What Is Salmonella?

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Medically reviewed by Sameena Zahoor, MD

Salmonella is a group of bacteria that cause a salmonellosis infection—a foodborne illness that affects over 1.3 million people in the United States annually. This infection leads to approximately 26,000 hospitalizations and 420 deaths in the U.S. every year.

Salmonella infection spreads through contaminated foods, from person to person, and from animal to person. Symptoms typically last 4-7 days and include diarrhea, abdominal cramps, and fever. Most people recover without specific treatment, but more severe cases may require hospitalization. Prevention strategies focus on proper food handling, cooking, and hand hygiene.

Types of Salmonella  

There are many different kinds of Salmonella, with over 2,500 types identified. The two main species are:

• Salmonella bongori
• Salmonella enterica

While all Salmonella types can cause disease in humans, some are host-specific. This means they’re more common in certain animals. For example:

• Salmonella enterica serotype Dublin is often associated with illness in cattle.
• Salmonella enterica serotype Choleraesuis is frequently linked to illness in pigs.

Salmonella enterica serotypes Enteritidis and Typhimurium are the two most significant types of Salmonella transmitted from animals to humans globally.

Salmonella Symptoms 

Salmonella can lead to a range of symptoms that usually begin within 6-72 hours after ingesting contaminated food or water. Symptoms vary from mild to severe. While some people may experience only mild gastrointestinal discomfort, others may develop more serious complications requiring medical attention.

Common symptoms of salmonellosis include:

• Diarrhea
• Abdominal cramps
• Fever, usually higher than 100.4°F

Less common symptoms include:

• Nausea
• Vomiting
• Headache
• Body aches
• Fatigue
• Dizziness when standing
• Loss of appetite

Most cases of Salmonella infection resolve within 4-7 days, but more severe cases may lead to complications like dehydration from fluid loss due to diarrhea and vomiting. Bacteremia (bloodstream infection) is another possible complication.

Certain populations—including infants, older adults, and people who are immunocompromised (have weakened immune systems)—are at higher risk of experiencing more severe symptoms and complications.

What Causes Salmonella? 

Ingesting contaminated food or water is the primary cause of Salmonella infection. Possible foods include:

• Raw or undercooked poultry
• Eggs
• Chicken, beef, and pork
• Unpasteurized dairy products
• Sprouts and salads
• Fruits and vegetables

Some recent salmonella outbreaks have been linked to processed foods like peanut butter, flour, frozen pot pies, and salami sticks.

Cross-contamination between raw and cooked foods, inadequate food handling practices, and poor sanitation contribute to the spread of salmonellosis. You can also get it from animals at home and at places like petting zoos and fairs.

Risk Factors

Some people are more susceptible to Salmonella infection. Risk factors include:

• Age: Children under 5 years old and adults over 65 years old are at higher risk of developing severe symptoms and complications.
• Immune status: People with compromised immune systems, including those with human immunodeficiency virus (HIV) or undergoing chemotherapy, are more susceptible to salmonellosis.
• Certain medical conditions: Chronic conditions like diabetes and gastrointestinal (GI) conditions like inflammatory bowel disease (IBD)—inflammation in your digestive tract—may increase the risk of developing severe infection.
• People taking certain medications: For example, stomach acid reducers can increase your risk of infection.

Living in or visiting areas with poor sanitation and hygiene practices may also increase the risk of exposure to contaminated food and water.

More Salmonella in Summer

Salmonella infection is more common during the summer due to foods being left out in warmer temperatures. Refrigerate or freeze prepared foods, leftovers, and foods likely to spoil quickly within one hour if the food is outside and the temperature is at least 90 degrees.

How Is Salmonella Diagnosed?  

Salmonella infection is typically diagnosed through laboratory testing of a stool sample. Additional diagnostic methods may be used if the infection spreads beyond the gastrointestinal tract. These tests detect the presence of Salmonella bacteria and include the following cultures:

• Blood
• Urine
• Bile, a digestive fluid related by the liver
• Cerebrospinal fluid (CSF), clear fluid that surrounds the brain and spinal cord
• Bone marrow, the spongy tissue in the center of bones

Salmonella Treatment  

Most Salmonella infections resolve on their own without specific treatment. However, individuals with severe symptoms, compromised immune systems, or certain underlying conditions may require medical attention.

