Italy has also reported one HUS case with an epidemiological link to Romania.
The outbreak of STEC infection associated with haemolytic uraemic syndrome (HUS) has affected mostly young children in February and March.
Twelve had microbiological and/or serological evidence of STEC O26 infection; 13 additional cases met the probable case definition by developing HUS, testing positive for another STEC O serogroup (O157) or by testing positive by PCR for stx1 and/or stx2 and eae genes.
Between 2010 and 2015, 101 HUS cases were diagnosed in Romania, with an average of annually reported cases of 16, a minimum of five cases in 2010 and a maximum of 25 in 2015.
Multiple strains and multiple sources?
The European Food Safety Authority (EFSA) and European Centre for Disease Prevention and Control (ECDC) said information from patients’ points towards a milk processing plant in Romania as a possible source of infection in a rapid outbreak assessment.
The milk processing plant exported cheese to four EU countries (Belgium, Germany, Italy and Spain) and one Italian importer further distributed it to France and Germany.
Closure was enforced by the local veterinary authorities of Arges district on 8 March but, according to local media, it reopened on Thursday (7 April).
In Romania, one fresh cheese product made of cow’s milk produced by the operator tested positive for E. coli O26 not possessing stx virulence genes. Other dairy products produced by the same firm tested positive for E. coli virulence genes stx1, stx2 and eae, said EFSA.
The precise source of contamination has not been identified since multiple dairy products made by the Romanian operator have tested positive for STEC O26, added the agency.
In Italy, a STEC O26 strain (positive for stx1, stx2 and eae) was isolated from a sample of the cheese produced by the Romanian operator, imported and consumed by the Italian child that later developed HUS (stool samples negative for STEC but serum samples positive for presence of antibodies against the LPS of E. coli O26).
PFGE analysis suggests there are potentially multiple strains from a common source or from multiple sources, said the agencies.
Sample collection results
A total of 574 samples from 141 food items at 24 different premises between 26 February and 14 March in five districts: Argeș, Bacau, Dolj, Ialomita and Vrancea were collected.
Results showed that from 16 types of food (five dairy products, 10 poultry and one mix beef and pork meat) in all the five districts, 86 samples were positive by real-time PCR for one or more of the investigated genes (stx1, stx2, eae) and O26.
Testing by the Cantacuzino Institute (in Romanian) showed cheese from Lactate Bradet was not the source of illnesses or chicken made in Bacau which was also suggested as an infection vehicle.
Environmental samples from the surface of various pieces of working equipment and components of the processing machinery and cheese packaging material at Lactate Bradet were all negative.
Stool samples from 19 employees of the Romanian operator found seven were positive for E. coli, with three positive for stx genes, including one for stx1, stx2 and eae, i.e. a probable case.
The last Romanian case had onset of symptoms on 14 March. The cheese eaten by the Italian case was imported in Italy from Romania on 1 March and was produced on 18 February with an expiry date of 18 April.
A recall was made of the company products in Romania on 5 March and in Italy on 15 March.
A total of 20,363.87kg of dairy products were withdrawn from six Romanian districts and destroyed.
At the time of the assessment, 2, 400kg of dairy products had been withdrawn and destroyed by Spanish authorities, 1,191.61kg by German authorities, a very small quantity in Belgium (150 kg), and 1,696.4kg of dairy products withdrawn by four importing Italian wholesalers.
ECDC and EFSA said potentially contaminated items could still be present in households.
“Since the precise source of contamination has not yet been identified, cases possibly linked to this outbreak may occur in Romania and in those EU countries to which the implicated food products have been distributed.”
The agencies recommended EU Member States consider enhancing monitoring for HUS and STEC cases.
They added if new cases possibly linked to the outbreak are identified, they should be reported to the Epidemic Intelligence Information System for food- and waterborne diseases (EPIS-FWD).
The National Institute of Public Health of Romania (INSP/NIPH) and the Romanian Ministry of Health formed an outbreak investigation team which experts from the ECDC later joined.
This is a stark reminder that STEC can cause infections with severe complications, particularly among young children, said an analysis in Eurosurveillance.
“Detection of outbreaks in the absence of sensitive and timely surveillance systems can be challenging, particularly if local laboratory capacities are not optimal.
“Improving local laboratories diagnostic capacities and performing unspecific HUS surveillance in children should be considered as a public health priority to avoid this from happening again.
“It is not yet clear when this outbreak started, and neither the vehicles nor the source of contamination were identified. However, after initial suspicion, the investigations confirmed the outbreak and its causative agent.”