Purpose: In spring and summer 2004, a multistate outbreak of infections caused by Salmonella enterica serovar Give (S. Give), a relatively rare serovar in Germany, was detected. In order to identify a common exposure and to describe the characteristics of infections caused by S. Give, an outbreak investigation was performed.
Materials and methods: In addition to passive surveillance through mandatory case-reporting, active case-finding was conducted. A case-control study was undertaken in order to identify the probable vehicle of infection. S. Give strains were isolated and molecular subtyping was performed by pulsed-field gel electrophoresis (PFGE). Rates of hospitalization were assessed in patients with S. Give infection, and compared to the rates found in patients infected by the most common serovar in Germany, S. enteritidis.
Results: From March to July 2004, 115 cases of gastroenteritis caused by S. Give were identified, with highest incidences being observed in the states of Lower Saxony and Saxony-Anhalt. Consumption of raw minced pork was strongly associated with S. Give infections (OR: 8.0; 95% CI 2.3-27.7; P = 0.001). This result was confirmed by the detection of common outbreak strains in isolates from both patients and pork, using PFGE. Infections caused by S. Give lead to hospitalization in 55% of patients > or = 60 years, but only in 17 % of younger patients (OR: 6.0; 95% CI 2.1-16.3; P < 0.001) and 33% in patients > or = 60 years with infections caused by S. enteritidis (OR: 2.5; 95% CI 1.1-5.4; P = 0.02).
Conclusion: This is, to our knowledge, the first documented multistate outbreak of salmonellosis associated with the consumption of raw minced pork in Germany. Since contamination of pork meat with Salmonella cannot be avoided, people with risk factors for severe infection should generally avoid the consumption of raw minced pork. The high hospitalization rates in patients > or = 60 years infected with S. Give possibly indicate a higher virulence of this specific serovar. Even in non-typhoidal salmonellosis, early antibiotic therapy should be considered depending on infecting serovar, age and medical history of the patient.