估计有9380万例沙门氏菌infections occur every year (1). Most of them are caused by foodborne ingestion of沙门氏菌germs. In the 1980 a considerable increase in沙门氏菌cases was recorded for chicken meat, eggs and egg products (2). This emerging public health problem is likely the result of declining genetic diversity of chickens in modern poultry farming practices (3).