Saleh, Omar Abu

Abstract Background Immunomodulators have been shown to improve the outcomes of patients with severe COVID-19. However, it is not known if tocilizumab or baricitinib use would be beneficial in transplant patients who are already receiving immunomodulating agents. Moreover, augmented immunomodulation may increase risk of opportunistic infection. There are few studies analyzing the outcomes and complications of these medications in this population. Methods This is a detailed review of the medical records of all transplant patients who received tocilizumab or baricitinib for COVID-19 indication at our multi-state transplant center from April 2020 to March 2022. Results A total of 57 transplant patients received tocilizumab (n=48) or baricitinib (n=9) for management of COVID-19. Baseline characteristics are in Table 1. 60% had received at least one dose of COVID-19 vaccine. At diagnosis, all patients were lymphopenic (median 0.4 x109 cells/L) with high CRP (median 76.8mg/L) and elevated IL-6 levels (median 145.5pg/ml.). The majority had reduction in transplant immunosuppression (75%) and received remdesivir (86%) and dexamethasone (90%). Majority were admitted to the ICU (68%), including 40% who required invasive mechanical ventilation (Table 2). Almost a third developed bacterial or fungal superinfection. Bacterial infections include respiratory cultures with Klebsiella spp, MRSA, P. aeruginosa, Enterobacter spp and Stenotrophomonas. Blood cultures were positive for Klebsiella spp, MDR P. aeruginosa, E faecalis. Fungal infections include three patients with Aspergillus spp infections who received antifungals. No statistical difference was seen in mortality between patients with infections and not infections group. No statistical difference was seen between type of transplants for infection or mortality. Mortality at 90 days was 46%. Conclusion Transplant patients who received tocilizumab or baricitinib for severe or critical COVID-19 have poor outcome. This case series found high rates of mortality and opportunistic superinfections after tocilizumab and baricitinib use compared to the current literature. Future directions include a matched case-control study to compare the outcomes in this population. Disclosures Raymund R. Razonable, MD, Gilead: Grant/Research Support|Glaxo Smith Kline: Advisor/Consultant|Novartis: DSMB|Regeneron: Grant/Research Support|Roche: Grant/Research Support.

Abstract Background Itraconazole is first-line treatment for mild-moderate blastomycosis and consolidation of moderate-severe disease. Itraconazole is metabolized to 3 metabolites, including an active metabolite hydroxy-itraconazole. The sum of itraconazole and hydroxy-itraconazole levels > 1.0 mcg/mL is guideline recommended for treatment of invasive fungal infections; conversely, some experts suggest targeting a parent compound level alone > 1.0 mcg/mL. This study aims to compare clinical outcomes and adverse drug reactions (ADRs) of combined itraconazole and hydroxy-itraconazole levels > 1.0 mcg/mL versus itraconazole parent compound alone > 1.0 mcg/mL in patients with blastomycosis. Methods This study is a single-center, retrospective chart review of patients ≥ 18 years with probable or proven Blastomyces infection who received itraconazole with at least one documented serum itraconazole level. The primary outcome was rate of partial or complete treatment response in patients with a combined itraconazole and hydroxy-itraconazole level > 1.0 mcg/mL versus itraconazole parent compound > 1.0 mcg/mL for > 75% of measured levels. ADRs attributable to itraconazole were compared between the groups. Treatment response rates and ADRs were compared between groups using two proportion z-tests. Results Total of 80 patients were included: 36 = combined itraconazole and hydroxy-itraconazole > 1.0, 32 = itraconazole parent alone > 1.0, 12 = 75% of all levels < 1.0. No statistically significant difference was observed between groups for blastomycosis rate of partial or complete treatment response (94.3% combined vs 96.6% parent, p=0.99). Significantly higher mortality was observed in patients failing to achieve itraconazole or itraconazole/hydroxy-itraconazole > 1.0 (2.8% combined vs 0% parent vs 25% neither, p=0.01). There was no significant difference in total ADRs between the three groups (p=0.56). Conclusion This limited evidence supports an itraconazole therapeutic target combining itraconazole and hydroxy-itraconazole > 1.0 for blastomycosis treatment. Disclosures Paschalis Vergidis, MD, AbbVie: DSMB|Cidara: Grant/Research Support|Scynexis: Grant/Research Support Christina G. Rivera, PharmD, Gilead: Grant/Research Support|Gilead: Honoraria|Insmed: Honoraria.

