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

Abstract

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.

Host Factors and Portal of Entry Outweigh Bacterial Determinants To Predict the Severity of Escherichia coli Bacteremia

“…Based on previous reports, the expected proportion of death was 15% (17,25,30,53). We therefore planned to include 1,000 patients.…”

“…Relatively few studies have jointly examined the roles of host and bacterial factors in the severity and outcome of this infection (14, 17, 25, 30-32, 36, 50). The discrepancies among the conclusions of those studies might reflect the retrospective (14,31,36,50) and/or monocenter (14,30,32,36,50) nature of most of them, the small number (30 to 185) of patients included (14, 17, 30-32, 36, 50), the small number of bacterial factors examined (14, 17, 25, 30-32, 36, 50), and the diversity of the disease's pathophysiological mechanisms.…”

Déterminants cliniques et bactériens au cours des infections extra-intestinales dues àEscherichia coli

“…Si, chez l'homme, les VF présents chez la souche sont importants pour le dévelop-pement d'une infection extra-intestinale à E. coli [2], la prédiction de la sévérité initiale de l'infection et son évolution ne peuvent reposer sur la seule étude de la virulence intrinsèque de la souche, et la prise en compte de facteurs liés à l'hôte, comme les comorbidités associées est également nécessaire [8,9]. Chez les patients immunocompétents qui, en général, ont rarement été traités par des antibiotiques, les bactéries, qu'elles soient ou non résistantes aux antibiotiques, doivent posséder plus de VF pour surmonter les défenses de l'hôte.…”

Genotypic analysis of Escherichia coli strains that cause urosepsis in the Aegean region

“…Thus, the need for new drugs capable of blocking different mechanisms related to pathogenicity is increasing (16). In addition to virulence factors and pathogenic clones of ExPEC, strains can also vary regionally (17). To develop new drugs, pathogenic microorganisms should be comprehensively analyzed at the molecular level by taking geographical conditions into consideration.…”