Supportive Care

Treatment typically involves supportive care to manage symptoms. Common treatments for salmonellosis include:

• Fluid replacement, either orally (by mouth) or intravenously (delivered into a vein with an IV) for dehydration
• Antidiarrheal medications
• Pain and fever relievers such as non-steroidal anti-inflammatory drugs (NSAIDs) or Tylenol (acetaminophen)
• Rest

Antibiotics

Antibiotics may be used for severe or invasive infections or people at high risk of complications. They can shorten the duration of illness and reduce the risk of complications. The type of antibiotic depends on the location of the infection. Some of the more commonly prescribed antibiotics for Salmonella include:

• Rocephin (ceftriaxone)
• Zithromax (azithromycin)
• Cipro (fluoroquinolone)

Always consult your healthcare provider for proper diagnosis and treatment recommendations.

How To Prevent Salmonella 

You can prevent Salmonella infection, or at least significantly reduce your risk. Here are some recommendations to follow at home:

• Clean and sanitize surfaces, including the inside walls and shelves of the refrigerator, cutting boards, countertops, and utensils that may have come into contact with contaminated foods.
• Wash your hands with warm water and soap after thoroughly cleaning and sanitizing to prevent the spread of bacteria.
• Wash your hands after using the toilet and changing diapers.
• Don’t prepare food or beverages for others if you have diarrhea due to a Salmonella infection.
• Refrigerate or freeze perishable foods and leftovers within two hours (one hour if the food is outside and the temperature is above 90 degrees).

If you have pets, take special care to avoid cross-contamination when handling their food. Wash pet food dishes as soon as pets finish eating. Don’t put your hands in your mouth after petting or playing with animals.

Complications

Complications from Salmonella infection can range from mild to severe and may include gastrointestinal issues, systemic (whole-body) illnesses, and potentially life-threatening conditions. They include:

• Bacteremia: Invasive infection can lead to bacteremia, where the bacteria enter your bloodstream. Bacteremia can lead to systemic illness and potentially life-threatening complications such as sepsis or septic shock if not promptly treated with antibiotics.
• Typhoid fever: This is a severe systemic illness caused by the bacterium Salmonella enterica serotype Typhi. It’s transmitted through contaminated food and water, particularly in areas with poor sanitation. Typhoid fever presents with prolonged high fever, headache, abdominal pain, and diarrhea. It can lead to emergency complications such as intestinal perforation (a hole in your digestive tract) or bacteremia if left untreated.
• Reactive arthritis: This type of arthritis is a complication of infection. Typical symptoms include joint pain, swelling, and inflammation. It often affects knees, ankles, and feet. Reactive arthritis can persist for weeks to months after the initial infection and may require medical management to alleviate symptoms and prevent long-term joint damage.

A Quick Review

Salmonella infection, or salmonellosis, is a significant bacterial infection and food-borne illness. It can spread through contaminated food, from person to person, or from animal to person. Symptoms include diarrhea, abdominal cramps, and fever.

Some people—including young children and older adults—are more susceptible to infection. In more severe cases, prompt diagnosis through stool sample testing is crucial for effective treatment. Treatment typically involves supportive care and possibly antibiotics. Prevention strategies focus on proper food handling and hygiene.

Contact your healthcare provider immediately if you suspect that you or a loved one has symptoms of Salmonella or another food-borne illness.

Frequently Asked Questions

What food is Salmonella found in?

Salmonella can be found in a variety of foods, including raw or undercooked poultry, eggs, meat, unpasteurized dairy products, and contaminated fruits and vegetables.

Is Salmonella the same as food poisoning?

Salmonella is a type of bacteria that can cause food poisoning, but not food poisoning is caused by Salmonella. Food poisoning is a broad term that refers to illnesses caused by consuming contaminated food or water. It can be caused by various pathogens including bacteria, viruses, and parasites.

How long are you contagious with Salmonella?

The duration of contagiousness for Salmonella depends on factors like your immune response and the particular strain of bacteria. If you have a Salmonella infection, don’t handle food or beverages for others until your diarrhea has completely resolved.

Read the original article on Health.com.