A retrospective study on Escherichia coli bacteremia in immunocompromised patients: Microbiological features, clinical characteristics, and risk factors for shock and death.

BACKGROUND: To evaluate clinical features, bacterial characteristics, and risk factors for shock and mortality of immunocompromised patients with Escherichia coli bacteremia. METHODS: A nearly 6-year retrospective study of E coli bacteremia in 188 immunocompromised patients at Xiangya Hospital was conducted. Demographic, clinical, and laboratory data were documented. Phylogenetic background and virulence factors of E coli isolates were detected by polymerase chain reaction. Risk factors for shock and mortality were also investigated. RESULTS: Of all 188 E coli isolates, most prevalent virulence factors were fimH (91.0%), followed by traT (68.6%) and iutA (67.0%), while papG allele I, gafD, and cdtB were not detected. Phylogenetic group D was dominant (42.0%) among all isolates, and group B2 accounted for 17.6%, while group A and B1 accounted for 28.2% and 12.2%, respectively. In univariate analysis, ibeA and cnf1 were associated with mortality, which were not found in multivariate regression analysis. 22.3% of patients suffered shock, and 30-day mortality rate was 21.3%. MDR (HR 2.956; 95% CI, 1.091-8.012) was the only risk factor for shock, while adult (HR 0.239; 95% CI, 0.108-0.527) was a protective factor. Multivariate analysis revealed that shock (HR 4.268; 95% CI, 2.208-8.248; P 2 (HR 2.073; 95% CI, 1.087-3.952; P = .027) were associated with fatal outcome. CONCLUSIONS: Escherichia coli bacteremia was highly lethal in immunocompromised patients, and host-related factors played major roles in poor prognosis, while bacterial determinants had little effect on outcome. This study also provided additional information about the virulence and phylogenetic group characteristics of E coli bacteremia.