Rare case of Proteus mirabilis native mitral valve endocarditis in an immunocompromised patient

Background Bacterial infective endocarditis caused by Proteus mirabilis is rare and there are few cases in the literature. The natural history and treatment of this disease is not as clear but presumed to be associated with complicated urinary tract infection (cUTI). Case presentation A 65-year-old female with a history of rheumatoid arthritis, factor V Leiden hypercoagulability, and prior saddle pulmonary embolism presented to the emergency department following a mechanical fall. Computed Tomography showed evidence of acute/subacute splenic emboli. Complicated UTI was likely secondary to a ureteral stone. Blood and urine cultures also grew out P. mirabilis. Transthoracic echocardiography revealed a mobile echogenic density on the anterior mitral valve (MV) leaflet consistent with a vegetation. The patient underwent MV replacement, and P. mirabilis was isolated from the surgically removed valve. Conclusions We hypothesize that the patient’s immunocompromised status following steroid and Janus Kinase inhibitor usage for rheumatoid arthritis contributed to Gram-negative bacteremia following P. mirabilis UTI, ultimately seeding the native MV. Additional studies with larger numbers of Proteus endocarditis cases are needed to investigate an association between immunosuppression and Proteus species endocarditis.

Risk factors for functional decline among survivors of Gram-negative bloodstream infection: A prospective cohort study

Objective To identify risk factors for functional decline after hospitalization for Gram-negative bacteremia. Patients and methods A prospective cohort study based on a randomized controlled trial conducted between January 1, 2013 and August 31, 2017 in Israel and Italy. Hospitalized patients with Gram-negative bacteremia who survived until day 90 and were not bedridden at baseline were included. The primary end point was functional decline at 90 days. Results Five hundred and nine patients were included. The median age of the cohort was 71 years (interquartile range [IQR], 60–80 years), 46.4% (236/509) were male and 352 of 509 (69%) patients were independent at baseline. Functional decline at 90 days occurred in 24.4% of patients (124/509). In multivariable analysis; older age (odds ratio [OR], 1.03; for an one-year increment, 95% confidence interval [CI] 1.01–1.05), functional dependence in instrumental activities of daily living at baseline (OR, 4.64; 95% CI 2.5–8.6), low Norton score (OR, 0.87; 95% CI 0.79–0.96) and underlying comorbidities: cancer (OR, 2.01; 95% CI 1.14–3.55) and chronic pulmonary disease (OR, 2.23 95% CI 1.12–4.42) and longer length of hospital stay (OR 1.09; for one-day increment, 95% CI 1.04–1.15) were associated with functional decline. Appropriate empirical antibiotic treatment was associated with lower rates of functional decline within 90 days (OR, 0.4; 95% CI 0.21–0.78). Conclusions Patients surviving bloodstream infections have poor long term trajectories after clinical recovery and hospital discharge. This has vast implications for patients, their family members and health policy makers.

Procalcitonin levels in patients with suspected sepsis

Background: Procalcitonin (PCT) was found to be a valuable and reliable biomarker for sepsis, especially in critical care patients for whom early recognition and prompt treatment could reduce mortality. Aims and Objectives: This study was aimed at correlating the levels of PCT as diagnostic marker for sepsis in relation to the culture positivity of various samples from blood, respiratory, urine, and exudates from patients admitted in a tertiary care hospital. Materials and Methods: Results of PCT level along with bacterial culture results of blood, respiratory, urine, and exudates were analyzed from 780 patients for a period of 1 year. Results: High PCT values ranging from 0.52 to 200 ng/ml were found in 331 patients admitted with suspected sepsis. Out of 135 cases of sepsis, 85 had blood culture positivity alone and 50 had culture positivity in blood and in other sites with the same organism. Among the 85 cases of bloodstream infections, in which no localized infections were identified, the median PCT was 33 for Gram-negative bacteremia, which was significantly higher as compared with a median of 16 for Gram-positive cocci. In UTI with bacteremia, the median PCT was 45.34 and in UTI without bacteremia, it was 5. Conclusion: From this study, we concluded that PCT values may be useful to distinguish Gram-negative and Gram-positive bacteremia, and furthermore, a high PCT value for patients with UTI may be helpful in predicting bacteremia.

