Necrotizing Pancreatitis Infected with Stenotrophomonas maltophilia: An Emerging Rare Multidrug-Resistant Organism

Stenotrophomonas maltophilia (SM) is a multidrug-resistant, Gram-negative (GN) bacillus that is an increasingly recognized nosocomial and environment pathogen. It is intrinsically resistant to carbapenems, a drug commonly utilized in the management of necrotizing pancreatitis (NP). We report a 21-year-old immunocompetent female with NP complicated by pancreatic fluid collection (PFC) infected with SM. One-third of patients with NP will develop infections by GN bacteria, while broad-spectrum antibiotics, including carbapenems, cover most infections, trimethoprim-sulfamethoxazole (TMP-SMX) is the first-line treatment antibiotic for SM. This case is critical because it highlights a rare pathogen that should be considered a causal pathogen in patients who do not respond to their care plan.

Clinical and laboratory evaluation of patients with SARS-CoV-2 pneumonia treated with high-titer convalescent plasma

Here, we report on a phase IIa study to determine the intubation rate, survival, viral clearance, and development of endogenous Abs in patients with COVID-19 pneumonia treated with convalescent plasma (CCP) containing high levels of neutralizing anti-SARS-CoV-2 Abs. Radiographic and laboratory evaluation confirmed all 51 treated patients had COVID-19 pneumonia. Fresh or frozen CCP from donors with high titers of neutralizing Abs was administered. The nonmechanically ventilated patients (n = 36) had an intubation rate of 13.9% and a 30-day survival rate of 88.9%, and the overall survival rate for a comparative group based on network data was 72.5% (1625/2241). Patients had negative nasopharyngeal swab rates of 43.8% and 73.0% on days 10 and 30, respectively. Patients mechanically ventilated had a day-30 mortality rate of 46.7%; the mortality rate for a comparative group based on network data was 71.0% (369/520). All evaluable patients were found to have neutralizing Abs on day 3 (n = 47), and all but 1 patient had Abs on days 30 and 60. The only adverse event was a mild rash. In this study on patients with COVID-19 disease, we show therapeutic use of CCP was safe and conferred transfer of Abs, while preserving endogenous immune response.

Hydroxychloroquine and tocilizumab therapy in COVID-19 patients-An observational study

Hydroxychloroquine has been touted as a potential COVID-19 treatment. Tocilizumab, an inhibitor of IL-6, has also been proposed as a treatment of critically ill patients. In this retrospective observational cohort study drawn from electronic health records we sought to describe the association between mortality and hydroxychloroquine or tocilizumab therapy among hospitalized COVID-19 patients. Patients were hospitalized at a 13-hospital network spanning New Jersey USA between March 1, 2020 and April 22, 2020 with positive polymerase chain reaction results for SARS-CoV-2. Follow up was through May 5, 2020. Among 2512 hospitalized patients with COVID-19 there have been 547 deaths (22%), 1539 (61%) discharges and 426 (17%) remain hospitalized. 1914 (76%) received at least one dose of hydroxychloroquine and 1473 (59%) received hydroxychloroquine with azithromycin. After adjusting for imbalances via propensity modeling, compared to receiving neither drug, there were no significant differences in associated mortality for patients receiving any hydroxychloroquine during the hospitalization (HR, 0.99 [95% CI, 0.80-1.22]), hydroxychloroquine alone (HR, 1.02 [95% CI, 0.83-1.27]), or hydroxychloroquine with azithromycin (HR, 0.98 [95% CI, 0.75-1.28]). The 30-day unadjusted mortality for patients receiving hydroxychloroquine alone, azithromycin alone, the combination or neither drug was 25%, 20%, 18%, and 20%, respectively. Among 547 evaluable ICU patients, including 134 receiving tocilizumab in the ICU, an exploratory analysis found a trend towards an improved survival association with tocilizumab treatment (adjusted HR, 0.76 [95% CI, 0.57-1.00]), with 30 day unadjusted mortality with and without tocilizumab of 46% versus 56%. This observational cohort study suggests hydroxychloroquine, either alone or in combination with azithromycin, was not associated with a survival benefit among hospitalized COVID-19 patients. Tocilizumab demonstrated a trend association towards reduced mortality among ICU patients. Our findings are limited to hospitalized patients and must be interpreted with caution while awaiting results of randomized trials. Trial Registration: Clinicaltrials.gov Identifier: NCT04347993.

2648. Terminating the Troll of Transplantation: Letermovir for Cytomegalovirus Prophylaxis

Background

Letermovir is a novel antiviral that was approved for cytomegalovirus (CMV) prophylaxis after allogeneic hematopoietic stem cell transplant (allo-HSCT). The objective was to assess the real-world outcomes of CMV prophylaxis with letermovir compared with preemptive therapy (PT) alone.

