite this increased sensitivity, mNGS changed clinical management in 20% of cases. Conclusion mNGS demonstrated superiority in accurate detection of infectious causes of clinical syndromes, however, changed clinical management in a minority of cases, suggesting timing of the mNGS test is critical. This study identified SOT and HSCT as high yield patient groups for implementation of a prospective study. Disclosures Beth K. Thielen, MD, PhD, Horizon: Advisor/Consultant|Horizon: Honoraria|Merck: Grant/Research Support.

979. Eligibility for and Use of Oral Antibiotic Therapy among Veterans with Osteo-articular Infections: A Retrospective Study across Eight Medical Centers

Abstract Background Osteoarticular infections are commonly treated with intravenous antibiotics even though oral antibiotics may be as effective. In this multicenter study, we evaluated how often patients with osteoarticular infections qualified for oral antibiotic therapy and how often oral antibiotics were prescribed. Methods We randomly selected 2 high-complexity Veterans Affairs (VA) hospitals from each of the 4 US Census regions. Next, we randomly selected patients admitted to these 8 facilities during 2018-2020 who had a discharge diagnosis of an osteoarticular infection, received ≥5 days of inpatient antibiotics, and had an Infectious Disease consult. Manual chart reviews were performed to confirm the diagnosis and to exclude patients who received < 4 weeks of total antibiotics or had infection of the skull, sacrum or pelvis. Eligibility for oral therapy was defined by the inclusion criteria used in a recent randomized controlled non-inferiority trial. Oral antibiotic stepdown was defined as starting an exclusively oral regimen within 2 weeks of antibiotic initiation. The chi-square test was used to compare categorical variables. Results After excluding 76 cases, the final cohort included 145 patients (median age 65, 98% male, 72% white). The most common types of osteo-articular infections were peripheral osteomyelitis (66%) and septic arthritis (14%). The most common isolated pathogen was Staphylococcus aureus (53%). Surgical debridement was performed in 104 (72%) patients, and the median antibiotic duration was 47 days (IQR 43-72). One hundred eight (74%) patients were eligible for oral step-down, but only 18 (17%) of these patients received it (Figure 1). Fourteen (78%) patients treated with oral step-down were from the same hospital. Among patients eligible for oral stepdown therapy, peripheral osteomyelitis was present in 15 (83%) of those who received oral therapy versus 58 (64%) of those who were eligible but did not receive it (p=0.12). Conclusion In this retrospective study across 8 geographically-diverse VA hospitals, three-quarters of patients with osteoarticular infections qualified for oral antibiotics but only 1 of 6 eligible patients actually received them. Oral antibiotics may be under-utilized for treating osteoarticular infections in routine practice. Disclosures Daniel J. Livorsi, MD, Merck & Co.: Grant/Research Support.

464: EVALUATION OF ANTIMICROBIAL STEWARDSHIP WHEN USING BIOFIRE FILMARRAY PNEUMONIA PANEL

Introduction: The goal of this study is to determine if the use of the BioFire Pneumonia Panel has led to positive impacts on antimicrobial stewardship in the intensive care units at Charleston Area Medical Center (CAMC). Methods: A total of 111 adult patients who were diagnosed with pneumonia in the intensive care unit (ICU), 59 patients diagnosed with standard of care and 52 patients diagnosed with the BioFire Pneumonia Panel, between September 1, 2018 – February 28, 2019 and September 1, 2019 – February 28, 2020, were included. For data collection, the following information was documented: length of stay, ICU length of stay, antibiotic indication, urine antigen collection and results, sputum culture collection and result, PCR collection and result, antibiotics, days of therapy, infectious disease consult, and if there was a C. diff diagnosis during admission. For each patient, their antimicrobial therapies were placed into one of eight categories regarding appropriate/inappropriateness of the therapy after a specific pathogen was or was not identified. Results: Standard of care showed more appropriate continuations in therapy with no change compared to BioFire PCR (30% vs 11%, p=0.015). Standard of care was less likely to have an appropriate escalation of therapy compared to BioFire PCR (0% vs 7.7%, p=0.03). There was no statistical difference between the two groups in appropriate discontinuation (1.7% vs 3.8%, p=0.48), appropriate de-escalation (27.1% vs 42.3%, p=0.09), inappropriate continuation (13.6% vs 13.5%, p=0.99), inappropriate escalation (8.5% vs 7.7%, p=0.88), or inappropriate de-escalation (13.6% vs 13.5%, p=0.99). The most common antibiotics used in each group were vancomycin and piperacillin/tazobactam, with the most common pathogen isolated being MRSA. Conclusions: Based on these results, the BioFire FilmArray Pneumonia Panel is a great tool that can help guide therapy, but the panel alone does not make an impact. The use of the PCR did not show a significant positive impact on antimicrobial stewardship other than escalating therapy guided toward a specific pathogen. Future directions for the use of the PCR for antimicrobial stewardship is to determine if the help of an antimicrobial stewardship pharmacist in combination with this tool can make a positive impact.

