656. E. coli Clone Sharing and Persistence within Households (HHs) in Relation to Fluoroquinolone (FQ) Resistance and ST131 Status
Session: Poster Abstract Session: Pathogenesis and Immune Response
Thursday, October 4, 2018
Room: S Poster Hall
  • IDWeek E.coli Poster-converted.pdf (498.4 kB)
  • Background: Extraintestinal E. coli infections, a perennial source of morbidity and mortality, are increasingly difficult to treat due to emerging antibiotic resistance. Within-HH sharing of E. coli strains may contribute to this problem, but is poorly understood. Accordingly, we assessed E. coli strain sharing within the HHs of veterans with a clinical E. coli isolate, including in relation to FQ resistance and ST131 status.

    Methods: Twenty-two veterans with a clinical E. coli isolate (11 FQ-resistant [FQ-R], 11 FQ-susceptible [FQ-S]) and their HH members underwent serial stool sampling (2-6 occasions each). Stool samples were cultured selectively for FQ-S and FQ-R E. coli. Per sample, 10 E. coli colonies underwent PCR-based profiling; 1 colony per profile underwent pulsotyping and PCR-based ST131 detection, as did all clinical isolates. Each strain's extent of within-HH sharing and colonization were calculated.

    Results: Of the 11 FQ-R clinical isolates, 7 were ST131 and 4 non-ST131; all FQ-S clinical isolates were non-ST131. The 22 HHs included 68 total subjects (49 humans, 19 pets), with a per-HH mean of 3 subjects, 9.5 total fecal samples, and 6.7 unique strains. The index patient’s stool yielded the corresponding clinical strain in 91% of FQ-R HHs, but only 45% of FQ-S HHs. Sharing of the clinical strain occurred in 45% of FQ-R HHs (43% if ST131, 50% if non-ST131), vs. 27% of FQ-S HHs. For the 22 clinical strains, the extent of within-HH sharing and colonization was greater for FQ-R than FQ-S strains (sharing index, 0.45 vs 0.15; colonization index, 0.47 vs 0.14). The FQ-R HHs also yielded 12 additional (non-clinical) FQ-R strains, the FQ-S HHs only 1. Non-clinical FQ-R strains colonized much less extensively than FQ-R clinical strains and were not shared between HH members.

    Conclusion: Compared to FQ-S clinical E. coli, FQ-R clinical E. coli more frequently colonize the index patient, are shared among HH members, and co-occur with other HH FQ-R strains, all of which may drive population-level resistance. Given the potentially important clinical implications of within-HH strain sharing and colonization, better understandings are needed of its mechanisms, including characteristics of the strain, host, and gut microbiota.

    Jessica Boettcher, DO1, Connie Clabots, BS MT(ASCP)2, Stephen B. Porter, MS2 and James R. Johnson, MD1,2, (1)Infectious Diseases and International Medicine, University of Minnesota, Minneapolis, MN, (2)Minneapolis Veterans Affairs Medical Center, Minneapolis, MN


    J. Boettcher, None

    C. Clabots, None

    S. B. Porter, None

    J. R. Johnson, Crucell/Janssen: Consultant , Consulting fee . Allergan: Grant Investigator , Research support . Merck: Grant Investigator , Research support . Melinta: Grant Investigator , Research support . Tetraphase: Grant Investigator , Research support . Syntiron: Consultant , Consulting fee .

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