Methods

This retrospective pre- and post-study evaluated the clinical impact of using letermovir prophylaxis in CMV-seropositive allo-HSCT recipients at our institution. The electronic medical record was used to identify patients that received PT alone from July 2016 to November 2017 and letermovir prophylaxis from November 2017 to March 2019. The primary endpoint was the proportion of patients with CMV infection requiring PT through week 24 after transplant. Secondary endpoints included the proportion of patients with CMV infection requiring PT through week 14 after transplant, time to CMV infection requiring PT, incidence of CMV disease, CMV-related hospitalization and all-cause mortality through week 14 and 24 after transplant. Safety data included incidence and time to engraftment and adverse effects due to letermovir. Chi-squared and t-test were utilized for categorical and continuous data respectively.

Results

The baseline characteristics were similar (Table 1) and 78.7% of patients were high risk for CMV. Fewer patients in the letermovir group (n = 50) than in the historic control group (n = 100) had CMV infection requiring PT through week 24 after transplant (9 [18%] vs. 63 [63%], P < 0.001). The mean time to CMV infection requiring PT through week 24 after transplant was 93.4 days (28–161) in the letermovir group vs. 37.4 days (11–126) in the historic control group (P < 0.001). The all-cause mortality and incidence of CMV-related hospitalization were not statistically different between the two groups through week 24 after transplant (Table 2). The incidence and time to engraftment were not statistically different between the two groups (Table 3).

Conclusion

Letermovir prophylaxis in the real-world setting resulted in less CMV infection requiring PT when compared with a historic control of patients receiving PT alone. The majority of patients in the letermovir group experienced delayed-onset CMV reactivation. Letermovir was well-tolerated with no apparent myelosuppressive toxicities.

Disclosures

All authors: No reported disclosures.

137. Impact of Rapid Susceptibility Testing on Outcomes in Patients with Bacteremia

Background

Early organism identification via rapid diagnostics has been shown to reduce time to effective antimicrobial therapy and improve patient outcomes in patients with bacteremia, but antimicrobial susceptibility testing is still required to optimize therapy. The objective of this study was to determine the impact of an institution-specific rapid susceptibility testing method on outcomes in patients with bacteremia.

Methods

This was a retrospective pre- and post-intervention study of 100 adult patients with bacteremia. Patients were excluded if they had polymicrobial infection, fungemia, blood cultures collected at outside hospitals, or if they expired prior to susceptibility results. Patients were identified through a report containing positive blood cultures from October 2017 to February 2018 (pre-intervention [PrI]) and October 2018 to February 2019 (post-intervention [PoI]). The primary endpoint was the rate of clinical failure (a composite of 28-day mortality or bacteremia persisting greater than 6 days). Secondary endpoints included microbiologic outcomes, time to effective and optimal therapy, length of stay (LOS) and therapy adjustments.

Results

Baseline characteristics were similar between groups; a third of the patients were immunosuppressed (Table 1). The most common sources of infection were urinary and intra-abdominal, and the most common organisms identified were E.coli and Klebsiella spp. No significant difference in the rate of clinical failure was identified between PrI and PoI (24% vs. 18%, P = 0.6242) (Table 2). In the PoI, the time to identification, susceptibility results, and effective therapy was significantly shorter with similar time to optimal therapy and LOS. In the PoI, antimicrobial stewardship program (ASP) interventions were made significantly sooner after susceptibility results.

Conclusion

In this small, retrospective, single-center study, the implementation of a rapid susceptibility testing method was associated with reduced time to susceptibility results and more rapid interventions by the ASP, but no difference in the rate of clinical failure or time to optimal therapy was identified.

Disclosures

All authors: No reported disclosures.

An Evaluation of Selected Indications and Appropriateness of Ampicillin/Sulbactam, an Unrestricted Antimicrobial, at a Single Center

BACKGROUND

With antimicrobial resistance on the rise and few new agents in development, it is important to exercise prudent judgment when utilizing antimicrobials. The Antimicrobial Stewardship Program (ASP) is responsible for facilitating the appropriate use of antimicrobials at the institution. Restricted antimicrobials and select additional antimicrobials are monitored by the ASP team to determine if the indications chosen by the ordering prescribers correspond to and are appropriate for the patients' infections. The purpose of this study was to review ampicillin/sulbactam, an unrestricted antimicrobial, due to its declining effectiveness against Escherichia coli.

