1292. Enterotoxigenic, Enteroaggregative and Diffusely Adherent Escherichia coli as Causes of Acute Diarrhea in Houston Children, 2011 to 2012
Session: Poster Abstract Session: Below the Diaphragm
Saturday, October 5, 2013
Room: The Moscone Center: Poster Hall C
Background: We studied the occurrence of enterotoxigenic E. coli (ETEC) by PCR, enteroaggregative E. coli (EAEC) and diffusely adherent E. coli (DAEC) by HEp-2 cell adherence pattern in children treated at a large Houston pediatric hospital.

Methods: Selected bacterial pathogens were identified in stool samples from 269 Houston children, age ranged from 15 days through 10 years with diarrhea during 2011 and 2012. Acute diarrhea was defined as the passage of ≥3 unformed stools in 24 hours and lasting ≤ 10 days. Stools were processed for bacterial pathogens including the three diarrheagenic E. coli.

Results: A Salmonella spp. was isolated from 3 children (1%). EAEC, ETEC and DAEC were identified in 84 (31%) of children (see table).

Pathogen

Number of Patients (%)

Diarrheagenic E. coli (DEC)

Enteroaggregative (EAEC)

43 (16)

Enterotoxigenic (ETEC)

34 (13)

Diffusely Adherent (DAEC)

7 (3)

Minimal inhibitory concentrations (MIC) of the 5 antimicrobial agents, including ciprofloxacin, rifaximin and rifamycin, trimethoprim/sulfamethoxazole and azithromycin were determined by the agar dilution method.  MICs were determined against 87 bacterial enteropathogens by the agar dilution method. Trimethoprim-sulfamethoxazole showed high level of resistance with MIC90 (level whereby 90% of test strains were inhibited) of 256µg/mL. Current first-line antibiotic agents, including fluoroquinolones and azithromycin were highly active in vitro against the two enteropathogens. Rifaximin, a poorly absorbed drug, had an MIC 90% of ≤ 32 µg/mL, the breakpoint for susceptibility.

Conclusion: The study identified an important frequency of the three DEC of interest. We are studying the strains by molecular methods to look for potential clonal spread of strains from nearby Mexico.

Zhi Jiang, MD, PhD, The University of Texas Houston School of Public Health, Houston, TX; University of Texas At Houston School of Public Health, houston, TX; University of Texas At Houston, HSC, Houston, TX, Julie Boom, MD, Immunization Project, Texas Childrenís Hospital, TX, USA, Houston, TX; Center for Vaccine Awareness and Research, Texas Childrenís Hospital, TX, USA, Houston, TX; Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA, Houston, TX, Leila Sahni, BS, MPH, Center for Infectious Diseases, University of Texas-Houston, School of Public Health and Medical School, Houston, Texas, USA, houston, TX; Immunization Project, Texas Childrenís Hospital, TX, USA, houston, TX and Herbert Dupont, MD, FIDSA, St. Luke's Episcopal Hospital and Kelsey Research Foundation and Kelsey-Seybold Clinic, Houston, TX

Disclosures:

Z. Jiang, None

J. Boom, None

L. Sahni, None

H. Dupont, None

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