Escherichia coli phylogenetic groups are associated with site of infection and level of antibiotic resistance in community-acquired bacteraemia: a 10 year population-based study in Denmark

• Published in: Journal of antimicrobial chemotherapy 2009-07, Vol.64 (1), p.163-168
• Main Authors: Bukh, Annette S., Schønheyder, Henrik C., Emmersen, Jeppe M. G., Søgaard, Mette, Bastholm, Søren, Roslev, Peter
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Aged; Aged, 80 and over; Antibiotics; Antibiotics. Antiinfectious agents. Antiparasitic agents; antimicrobials; Bacterial diseases; Bacterial sepsis; Bacterial Typing Techniques; Biological and medical sciences; bloodstream infections; Child; Child, Preschool; Cluster Analysis; Community-Acquired Infections - microbiology; Denmark; DNA, Bacterial - genetics; Drug resistance; Drug Resistance, Bacterial; E coli; Epidemiology; Escherichia coli; Escherichia coli - classification; Escherichia coli - genetics; Escherichia coli - isolation & purification; Escherichia coli Infections - microbiology; Female; Genotype; Genotype & phenotype; Human bacterial diseases; Humans; Infant; Infant, Newborn; Infections; Infectious diseases; Male; Medical sciences; Microbial Sensitivity Tests; Middle Aged; PCR; Pharmacology. Drug treatments; Polymerase Chain Reaction; Young Adult
• ISSN: 0305-7453; 1460-2091
• DOI: 10.1093/jac/dkp156

Objectives The aim of this study was to assess whether Escherichia coli phylogenetic groups were associated with the site of infection and the level of antibiotic resistance in community-acquired bacteraemia (CAB). Methods The population-based cohort study included 1533 unique isolates of E. coli from Danish patients with CAB during a 10 year period. Triplex PCR was used to classify the phylogenetic groups, and susceptibility testing was performed by disc diffusion. Data were analysed using contingency tables and logistic regression. Results Overall, 65.9% of the 1533 E. coli isolates belonged to phylogroup B2, 16.6% to D, 13.1% to A and 4.4% to B1. B2 was the most prevalent group for all sites of infection, ranging from 69.9% in cases with a urinary tract site of infection to 54.8% in cases with a hepatobiliary tract site of infection. Antibiotic resistance to one and more than three antibiotics, respectively, was most frequent in group D (11.4%/33.9%), followed by A (5.5%/26.9%), B1 (5.9%/19.1%) and B2 (6.7%/7.5%). Regression analysis, with group B2 as reference, confirmed that groups A and B1 were associated with a site of infection other than the urinary tract and that groups A and D were associated with resistance to antibiotics including ampicillin, sulphonamide, trimethoprim, gentamicin and quinolones. Conclusions Phylogenetic group B2 was predominant in E. coli CAB. This was the least resistant of the four groups. Phylogroups A and B1 were associated with sites of infection other than the urinary tract, and resistance to multiple antibiotics was most prevalent for groups A and D.