METHODS

A retrospective chart review was conducted with adult inpatients receiving ampicillin/sulbactam. One hundred consecutive orders for ampicillin/sulbactam were reviewed.

RESULTS

The greatest number of orders for ampicillin/sulbactam came from the Emergency Trauma, Medicine, and Surgery services. The indications selected by the ordering providers were: skin and soft tissue infection (33 orders), community-acquired respiratory infection (22 orders), other (14 orders), intra-abdominal infection due to susceptible organism (13 orders), urinary tract infection (nine orders), head/neck infection (five orders), infection due to human or animal bite (three orders), and diabetic foot infection (one order).

CONCLUSIONS

The correct indication was selected in 78% of orders that were reviewed for correctness. Empiric ampicillin/sulbactam was appropriate in 51% of orders, with the majority of inappropriate empiric usage being intra-abdominal and urinary tract infections.

Febrile neutropenia in hematologic malignancies: Validation of a model to select patients manageable in the outpatient setting safely

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Background: Febrile neutropenia (FN) is usually treated in an inpatient setting with empiric IV antibiotics. Accurate identification of low-risk hematologic malignancy (HM) pts (highest risk for life-threatening events) appropriate for outpatient management may reduce healthcare costs without impacting outcomes adversely. Prior studies using predictive models to identify low risk FN pts have not been validated in HM pts. Aim: To identify low risk HM pts as candidates for safe outpatient management. Methods: To determine parameters associated with an uncomplicated FN course in HM pts we tested the association between Talcott’s criteria (Talcott et al JCO Oct 2011) and additional candidate risk factors with the development of a medical event (ME) requiring urgent intervention. We conducted a retrospective cohort study of stable HM pts, admitted for FN management. Utilizing Cox regression, we examined the following factors: Talcott criteria, age, insurance status, prophylactic G-CSF/antibiotics, vitals signs and organ function. Results: We identified 97 consecutively admitted pts who met eligibility criteria of whom 27 pts developed a ME during the admission (validated by 2 investigators blinded to exposure status). In univariate analysis, Talcott’s criteria successfully identified pts at low risk for developing a ME (HR .4, p=.04 CI .17-.97). Additionally a preserved DPB (>65 mmHg) was also protective (HR .22 p<.01 CI .11-.51). Talcott’s criteria and DBP remained independent predictors of uncomplicated FN in a multivariate cox regression (AUROC curve=75%). Conclusions: This study provides support for the use of Talcott’s criteria in HM pts. The addition of DBP to Talcott’s model further improves its ability to identify low risk HM pts. Once prospectively validated, this approach may have important clinical and financial implications. [Table: see text]

Treatment of respiratory syncytial virus infection in adult patients with hematologic malignancies based on an institution-specific guideline

A total of 26 adults with hematologic malignancies and/or hematopoietic stem cell transplant were treated for respiratory syncytial virus (RSV) infection based on an institutional guideline. Thirteen patients received aerosolized ribavirin, and 13 received aerosolized ribavirin and intravenous palivizumab. Two deaths, not attributed to RSV infection, occurred within 90 days of diagnosis.

Prevention of peritransplantation viridans streptococcal bacteremia with early vancomycin administration: a single-center observational cohort study

BACKGROUND

Viridans streptococcal bacteremia (VSB) after allogeneic hematopoietic stem cell transplantation (HSCT) is associated with substantial mortality. Prevention of this serious complication is therefore a high priority. The objective of this study was to evaluate the effect of early vancomycin administration on rates and outcomes of VSB.

METHODS

We analyzed the effect of early vancomycin on the incidence of VSB in a cohort of 430 consecutive HSCTs performed during the period of 1 January 1998 to 30 September 2002. The primary end point was time to diagnosis of VSB. Early vancomycin was defined as >or=2 doses of vancomycin between days -7 through +7 after HSCT or diagnosis of VSB, whichever occurred first. Risk factors for VSB were identified in univariate and multivariate Cox proportional hazard models.

RESULTS

The incidence of VSB in the cohort was 7.4%. The incidence of VSB in patients who did not receive early vancomycin was 24.8%, compared with 0.3% in patients who did (P<.001). Additional risk factors were female sex, conditioning with total body irradiation, and diagnosis of chronic myelogenous leukemia.

CONCLUSIONS

The attributable mortality rate for VSB in our cohort was 21%. Early vancomycin was associated with decreased VSB (hazard ratio, 0.02; 95% confidence interval, 0.003-0.19) after controlling for age, sex, underlying disease, and transplantation variables. The benefits of vancomycin prophylaxis for the prevention of VSB and associated mortality need to be evaluated in a prospective clinical trial.