MRSA

Staphylococcus aureus means "golden cluster seed" in Latin, because these bacteria grow in clusters, a bit like grapes, and are golden or yellow-coloured. This mask is actual a whole colony of bacteria— each of the spheres is an individual bacterium. They normally live on our skin or inside our noses without causing any health problems— about one in three healthy people are thought to be carriers of the bacteria. If they get inside us, though, they can cause pneumonia, boils, and other infections. Our immune systems can usually fight off the bacteria on their own, but it's a worry in hospitals because of the large number of people there who are already ill or weakened from surgery or injuries. These people's immune systems may not be strong enough to combat the infection without the help of antibiotics.

For years, it was simple enough for doctors to use penicillin, methicillin, or another antibiotic to control staph bacteria, but more recently, certain strains of Staphylococcus aureus have evolved a resistance to antibiotics. MRSA stands for "Methicillin-resistant Staphylococcus aureus," which are immune to methicillin and penicillin. Sometimes they get called "multiple resistant" instead of "methicillin resistant" because nowadays they've become resistant to lots of other antibiotics as well. This is because after years of being killed off by antibiotics, most surviving bacteria have been the ones with genetic mutations allowing them to resist the drugs. Those bacteria have reproduced and passed on their DNA to their children, the bacteria of today, which is how evolution works!

The spread of MRSA is a real concern in hospitals, which is why if you go to one, you'll probably notice hand washing stations all over the place. Alcohol handwashing gels can destroy the bacteria on your hands so that you don't spread it from place to place, and doctors and cleaners are now trained to take care to avoid spreading the bacteria through their workplaces by careful sanitization and hand washing.