949. Impact of Antimicrobial Stewardship Pharmacist Participation in Pediatric Infectious Diseases Rounds on Prospective Audit and Feedback Recommendations

Abstract Background Prospective audit and feedback (PAF) is a core strategy of antimicrobial stewardship programs (ASPs). To improve communication of PAF recommendations to the inpatient pediatric infectious diseases (ID) consult service, the ASP pharmacists at our hospital were integrated into ID rounds. The purpose of this study was to assess the impact of ASP pharmacy participation in ID rounds on the rate of ASP recommendations. Methods Prior to implementation of the ASP pharmacist rounding service, the ASP pharmacist did not routinely attend rounds or communicate PAF recommendations directly to the ID consult service. Starting 1/3/22, the ASP pharmacists had daily (M-F) in-person discussions with the ID team regarding their patients’ antimicrobials. Audits performed between 1/4/21-12/30/21 and 1/3/22-4/29/22 on patients with an ID consult were included in the non-rounding cohort (NRC) and rounding cohort (RC), respectively. We compared PAF recommendation rates, characteristics, and acceptance rates between the two cohorts. Results There was an increase in PAF recommendation rate in the RC compared to NRC (188/485 [39%] vs 359/1234 [29%], p < 0.001). Antibiotics were the antimicrobial category mostly likely to have a recommendation and the rate of antibiotic PAF recommendations was higher in the RC compared to the NRC (132/341 [39%] vs. 271/934 [29%], p = 0.001) (Table 1). The most common recommendation types in both cohorts were to optimize the antimicrobial dose and antimicrobial discontinuation. Recommendations were more frequently communicated to the ID team in the RC compared to NRC (125/188 [66%] vs. 107/359 [30%], p < 0.001). The recommendation acceptance rate was similar between the two cohorts (159/188 [85%] RC vs. 290/359 [81%] NRC, p = 0.29). CNS: Central nervous system; IV: Intravenous; NRC: Non-rounding cohort; PAF: Prospective audit and feedback; PO: Per os, oral; RC: Rounding cohort; SSTI: Skin and soft tissue infection; UTI: Urinary tract infection. Conclusion Implementation of a pediatric ASP pharmacist rounding service increased the PAF recommendation rate and improved recommendation communication with the pediatric ID consult service. Participation in rounds may better inform ASP pharmacist PAF recommendations. Future studies describing the potential benefit to the ID team by having an ASP pharmacist present on rounds are warranted. ASPs should consider formal integration of ASP pharmacists as part of the ID consult service to further improve the quality of antimicrobial prescribing. Disclosures All Authors: No reported disclosures.

