[Outbreak caused by Escherichia coli in Chalco, Mexico].
OBJECTIVE
To identify the etiologic agent responsible for a disease outbreak following an overflow of sewage water in Valle de Chalco, Mexico.


METHODS
A retrospective cross-sectional study was carried out. Rectal samples were collected from the population of Chalco valley, who suffered from diarrhea and vomiting during a natural disaster that took place on May 31, 2000. The Instituto de Diagnóstico y Referencia Epidemiológicos (Epidemic Reference and Diagnosis Institute, InDRE, Ministry of Health), received 1521 rectal swab samples from diarrhea cases, to test for E. coli strains. Statistical analysis was performed to find a difference of proportions between cases and non-cases (chi-squared test). ETEC, EIEC, EPEC and EHEC pathogenic E. coli groups were hybridized by colony blot.


RESULTS
Strains isolated were ETEC (62.2%), EIEC (0.84%), EPEC (0.84%), and EHEC non-O157:H7 (0.08%); there was no hybridization in 36.02% of E. coli strains. Other isolated microorganisms were Salmonella spp (0.45%) and Shigella spp (0.06%).


CONCLUSIONS
Enterotoxigenic E. coli was the most likely etiologic agent. Sanitary control strategies should be targeted to preventing outbreaks caused by this pathogenic agent. The English version of this paper is available at: http://www.insp.mx/salud/index.html.
Cortés-Ortiz
Iliana Alejandra
IA
Laboratorio de Bacteriología Molecular, Instituto de Diagnóstico y Referencia Epidemiológicos, México, D.F., México. indre@cenids.ssa.gob.mx
Rodríguez-Angeles
Guadalupe
G
Moreno-Escobar
Eustolia Alejandra
EA
Tenorio-Lara
Jesús Manuel
JM
Torres-Mazadiego
Benita Pilar
BP
Montiel-Vázquez
Edith
E
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015373:Bacterial Typing Techniques; D002648:Child; D002675:Child, Preschool; D003967:Diarrhea / Q000453:epidemiology* / Q000382:microbiology; D004196:Disease Outbreaks; D004926:Escherichia coli / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000453:epidemiology*; D005260:Female; D006801:Humans; D007171:Implosive Therapy; D007223:Infant; D008297:Male; D008800:Mexico / Q000453:epidemiology; D008875:Middle Aged; D012007:Rectum / Q000382:microbiology; D012475:Salmonella / Q000302:isolation & purification; D012722:Sewage; D012760:Shigella / Q000302:isolation & purification
D012722:Sewage