Abbo, Lilian M.

ABSTRACT Clinical and Laboratory Standards Institute (CLSI) recommends a blood culture contamination (BCC) threshold of <3%, with ≤1% considered optimal. However, there is not a standardized definition of BCC, and the effect of multiple definitions on BCC rates or what definitions laboratories use remain unknown. We surveyed 52 hospitals and analyzed 362,078 blood cultures (BCx) collected 1 September 2019 to 31 August 2021 from 62 intensive care units (ICUs) and 231 wards from 48 of these hospitals. We calculated and compared BCC rates using the College of American Pathologists (CAP) or CLSI criteria (both utilize a limited number of skin commensals to define BCC) and the comprehensive National Healthcare Safety Network (NHSN) commensal list. We characterized factors associated with BCC and related outcomes (central-line associated bloodstream infection [CLABSI] and vancomycin use). BCC, BCx positivity, and single BCx rates were monitored by 100%, 39%, and 21% of hospitals, respectively. Hospitals used CAP (65%), CLSI (17%), and NHSN (17%) criteria to define BCC. Mean BCC rate by CAP (CAP-BCC) was 1.38% for ICUs and 0.96% for wards. BCC rates remained similar by CLSI criteria but increased when using NHSN list. Sharing BCC data outside of the laboratory, measuring additional BCx quality indicators, and limiting central catheter-drawn BCx were associated with lower BCC rates. BCC was associated with higher CLABSI rates in ICUs. This study demonstrated variability in laboratory practices and opportunities to optimize BCx stewardship. IMPORTANCE Blood culture contamination (BCC) is associated with patient harm and unnecessary use of healthcare resources. BCC thresholds have been established; however, multiple BCC definitions exist. There is limited data on how BCC rates differ depending on the BCC definition used, what definitions laboratories most commonly use, or their approach to other blood cultures (BCx) quality indicators such as single rates or BCx positivity. A cross-sectional multicenter survey and analysis of BCx data from intensive care unit and wards revealed that most laboratories did not track single BCx or BCx positivity rates and that there was variability in how BCC was defined. Additionally, BCC rates were influenced by the definition used. BCC was associated with increased central-line associated bloodstream infection rates.

Abstract Background Carbapenem-resistant Acinetobacter baumannii (CRAb) is 1 of the most problematic antimicrobial-resistant bacteria. We sought to elucidate the international epidemiology and clinical impact of CRAb. Methods In a prospective observational cohort study, 842 hospitalized patients with a clinical CRAb culture were enrolled at 46 hospitals in five global regions between 2017 and 2019. The primary outcome was all-cause mortality at 30 days from the index culture. The strains underwent whole-genome analysis. Results Of 842 cases, 536 (64%) represented infection. By 30 days, 128 (24%) of the infected patients died, ranging from 1 (6%) of 18 in Australia-Singapore to 54 (25%) of 216 in the United States and 24 (49%) of 49 in South-Central America, whereas 42 (14%) of non-infected patients died. Bacteremia was associated with a higher risk of death compared with other types of infection (40 [42%] of 96 vs 88 [20%] of 440). In a multivariable logistic regression analysis, bloodstream infection and higher age-adjusted Charlson comorbidity index were independently associated with 30-day mortality. Clonal group 2 (CG2) strains predominated except in South-Central America, ranging from 216 (59%) of 369 in the United States to 282 (97%) of 291 in China. Acquired carbapenemase genes were carried by 769 (91%) of the 842 isolates. CG2 strains were significantly associated with higher levels of meropenem resistance, yet non-CG2 cases were over-represented among the deaths compared with CG2 cases. Conclusions CRAb infection types and clinical outcomes differed significantly across regions. Although CG2 strains remained predominant, non-CG2 strains were associated with higher mortality. Clinical Trials Registration. NCT03646227.

Abstract Background Hospital-Acquired Pneumonia (HAP), defined as pneumonia that occurs 48 hours or more after hospital admission, is considered a part of the health care-associated infections (HAIs). HAIs are one of the top ten causes of death in the United States. Correct diagnosis of HAIs is key to reducing its impact, however, the diagnosis of HAP is challenging because clinical findings are nonspecific and there is no combination of signs, symptoms, and laboratory or imaging results that can predict this diagnosis with a good sensitivity or specificity. This study aims to clarify the prioritization of clinical elements considered in the diagnosis of HAP by physicians at our center. Methods This is a cross-sectional study at a large, tertiary care academic center in Miami, Florida. The target population included hospitalists, internal medicine residents, critical care and infectious disease fellows. REDCap was used to administer the survey and collect data. A rank individual analysis was conducted to assess for the most significant diagnostic criteria overall. Kruskal-Wallis analysis was conducted to assess for significance of the individual diagnostic criteria. Results At the end of the survey period, 130 people responded (45.8% of sent surveys). Overall Kruskal-Wallis rank sum test of the systemic factors showed significant differences between the diagnostic criteria chosen. The presence of a new or worsening infiltrate on imaging was selected as most important. After that, fever, a positive respiratory culture, worsening hypoxia and new cough and shortness of breath were in the second tier of important criteria (Figure 1). The median number of factors needed to have HAP in the differential diagnosis and start empiric treatment was 3, while the needed number to secure the diagnosis of HAP was 4. In an immunocompromised patient, the median number of factors needed was 2 (Figure 2). Color red, represents selection 1 - meaning, the larger the tab, it means that specific factor was highly considered as the first factor in the diagnosis of HAP. Color green represents second most selected factor Color blue represents third most selected factor Upper box: median number of factors needed to secure the diagnosis of HAP Mid box: median number of factors needed to include HAP as the differential diagnosis in an immunocompromised patient Lower box: media number of factors needed to have HAP in the differential and start empirical treatment Conclusion In this study, we observed that the most highly considered criteria for the diagnosis of HAP are new or worsening infiltrate on imaging, new or worsening hypoxia, and respiratory cultures with growth of a classical respiratory pathogen. Most of these criteria are part of the IDSA guidelines on the evaluation and treatment of HAP. Future directions include developing a decision support tool for diagnosing HAP. Disclosures All Authors: No reported disclosures.

The prevalence of carbapenem-resistant Klebsiella pneumoniae (CR Kp ) infections in nosocomial settings remains a public health challenge. High-risk clones such as clonal group 258 (CG258) are particularly concerning due to their association with bla KPC carriage, which can severely complicate antimicrobial treatments.