title: Enteroaggregative Escherichia coli associated with a foodborne outbreak of gastroenteritis.
abstract: This study investigated two foodborne outbreaks of gastroenteritis that occurred 10 days apart among individuals who had meals at the restaurant of a farm holiday resort. Mild gastrointestinal symptoms were reported and none of the patients needed hospitalization. Mean incubation times were 45 and 33 h, and the overall attack rates were 43.5 and 58.3%, respectively. Stool sample examination was negative for common enteric pathogens in both outbreaks. Specimens from 13 people involved in the second outbreak and 3 restaurant staff were examined for diarrhoeagenic Escherichia coli. An enteroaggregative E. coli (EAEC) strain of serotype O92:H33 was isolated from six participants and one member of staff. In particular, the EAEC strain was isolated from five of the six cases of diarrhoea examined. The strain showed an aggregative pattern of adherence to HEp-2 cells, did not produce a biofilm and possessed the virulence-related genes aat, aggR, aap and set1A, but not the astA gene. A retrospective cohort study indicated a pecorino cheese made with unpasteurized sheep milk as the possible source (P<0.001). Samples of the cheese had E. coli counts higher than 10(6) c.f.u. g(-1), but the outbreak EAEC strain was not isolated. This report confirms that EAEC infections are probably underdiagnosed because of the limited availability of laboratories capable of identifying this group of pathogenic E. coli.
authors: Dipartimento di Sanità Pubblica Veterinaria e Sicurezza Alimentare, Istituto Superiore di Sanità, Viale Regina Elena, 299, 00161 Rome, Italy.
authors: Gaia
authors: G
authors: Scavia
authors: Istituto Zooprofilattico Sperimentale dell'Umbria e delle Marche, Macerata, Italy.
authors: Monica
authors: M
authors: Staffolani
authors: Istituto Zooprofilattico Sperimentale dell'Umbria e delle Marche, Macerata, Italy.
authors: Stefano
authors: S
authors: Fisichella
authors: Istituto Zooprofilattico Sperimentale dell'Umbria e delle Marche, Macerata, Italy.
authors: Gianluca
authors: G
authors: Striano
authors: Azienda Sanitaria Unica Regionale, Civitanova Marche, Italy.
authors: Stefano
authors: S
authors: Colletta
authors: Azienda Sanitaria Unica Regionale, Civitanova Marche, Italy.
authors: Giovanni
authors: G
authors: Ferri
authors: Dipartimento di Sanità Pubblica Veterinaria e Sicurezza Alimentare, Istituto Superiore di Sanità, Viale Regina Elena, 299, 00161 Rome, Italy.
authors: Martina
authors: M
authors: Escher
authors: Dipartimento di Sanità Pubblica Veterinaria e Sicurezza Alimentare, Istituto Superiore di Sanità, Viale Regina Elena, 299, 00161 Rome, Italy.
authors: Fabio
authors: F
authors: Minelli
authors: Dipartimento di Sanità Pubblica Veterinaria e Sicurezza Alimentare, Istituto Superiore di Sanità, Viale Regina Elena, 299, 00161 Rome, Italy.
authors: Alfredo
authors: A
authors: Caprioli
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000818:Animals; D002611:Cheese / Q000382:microbiology; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D004196:Disease Outbreaks; D004926:Escherichia coli / Q000302:isolation & purification*; D004927:Escherichia coli Infections / Q000453:epidemiology / Q000382:microbiology*; D005243:Feces / Q000382:microbiology; D005516:Food Microbiology; D005517:Foodborne Diseases / Q000453:epidemiology / Q000382:microbiology*; D005759:Gastroenteritis / Q000453:epidemiology / Q000382:microbiology*; D006801:Humans; D007558:Italy / Q000453:epidemiology; D008875:Middle Aged; D012189:Retrospective Studies; D012756:Sheep; D011795:Surveys and Questionnaires