Relationship of Phylogenetic Background, Biofilm Production, and Time to Detection of Growth in Blood Culture Vials with Clinical Variables and Prognosis Associated with Escherichia coli Bacteremia

• Published in: Journal of Clinical Microbiology Vol. 44; no. 4; pp. 1468 - 1474
• Main Authors: Martínez, Jose A, Soto, Sara, Fabrega, Anna, Almela, Manel, Mensa, Josep, Soriano, Alex, Marco, Francesc, Jimenez de Anta, María T, Vila, Jordi
• Format: Journal Article
• Language: English
• Published: Washington, DC American Society for Microbiology 01-04-2006
• Subjects: Aged; Bacteremia - blood; Bacteremia - diagnosis; Bacteremia - epidemiology; Bacteremia - microbiology; Bacterial diseases; Bacterial sepsis; Bacteriology; Biofilms - growth & development; Biological and medical sciences; Escherichia coli; Escherichia coli - classification; Escherichia coli - genetics; Escherichia coli - growth & development; Escherichia coli Infections - blood; Escherichia coli Infections - complications; Escherichia coli Infections - diagnosis; Escherichia coli Infections - epidemiology; Female; Fundamental and applied biological sciences. Psychology; Human bacterial diseases; Humans; Infectious diseases; Male; Medical sciences; Microbiology; Middle Aged; Miscellaneous; Phylogeny; Prognosis; Infection; Prognosis; Microbiology; Escherichia coli; Bacteriosis; Biofilm; Bacteria; Phylogeny; Detection; Blood culture; Bacteremia; Enterobacteriaceae
• ISSN: 0095-1137; 1098-660X; 1098-5530
• DOI: 10.1128/JCM.44.4.1468-1474.2006

In patients with Escherichia coli bacteremia, data on the relationship of phylogenetic background, biofilm production, and degree of bacteremia with clinical variables and prognosis are scarce. During a 1-year period, all adults with bacteremia due to Escherichia coli diagnosed at a university center were enrolled. Determination of phylogenetic background, biofilm production, and genotyping was performed with all strains, and the time to positivity of blood culture vials was recorded. A total of 185 episodes of diverse-source E. coli bacteremia was analyzed. Strains of phylogroup D were predominant (52%). Phylogroup A isolates were associated with pneumonia and prior antibiotic intake, B1 with an abdominal source of infection, B2 with the absence of urological abnormalities, and D with urological abnormalities and age below 65 years. Resistance to antibiotics and no biofilm production were concentrated in phylogroup A strains. Biofilm production was not associated with any clinical variable. An immunocompromising condition (odds ratio [OR] = 5.01, 95% confidence interval [CI] = 1.4 to 17.9), peritonitis (OR = 17, 95% CI = 3.32 to 87), pneumonia (OR = 9.97, 95% CI = 1.96 to 50.6), and </=7 h to bacteremia detection (OR = 4.37, 95% CI = 1.38 to 13.8) were the best predictors of a fatal outcome. Results from this study suggest that the distribution of phylogenetic backgrounds among E. coli strains involved in diverse-source bacteremia may be subject to geographical variation and that, in afflicted individuals, some high-risk sources, the patient's underlying condition, and the degree of bacteremia are more important than microbial factors in determining the outcome. Time to positivity of blood culture vials may be a variable of potential clinical impact.