The report discussed here brings data from the third quarter of 2007 on cases of Salmonella, Verocytotoxin-producing Escherichia coli (VTEC) and Campylobacter in the European Union (EU) and European Fair Trade Association (EFTA) countries. For this period, 25 countries provided data on Salmonella, 16 on VTEC, and 15 on Campylobacter (see the list of contributors). In 2006, respectively 27, 17 and 17 countries reported data for the third quarter of the year. As different countries reported in both years, direct comparisons and comments on trends in the data between these two years are avoided. At the time of writing this paper, ECDC does not yet have access to all historical data collected by Enter-net. Comparison across quarters from different years will be possible in future reports, once this data is available.
The former Enter-net surveillance hub collected data on Salmonella, VTEC and Campylobacter until 2 October, 2007. These data were collated in the Enter-net databases and included microbiological and epidemiological data on each laboratory case confirmed by the national reference laboratories. The Salmonella database has been in existence since 1995, the VTEC database since 2000 and the Campylobacter database since 2005 . Data collected from the beginning of October 2006 were transferred to the ECDC on 2 October, 2007. Data for the third quarter of 2007 were submitted from countries directly to ECDC, where they were analysed and summarized before being returned to the network participants for approval.
Public domain versions of the quarterly reports are posted on the ECDC website . When making comparisons between countries, one should take into account such factors as the variability of case definitions, reporting requirements, surveillance systems and microbiological methods employed.
The total number of human Salmonella isolates reported in the third quarter of 2007 was 29,294* by 25 countries. For comparison, 34,854 cases were reported in the same period of 2006. The majority of isolates were S. Enteritidis or S. Typhimurium (Table 1). With respect to emerging serotypes, 239 cases of Salmonella Java were reported in the third quarter of 2007, compared to 75 cases in the analogous period of 2006. This is believed to be related to an outbreak of 172 cases of S. Java occurring in Sweden, associated with a common exposure to imported spinach, although this has not been confirmed with microbiological evidence . The majority of cases of Salmonella were reported in persons aged between 15 and 64 years (45%), which is also the largest age group. Cases younger than five years constituted approximately a quarter of all cases (25%).
Most frequently, Salmonella isolates were found to be resistant to sulphonamides (20% of all isolates tested), nalidixic acid (16%) and tetracyclines (16%) (Table 2). In the third quarter of 2006, the highest proportions of isolates were resistant to sulphonamides (24%), ampicillin (17%) and tetracyclines (16%).
Multi-drug resistance (MDR), defined as resistance to four or more unrelated antimicrobials, was found most frequently among S. Group B (48%) and S. Haifa (46%). Among the more common serotypes, MDR was highest in S. Kentucky (41%), S. Virchow (39%) and S. Typhimurium (38%).
Verocytotoxin-producing Escherichia coli (VTEC)
The total number of VTEC cases reported in the third quarter of 2007 was 594 from 16 countries. During the same period in 2006, 605 cases were reported from 17 countries. The most commonly identified serogroup was E. coli O157, which in the third quarter of 2007 represented the majority of all reported serogroups (56%) and of all known serogroups (65%) (Table 3). In the same period in 2006, E. coli O157 represented 42 % of all serogroups. Phage Types 8, 32 and 4 were reported most frequently in the third quarter of 2007, whereas phage type 21/28 was reported most frequently in the third quarter of 2006.
In the third quarter of 2007, the highest proportion of VTEC isolates was resistant to sulphonamides (31%), streptomycin (24%) and tetracyclines (19%). The proportion of reported MDR isolates was 7% (Tables 4 and 5). The proportion of MDR isolates reported in the third quarter of 2006 was 11%.
VTEC infections manifested most commonly as bloody diarrhoea and haemolytic-uremic syndrome (HUS). Bloody diarrhoea was reported more frequently in cases with VTEC O157 infections, compared to non-O157 infections, while HUS was as common in O157 cases as among non-O157 cases.
