Escherichia coli Bacteremia in Children
Escherichia coli Bacteremia in Children
Background:Escherichia coli bacteremia is a major cause of severe sepsis in children. Little is known about predictors of severity.
Methods: We analyzed 84 children ≤18 years of age with E. coli bacteremia from the prospective COLIBAFI study performed during 2005–2007. The severity of bacteremia was defined as occurrence of death or transfer to intensive care unit. Studied characteristics included age, gender, birth weight, history of prematurity, immunodepression, nosocomial infection, portal of entry, phylogenetic group and subgroup belonging, O-type, virulence gene content and antimicrobial susceptibility. We compared bacterial characteristics in urinary- versus digestive-source bacteremia, in children ≤3 versus >3 month of age, and in children versus adults. We also searched for risk factors of severity.
Results: Median age was 2.4 months, 57% males. Most frequent portals of entry were urinary (66.2%) and digestive (19.5%) tracts. Most isolates (63.1%) belonged to B2 phylogroup. Strains in children ≤3 months of age exhibited more virulence genes, especially neuC and fyuA/irp2, and were less resistant to antibiotics than in children >3 months of age. Comparing community-acquired urinary-source bacteremia between children and adults, we found that bacteremia were less severe in children, whose strains exhibited a specific virulence gene repertoire and had a higher resistance score than in adults. Seventeen children (20.2%) had a severe bacteremia and 8 died. Non-urinary portal of entry and age ≤3 months of age were the only risk factors associated with severity.
Conclusions:E. coli strains responsible for bacteremia exhibit specific characteristics according to age of children. However, host characteristics and portal of entry are the main determinants of severity of E. coli bacteremia in children, as observed in adults.
Severe sepsis in children remains a common cause of hospitalization. Bacteremia account for 25% of hospitalization for severe bacterial infections, and mortality rate is as high as 17%. Few temporal changes in the distribution of bacterial species in bloodstream infections have been reported. In industrialized countries, Streptococcus pneumoniae, Staphylococcus aureus and Escherichia coli figure among the 5 more frequently isolated organisms.
E. coli is a commensal bacteria of the gut. Some strains can cause however intestinal or extraintestinal infections because of specific virulence factors. The structure of E. coli population is mainly clonal, with 7 principal phylogenetic groups (A, B1, B2, C, D, E and F) and numerous clonal complexes. Most clinical extraintestinal pathogenic E. coli belong to the B2 phylogroup and to a lesser extent to the D phylogenetic group. Some clones or clonal complexes have been linked to specific syndromes.
In adults, mortality of E. coli bacteremia has been reported to be as high as 13% in a recent study performed by our group. We showed that host factors and the portal of entry are the main drivers of mortality during E. coli bacteremia. The only bacterial characteristic influencing the prognosis was the presence of virulence factor ireA, which was negatively associated with death. Phylogenetic belonging of the strains was not a significant predictor.
Studies of E. coli bloodstream infections in children, especially in urinary-source bacteremia, linked some virulence factors to the development of bacteremia. They include adhesins, iron uptake systems, protectins and toxins, with differences according to the portal of entry. A higher content in virulence factors was thus reported in strains causing urosepsis when compared with strains causing urinary tract infections without bacteremia. However, there is a lack of prospective studies taking into account both host and bacterial characteristics versus the clinical outcome of E. coli bacteremia in children.
To better understand the pathophysiology and severity of E. coli bacteremia in children, we analyzed the cohort of children ≤18 years of age of the COLIBAFI study. We compared bacterial characteristics (1) in bacteremia from urinary versus digestive origin, (2) in children ≤3 versus >3 months of age and (3) in community-acquired urinary-source bacteremia in children versus adults. Then we searched for clinical and bacterial risk factors associated with the severity of E. coli bacteremia in children.
Abstract and Introduction
Abstract
Background:Escherichia coli bacteremia is a major cause of severe sepsis in children. Little is known about predictors of severity.
Methods: We analyzed 84 children ≤18 years of age with E. coli bacteremia from the prospective COLIBAFI study performed during 2005–2007. The severity of bacteremia was defined as occurrence of death or transfer to intensive care unit. Studied characteristics included age, gender, birth weight, history of prematurity, immunodepression, nosocomial infection, portal of entry, phylogenetic group and subgroup belonging, O-type, virulence gene content and antimicrobial susceptibility. We compared bacterial characteristics in urinary- versus digestive-source bacteremia, in children ≤3 versus >3 month of age, and in children versus adults. We also searched for risk factors of severity.
Results: Median age was 2.4 months, 57% males. Most frequent portals of entry were urinary (66.2%) and digestive (19.5%) tracts. Most isolates (63.1%) belonged to B2 phylogroup. Strains in children ≤3 months of age exhibited more virulence genes, especially neuC and fyuA/irp2, and were less resistant to antibiotics than in children >3 months of age. Comparing community-acquired urinary-source bacteremia between children and adults, we found that bacteremia were less severe in children, whose strains exhibited a specific virulence gene repertoire and had a higher resistance score than in adults. Seventeen children (20.2%) had a severe bacteremia and 8 died. Non-urinary portal of entry and age ≤3 months of age were the only risk factors associated with severity.
Conclusions:E. coli strains responsible for bacteremia exhibit specific characteristics according to age of children. However, host characteristics and portal of entry are the main determinants of severity of E. coli bacteremia in children, as observed in adults.
Introduction
Severe sepsis in children remains a common cause of hospitalization. Bacteremia account for 25% of hospitalization for severe bacterial infections, and mortality rate is as high as 17%. Few temporal changes in the distribution of bacterial species in bloodstream infections have been reported. In industrialized countries, Streptococcus pneumoniae, Staphylococcus aureus and Escherichia coli figure among the 5 more frequently isolated organisms.
E. coli is a commensal bacteria of the gut. Some strains can cause however intestinal or extraintestinal infections because of specific virulence factors. The structure of E. coli population is mainly clonal, with 7 principal phylogenetic groups (A, B1, B2, C, D, E and F) and numerous clonal complexes. Most clinical extraintestinal pathogenic E. coli belong to the B2 phylogroup and to a lesser extent to the D phylogenetic group. Some clones or clonal complexes have been linked to specific syndromes.
In adults, mortality of E. coli bacteremia has been reported to be as high as 13% in a recent study performed by our group. We showed that host factors and the portal of entry are the main drivers of mortality during E. coli bacteremia. The only bacterial characteristic influencing the prognosis was the presence of virulence factor ireA, which was negatively associated with death. Phylogenetic belonging of the strains was not a significant predictor.
Studies of E. coli bloodstream infections in children, especially in urinary-source bacteremia, linked some virulence factors to the development of bacteremia. They include adhesins, iron uptake systems, protectins and toxins, with differences according to the portal of entry. A higher content in virulence factors was thus reported in strains causing urosepsis when compared with strains causing urinary tract infections without bacteremia. However, there is a lack of prospective studies taking into account both host and bacterial characteristics versus the clinical outcome of E. coli bacteremia in children.
To better understand the pathophysiology and severity of E. coli bacteremia in children, we analyzed the cohort of children ≤18 years of age of the COLIBAFI study. We compared bacterial characteristics (1) in bacteremia from urinary versus digestive origin, (2) in children ≤3 versus >3 months of age and (3) in community-acquired urinary-source bacteremia in children versus adults. Then we searched for clinical and bacterial risk factors associated with the severity of E. coli bacteremia in children.
