915. Implementation of Face-to-Face Antimicrobial Stewardship Rounding at a Veterans Affairs Hospital

Background

The Veterans Affairs Central California Healthcare System (VACCHCS) antimicrobial stewardship program primarily utilizes prospective audit-feedback. Initially, antimicrobial recommendations were communicated to medicine and surgery teams exclusively through chart notes. Beginning September 2021, a new process was initiated whereby all antibiotic recommendations were communicated to care teams during daily face-to-face rounds. This pre-post cohort study is an assessment of the changes in antimicrobial use, inpatient mortality and 30-day readmissions that occurred with the intervention.

Methods

Both pre- and post- intervention, all admitted patients with active antibiotic orders were reviewed for antibiotic optimization by an ID team and a chart note was written to document recommendations. Post-intervention, recommendations were communicated via daily face-to-face rounds with medicine and surgery services. Total antibiotic use was collected from the National Healthcare Safety Network’s Antimicrobial Use and Resistance (NHSN-AUR) Module as antibiotic days-of-therapy per 1000 patient days (DOT/1000). Monthly in-hospital mortality and 30-day readmission data were collected from the VA’s Corporate Data Warehouse. Median monthly amounts of each measure were compared pre- and post-intervention. Antibiotic use was compared monthly for 2 years prior and 3 months post intervention, whereas mortality and readmission outcomes included 2 years prior and 6 months post-intervention.

Results

Pre and post-intervention median monthly antibiotic use was 728 and 741 DOT/1000, respectively. Median monthly mortality was seven deaths pre-intervention and six post-intervention. Median monthly 30-day readmissions were 48 pre-intervention and 36 post-intervention.

Conclusion

Total antibiotic use slightly increased after the intervention. Further post-intervention observation is needed in order to better characterize impact on antimicrobial use. Monthly in-hospital mortality and 30-day readmission data were decreasing prior to our intervention and continued to decrease post-intervention.

Disclosures

All Authors: No reported disclosures.

Elucidating Pathways Mediating the Relationship Between Male Sex and COVID-19 Severity

PURPOSE

To examine associations between male sex and SARS-CoV-2 test positivity, severe COVID-19 disease, and death in a single-site cohort, and assess whether male sex impacts risk for severe COVID-19 disease through socioeconomic status (SES), comorbidities, or inflammation.

MATERIALS AND METHODS

We conducted a retrospective cohort study with data collected from University of Washington Medicine EMR from March 1 to September 29, 2020. All persons, regardless of age, were included if they had a conclusive diagnostic COVID-19 PCR test result. Our exposure was sex assigned at birth. We used Poisson regression to assess associations between sex and COVID-19 test positivity, disease severity and COVID-19 related death, and linear regression to compare viral cycle threshold at the first positive test. We conducted mediation analyses to assess interventional indirect effects of male sex on severe COVID-19 risk through socioeconomic status (SES, based on area deprivation and insurance type), comorbidities, and inflammation status. Models controlled for age and race/ethnicity.

RESULTS

Of 32,919 males and 34,733 females included, 1469 (4.5%) and 1372 (4.0%) tested positive for SARS-CoV-2, respectively. Males were 14% more likely to test positive (RR = 1.14; 95% CI: 1.06-1.23), had 80% higher risk for severe COVID-19 disease (RR = 1.80; 95% CI: 1.39-2.33) and had 58% higher risk for death (RR = 1.58; 95% CI: 1.10-2.26) compared to females after adjusting for age and race/ethnicity. Mediation analyses indicated non-significant interventional indirect effects of male sex on severe COVID-19 disease through elevated inflammatory markers, SES and comorbidities, but the greatest effect was through the inflammation pathway.

CONCLUSION

Males appear to be at higher risk at all steps of the continuum of COVID-19 illness. The strongest mediating signal, albeit non-significant, is with inflammatory pathways. Further elucidation of causal pathways linking sex and COVID-19 severity is needed in larger cohorts.

37. Impact of a Vancomycin/Piperacillin-tazobactam Audit and Feedback Program

Background

Vancomycin and piperacillin-tazobactam (VPT) combination therapy is associated with nephrotoxicity and provides broad-spectrum coverage that may be unnecessary. We conducted a pre-post implementation study to assess the impact of an audit and feedback program for VPT at our academic medical center.

