Salmonella are one of the most important pathogens in humans and animals.
Salmonella is a genus of the family of Enterobacteriaceae .
As a result of experiments indicating a high degree of DNA similarity, all
Salmonella organisms are now classified in a single species,
Salmonella enterica The antigenic classification or serotyping of
Salmonella used today is a result of extensive studies on antibody
interactions with bacterial surface antigens. There are more than 2,000 serovars
in the species of S. enterica . Among them, some, such as S.
Typhi and S. Paratyphi, are highly adapted to humans and have no other
known natural hosts. Others, such as S. Typhimurium and S.
Enteritidis, have a broad host range and can infect a wide variety of animals.
Some serovars, such as S. Choleraesuis (swine), S.
Dublin (cattle) and S. Arizonae (reptiles), are most adapted to
a specific animal species but occasionally infect humans. These nontyphoid
Salmonella can cause protean manifestations in humans, including acute
gastroenteritis, bacteremia, and extraintestinal localized infections involving
many organs. S. Choleraesuis infections are very rampant in Taiwan province.
It is not only a host-adapted serovar of Salmonella
that causes swine paratyphoid, but also is highly pathogenic to humans,
usually causing septicemic disease with little involvement of
the intestinal tract. The resulting S.
Choleraesuis reservoir in swine is a concern, not only
because of its disease-causing potential in young pigs
but also because of its public health implications for humans.
Although Salmonella is one of the most extensively studied
bacterial species in terms of its physiology, genetics, cell structure,
development, and host immune response, we are only just beginning to
understand at cellular and molecular levels how S.
Choleraesuis causes invasive infections in humans.