1742. Antibiotic Use in the Podiatry Clinic: Antimicrobial Stewardship Setting Foot in Uncharted Territory

Abstract Background Podiatrists independently manage diabetic foot ulcers (DFU), often complicated by diabetic foot infections (DFIs). The prevalence of DFU is 40 - 60% and guidelines vary in their recommendations for DFI, creating a target for antimicrobial stewardship. However, the prevalence and appropriateness of antibiotics prescribed by podiatrists has not been reported. We describe both variables among patients with DFU in a podiatry clinic. Methods We conducted a retrospective chart review of all consecutive patients > 18 years of age with DFUs, infected or not, who had at least one visit to the UPMC Mercy Wound Clinic (Pittsburgh, PA) in 2020. We defined severity of infection using the PEDIS score and diagnosis of osteomyelitis (OM) (Figure 1). We collected data on antibiotics prescribed by podiatry in the clinic or by any provider during a hospitalization for DFI. Figure 2 shows our appropriateness criteria. Figure 1:Stratification of Severity of Diabetic Foot InfectionFigure 2:Criteria for Appropriateness of Antibiotic Use in Diabetic Foot Ulcers Results Of 72 patients with DFU, 32 (44.4%) received an antibiotic. Compared to those who did not receive antibiotics, patients who did were more likely male (86.2% vs. 63.6%), had a higher PEDIS score (2.03 vs. 1.49), and were more frequently diagnosed with OM (71.9% vs. 26.8%). (Table 1). Table 2 shows the most common antibiotics. Among the five patients with no to mild infection, none received appropriate treatment (Table 3). Two patients in that category received IV antibiotics (when hospitalized for DFI), and neither received an Infectious Diseases (ID) consult. The other three were considered inappropriate due to durations > 7 days. The mean length of treatment for patients with mild infection was 12.6 (4.56). The two patients with moderate infection who received antibiotics had “inappropriate” courses; however, both had complicated Staphylococcus aureus bacteremia, and therefore 4-6 weeks courses were justified. All 12 inappropriate courses in severe infections were due to courses > 42 days. Conclusion Prescription of antibiotics among patients with DFU was common. Our findings suggest potential targets for antimicrobial stewardship: unnecessarily long courses an IV antibiotic use in patients with mild or no infection. Our criteria can be refined to recognize situations in which prolonged therapy may be justified, and larger studies are warranted. Disclosures All Authors: No reported disclosures.

1024. Transitions of Care Quality Metrics in Patients Discharged on Parenteral Antimicrobial Therapy in a Large Urban Hospital that Lacks a Formal Outpatient Parenteral Antimicrobial Therapy Program

Abstract Background With the evidence demonstrating the need for antimicrobial stewardship in the transition from inpatient to outpatient intravenous (IV) antibiotic therapy, it is imperative to have effective communication and coordination in a multidisciplinary team. Studies have demonstrated the utility of initiating a formal Outpatient Parenteral Antimicrobial Therapy (OPAT) program. The goal of this study is to assess quality metrics in a sample of patients discharged on IV antibiotics prior to initiation of a pilot OPAT program. Methods This is a retrospective, multicenter chart review of patients admitted to Temple University Health System from 10/1/2020 - 10/31/2021 who were discharged on IV antibiotics. There were no exclusion criteria. Patients with multiple admissions were documented as separate occurrences. Qualitative data were collected on the appropriateness of OPAT indication, pathogens targeted, antibiotics used, performance of infectious diseases (ID) consult, line selected, outcomes, and demographics. The primary endpoint is the percentage of global IV antibiotic prescribing errors (antibiotic, dose, route, frequency, duration, parenteral access device). Results There were 748 total discharges on IV antimicrobials in 705 unique patients. We chose a random sample of 109 discharges. Twenty (18%) had an oral antimicrobial available as an option. Antibiotic selection, dosing, duration, and access were correct 92%, 82%, 64% and 65% respectively (Table 2). ID recommended laboratory monitoring for 44 (40%) patients, of which 8 (18%) were sent to ID clinic; all had abnormal findings. Of the 25 patients who required ID follow-up, 11 had a scheduled ID appointment of which 8 attended. There was no mortality within 30 days from the 8 patients, but 2 were readmitted within 30 days. Overall, 39% patients readmitted within 30 days, 6% had mortality within 30 days and 50% were known to have completed therapy. Conclusion Our study captured a 65% rate of prescribing errors in a sample of 109 patients receiving IV antibiotics at discharge. The findings demonstrate an urgent need for an OPAT program to help with antimicrobial, parenteral access selection, monitoring, and follow-up with ID. By implementing this program, we hope to improve our ID follow-up, lab monitoring, and readmission metrics. Disclosures All Authors: No reported disclosures.