Methods

Automated alerts were used to identify patients on VPT at the University of Washington Medical Center (UWMC)-Montlake (ML) and UWMC-Seattle Cancer Care Alliance (SCCA) hospitals. Baseline data was collected on patients from 1/20/20-6/2/20: electronic medical records were reviewed for antibiotic indication, duration, renal function, and presence of Infectious Disease (ID) consult. From 6/25/20-10/31/20, all patients on combination therapy without an ID consult were reviewed by the antimicrobial stewardship programs at ML and SCCA, respectively. If intervention was warranted, the ML steward discussed the case with the provider then documented the conversation. The SCCA steward, instead, discussed the case with the team pharmacist. The primary outcome was change in VPT duration post intervention. Secondary outcomes included nephrotoxicity rates and carbapenem escalation.

Results

Prior to the intervention, 66 ML and 33 SCCA patients were started on the combination compared to 110 ML and 50 SCCA patients post-intervention. Overall, 50% of ML and 14% of SCCA patients were on surgical primary services. Amongst ML patients, there was a decrease in patients on VPT for > 4 days (22 % to 8%), incidence of renal injury (30.3% to 10%), and percentage of ID consults (53.0% to 43.6%). Escalation to a carbapenem was stable (4.5% to 4.5%). In SCCA patients the percentage of patients on VPT for > 4 days decreased slightly (18.2% to 15.2%), incidence of renal injury was stable (18.2% to 18%), percentage of ID consults increased (45.5% to 50.0%), and escalation to a carbapenem was stable (12.1% vs 13.5%).

Conclusion

Prospective audit and feedback of VPT was associated with a decrease in duration and nephrotoxicity in ML but not SCCA patients. The difference in outcomes could be due to the patient populations, primary services, or intervention process. This study highlights the importance of tailoring interventions even within the same medical system.

Disclosures

All Authors: No reported disclosures

Fatal infection with enterocolitis from methicillin-resistant Staphylococcus aureus and the continued value of culture in the era of molecular diagnostics

MRSA enterocolitis is under-recognized in the setting of PCR testing. In this case report, we describe risk factors, the importance of stool culture, and the third published case of MRSA enterocolitis in a patient with leukemia. In addition, we performed a retrospective analysis of all stool cultures at our institution that have grown Staphylococcus aureus, and we describe an additional five cases. We also report the diagnostic yield of organisms detected by culture, but not on the FilmArray panel. While rare, these cases demonstrate that MRSA in stool may indicate a severe and potentially life-threatening infection, particularly in immunocompromised persons.

72. Improving Antibiotic Prescribing in Interventional Radiology Using Clinical Decision Support Tools to Assess Penicillin Allergies

Background

Patients labeled with penicillin allergies often receive alternative antibiotics, leading to increased cost, higher risk of adverse events, and decreased efficacy of procedural prophylaxis. However, most of those patients can tolerate a cephalosporin. University of Washington Medical Center – Montlake (UWMC-ML) Interventional Radiology (IR) frequently administer a pre-procedure prophylactic cephalosporin. We worked with the clinicians in IR to develop tools to allow them to better assess penicillin allergies, make the most appropriate antibiotic choice, and update the patient’s allergy documentation.

Methods

We identified all patients who underwent procedures in IR between 2017–2019. Chart review was done to determine the procedures performed, patient demographic information, allergies, allergy documentation, and prophylactic antibiotics received.

In May 2020 we implemented new Clinical Decision Support tools, including an online assessment app (https://tinyurl.com/IRPCNAllAssess) and handouts to guide antibiotic decision making to clinicians in IR.

Results

From 2017 to 2019, 381 patients underwent 958 procedures in IR. Of those, 379 patients underwent 496 procedures for which the recommended first line choice for antibiotic prophylaxis is a cephalosporin. Of patients who received pre-procedure prophylactic antibiotics for those procedures, 15.9% [n=11] of patients with penicillin allergies received the first line antibiotic, compared to 89.9% [n=319] of patients without a reported penicillin allergy. Since implementation, the online app has been used to evaluate 9 patients, of whom 8 had penicillin allergies. All 8 patients safely received the first line antibiotic (3 were delabeled, 4 reported a history of mild reactions, and 1 reported a history of an immediate IgE mediated response to penicillin but safely received cefazolin).

