Leukemia and risk of recurrent Escherichia coli bacteremia: genotyping implicates E. coli translocation from the colon to the bloodstream

Abstract

In patients with leukemia, the portal(s) and reasons for the persistence of an Escherichia coli recurrent bacteremia remain unclear. Adult Hematology Clinic (AHC) databases at the State Clinical Hospital in Gdańsk were reviewed to evaluate the frequency of E. coli bacteremia between 2002 and 2005. Blood and bowel E. coli strains were obtained and the genetic relatedness of the strains was analyzed. The rate of E. coli bacteremia per 1,000 admissions at the AHC was higher (85.0) than in the other clinics of the hospital (2.9), p < 0.001. A higher mortality was observed in patients with a history of E. coli versus non-E. coli bacteremia [30/95 (31 %) vs. 53/430 (12 %), p < 0.001]; 72.8 % of patients with leukemia had an unknown source of bacteremia. In 2005, 6 out of 25 (24 %) patients with leukemia had ≥2 episodes of E. coli-positive blood cultures. These gastrointestinal E. coli isolates were replaced within 3-8 weeks with a new E. coli H genotype. A recurrent episode of bacteremia was usually caused by an infection with a transient E. coli H genotype identical to that found in the subject's bowel. Consistent with the definition of bowel/blood translocation, the bowel appeared to be a portal for E. coli in these subjects and, hence, a clear source for their recurring bacteremia.

Fig. 1

Polymerase chain reaction melting profiles (PCR MP) fingerprints for representative Escherichia coli isolates from patients of the Adult Hematology Clinic (AHC) ward showing H genotypes from H1 to H20. PCR MP fingerprinting H types are given above each lane. The DNA amplicons were electrophoresed on 6 % polyacrylamide gels

Fig. 2

Representative results of monitoring the spread of bacteria within patients by using the PCR MP technique. The isolates shown represent three patients: genotype H11 from patient P5, genotype H20 from patient P9, and genotype H22 from patient P18. Lanes marked by numbers indicate the number of the isolate shown in Table 5. Lanes marked by B and S contain strains isolated from blood and stool, respectively. The DNA amplicons were electrophoresed on 6 % polyacrylamide gels