Staphylococcus Aureus is a facultative anaerobe which reside on human skin or mucous membranes.
Under the microscope they look round (cocci) in shape. There are a number of strains that can cause infections, either by invading cells or releasing a toxin. One type that has been causing concern is Staphylococcus aureus, especially methicillin resistant Staphylococcus aureus (MRSA) which is resistant to a wide array of antibiotics and can cause a number of infections.
Staphylococcus aureus is the most dangerous of all of the many common staphylococcal bacteria. These gram-positive, sphere-shaped (coccal) bacteria (see figure How Bacteria Shape Up) often cause skin infections but can cause pneumonia, heart valve infections, and bone infections.
Staphylococcus aureus is present in the nose (usually temporarily) of about 30% of healthy adults and on the skin of about 20%. The percentages are higher for people who are patients in a hospital or who work there.
The bacteria can spread from person to person by direct contact, through contaminated objects (such as gym equipment, telephones, door knobs, television remote controls, or elevator buttons), or, less often, by inhalation of infected droplets dispersed by sneezing or coughing.
Carriers are people who have the bacteria but do not have any symptoms caused by the bacteria. Carriers can move the bacteria from their nose to other body parts with their hands, sometimes leading to infection. People who are hospitalized or work in a hospital are more likely to be carriers.
S. aureus is the leading cause of skin and soft tissue infections, such as abscesses, boils, furuncles, and cellulitis (red, swollen, painful, warm skin). S. aureus germs can also cause more serious infections, such as pneumonia, bloodstream infections, endocarditis (infection of the inner lining of the heart chambers and heart valves), and bone and joint infections.
Common symptoms of S.Aureus
1. SKIN INFECTIONS
- Boils – The most common type of staph infection is the boil, a pocket of pus that develops in a hair follicle or oil gland. The skin over the infected area usually becomes red and swollen.
Impetigo – This contagious, often painful rash can be caused by staph bacteria. Impetigo usually features large blisters that may ooze fluid and develop a honey-colored crust
Cellulitis – An infection of the deeper layers of skin — causes skin redness and swelling on the surface of your skin. Sores (ulcers) or areas of oozing discharge may develop, too.
Staphylococcal scalded skin syndrome – Toxins produced as a result of a staph infection may lead to staphylococcal scalded skin syndrome. Affecting mostly babies and children, this condition features fever, a rash and sometimes blisters. When the blisters break, the top layer of skin comes off — leaving a red, raw surface that looks like a burn.
2. FOOD POISONING
Staph bacteria are one of the most common causes of food poisoning. Symptoms come on quickly, usually within hours of eating a contaminated food. Symptoms usually disappear quickly, too, often lasting just half a day.
A staph infection in food usually doesn’t cause a fever. Signs and symptoms you can expect with this type of staph infection include:
- Nausea and vomiting
- Diarrhea
- Dehydration
- Low blood pressure
3. BACTEREMIA
It is also known as blood poisoning, bacteremia occurs when staph bacteria enter a person’s bloodstream. A fever and low blood pressure are signs of bacteremia. The bacteria can travel to locations deep within your body, to produce infections affecting:
- Internal organs, such as your brain, heart or lungs
- Bones and muscles
- Surgically implanted devices, such as artificial joints or cardiac pacemakers
4. TOXIC SHOCK SYNDROME
This life-threatening condition results from toxins produced by some strains of staph bacteria and has been linked to certain types of tampons, skin wounds and surgery. It usually develops suddenly with:
- A high fever
- Nausea and vomiting
- A rash on your palms and soles that resembles sunburn
- Confusion
- Muscle aches
- Diarrhea
- Abdominal pain
5. SEPTIC ARTHRITIS
Septic arthritis is a painful infection in a joint. The infection can come from germs that travel through your bloodstream from another part of your body. Septic arthritis can also occur when a penetrating injury delivers germs directly into the joint.
Infants and older adults are most likely to develop septic arthritis. Knees are most commonly affected, but septic arthritis also can affect hips, shoulders and other joints. The infection can quickly and severely damage the cartilage and bone within the joint, so prompt treatment is crucial.
References :
- Jameson JL, et al., eds. Staphylococcal infections. In: Harrison’s Principles of Internal Medicine. 20th ed. The McGraw-Hill Companies; 2018. https://accessmedicine.mhmedical.com. Accessed Jan. 27, 2020.
- Holland TL, et al. Clinical manifestations of Staphylococcus aureus infection in adults. https://www.uptodate.com/contents/search. Accessed Jan. 28, 2020.
- Fowler VG, et al. Clinical approach to Staphylococcus aureus bacteremia in adults. https://www.uptodate.com/contents/search. Accessed Jan. 28, 2020.
- Staphylococcal infections. Merck Manual Professional Version. https://www.merckmanuals.com/professional/infectious-diseases/gram-positive-cocci/staphylococcal-infections?query=staph infection. Accessed Jan. 28, 2020.
- Staphylococcal (staph) food poisoning. Centers for Disease Control and Prevention. https://www.cdc.gov/foodsafety/diseases/staphylococcal.html. Accessed Jan. 28, 2020.
- Methicillin-resistant Staphylococcus aureus (MRSA). Centers for Disease Control and Prevention. https://www.cdc.gov/mrsa/community/index.html. Accessed Jan. 28, 2020.
- Menstrual cycle. U.S. Department of Health & Human Services. https://www.womenshealth.gov/menstrual-cycle/your-menstrual-cycle/. Accessed Jan. 28, 2020.
- 4 steps to food safety. FoodSafety.gov. https://www.foodsafety.gov/keep-food-safe/4-steps-to-food-safety. Accessed Jan. 28, 2020.