Conclusion

IR evaluates hundreds of patients who may receive prophylactic antibiotics each year. By providing tools to assess penicillin allergies, we were able to improve both their prescribing and de-label patients which will provide a much broader impact on their care than on just their current procedure. Our free tool can be accessed at the website above, and we will demonstrate in person.

Disclosures

All Authors: No reported disclosures

Clinical Features and Outcomes of 105 Hospitalized Patients With COVID-19 in Seattle, Washington

BACKGROUND

Washington State served as the initial epicenter of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic in the United States. An understanding of the risk factors and clinical outcomes of hospitalized patients with coronavirus disease 2019 (COVID-19) may provide guidance for management.

METHODS

All laboratory-confirmed COVID-19 cases in adults admitted to an academic medical center in Seattle, Washington, between 2 March and 26 March 2020 were included. We evaluated individuals with and without severe disease, defined as admission to the intensive care unit or death.

RESULTS

One hundred five COVID-19 patients were hospitalized. Thirty-five percent were admitted from a senior home or skilled nursing facility. The median age was 69 years, and half were women. Three or more comorbidities were present in 55% of patients, with hypertension (59%), obesity (47%), cardiovascular disease (38%), and diabetes (33%) being the most prevalent. Most (63%) had symptoms for ≥5 days prior to admission. Only 39% had fever in the first 24 hours, whereas 41% had hypoxia at admission. Seventy-three percent of patients had lymphopenia. Of 50 samples available for additional testing, no viral coinfections were identified. Severe disease occurred in 49%. Eighteen percent of patients were placed on mechanical ventilation, and the overall mortality rate was 33%.

CONCLUSIONS

During the early days of the COVID-19 epidemic in Washington State, the disease had its greatest impact on elderly patients with medical comorbidities. We observed high rates of severe disease and mortality in our hospitalized patients.

The predicted ABC transporter AbcEDCBA is required for type IV secretion system expression and lysosomal evasion by Brucella ovis

Brucella ovis is a major cause of reproductive failure in rams and it is one of the few well-described Brucella species that is not zoonotic. Previous work showed that a B. ovis mutant lacking a species-specific ABC transporter (ΔabcBA) was attenuated in mice and was unable to survive in macrophages. The aim of this study was to evaluate the role of this ABC transporter during intracellular survival of B. ovis. In HeLa cells, B. ovis WT was able to survive and replicate at later time point (48 hpi), whereas an ΔabcBA mutant was attenuated at 24 hpi. The reduced survival of the ΔabcBA mutant was associated with a decreased ability to exclude the lysosomal marker LAMP1 from its vacuolar membrane, suggesting a failure to establish a replicative niche. The ΔabcBA mutant showed a reduced abundance of the Type IV secretion system (T4SS) proteins VirB8 and VirB11 in both rich and acid media, when compared to WT B. ovis. However, mRNA levels of virB1, virB8, hutC, and vjbR were similar in both strains. These results support the notion that the ABC transporter encoded by abcEDCBA or its transported substrate acts at a post-transcriptional level to promote the optimal expression of the B. ovis T4SS within infected host cells.

Innate immune recognition of flagellin limits systemic persistence of Brucella

Brucella are facultative intracellular bacteria that cause chronic infections by limiting innate immune recognition. It is currently unknown whether Brucella FliC flagellin, the monomeric subunit of flagellar filament, is sensed by the host during infection. Here, we used two mutants of Brucella melitensis, either lacking or overexpressing flagellin, to show that FliC hinders bacterial replication in vivo. The use of cells and mice genetically deficient for different components of inflammasomes suggested that FliC was a target of the cytosolic innate immune receptor NLRC4 in vivo but not in macrophages in vitro where the response to FliC was nevertheless dependent on the cytosolic adaptor ASC, therefore suggesting a new pathway of cytosolic flagellin sensing. However, our work also suggested that the lack of TLR5 activity of Brucella flagellin and the regulation of its synthesis and/or delivery into host cells are both part of the stealthy strategy of Brucella towards the innate immune system. Nevertheless, as a flagellin-deficient mutant of B. melitensis wasfound to cause histologically demonstrable injuries in the spleen of infected mice, we suggested that recognition of FliC plays a role in the immunological stand-off between Brucella and its host, which is characterized by a persistent infection with limited inflammatory pathology.

