Methods: We characterized EPEC subtypes in stools from healthy individuals with no diarrhea (HI, N=21), cancer patients with diarrhea and negative NAAT (DN, N=25) and patients with diarrhea positive NAAT for EPEC (DP, N=54). EPEC isolated from stool cultures were tested for eaeA and bfp, stx and other E. coli pathotypes. We estimated the number of fecal EPEC using a qPCR for eaeA, efa1/lifA that detected 5.6x101 to 5x107 cfu/mg of stool.
Results: Demographic characteristics and underlying malignancy were similar between DN and DP groups. DP were more likely to have diarrhea on admission than DN [46/52 (88%) vs. 13/25 (52%), p<0.01]. Stool cultures confirmed EPEC in 24/52 (60%) DP of which 23/24 (96%) were aEPEC. Fecal qPCR for eaeA confirmed EPEC in 43/52 (83%) of DP, 0/25 DN and in 3/21 (14%) of HI (p<0.001). DP excreted a higher number of EPEC cfu/mg of stool than HI (median 168 vs. 1.18 cfu/mg, p<0.001) and only DP excreted EPEC efa1/lifA (+) [14/52 DP (27%) vs. 0/25 DN and 0/21 HI; p< 0.001]. When compared to DP EPEC efa1/lifA (-), DP EPEC efa1/lifA (+) had a longer median duration of illness (3d vs 1d, p<0.05); more likely to be hematopoietic stem cell transplant recipients [7/14 (50%) vs. 7/38 (18%), P<0.05] and had a higher EPEC eaeA fecal burden (median 3885 vs. 84 cfu/mg, p< 0.05). Co-infections with other pathogens were equally represented in efa1/lifA (-) and efa1/lifA (+) DP subgroups [8/14 (57%) vs 21/38 (55%) p=NS].
Conclusion: Most EPEC in cancer patients with diarrhea are aEPEC acquired in the community and when carrying efa1/lifA (+), are associated with more severe disease.
L. Carlin, None