Eurosurveillance - Volume 16, Issue 19, 12 May 2011

An epidemic of Mycoplasma pneumoniae infection began in Denmark in late 2010. A similar increase in M. pneumoniae infections was noted in England and Wales in the same period, with a decline in early 2011. Multiocus variable number tandem repeat analysis typing and analysis of macrolide resistance markers indicate that at least nine known and two novel strain types were circulating in England and Wales during October 2010 to January 2011. There was no evidence of macrolide resistance.

In March 2011, a 40 year-old French man was diagnosed with diphtheria caused by toxigenic Corynebacterium diphtheriae. Fifty-three close contacts were identified from whom throat samples were analysed. C. diphtheriae was found only in the asymptomatic partner of the index case. The two cases had travelled in Spain during the incubation period of the index case. Investigation around the second case identified 13 new close contacts. None of them was found to be infected.

In March 2011, the Norwegian Institute of Public Health identified a possible outbreak involving 21 cases of Yersinia enterocolitica O:9 infection with similar MLVA-profiles. Preliminary results of epidemiological and microbiological investigations indicate bagged salad mix containing radicchio rosso (also known as Italian chicory) as a possible source. As a result of the investigation, bagged salad mixes of a specific brand were voluntarily withdrawn from the market by the producer.

Between April and June 2010, a small national outbreak of Salmonella Typhimurium with a particular multilocus variable-number tandem repeat analysis (MLVA) type was identified in Denmark through laboratory-based surveillance. The outbreak involved twenty cases, primarily living within the greater Copenhagen area. Half of the cases were children aged ten years or younger and 12 were male; three cases were hospitalised. A matched case-control study showed a strong link between illness and eating a particular salami product containing pork and venison, matched odds ratio (mOR):150, confidence interval (CI): 19-1,600. The salami had been produced in Germany. Microbiological confirmation in food samples was sought but not obtained. Danish consumers were notified that they should return or dispose of any packages from the suspected salami batch. Because the salami product had potentially been sold in other European countries, the European Centre for Disease Prevention and Control urgent enquiry and Rapid Alert System for Food and Feed systems were used to highlight the possibility of outbreaks in these countries. Case-control studies are a strong tool in some outbreak investigations and evidence from such studies may give sufficient information to recall a food product. .