182. Clinical Presentation of Patients with Staphylococcus lugdunensis Positive Blood Cultures After the Implementation of Rapid Molecular Blood Culture Diagnostics

Abstract Background Since the implementation of improved laboratory techniques, coagulase negative Staphylococcus (CoNS) have been routinely speciated to screen for S. lugdunensis (SL), which has led to increased identification. The objective of this study is to describe the characteristics of patients with SL positive blood cultures after the introduction of Verigene® Gram-Positive Blood Culture Nucleic Acid Test (BC-GP) in two large medical systems. Methods Retrospective review of all blood culture isolates positive for SL from Memorial Hermann Hospital System (14 hospitals) and HarrisHealth System (two acute care hospitals) since implementation of BC-GP. Results Between 2017 – 2021, 157 patients had SL positive blood cultures. 18 were eliminated as cultures were positive for bacteria other than CoNS, and 7 eliminated as patients were discharged prior to culture results. Of the remaining 132 patients, 39 (29.5%) were labelled contaminants by the treating physician and 93 were considered true bacteremia. Patients with hardware/implanted materials were more likely considered to have true bacteremia, while patients with other CoNS species in blood cultures were more likely considered contaminants. Only one death was attributed to SL bloodstream infection in the true bacteremia group. None of the deaths in the contaminated group were attributed to SL infection. Of the 93 patients labelled true bacteremia, the source was most frequently listed as central line associated bloodstream infection (17.2%), followed by skin/soft tissue infection (11.8%), and infective endocarditis (IE) (10.8%). Table 1. Characteristics of Patients with S. lugdunensis Positive Blood Cultures Conclusion In our study, 29% of patients with positive blood culture for SL were deemed contaminants. Patients without hardwares or positive concomitant other CoNS species from the same blood culture were often considered as contaminated cases. The incidence of IE remains as high as 10.8% in those patients identified to have true bacteremia (7.6% overall in our cohort), although lower than previously reported cases. Careful evaluation is warranted in patients with positive SL blood culture to rule out severe infections and avoid unnecessary courses of antibiotic therapy. This study suggests that increased identification of SL may impact our understanding of its significance and pathogenicity over time. Disclosures All Authors: No reported disclosures

Background. Risk factors for community-associated Staphylococcus aureus bacteremia (SAB) are incompletely understood. We used Geographic Information Systems (GIS) and spatial statistics to analyze demographic and geographic epidemiology of SAB in the community.
Methods. We used the S. aureus Bacteremia Group Prospective Cohort Study (SABG-PCS) at Duke University Medical Center to obtain demographic and clinical data. We used the American Community Survey and U.S. Census to supply neighborhood variables. Secular trends in demographic and clinical characteristics of SAB patients prospectively enrolled between 1995 and 2015 (n = 2478) were determined using linear regressions. To characterize spatial patterns in Methicillin-resistant S. aureus (MRSA) bacteremia compared to Methicillinsusceptible S. aureus (MSSA) bacteremia, we used GIS mapping and selected a subgroup of patients (n = 667) living in and around Durham County, North Carolina. We then created generalized additive models (GAMs) using this subgroup to detect geographic heterogeneities in probabilities of MRSA infections compared to MSSA infections.
Results. We found evidence of changing demographic and clinical characteristics of SAB patients over the 21-year period. The proportion of infections acquired in the community increased significantly (p < 0.0001). However, we did not detect spatial heterogeneities of MRSA infections in Durham County. Patient location of residence was not significantly associated with antimicrobial-resistant infections. Patient age and year of hospital admission were the only statistically significant covariates in our spatial models.
Conclusion. We utilized a novel method to analyze SAB in the community using GIS and spatial statistics. Future research should prioritize community transmission of S. aureus to identify robust risk factors for infection. Background. Since the implementation of improved laboratory techniques, coagulase negative Staphylococcus (CoNS) have been routinely speciated to screen for S. lugdunensis (SL), which has led to increased identification. The objective of this study is to describe the characteristics of patients with SL positive blood cultures after the introduction of Verigene® Gram-Positive Blood Culture Nucleic Acid Test (BC-GP) in two large medical systems.
Methods. Retrospective review of all blood culture isolates positive for SL from Memorial Hermann Hospital System (14 hospitals) and HarrisHealth System (two acute care hospitals) since implementation of BC-GP.
Results. Between 2017 -2021, 157 patients had SL positive blood cultures. 18 were eliminated as cultures were positive for bacteria other than CoNS, and 7 eliminated as patients were discharged prior to culture results. Of the remaining 132 patients, 39 (29.5%) were labelled contaminants by the treating physician and 93 were considered true bacteremia. Patients with hardware/implanted materials were more likely considered to have true bacteremia, while patients with other CoNS species in blood cultures were more likely considered contaminants. Only one death was attributed to SL bloodstream infection in the true bacteremia group. None of the deaths in the contaminated group were attributed to SL infection. Of the 93 patients labelled true bacteremia, the source was most frequently listed as central line associated bloodstream infection (17.2%), followed by skin/soft tissue infection (11.8%), and infective endocarditis (IE) (10.8%). Conclusion. In our study, 29% of patients with positive blood culture for SL were deemed contaminants. Patients without hardwares or positive concomitant other CoNS species from the same blood culture were often considered as contaminated cases. The incidence of IE remains as high as 10.8% in those patients identified to have true bacteremia (7.6% overall in our cohort), although lower than previously reported cases. Careful evaluation is warranted in patients with positive SL blood culture to rule out severe infections and avoid unnecessary courses of antibiotic therapy. This study suggests that increased identification of SL may impact our understanding of its significance and pathogenicity over time.
Disclosures. Background. Left ventricular assist device infections (LVADIs) contribute significantly to morbidity and mortality. The lack of evidenced-based treatment recommendations results in substantial variability in clinical practice. The purpose of this study was to evaluate the management of LVADIs at our institution to better assess practice patterns and standardize treatment decisions.
Methods. This was a retrospective study including adults diagnosed with an initial LVADI from January 1, 2013 to July 1, 2019. Exclusion criteria included concomitant non-LVADI, patients with other mechanical circulatory systems, or pregnancy. Pertinent patient, LVAD, infection, management, and clinical outcome data was collected and described with descriptive statistics.
Conclusion. This study offers unique insight into initial vs. recurrent LVADIs as well as infection characteristics and clinical outcomes at a large academic medical center. Future studies with additional focus on risk factors for recurrence would be beneficial for drawing conclusions on the efficacy of current practices and shaping future treatment guidelines.
Disclosures. Background. Staphylococcus aureus bacteremia (SAB) is associated with high morbidity and mortality. Infectious disease consultation (IDC) is associated with increased adherence to guideline management and improved patient outcomes. We describe the IDC rate over time and impact of IDC on the management and outcomes of patients with SAB.
Methods. This retrospective chart review includes adult patients (≥ 18 years) hospitalized at the University of Alberta Hospital, Edmonton, Canada who had at least 1 blood culture growing Staphylococcus aureus during two time periods (A: Jan 2010 to Dec 2012; B: Jan to Oct 2020). Patients who died or were made palliative within 48hrs following bacteremia were excluded. Descriptive statistics were used to compare appropriateness of SAB management and outcomes in patients receiving IDC and those who did not (NIDC).