1846. Outcomes in Intravenous to Oral Antimicrobial Therapy in Beta-Streptococcus Species

Abstract Background Uncomplicated bloodstream infections (uBSI) are common and often receive prolonged courses of intravenous (IV) antibiotics, increasing risk for catheter-associated complications and hospitalization costs. β-hemolytic Streptococcus spp. are a common cause of BSI and have reliable susceptibility to many oral antibiotics. Clinically improving patients without persistent BSI and a controlled source of infection are candidates for oral antimicrobial therapy (OAT) but despite anecdotal practice, there are few studies affirming the practice of OAT for gram-positive uBSI. We evaluated IV to OAT transitions for treating β-hemolytic streptococcal uBSI. Methods This retrospective cohort study included patients >18 years old hospitalized between 1/1/2013 and 12/31/2019 diagnosed with uBSI due to β-hemolytic Streptococcus. Patients were excluded if BSI was due to endovascular, central nervous, or bone/joint infection without source control. We compared outcomes in patients treated with IV only to those transitioned to OAT including: 30-day mortality, antimicrobial therapy, BSI relapse, 30-day rehospitalization, adverse drug events, and reversion to IV therapy. Fisher’s exact test was used for categorical variables; Mann-Whitney test and independent t-test for continuous variables. Results A total of 238 Streptococcus BSI (of 321 BSI screened) were included (83 excluded as complicated, pediatric, or outpatient). OAT was used in 153 (64%). Cohort demographics were similar (table 1). Infectious disease (ID) consultation was not statistically associated with OAT transition; in fact, ID consults tended to use less OAT (66% IV vs. 54% OAT p=0.10). Hospital length of stay was statistically shortened in the OAT cohort with a median of 5 (interquartile range 4) vs. 7.5 (10.5) (p< 0.0001). Patients transitioned to OAT were more likely to finish their antibiotic course outpatient (93 vs. 61% p< 0.001). Thirty-day mortality was decreased in the OAT cohort (2% vs. 13% p< 0.0001). Adverse events were not statistically significant between the groups. Conclusion Opportunities exist to modify practice management of uBSI. For β-hemolytic Streptococcus uBSI, OAT was associated with decreased length of stay without adverse clinical outcomes. Disclosures Bryan T. Alexander, PharmD, BCIDP, AAHIVP, Astellas Pharma: Advisor/Consultant Trevor C. Van Schooneveld, MD, bioMerieux: Advisor/Consultant|bioMerieux: Grant/Research Support|Insmed: Grant/Research Support|Merck: Grant/Research Support|Thermo-Fischer: Advisor/Consultant Jasmine R. Marcelin, MD, Pfizer (Grant reviewer): Honoraria.

2150. Surgical Prophylaxis in Pediatric Liver Transplant Recipients: Variations in Protocol and Impact on 30-Day Surgical Site Infections

Abstract Background Children undergoing liver transplantation are at risk for surgical site infections (SSI). IDSA/ASHP/SIS/SHEA guidelines recommend surgical prophylaxis with a third-generation cephalosporin plus ampicillin or piperacillin-tazobactam alone. The study objectives were to describe the surgical prophylaxis used at our institution, obtain data on whether prophylactic antimicrobials are adjusted for multidrug resistant organisms and to determine whether adjustments correlate with SSI. Methods Pediatric liver transplant procedures, with associated peri-operative and intra-operative antimicrobials, were extracted from our institutions’ Anesthesia Record Keeping System (ARKS) between 2005-2022. Medical records were reviewed for demographics, microbiological data (e.g., colonization), protocol deviations and 30-day CDC/NHSN SSIs. Results Seventy-one procedures were performed in 69 patients, median age 3 years (range, 5 months- 17 years), where 89% had a pre-transplant infectious disease consultation. Variations from protocol occurred in 39% (n=28), of which 3 were consult-directed. Sixteen were colonized with an organism prior to transplant (3 MDRO and 1 Candida spp.), of which 10 had a protocol adjustment (p< 0.001). The most common additional antimicrobials were vancomycin (n=17) and fluconazole (n=8). Reasons for fluconazole were fulminant liver failure (n=2), surgeon concern (n=3), colonization or prolonged antimicrobials prior to transplant (n=2) and continuation of prophylaxis (n=1). Ten procedures were complicated by an SSI (14%). SSI rates did not differ in those with and without protocol adjustments (p=0.50). Conclusion Adjustments to guideline concordant surgical prophylaxis recommendations occurred in 39% of pediatric liver transplant procedures, with the most common being addition of vancomycin or fluconazole. Adjustments were based on a pre-transplant infectious disease consult recommendations in 11% of cases. Protocol adjustment correlated with any pretransplant microbiology culture result, but not with either MDRO colonization or subsequent SSI. Antimicrobial stewardship efforts may be indicated to address variations in antimicrobial prophylaxis in pediatric liver transplant patients. Disclosures All Authors: No reported disclosures.