1243. Eravacycline in Bacteremia: A Case Series

Background Eravacycline (ERV) is FDA-approved for the treatment of complicated intra-abdominal infections, but there is limited experience for non-FDA approved indications. Methods We present five cases that utilized ERV for treatment of bacteremia. Results Patient 1 in septic shock (SS) started on vancomycin (VAN) and ceftazidime-avibactam (CZA). Blood culture (BC) finalized to E. coli and regimen narrowed to CZA. On day 9, gram-positive cocci in chains in BC grew and VAN was added. BC finalized to VRE faecium and regimen was modified to ERV on day 12. Repeat BC on day 15 finalized to no growth with no recurrence of bacteremia until discharged (day 78). Patient 2 treated for MSSA bacteremia with cefazolin and subsequent K. pneumoniae VAP treated with ceftriaxone (CRO) (day 18-26). On day 27, meropenem (MEM) was initiated for gram-negative bacteremia and started on IV trimethoprim/sulfamethoxazole (TMP/SMX) the following day for pneumonia caused by TMP/SMX-susceptible S. maltophila. BC finalized on day 29 to S. maltophila resistant to TMP/SMX, regimen modified to ERV. Repeat BC on day 30 finalized to no growth and ERV was continued until day 42 with no recurrence of bacteremia; however, patient died on day 45. Patient 3 with renal failure and on day 11, CRO started for SBP prophylaxis. On day 13, switched to daptomycin and cefepime (FEP) as patient was febrile and BC repeated. BC finalized to VRE faecium and was started on ERV on day 17 and completed a 7-day course with no recurrence of bacteremia; however, patient died on day 34. Patient 4 initially treated for bacterial superinfection with CRO and azithromycin, and subsequent worsening pneumonia treated with VAN and MEM (day 10-17). On day 19, patient was febrile and treated with VAN and FEP until day 27. Repeat BC on day 29 finalized to VRE species and modified to ERV on day 32. ERV continued for a 7-day course and was discharged with no repeat BC obtained to confirm clearance. Patient 5 in SS started on VAN and MEM. On day 3, BC on admission finalized to VRE faecium and therapy switched to ERV. Repeat BC taken on day 3 after ERV initiation were negative. Discharged to complete two-week course of ERV. Conclusion ERV may be an option for bacteremia as demonstrated by clearance in four of five cases. More studies must be conducted as these reports show variable clinical outcomes. Disclosures Joshua R. Rosenberg, MD, Allergan/Abbvie (Consultant)La Jolla/Tetraphase (Consultant)Melinta (Consultant)Merck (Consultant)Paratek (Consultant)Sanofi (Consultant)Shionogi (Consultant)

198. Evaluation of Oral Step-down versus Continued Intravenous Antimicrobial Therapy in Immunocompromised Patients Hospitalized with Gram-Negative Bacteremia

Background Bloodstream infections are associated with considerable morbidity and mortality in the United States. Most patients initially receive parenteral antibiotics for gram-negative bacteremia, and more data is emerging supporting de-escalation to oral (PO) antibiotics to complete treatment. Previous studies evaluating PO antibiotics for gram-negative bacteremia often exclude or have underrepresented immunocompromised patients. This study evaluated clinical failure in immunocompromised patients receiving intravenous (IV) antibiotics compared to patients transitioned to PO antibiotics for gram-negative bacteremia. Methods A single center, retrospective cohort study was conducted at 446-bed academic medical center. Patients were included if they were immunocompromised and admitted with a positive blood culture for E. coli, Klebsiella spp., Citrobacter spp., Serratia spp., Enterobacter spp., Proteus spp., P. aeruginosa. between November 4, 2017 to November 4, 2020. Patients were excluded from this study if they had polymicrobial bacteremia, no source control within the first 5 days, or an indication for prolonged duration of treatment. The primary endpoint of this study was clinical failure defined as an escalation from PO to IV antibiotics, worsening clinical status, or readmission for the same infection within 30 days of discharge. The secondary endpoints included 30-day mortality, 90-day mortality, 30-day readmission, and time to microbiologic clearance. Results A total of 31 immunocompromised patients were included in the study with 26 patients receiving PO step-down therapy and 5 patients being continued on IV treatment for gram-negative bacteremia. There was no difference in the primary outcome of clinical failure between the PO step-down group versus the IV therapy group (15.4% vs 20%; p = 0.613). The most common immunocompromised state in both groups was being HIV positive. Patients in the PO step-down group had a significantly shorter hospital length of stay (7.4 days vs. 13.6 days; p = 0.016). Conclusion Oral step-down therapy for gram-negative bacteremia showed similar clinical failure rates to continuous IV therapy in the immunocompromised patient population and may be an option to shorten hospital length of stay. Disclosures All Authors: No reported disclosures

