Research Digest is a periodic installment that recognizes the world-class clinical research performed right here at UNMC ID. Today, we review two recent articles highlighting prevention and identification of central venous catheter contamination or infection. As always, check out the linked full articles for more details.
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This study evaluated the effectiveness of an initial specimen diversion device (ISDD) in reducing contamination of central venous catheter (CVC) blood cultures. Using an in vitro model, researchers simulated CVC colonization and contamination and compared standard blood culture methods with ISDD. The ISDD detected 100% of colonized CVCs while reducing false-positive cultures from 36% to 16%.
Colonization models showed that while both methods detected bacteria, ISDD cultures had significantly lower bacterial loads and longer time-to-positivity (TTP), indicating exclusion of the heavily colonized initial blood sample. The contamination model demonstrated a 56% reduction in contamination rates with ISDD use, though statistical significance was not reached (p = 0.196).
Findings suggest that ISDD use may enhance the specificity of CVC blood cultures by reducing contamination while maintaining sensitivity. Given the clinical burden of blood culture contamination—leading to unnecessary antibiotics, catheter removals, and prolonged hospital stays—the study supports further clinical trials to assess ISDD utility in obtaining blood cultures via CVCs. Read the full article here.
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This study applied whole genome sequencing (WGS) to differentiate true catheter-related bloodstream infections (CRBSIs) from blood culture contamination in 14 cases of Staphylococcus epidermidis central line-associated bloodstream infections (CLABSIs). WGS analysis showed disparate strains in 42.9% of cases, suggesting contamination, while clinical review suggested contamination in 57.1% of cases.
Researchers analyzed 42 S. epidermidis isolates from peripheral blood and central venous catheters (CVCs) from 14 patients at a 680-bed academic hospital who were classified as having a CLABSI per CDC criteria. Clinical review categorized cases as likely CRBSI, likely contamination, or ambiguous. WGS determined strain relatedness to definitively classify strains as identical or disparate. Identical strains in peripheral and CVC cultures were suggestive of true infection, whereas disparate strains indicated contamination. In 69.2% of cases, WGS and clinical assessments aligned; however, in four cases, clinical assessment favored contamination while WGS suggested true infection.
The findings highlight the limitations of traditional CLABSI definitions, which may overdiagnose infections due to blood culture contamination. WGS can improve diagnostic precision by distinguishing true infections from contaminants, potentially refining CLABSI surveillance metrics and antibiotic stewardship. Further studies are needed to integrate WGS into routine clinical decision-making. Read the full article here.
*We are trying a new approach using AI to help summarize articles. These publications were summarized by ChatGPT (https://chatgpt.com/) and approved by the authors. There is always room for improvement. Let us know if we got it right, or if we got it wrong!*
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