Salmonellosis
Definitions & Key takeaways
Salmonellosis is an infection caused by Salmonella bacteria. It is typically transmitted through contaminated food or water. Symptoms are caused by an inflammatory response to the bacteria that often leads to diarrhea and abdominal discomfort. A clinical diagnosis is usually adequate to guide rehydration treatment but cultures should be done in severe cases to recognize serotypes that require antibiotics.
Salmonellosis is an infection caused by the bacteria Salmonella. There are several different types of Salmonella bacteria including Salmonella enteritidis, Salmonella typhimurium, and Salmonella typhi. Salmonellosis is primarily spread by ingestion of contaminated food/water and through contact with infected animals or persons. Symptoms include fever, headache, weakness, stomach pain, a rash of flat, rose-colored spots on the trunk or abdomen, loss of appetite, and constipation or diarrhea. Prevention is by practicing good food safety, proper body hygiene, and limiting close contact with infected people or animals.
Salmonellosis is a bacterial infection caused by Salmonella bacteria, which have 2 species, S. enterica and S.
bongori and over 2400 serotypes. Some of these serotypes are named.
In such cases, people often shorten the scientific name to include only the genus and serotype; for example, S. enterica, subspecies enterica, serotype Typhi is shortened to Salmonella Typhi.
Salmonellosis is usually transmitted through contaminated food or water and is typically caused by serotypes of the Salmonella enterica species.
All Salmonella bacteria are bacilli, which means rod-shaped bacteria. Salmonella has flagella all over its surface, allowing it to move.
In humans, most cases are caused by the S. Enteritidis and S.
Typhimurium serotypes. Other serotypes of Salmonella enterica cause similar infections in other warm-blooded animals.
These include S. Gallinarum in poultry, S.
Abortusovis in sheep, S. Choleraesuis in pigs, S.
Dublin in cattle, and S. Arizonae in reptiles, among others.
All of these strains can also infect humans. In humans, Salmonella is typically transmitted through the fecal-oral route, after infected feces come into contact with various foods including raw meat, poultry, eggs, unpasteurized milk, and crops.
Salmonella can also be present on the skin of reptiles and birds and be transmitted through contact with these animals. When the bacteria are ingested, they travel through the digestive tract, invading and multiplying in intestinal cells.
Infected cells then release proinflammatory cytokines, causing an inflammatory response. This results in gastroenteritis, or inflammation of the intestinal tract, causing abdominal pain and severe diarrhea.
The bacteria can also enter the blood, termed bacteremia, and cause enteric fever. From there, they can make their way to other organs like the liver, lungs, heart, and bone to cause focal Salmonella infection.
These symptoms and signs usually arise in humans between 12 and 48 hours after ingestion of the bacteria and typically last for 4 to 7 days.
The Salmonella Typhimurium serotype can cause typhoid fever, which is characterized by similar symptoms including high fever, headache, abdominal pain, and either constipation or diarrhea.
Unlike most other Salmonella infections, typhoid fever can be life threatening and often requires antibiotic treatment. In infected livestock, most adults have acute enteritis, with fever and severe diarrhea.
In horses, abdominal pain may lead to colic. In newborn animals, enteritis is often followed by bacteremia.
Diagnosis of salmonellosis is based primarily on clinical signs and symptoms. It can be confirmed by culture of stool, blood, urine, or tissue.
However, test results usually come back after symptoms have resolved and therefore diagnosis is usually based on symptoms.
In animals diagnosis can often be suspected based on symptoms, but salmonellosis will need to be distinguished from other causes of bacterial enteritis.
As in people, diagnosis can be confirmed by culture of feces, blood, or body tissues. Treatment for salmonellosis in people is focused mainly on replenishing body fluids and electrolytes to remedy dehydration.
In some cases, hospitalization may be required to deliver fluids intravenously. Antibiotics are typically avoided because they may prolong the infection in less severe cases.
However, if it is suspected that the Salmonella infection is focal or systemic, or if the patient is immunocompromised, antibiotics such as ciprofloxacin, azithromycin, ceftriaxone, or trimethoprim/sulfamethoxazole may be prescribed.
Early treatment is essential for bacteremic salmonellosis in animals, but use of antimicrobial agents for intestinal salmonellosis is controversial.
Oral antibiotics may be ineffective and there is concern about prolonging carriage and excretion of the organism. .
Fluid therapy to correct acid-base imbalance and dehydration may be necessary. Prevention is often the best course of action and includes hand-washing after touching raw meat or live animals; proper handling of raw meat to avoid cross-contamination while preparing foods; and adequate cooking of meat and eggs before eating.
Carrier animals, which are asymptomatic adults that shed the bacteria, and contaminated feed are factors that make control harder in livestock.
In many countries, government-backed programs have been introduced to reduce infection levels among food animals, especially poultry and pigs.
Vaccines are available for some animal species and may reduce symptoms along with lowering herd infection rates. ##Summary All right, as a quick recap: salmonellosis is an infection caused by Salmonella bacteria.
It is typically transmitted through contaminated food or water. Symptoms are caused by an inflammatory response to the bacteria that often leads to diarrhea and abdominal discomfort.
A clinical diagnosis is usually adequate to guide rehydration treatment but cultures should be done in severe cases to recognize serotypes that require antibiotics.
rehydration treatment, but culture should be done in severe cases to recognize
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