title: Molecular epidemiology of diarrhoeagenic Escherichia coli associated with sporadic cases and outbreaks of diarrhoea between 2000 and 2001 in India.
abstract: Diarrhoeal infection caused by Escherichia coli is common in India with occasional outbreaks. However, association of different pathotypes of diarrhoeagenic E. coli (DEC) with the disease and its phenotypic and genotypic characteristics are not fully demonstrated. In this study, E. coli strains from sporadic cases and outbreaks of diarrhoea during 2000-2001 were confirmed as DEC by polymerase chain reaction (PCR) targeting the specific virulence genes. DEC represented by enterotoxigenic E. coli (ETEC), enteropathogenic E. coli (EPEC) and enteroaggregative E. coli (EAggEC) were mostly belonged to O serogroups 25, 86a, 114 and 146. The gene astA was frequently detected among ETEC and EAggEC than EPEC. After initial screening of 200 DEC strains with serology and antibiotic susceptibility test, 32 strains representing ETEC, EPEC, and EAggEC isolated from different areas of India were included in the pulsed-field gel electrophoresis (PFGE) analysis. Using the PFGE results, the hierarchical representation of different linkage levels between the DEC strains were determined by unweighed pair-group arithmetic mean (UPGAMA) method. Except for few strains, clonotyping by PFGE revealed no correlation between pathotypes and serogroups as well as the place of isolation of the DEC strains. The prevailing clonal diversity among the different categories of DEC strains suggests that the pathotypes of DEC belonged to diverse clones.
authors.affiliation: National Institute of Cholera and Enteric Diseases, Beliaghata, Calcutta, India.
authors.forename: Soumen
authors.initials: S
authors.lastname: Kahali
authors.forename: Bhaswati
authors.initials: B
authors.lastname: Sarkar
authors.forename: Subhra
authors.initials: S
authors.lastname: Chakraborty
authors.forename: Ragini
authors.initials: R
authors.lastname: Macaden
authors.forename: J S
authors.initials: JS
authors.lastname: Deokule
authors.forename: Mamatha
authors.initials: M
authors.lastname: Ballal
authors.forename: Ranjan K
authors.initials: RK
authors.lastname: Nandy
authors.forename: S K
authors.initials: SK
authors.lastname: Bhattacharya
authors.forename: Yoshifumi
authors.initials: Y
authors.lastname: Takeda
authors.forename: T
authors.initials: T
authors.lastname: Ramamurthy
mesh_terms: D016000:Cluster Analysis; D003967:Diarrhea / Q000453:epidemiology / Q000382:microbiology*; D004196:Disease Outbreaks; D024881:Drug Resistance, Bacterial; D016521:Electrophoresis, Gel, Pulsed-Field; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics* / Q000472:pathogenicity; D004927:Escherichia coli Infections / Q000188:drug therapy / Q000453:epidemiology / Q000382:microbiology*; D005243:Feces / Q000382:microbiology; D005798:Genes, Bacterial; D006801:Humans; D007194:India / Q000453:epidemiology; D017720:Molecular Epidemiology; D016133:Polymerase Chain Reaction; D014774:Virulence / Q000235:genetics