546. Resolution of a Cluster of Travel-Associated Leptospira santarosai Infection in Four Adolescents by Plasma Microbial Cell-Free DNA Detection with the Karius Test®

Abstract Background Leptospira can cause severe infections but their diagnosis can be challenging. Diagnosis is limited by nonspecific, protean clinical symptoms; the fastidious nature of Leptospira; and poor specificity, sensitivity, and long turnaround times of serologic testing. Given these limitations, identifying epidemiological clusters of leptospirosis can be challenging. Rapid, non-invasive diagnosis of leptospirosis by microbial cell-free DNA (mcfDNA) next-generation sequencing (NGS) of plasma offers a means to overcome these limitations in individual diagnosis and public health epidemiological surveillance. Methods The Karius Test® (KT) detects and quantifies mcfDNA in molecules/µL (MPM) in plasma from a curated genomic database of >20,000 organisms reporting on >1000 pathogens through the Karius CLIA certified/CAP accredited lab (Redwood City, CA). Four KT detections of Leptospira santarosai were identified April - August 2021 across four independent United States institutions. Clinical review was performed by pediatric infectious diseases consultants. Results KT detected L. santarosai in four adolescents with travel to Costa Rica or Belize (Table). A broad work-up was performed in all patients. McfDNA NGS was the first test to identify L. santarosai as the diagnosis in all cases with an average time to diagnosis of 2.5+/- 0.58 days from sample collection, enabling narrowed, targeted antibiotic treatment. L. santarosai mcfDNA was positive in three patients despite pretreatment; average L. santarosai mcfDNA concentration was 173.5+/- 186.1 MPM. Leptospira serologies were confirmatory in three patients, potential epidemiological exposures were identified in all patients, and all recovered. Conclusion KT enabled rapid, non-invasive diagnosis of diverse manifestations of L. santarosai against a competing broad differential in four adolescent travelers returning from Costa Rica or Belize. The resolution of the etiology of this cluster of patients with leptospirosis demonstrates the potential utility of mcfDNA to quickly diagnose and support case definitions of reportable diseases and the potential importance of plasma mcfDNA NGS in public health and epidemiological surveillance. Disclosures Asim A. Ahmed, MD, Karius: Employee|Karius: Stocks/Bonds Sara Saporta-Keating, MS, MD, Pfizer: Co-investigator in investigator-driven study sponsored by Pfizer.

909. Impact of Implementing an IV to PO Antibiotic Treatment Protocol for Orthopedic Infections on Prescribing Habits and Health Utilization Outcomes