Abstract Background Beta-lactam therapeutic drug monitoring (BL TDM; drug level testing) can facilitate improved outcomes in critically ill patients. Yet less than 20% of hospitals have implemented BL TDM. The purpose of this study was to characterize provider perceptions and key considerations for successful implementation of BL TDM. Methods This was a sequential mixed methods study from 2020 to 2021 of stakeholders at three academic medical centers with varying degrees of BL TDM implementation - Mayo Clinic (BL TDM not implemented), University of Florida Health Shands (partially implemented), and Royal Brisbane and Women’s Hospital (fully implemented). Stakeholders completed a survey to characterize their knowledge, perceptions, and experience with BL TDM. A diverse group of 30 respondents were then purposively sampled for semi-structured interviews. Results from the two strands were integrated, themes were identified, and findings were situated within implementation science frameworks. Results Among the 138 survey respondents (22% response rate), the majority were physicians (38%) and pharmacists (33%). 71% practiced in critical care and 21% in infectious diseases. The majority of respondents felt BL TDM was relevant to their practice and improved medication effectiveness and safety (Figure 1). Two implementation themes were identified: individual internalization and organizational features. Individuals needed to internalize, make sense of, and agree to BL TDM implementation which was positively influenced by repeated exposure to evidence and expertise. The process of internalization seemed more complex with BL TDM than with other antibiotics (i.e., vancomycin). Organizational considerations relevant to BL TDM implementation included adequate physical and informational infrastructure, access to trained personnel, supportive governance/leadership, and robust process and workflow development. Conclusion We found broad enthusiasm about the relevance and potential benefits of BL TDM among stakeholders. Prior literature suggested the primary barrier to implementation was assay availability, but we identified many more individual and organizational attributes which impacted the scale and spread of BL TDM. Disclosures Sara Ausman, PharmD, Gilead: Honoraria Christina G. Rivera, PharmD, Gilead: Grant/Research Support|Gilead: Honoraria|Insmed: Honoraria Jason Roberts, BPharm(Hons), PhD, FSHP, FISAC, British Society of Chemotherapy: Grant/Research Support|Cipla: Honoraria|Gilead: Advisor/Consultant|MSD: Advisor/Consultant|MSD: Honoraria|Pfizer: Board Member|Pfizer: Honoraria|Qpex: Grant/Research Support|Sandoz: Board Member|Summit: Advisor/Consultant|Wolters Kluwer: Advisor/Consultant Marc H. Scheetz, PharmD, MSc, Abbvie: Advisor/Consultant|Allecra: Grant/Research Support|Merck: Advisor/Consultant|Nevakar: Advisor/Consultant|Nevakar: Grant/Research Support|Premier Healthcare Solutions: Honoraria|Spero: Advisor/Consultant|SuperTrans Medical: Advisor/Consultant|SuperTrans Medical: Grant/Research Support|Takeda: Advisor/Consultant|Third Pole Therapeutics: Advisor/Consultant.

Abstract Background There are not established clinical breakpoints (CBP) for antifungals against Cryptococcus species; However, the analysis of their MICs using epidemiological cut-off values (ECVs) can help to distinguish wild-type (WT) isolates from non-WT strains that may harbor intrinsic or acquired resistance to antifungals. Herein, we analyze the MIC distribution of antifungals against Cryptococcus spp. isolated over the last decade at our reference laboratory. Methods We conducted a retrospective evaluation of antifungals MICs for Cryptococcus neoformans and Cryptococcus gattii complex isolates from various sources that were processed at the Mayo Clinic Laboratory from November 18, 2011 to June 7, 2021. Antifungal susceptibility testing was performed by the Clinical & Laboratory Standards Institute (CLSI) standards (CLSI M59-ED3:2020). We used recommended ECVs to define if the isolates were WT or non-WT, and described the change in the percentage of WT isolates over time. Results During the study period, C. neoformans was isolated from 632 samples collected from 533 patients. Sample sources included cultures from blood (n=301), cerebrospinal fluid (n=230), respiratory (n=71), and other sources (n=30). The overall percentage of WT isolates for amphotericin B (AMB), 5-flucytosine, and fluconazole were 77%, 98% and 91% respectively with no significant difference based on various sources (Table). We noticed an overall increase in MICs for AMB, with 100% WT isolates in 2011 compared to 79% in 2021. No such increase was seen for fluconazole or 5-Flucytosine (Figure). Irrespective of the source or the year of isolation, WT strains for itraconazole, voriconazole, and posaconazole were consistently > 93%. C. gattii was isolated from 16 samples, and 94% were WT strains for AMB and 100% for the other antifungals. CLSI, Clinical and Laboratory Standard Institute; CSF, cerebrospinal fluid; ECVs, epidemiologic cut-off values. AMB, amphotericin B; FLU, fluconazole; 5FC, 5-flucytosine. Conclusion In the last decade, we have observed an overall increase in MICs of AMB for C. neoformans. The number of WT strains for other antifungals was high and not significantly changed during the study frame. Further studies are needed to identify the clinical implications of these findings. Disclosures Paschalis Vergidis, MD, AbbVie: DSMB|Cidara: Grant/Research Support|Scynexis: Grant/Research Support.

