Intestinal Colonization with Escherichia coli Sequence Type 131 (ST131) and Other Fluoroquinolone (FQ)-Resistant E. coli (FQREC) within Households (HHs) of Veterans. (4th October 2017) - Mohamed, Muhanad
Abstract: Background: Among veterans, FQREC infections are caused mainly by E. coli ST131, a recently emerged disseminated clonal group that contains multiple virulence genes. Infecting FQREC strains typically arise from the host's gut reservoir. Within-HH transmission therefore may underlie the ST131 pandemic, and may be influenced by host and/or bacterial characteristics. Methods: We conducted fecal surveillance for 91 veterans and their 157 HH members, including 72 pets. Fecal cultures were processed extensively to resolve unique E. coli clones, as defined by random amplified polymorphic DNA (RAPD) analysis and pulsed-field gel electrophoresis (PFGE). Seven E. coli phylogenetic groups and 53 extraintestinal virulence genes were detected by multiplex PCR. Patterns of within-HH strain sharing were evaluated statistically in relation to host and bacterial characteristics. Results: Of the 350 identified fecal E. coli clones, 59 (17%) were shared within a HH. Within-HH strain sharing involved 56 (23%) of the 248 subjects and 27 (30%) of the 91 HHs. The prevalence of strain sharing, while not varying significantly by host group, was slightly higher for humans (24%) than pets (19%), and among humans was somewhat higher for children (40%) than adults (18%) and for females (27%) than males (20%). In contrast, strain sharing was significantly more likely for FQREC (32% for ST131, 31% for non-ST131) than for FQ-susceptible strains (10% for ST131, 15% for non-ST131) (P = .007). Likewise, as compared with other strains, the 59 shared strains more frequently contained gafD, yfcV, sat, pic, fyuA, iutA, kpsMII, usp, and H7 fliC (P < .05 for each), and had significantly higher virulence gene scores (median, 10.0 vs. 7.2: P = .03). Conclusion: Intestinal E. coli strains were shared extensively among veterans and their human and animal HH members. The frequency of strain sharing varied minimally in relation to host characteristics, but was significantly associated with multiple bacterial characteristics, including FQ resistance, specific virulence genes, and virulence gene score. Since such traits may promote intestinal colonization and/or host-to-host transmission, interventions that target them conceivably could reduce colonization and transmission, including for ST131. Disclosures: J. R. Johnson, Crucell/Janssen: Consultant, Consulting fee. Merck: Grant Investigator, Grant recipient. Tetraphase: Grant Investigator, Research grant. Actavis/Allergan: Grant Investigator, Grant recipient