The majority of VTEC O157 cases were reported in females (58%), whereas non-O157 cases were evenly divided between males and females. VTEC O157 cases were typically older and aged between 16 and 64 years (42%), whereas non-O157 cases were more frequently reported in children aged between one and five years (47%).
The incidence rate of Campylobacter infections among 15 reporting European Union countries was 6.9 per 100,000 population in the third quarter of 2007. In the same period in 2006 the rate was 7.3 per 100,000 population. C. jejuni was the predominant species identified (representing 62% of the total and 93% of all known species) (Table 7). In the third quarter of 2007, most cases were reported in persons aged between 15 and 64 years (59%) and of male gender (53%). Data on 90% of travel-associated cases included a source country. The top three reported source countries were Spain (371 cases and 25% of all sources identified), Turkey (315, 21%) and Bulgaria (259, 17%).
In the third quarter of 2007, a total of 1,096 isolates were tested for antimicrobial resistance. In contrast, only 207 were reported to have been tested in the third quarter of 2006. The highest proportion of C. jejuni and C. coli isolates were resistant to tetracyclines, nalidixic acid and tetracyclines, with the proportion of resistant C. coli isolates nearly triple that of C. jejuni. Multidrug-resistance was identified in 10% of all isolates tested in the third quarter of 2007, and was most frequent among C. coli species (23%) (Table 8). In the third quarter of 2006, 18% of all isolates tested were reported to be MDR.
The first quarterly report by ECDC on cases of Salmonella, VTEC and Campylobacter is limited by its inability to compare data with prior reports due to a lack of consistency in reporting countries and systems. For the purpose of interpretation, however, we compared the findings from this report with those from the Community Summary Report on Trends and Sources of Zoonoses, Zoonotic Agents, Antimicrobial resistance and Foodborne outbreaks in the European Union in 2006 (Zoonoses Report) . We found that the proportions of S. Enteritidis and S. Typhimurium to other serotypes were similar, as was the breakdown of the ages of the reported cases. S. Java stands out for being reported more frequently than expected due to an outbreak occurring in Sweden briefly described in the report. Salmonella drug-resistance data is consistent with the findings from the 2006 third quarterly report, concerning levels of resistance to commonly used antibiotics, particularly sulphonamides and tetracyclines.
Other noteworthy findings in the present report are that VTEC O157 cases constitute a larger proportion of all reported serotypes in the third quarter of 2007 when compared with findings of the 2006 Zoonoses Report  where 47% were VTEC O157, and with the third quarterly report of 2006 in which 42% were reported as VTEC O157. To see more bloody diarrhoea among VTEC O157 cases than among non O157 cases is something to be expected. Finding as many HUS cases among both VTEC O157 and non-O157 cases, however, is unusual, as typically there are many more HUS cases associated with VTEC O157 than with non-O157. This finding may be explained partly by the fact that some countries have not been testing for non-O157 isolates and only now are beginning to do so . The proportion of C. jejuni to C. coli cases reported, and their respective resistance patterns offer no deviations from findings over 2006 . Yet the fact that few VTEC and Campylobacter specimens submitted in the third quarter of 2007 demonstrated multi drug-resistance is difficult to interpret, due to a small number of countries reporting this information and a need for many more samples to be analyzed before trends can be interpreted.
A special thank you to Henriette De Valk, Lisa King, Anja Siitonen, Yvonne van Duynhoven, Kassiani Mellou, Regina Vorou, Angelika, Johanna Takkinen, Andrew Amato and Andrea Ammon for their comments and improvements.
This paper could not have been prepared without the contribution of all network participants. The participants of the network are the microbiologists in charge of the National Reference Laboratories for Salmonella, Verocytotoxin-producing Escherichia coli and Campylobacter infections, and the epidemiologists with responsibility for their national surveillance. These individuals are only a part of large group of people contributing to the network. There are innumerable medics, scientists, laboratory technicians, epidemiologists and IT specialists working in each institute who provide support and input to the operation, development and success of the network.
