Enteropathogenic Escherichia coli Infection in Cancer and Immunosuppressed Patients

Background. The role of enteropathogenic Escherichia coli (EPEC) as a cause of diarrhea in cancer and immunocompromised patients is controversial. Quantitation of fecal bacterial loads has been proposed as a method to differentiate colonized from truly infected patients. Methods. We studied 77 adult cancer and immunosuppressed patients with diarrhea and EPEC identified in stools by FilmArray, 25 patients with pathogen-negative diarrhea, and 21 healthy adults without diarrhea. Stools were studied by quantitative polymerase chain reaction (qRT-PCR) for EPEC genes eaeA and lifA/efa-1 and strains characterized for virulence factors and adherence to human intestinal enteroids (HIEs). Results. Patients with EPEC were more likely to have community-acquired diarrhea (odds ratio, 3.82 [95% confidence interval, 1.5-10.0]; P = .008) compared with pathogen-negative cases. Although EPEC was identified in 3 of 21 (14%) healthy subjects by qPCR, the bacterial burden was low compared to patients with diarrhea (<= 55 vs median, 6 x 10(4) bacteria/mg stool; P < .001). Among EPEC patients, the bacterial burden was higher in those who were immunosuppressed (median, 6.7 x 10(3) vs 55 bacteria/mg, P < .001) and those with fecal lifA/ifa-1 (median, 5 x 10(4) vs 120 bacteria/mg; P = .015). Response to antimicrobial therapy was seen in 44 of 48 (92%) patients with EPEC as the sole pathogen. Antimicrobial resistance was common and strains exhibited distinct patterns of adherence with variable cytotoxicity when studied in HIEs. Cancer care was delayed in 13% of patients. Conclusions. Immunosuppressed cancer patients with EPEC-associated diarrhea carry high burden of EPEC with strains that are resistant to antibiotics, exhibit novel patterns of adherence when studied in HIEs, and interfere with cancer care.

Automated summary

Enteropathogenic Escherichia coli (EPEC) role in cancer and immunocompromised patient diarrhea remains controversial. Quantitation of fecal bacterial loads can differentiate colonized from infected patients. Patients with EPEC had higher bacterial burden in immunosuppressed and those with specific genes. Majority of EPEC patients responded to antimicrobial therapy. Antimicrobial resistance and novel adherence patterns were observed, impacting cancer care in some patients.