Household (HH) outbreak of ESBL-producing E. coli sequence type 131 (ST131) infection with high rate of ST131 intestinal colonization and extensive strain sharing among HH members
Methods: E. coli was isolated from urine (index patient only) and fecal specimens from all 7 HH members, including the index patient, 3 older siblings, 2 parents, and 1 dog. Isolates were characterized by SNP PCR to detect ST131 and its (ESBL-associated) H30-Rx subtype, pulse-field gel electrophoresis to resolve unique strains, and FQ resistance testing.
Results: The index patient, a formerly preterm infant with history of admission to the neonatal intensive care unit presented at 40 days of life with an ESBL-producing E. coli UTI. Despite appropriate therapy and no evidence of vesicoureteral reflux or genitourinary abnormalities, she developed three recurrences of ESBL E. coli UTI over the next 3 months. During this period, a 2-year-old sister was also diagnosed with ESBL E. coli UTI. The index patient’s urine isolate represented pulsotype 903 of the FQ-resistant, ESBL-producing H30-Rx subclone of E. coli ST131. The same ST131 strain was identified in fecal samples from the index patient and 4 of other asymptomatic human HH members at the initial sampling, and from the index patient and 3 other HH members at a second sampling 10 weeks later. In addition, 2 pulsotypes of FQ-susceptible non-ST131 E. coli were each shared by two HH members.
Conclusion: In this HH outbreak investigation of ESBL-producing ST131 UTI, clinical and colonizing isolates of ST131 represented the same strain, and nearly all HH members had ST131 intestinal colonization for several months. These findings suggest that ST131 E. coli is an efficient and persistent colonizer that can be easily transmitted within HHs, including among children. Strategies to prevent ST131 spread within the community are urgently needed.
C. Clabots, None
B. D. Johnston, None
S. B. Porter, None
B. S. Slater, None
R. Banerjee, None
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