IBDP Biology: Methicillin Resistant Staphylococcus aureus (MRSA)

• Methicillin Resistant Staphylococcus aureus.
• 1 in 3 carries SA on the surface of skin, or in our nose, without developing an infection.
• However, if SA bacteria get into the body through a break in the skin they can cause infections such as boils, abscesses, or impetigo.
• If they get into the bloodstream they can cause more serious infections.
• Most SA infections can be treated with antibiotics such as methicillin.
• However, SA is becoming increasingly resistant to most commonly used antibiotics.
• MRSA is no more infectious than other types of SA bacteria.
• However, MRSA infections are more difficult to treat due to the antibiotic-resistance of the bacteria.
• When bacteria encounter an antibiotic, such as methicillin, some of the bacteria may survive. Some bacteria mutate to develop a resistance to the antibiotic.
• The surviving antibiotic-resistant bacteria can multiply.

• When it comes to IBDP Biology,  MRSA bacteria is usually spread through person-to-person contact with someone who has an MRSA infection, or who is colonised by the bacteria.
• It can also spread through contact with towels and sheets.
• MRSA infections are most common in people who are already in hospital.
• Those in hospital are more likely to develop MRSA infections.
• Exposure to antibiotics is more common.
• Those who are most at risk of MRSA include those who have:
  • A weakened immune system, such as the elderly, newborn babies, or those with a long-term health condition such as diabetes, cancer or HIV/AIDS.
  • An entry point for the bacteria to get into their body, such as a surgical wound, a catheter, or an intravenous tube.

• Most SA infections are skin infections.
• If SA bacteria are able to enter the bloodstream they can affect almost any part of the body. They can cause:
  • septicaemia (blood poisoning),
  • septic shock (widespread infection of the blood that leads to a fall in blood pressure and organ failure),
  • severe joint problems (septic arthritis),
  • bone marrow infection (osteomyelitis),
  • internal abscesses anywhere within the body,
  • of the tissues that surround the brain and spinal cord (meningitis),
  • infection (pneumonia), and 
  • infection of the heart lining (endocarditis)

• Wash your hands thoroughly before and after visiting someone in hospital.
• Hospital staff should maintain very high standards of hygiene.
• Before and after caring for any patient, hospital staff should make sure they have thoroughly washed and dried their hands.
• Use fast-acting, special antiseptic solutions, like alcohol rubs or gels.
• When it comes to IBDP Biology,  staff should wear disposable gloves when they have physical contact with open wounds.

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