salmonella

Salmonella is a common bacterial disease that affects the intestinal tract. It is a type of gastroenteritis caused by bacteria. The salmonella bacteria typically live in animal and human intestines and are shed through stool. Most salmonella infections in Australia are caused by eating contaminated food or coming in contact with an infected person.

	Non-typhoidal	Typhoidal (Typhoid fever)
Causes	Salmonella enteriditis pathogen Gram negative rod shaped bacteria Polysaccharide layer outside cell Can live outside and inside of host cells Have flagella (motility) Can be found in humans, animals (poultry, eggs, pets, turtles) Transferred by food or faecal-oral route Direct contact with infected humans or animals	Salmonella typhi pathogen Gram negative rod shaped bacteria Polysaccharide layer outside cell Can live outside and inside of host cells Have flagella (motility) Only infects humans Faecal- oral Endemic to Asia, Africa, Latin America, Caribbean
Clinical Features	Targets epithelial layer of mucosal lining of small intestine Inflammation of small intestines and colon Ulcers and dysfunction of GI tract	Targets epithelial layer of mucosal lining of small intestine Inflammation of small intestines and colon Necrosis (death) and hypertrophy (enlargement) of surrounding tissue If invasive can reach other organs, blood stream and can develop sepsis (pathogen released in blood vessels causing bacteraemia)
Symptoms	Presents 24-48 hours after food ingestion Loose stools/ diarrhoea that can be bloody Nausea, vomiting Fever Abdominal cramps Headaches Chills	Appear 1-2 weeks after infection and takes 4-6 weeks to resolve High, sustained fever Abdominal pain Constipation then diarrhoea Rose/salmon coloured spots on chest/abdomen Dehydration Weakness Headaches Cloudy/confused mental state Hepatosplenomegaly (enlarged spleen and liver)
Prognosis	Usually resolves on its own within a week Can disseminate via blood Dehydration from fluid loss in diarrhoea	Can be fatal if left untreated Can chronically infect patients who are then subject to being carriers of the bacteria for decades

Causes

There are many causes of salmonella including

Undercooked food from infected animals such as chicken, eggs and dairy
Contaminated food eg vegetables cut with same knife as raw chicken
Contaminated water
Handling animals without washing hands afterwards
Contact with infected person
Surfaces with bacteria on them eg nappies, toilets

Risk Factors

Age- young children (<5) and older adults
Season- more common in summer
Low gastric acidity
Recently taken antibiotics
Have inflammatory bowel disease (IBD)
Immunodeficiency
- Sickle cell disease
Alcoholism
IV drug use
International travel (increased exposure)

Treatment

Most people recover from salmonella without medical intervention within a week. If you have severe symptoms, a doctor may prescribe antibiotics. Resting and rehydrating is also vital in recovering from salmonella, whether this is via water/oral rehydration drinks (sports drinks, fruit juice) or IV fluids if you are very sick (1).

You should contact your doctor if:

Symptoms last longer than a few days
Diarrhoea is sever or bloody
You are at risk for severe salmonella (young children, older people and people with poor immune systems) (2).

Prevention

There are many ways to prevent contracting salmonella. These include:

Handling, storing and cooking food safely
- Cooking meat and poultry until the middle is not pink
- Refrigerated food should be kept at less than 5 degrees
- Hot food should be kept above 60 degrees
- Thaw frozen food in a fridge/microwave rather than at room temperature
- Use different chopping boards/utensils to avoid cross contamination (2)
Washing your hands
- After using toilet
- After changing nappies
- After touching animals
- Before and after preparing food
- Before eating
When travelling to countries in Asia, Middle East, Africa
- Avoid foods that could be contaminated (salads, raw/cold seafood, cold meat)
- Use bottled water to drink and brush teeth
- Avoid ice in drinks
- Avoid washed or cut fruit (1)

Controlling the spread of salmonella

If diagnosed with salmonella, your doctor is required to inform the department of health to prevent further spread and outbreaks of salmonella. The department will then investigate clusters of cases to try identify common links to develop prevention strategies and put in control measures (2).

Furthermore, if you have already contracted salmonella there are many ways that you can control spreading the infection further, including:

Cleaning contaminated surfaces such as toilets with detergent, hot water and bleach based products
Staying home from work or school until at least 24 hours after your symptoms stop
Staying home if you are in the healthcare, food or childcare industry for at least 48 hours after symptoms subside
Avoid preparing food for others until 24 hours after your symptoms stop (1)