Abstract Background Methicillin-susceptible Staphylococcus aureus (MSSA) bacteremia requires weeks of IV antimicrobial therapy for treatment with antistaphylococcal penicillins (ASP) and first-generation cephalosporins being mainstays of therapy. While effective, use of these agents in the outpatient setting requires frequent dosing along with close toxicity monitoring through the duration of therapy. Ceftriaxone is an appealing alternative given daily dosing and tolerability, but efficacy in this setting remains uncertain. We sought to review outcomes of patients who received ceftriaxone versus an ASP and first-generation cephalosporins for definitive therapy of MSSA bacteremia. Methods Following IRB approval, we reviewed medical records of a retrospective adult cohort diagnosed with MSSA bacteremia treated with ceftriaxone, cefazolin, or an ASP between January 2018 and December 2019 at Mayo Clinic campuses. Treatment was defined as the antibiotic used in the outpatient setting. The primary outcome was 90-day treatment failure, defined as a composite of mortality and microbiologic relapse. Secondary outcomes were 30-day treatment failure and individual components of treatment failure. Multivariable Cox regression analysis was performed to analyze for an association between ceftriaxone use and the primary outcome after adjusting for factors that may also impact outcomes. Kaplan-Meier curves were compared utilizing a log-rank test for survival between groups. Results A total of 223 patients with the accompanying characteristics met study criteria (Table 1). Thirty-seven received ceftriaxone (16.5%) and 186 (83.4%) were treated with cefazolin or an ASP. Ninety and 30-day treatment failure were higher in those treated with ceftriaxone (27%, 8.1%) compared to cefazolin or an ASP (8.6%, 3.8%). Multivariable analysis for risk of 90-day treatment failure revealed a hazard ratio of 2.91 for ceftriaxone (Table 2) and a significant difference in event-free survival for those treated with ceftriaxone compared to cefazolin or an ASP (Figure 1). Conclusion Patients receiving definitive therapy with ceftriaxone for MSSA bacteremia experienced a higher rate of 90 and 30-day treatment failure and a lower rate of event-free survival as compared to those treated with cefazolin or an ASP. Disclosures All Authors: No reported disclosures.

Abstract The diagnosis of Q fever can be challenging and a high index of suspicion is necessary. Within this case series, we highlight the utility of the microbial cell-free DNA next-generation sequencing or Karius Test in the timely diagnosis and management of acute Q fever.

Abstract Background Population-based studies of Staphylococcus aureus bacteremia (SAB) in the United States are limited. We provide a contemporary evaluation of SAB incidence in Olmsted County, Minnesota, from 2006 to 2020. Methods This was a retrospective population-based study of all adult patients with SAB residing in Olmsted County from 1 January 2006 through 31 December 2020. Initial episodes of SAB were identified using the microbiology laboratory databases at both Olmsted Medical Center and Mayo Clinic Rochester. Results Overall, 541 incident SAB cases were identified with a median age of 66.8 (interquartile range, 54.4–78.5) years, and 60.4% were male. Among these cases, 298 (56.2%) were due to methicillin-susceptible S aureus (MSSA) and 232 (43.8%) cases of methicillin-resistant S aureus (MRSA). The overall age- and sex-adjusted SAB incidence rate (IR) was 33.9 (95% confidence interval [CI], 31.0–36.8) cases/100 000 person-years (PY). Males had a higher age-adjusted IR of 46.0 (95% CI, 41.0–51.0) cases/100 000 PY compared to females (IR, 24.4 [95% CI, 21.1–27.7] cases/100 000 PY). Age- and sex-adjusted SAB IRs due to MSSA and MRSA were 18.7 and 14.6 cases/100 000 PY, respectively, and the percentage of incident SAB cases due to MRSA fluctuated across the study period. There was no apparent temporal trend in SAB incidence over the study period (P = .093). Conclusions Our investigation represents the only contemporary population-based study in the United States. Despite the impression that SAB incidence may have increased based on Centers for Disease Control and Prevention surveillance data, our finding of no change in SAB incidence was somewhat unanticipated.