1126. Short-Course Therapy and Transition to Enteral Antibiotics for Uncomplicated Bacteremia Due to Enterobacterales Species

Background Gram-negative bacteremia historically has been treated with 10-14 days of parenteral antibiotics. However, data supporting this practice are lacking, and recent evidence shows equivalent outcomes for short-course (SC) therapy (7 days) and early (by day 5) conversion to highly bioavailable enteral (PO) antibiotics for Enterobacterales bacteremia. Methods Under a QI framework, we used PDSA cycles to reduce treatment duration and increase use of PO levofloxacin or trimethoprim-sulfamethoxazole for uncomplicated Enterobacterales bacteremia among Infectious Diseases (ID) clinicians at a children’s hospital in Boston, MA. We conducted an education session on evidence to support these practices for ID faculty and fellows in October 2020. In December 2020, we implemented standardized recommendations for a 7-day duration and early PO transition for eligible patients (≥ 3-months-old, ≤ 2 days monomicrobial bacteremia, with source control and return to baseline clinical status) that could be inserted automatically into electronic consult notes. In February 2021, we reinforced this practice to ID providers. We collected data before and after these interventions on ID recommendations and on patients’ actual antibiotic management. Results From 11/01/20 to 05/31/21, mean recommended treatment decreased from 10.6 to 9.5 days; however, mean duration received was similar (11.2 vs 11.7 days) (Figure 1). The percentage of patients for whom ID recommended PO conversion and in whom transition to PO agents by day 5 occurred increased from 27% to 37.5%. Figure 1. Change in average duration of antibiotics recommended and received, in days Conclusion Education and creation of automated standardized recommendations led to decreased recommended treatment durations and increased PO conversions for Enterobacterales bacteremia, but only modestly. This quality improvement initiative demonstrates the potential benefits of education and electronic documentation tools to facilitate evidence-based practice changes, but also highlights the difficulty in changing practice even amongst ID clinicians. Further PDSA cycles will be targeted at increasing more consistent awareness among a large ID division in addition to other stakeholders. Disclosures Gabriella S. Lamb, MD, MPH, Nothing to disclose

Effectiveness of an Electronic Automated Antibiotic Time Out Alert in the Setting of Gram-Negative Bacteremia

To minimize complications associated with over-utilization of antibiotics, many antimicrobial stewardship programs have incorporated an antibiotic time out (ATO); however, limited data are available to support its effectiveness. This was a single-center retrospective cohort study assessing the impact of the automated electronic ATO in the setting of Gram-negative bacteremia. The primary outcome was the proportion of patients who received a modification of therapy within 24 h of final culture results. Secondary outcomes included modification at any point in therapy, time to modification of therapy, time to de-escalation, and days of therapy of broad-spectrum antibiotics. There was a total of 222 patients who met inclusion criteria, 97 patients pre-ATO and 125 patients post-ATO. The primary outcome of modification of therapy within 24 h of final culture results was not significantly different (24% vs. 30%, p = 0.33). The secondary outcome of modification of therapy at any point in therapy was not significantly different between the two groups (65% vs. 67%, p = 0.73). All other secondary outcomes were not significantly different. The ATO alert was not associated with a higher rate of antibiotic modification within 24 h of culture results in patients with GNB. Further efforts are needed to optimize the ATO strategy and antibiotic prescribing practices.