ABSTRACT
The salmonellae are short plump rods which occur singly in pairs or in chains. The organisms stain Gram-negative and are actively motile. All known Salmonella species are pathogenic for man and domesticated animals. Isolates that fulfill the selected biochemical prerequisites of the genus fall into three groups: typhi, cholerae suis, and enteritidis. Subclassification is achieved by serologic segregation based on the somatic (O) and flagella (H) antigens. More than 1400 serotypes have thus been identified; however, just 11 serotypes account for approximately 60-70% of human isolates. These include S. enteritidis, serotypes typhimurium, enteritidis, copenhagen, newport, heidelberg, infantis, thompson, blockley, dergy and S. typhi.