Abstract Background The Oral versus Intravenous Antibiotics for Bone and Joint Infection Trial concluded that oral antibiotics administered during the first six weeks of therapy for orthopedic infections were non-inferior to parenteral antibiotics. Previously, we also conducted a retrospective cohort study of patients at our center with an orthopedic infection. Patients transitioned to oral therapy had significantly fewer adverse events and similar incidences of one year treatment failure compared to patients maintained on parenteral vancomycin. Methods To increase use of oral antibiotics for orthopedic infections, we created a protocol for changing IV to PO antibiotics prior to hospital discharge. We evaluated its effect on prescribing practices and healthcare utilization outcomes. Patients with an orthopedic infection were included if they were discharged within the 90-day pre- and post-protocol study periods, had an inpatient Infectious Disease consult, and were initiated on parenteral vancomycin while inpatient. The primary outcome compared the incidence of oral antibiotics prescribed at discharge. Secondary outcomes included incidence of adverse drug reactions, discharge dispositions, hospital length of stay, canceled follow-up appointments, unplanned readmissions, and early treatment failure. Results Fifty patients were included, 22 and 28 patients in the pre- and post-protocol groups, respectively. Twenty-three (82%) patients in the post-protocol group were prescribed oral antibiotics at discharge compared to 8 (36%) patients in the pre-protocol group. Twenty-three (82%) patients in the post-protocol group were discharged home compared to 13 (59%) patients in the pre-protocol group. Of note, 7 (25%) patients in the post-protocol group had early treatment failure compared to 1 (5%) patient in the pre-protocol group, and 8 (29%) patients in the post-protocol group compared to 4 (18%) patients in the pre-protocol group had an unplanned readmission. Conclusion Providing physicians with an oral antibiotic protocol for orthopedic infections significantly increased the number of oral antibiotic prescriptions at hospital discharge, but the higher rates of treatment failure observed after protocol implementation are concerning and warrant further investigation. Disclosures Russell J. Benefield, PharmD, BCPS-AQ ID, Paratek Pharmaceuticals: Grant/Research Support.

1848. Predictors of 6-Month Mortality in Staphylococcus aureus Bacteremia: A Population-Based Study in Olmsted County, Minnesota, from 2006 to 2020

Abstract Background Staphylococcus aureus has high mortality rates, which is influenced by several factors related to the host-pathogen interaction. The current study aims to provide a contemporary evaluation of predictors of 6-month mortality rate in a population-based cohort of incident Staphylococcus aureus bacteremia (SAB) cases. Methods Retrospective population-based study of 541 adult residents of Olmsted County, MN with monomicrobial SAB from January 1, 2006 through December 31, 2020. The study’s primary outcome was 6-month mortality rate, and a survival analysis was prepared by the Kaplan-Meier method. Multivariable Cox regression was used to investigate risk factors associated with 6-month mortality. Results The median (IQR) age of 541 patients with SAB was 66.8 (54.4-78.5) years and 39.6% were female. The median Charlson Comorbidity Index (CCI) was 2 (1-4). SAB cases were healthcare-associated in 49.2% and 56.2% were methicillin-susceptible. Twenty percent of SAB cases had an unknown infection source and 38.3% had complicated bacteremia. There were 7 relapses within the first 12 weeks of follow-up, corresponding to a cumulative incidence rate of 1.3%. There were no re-infections through the remainder of the 6-month follow-up, although there were 2 recurrences after 7 months. Eighty-nine (16.5%) patients died within 1 month of SAB diagnosis and 144 (26.7%) patients died during the 6-month follow-up period. In a multivariable analysis, older age, elevated CCI, unknown source of SAB, and intensive care unit (ICU) admission were significant predictors of an increased 6-month mortality rate. In contrast, presence of diabetes mellitus was significantly associated with a decreased 6-month mortality rate; also, undergoing infectious diseases consultation was associated with reduced mortality in the first 2 weeks, but not for the remainder of the 6-month follow-up period. Conclusion To our knowledge, the current investigation represents the only contemporary population-based study determining significant predictors of mortality in SAB patients, namely, older age, higher CCI, unknown source of SAB, and ICU admission. This study also described one of the lowest 30-day mortality rates reported over the past 2 decades. Figure 1.Survival and reinfection rates of patients with SAB over 6 months. Abbreviations: SAB, Staphylococcus aureus bacteremia. Foot notes: The overall survival curve was derived by the Kaplan-Meier estimator, while the curve for reinfection was estimated by the cumulative incidence function taking into account the competing risk of death. Disclosures Larry M. Baddour, M.D., Boston Scientific: Advisor/Consultant|Botanix Pharmaceuticals: Advisor/Consultant|Roivant Sciences: Advisor/Consultant|UpToDate, Inc.: Royalty payments - authorship duties.