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Background
Salmonella species are responsible for two distinct syndromes. Nontyphoidal Salmonella are common causes of food borne gastroenteritis. Typhoidal Salmonella cause enteric fever; an important differential diagnosis in any traveller returning from a tropical country with fever.
Objective
This article describes the spectrum of disease that occurs with Salmonellosis infections and particular subgroups of patients who are more susceptible to severe disease. An appreciation of this will allow the clinician to manage these infections appropriately.
Discussion
Nontyphoidal Salmonellosis infections causing gastroenteritis are common in our community. Infection is caused by ingesting contaminated food or water, or occasionally by contact with an infected person. Most cases are self limiting and the focus of management is effective rehydration. Antibiotic therapy is seldom warranted but important exceptions exist including neonates, the immunocompromised, and in particular circumstances, the elderly. Enteric fever always warrants antibiotic treatment. Notification to the appropriate health authority assists with investigating possible outbreaks.
Salmonella species are motile Gram negative bacilli responsible for a range of clinical manifestations in humans. The most common of these is gastroenteritis. Infections are caused by contact with contaminated food or water, or less commonly, after contact with an infected individual.
There are over 2000 serotypes of Salmonella species described, however a relatively small number are important pathogens in humans.1 It is important to distinguish between:
* Salmonella serotypes causing enteric fever, and
* 'nontyphoidal Salmonella' serotypes (Table 1).
The causative organisms of enteric fever are S. Typhi and S. Paratyphi A, B and C. These are acquired after ingesting food or water contaminated with the bacteria. These serotypes are not endemic in Australia and enteric fever occurs almost exclusively in tropical and developing countries with poor standards of hygiene. Cases in Australia occur in returned travellers. The syndrome is marked by fever and abdominal symptoms, with a high rate of complications and mortality if untreated.
Many other nontyphoidal serotypes cause the remainder of clinical disease, such as gastroenteritis; these vary according to geographic location. In Australia the most common serotype is S. Typhimurium.2
The natural habitat for nontyphoidal Salmonella species is farm and pet animals, in particular, poultry and eggs.1 Ingesting raw or undercooked food or cooked food that is cross contaminated may lead to human infection. The incidence of...