Anti-inflammatory role of IL-10 producing macrophages during early Brucella abortus infection (117.20)

Chronic bacterial diseases such as Brucellosis may result from the pathogen’s ability to evade the initial immune response. Moreover, since Brucella spp. is known to target phagocytes, we investigated its effects on macrophage (mø) phenotype and induction of anti-inflammatory responses. Brucella did not induce alternative activation of mø in cultured bone marrow-derived mø (BMM) or in splenic CD11b+ cells isolated from mice during early infection. However, upregulation of interleukin 10 (IL-10) in serum, spleen and splenic mø from B. abortus infected mice was observed as early as 3 days post infection. Infection of BMM from MyD88-/-, TLR2-/-, TLR4-/-, TLR2/4-/- and TLR9-/- mice demonstrated that IL-10 induction was MyD88 dependent and was partially dependent on pathogen recognition by TLR2 and TLR4. Functionally, in vitro IL-10-/- BMM infection resulted in significantly higher pro-inflammatory cytokine production and decreased bacterial intracellular survival. In vivo 9 days infection of IL-10-/- mice confirmed a lower ability of B. abortus to survive in absence of IL-10, as well as higher induction of pro-inflammatory cytokines, resulting in increased pathology in liver and spleen of infected mice. Taken together, our results suggest that early IL-10 induction by infected mø contributes to an initial balance between pro-inflammatory and anti-inflammatory cytokines that is beneficial to the pathogen, thereby leading to enhanced bacterial survival and persistent infection.

Comparison and Reproducibility of H-Passivation of Si(100) with HF in Methanol, Ethanol, Isopropanol and Water by IBA, TMAFM, and FTIR'

Three different HF:alcohol solutions are investigated to etch native SiO2 and passivate Si(100) surfaces with H which can the be desorbed at low temperature (T < 600°C). The resulting passivated Si(100) surfaces are compared using as a reference Si(100) passivated by a standard aqueous HF: solution (1:98 parts of HF: H2O). After a modified RCA cleaning, Si(100) etched by HF:Methanol, HF:IPA, or HF:Ethanol, is characterized by Ion Beam Analysis (IBA), Tapping Mode Atomic Force Microscope (TMAFM), and Fourier Transform Infrared Spectroscopy (FTIR). The absolute coverage of O and C is measured by nuclear reaction analysis (NRA) combined with ion channeling at 3.05 MeV for O and 4.265 MeV for C. Hydrogen is measured via the elastic recoil detection (ERD) of 4He2+ at 2.8 MeV.

Compared to aqueous HF, HF:alcohol passivates Si(100) leaving a lower O residue by an average factor of 0.62 and a similar C residue. H coverage is higher by an average factor of 1.43. Surface coverages are found to be reproducible in average by 1.4 × 1014 atoms/cm2 for C, and by 1.25 × 1014 atoms/cm2 for O when measured by IBA on samples identically processed. H coverage is reproducible within 5.5% when measured by ERD.

Selective area analysis by TMAFM shows that an increasing number of particulates is responsible for the apparent increase in root-mean -square (rms) surface roughness when the rms is measured over a whole image. Taking this effect into account, all passivated surfaces exhibit similar roughness when compared to the original Si(100) surface with little difference between alcohols and with the reference aqueous HF solution.

FTIR in the attenuation total reflection (ATR) mode detected SiHx species mostly as a dihydride. Both IBA and FTIR detected significant levels of oxygen on surfaces passivated HF in alcohol and aqueous HF. This indicates that while Si(100) exhibits more H when passivated with HF in alcohol and can be desorbed at lower temperature than when treated with aqueous HF, H is not bonded to Si only but likely bonds into a more complex surface termination, such as SiOH.