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Original Articles
Phenotypic and Genotypic Characteristics of Enteropathogenic E. coli Isolated from Children with Diarrhea in Gwangju City
Sun Young Kim, M.D.1, Tae Hyung Cho, M.D.1, Jinghua Cui, M.D.2, Lanji Huang, M.D.2, Young Youn Choi, M.D.1 and Phil Youl Ryu, M.D.2
Department of Pediatrics1, Research Institute of Vibrio Infection and Genome Research Center for Enteropathogenic Bacteria, Department of Microbiology2, Chonnam National University Medical School, Gwangju, Korea.
Vol.37 Num.6 (p319~329)
Background:Enteropathgenic Escherichia coli (EPEC) commonly causes infantile diarrhea in the developing countries. This study aims to find out the phenotypic and genotypic characteristics of EPEC in children with diarrhea in Gwangju city.
Methods:We isolated 35 strains from the stool obtained from diarrheal patients and investigated the presence of various virulence genes, adherence patterns, hemolysis, and antibiotic resistance patterns.
Results:All isolates were negative for the EPEC adherence factor (EAF) plasmid, and 14 isolates were bfpA-positive by PCR. The eae, tir, espA, and espB genes were analyzed by multiplex PCR. When the results of the four multiplex PCRs were analysed, we observed that the rate of the presence of eae?-tir?-espA?-espB? was highest. The incidence of enteroaggregative E. coli heat- stable enterotoxin (east) was 17.1%. Analysis of Hep-2 cell adherence showed three adherence patterns:the localized adherence pattern, the diffuse adherence pattern, the localized adherence-like pattern. In hemolysin assay, four isolates produced enterohemolysin. The resistance rate of isolates against tetracycline, streptomycin, ampicillin, and rifampin was 56%, 39%, 34%, and 34%, respectively. All isolates were susceptible to ciprofloxacin and colistin.
Conclusion:In our study, the rate of the presence of eae?-tir?-espA?-espB? was the highest. Analysis of Hep-2 cell adherence showed various adherence patterns. Seventy-five percent of isolates were resistant to at least one antibiotic and 28% were resistant to four or more antibiotics.
Keywords : EPEC, Childhood diarrhea