Outbreak of S Enteritidis PT4B Infection in the Netherlands

Outbreak of S. Enteritidis PT4BInfection in the Netherlands
December 20,2000
Eurosurveillance Weekly
Acluster of 12 cases of infection with Salmonella enteritidis phage type (PT) 4bwas identified in the Netherlands in the last week of November 2000 from datafrom the national reference laboratory system that includes 62% of alllaboratory diagnoses of salmonellosis in the country.


SinceNetherlands adopted the English phage typing system in 1997 no cases of thisphage type had been reported, and information from participants in the Enter-netnetwork showed that it was rare in most of Europe. One week before these caseswere detected, S. enteritidis PT4b was reported through the national referencelaboratory system, coming from a private quality control analysis of one batchof bean sprouts.


By 15December the number of cases had risen to 25, and a second report ofcontaminated bean sprouts from the same producer was received. Cases werescattered throughout the country and all had become ill between 3 and 24November. Sixteen of the cases were females and all age groups (1 to 65 years)were affected; most were children under 10 years of age.

Thecommonest notified symptoms reported were diarrhoea (bloody diarrhoea in manycases), abdominal cramps, fever, and vomiting. Most of the cases were ill formore than a week.

Thegastroenteritis epidemiology team of the Rijksinstituut voor olksgezondheit enMilieu (RIVM, the Dutch institute for public health and the environment)interviewed eight of the first 12 cases with an extensive
trawling questionnaire to identify common factors. These interviews identifiedthree possible risk factors for infection ­ eating chicken, eggs, and beansprouts. A case control study is under way to investigate if there
is a real association between the cases and any of these food items. At the sametime, the company that produced and distributed the contaminated sprouts wascontacted and voluntarily took several measures, including intensified testingand blockade of the raw materials from which the contaminated sprouts were grownand amendment of decontamination procedures at the start of cultivation. Thecompany was inspected and environmental samples were taken.

Reportedby Teresa Fernandes, Yvonne T H P van Duynhoven (Y.van.Duynhoven@rivm.nl),Carolien M de Jager, Wim JB Wannet, Wilfrid van Pelt (W.van.Pelt@rivm.nl),Rijksinstituut voor Volksgezondheit en Milieu, Bilthoven, Netherlands.