- Austria2: Christian Kornschober, Reinhild Strauss, Robert Muchl, Sandra Jelovcan, Gabriela El Belazi, Burkhard Springer, Manfred Dierich, Reinhard Würzner;
- Belgium1,2,3: Françoise Wuillaume, Denis Piérard, Jean-Marc Collard, Sophie Bertrand;
- Bulgaria1: Kremena Parmakova, Petar Petrov, Katyusha Ivanova, Vania Mehandjieva;
- Cyprus1: Panayiota Maikanti Charalambous, Myrto Chronidou;
- Czech Republic1,3: Marta Prikazs, Renata Karpiskova, Daniela Dedicova;
- Denmark1,2: Eva Møller Nielsen, Steen Ethelberg, Flemming Scheutz, Kåre Mølbak;
- Estonia1,2,3: Jevgenia Epshtein, Inna Sarv, Unna Joks;
- Finland1,2,3: Markku Kuusi, Anja Siitonen;
- France1,2,3: Henriette De Valk, François-Xavier Weill, Nathalie Jourdan, Lisa King, Ingrid Filliol, Patricia Mariani, Francis Mégraud and Emmanuelle Espié;
- Germany1,2,3: Angelika Fruth, Alexander Friedrich, Klaus Stark;
- Greece1: Panayotis T. Tassios, Rengina Vorou, Kassiani Mellou, Alkis Vatopoulos, Georgia Mandilara;
- Hungary1,2,3: Katalin Krisztalovics, Maria Herpay, Maria Vidane Szucs;
- Ireland1,2,3: Paul McKeown, Anne Carroll, Martin Cormican, Eleanor Mcnamara;
- Italy1: Ida Luzzi, Alfredo Caprioli, Marta Ciofi degli Atti, Gaia Scavia, Pasquale Galetta;
- Latvia1,3: Sandra Magone, Solvita Selderina, Ruta Paberza, Bormane, Svetlana Makarova;
- Lithuania1: Galina Zagrebneviene, Vilma Jonaitiene, Indre Mackeviciute;
- Luxembourg1: Francois Schneider, Patrick Hau, Joel Mossong, Catherine Ragimbeau;
- Malta1,3: Anthony Gatt, Paul Cuschieri, Christopher Barbara, Charmaine Gauci;
- The Netherlands: Yvonne Van Duynhoven, Wilfrid Van Pelt, Wim Wannet;
- Poland: Malgorzata Sadkowska-Todys, Jolanta Szych, Grzegorz Madajczak, Sebastian Wardak;
- Portugal: Cristina Furtado, Jorge Machado;
- Romania1: Maria Damian, Zota Lavinia Cipriana, Tatu-Chitoiu Dorina, Adriana Pistol;
- Slovakia1,2,3: Lucia Hrivniakova, Margareta Slacikova, Dagmar Gavacova, Henrieta Kocianová;
- Slovenia2: Eva Grilc, Tjasa Zohar Cretnik, Marija Trkov;
- Spain1,2,3: Pilar Soler, M. Aurora Echeita;
- Sweden1,2,3: Sofie Ivarsson, Yvonne Andersson, Sven Lofdahl, Ralfh Wollin, Margareta Lofdahl, Lars Engstrand;
- United Kingdom1,2,3: Bob Adak, Tom Cheasty, John Cowden, Mary Hanson, John Coia, Tansy Peters, Paul McKeown;
- Iceland: Gudrun Sigmundsdottir, Hjordis Hardardottoir;
- Liechtenstein: Erne Sabine;
- Norway1,2,3: Karin Nygard, Joergen Lassen, Line Vold;
- Switzerland1: Herbert Haechler, Karim Boubaker, Hans Schmid.
Data submitted for: 1Salmonella
VTEC and/or 3Campylobacter
for the third quarter of 2007.