Staphylococcus is a common genus of cocci bacteria with a positive Gram stain. The name “Staphylococcus” is derived from Greek words that describe the shape of the bacteria: round granules that form the shape of a cluster of grapes. Staphylococci tend to be found in clusters, while other types of cocci bacteria may group together in other patterns, such as chains or pairs. Staphylococcus bacteria are found around the world on other living organisms, and some species reside within the soil.
The Staphylococcus genus is comprised of over forty different species of bacteria. Each species of Staphyloccus bacteria may have several different strains that have different properties due to mutations. Some of these bacteria live on host organisms, and others are free-living. Those that live on other organisms may be potentially pathogenic, or they may be a harmless member of the bacterial flora on the mucus membranes and skin. The most clinically significant species of Staphylococcus bacteria is S. aureus. Another potentially pathogenic Staphylococcus species is S. haemolyticus, which tends to cause opportunistic infections. Staphylococcus species that cause human disease may be resistant to one or more drugs. Methicillin-resistant S. aureus, or MRSA, is an emerging threat that is resistant to the first line of antibiotics used for treating bacterial infections.
Human infection with S. aureus, S. haemolyticus or another species of pathogenic bacteria in the genus Staphylococcus usually takes the form of a minor skin infection. This usually occurs when the bacteria are able to enter the skin through a small abrasion or open wound. A Staph infection usually causes a skin rash or other abnormal skin symptoms, such as boils. Skin infections caused by staphylococci are usually easily treated with antibiotics. If the infection is not treated, however, it can spread to other parts of the body and cause serious problems. In the late stages of the infection, serious symptoms such as pneumonia, endocarditis, bone infections and septic shock can occur.
It is important to get any bacterial infection examined by a doctor and prevent it from spreading and becoming life-threatening. Staph infections are usually easy to get rid of with antibiotics. Most Staph infections are susceptible to basic antibiotics like penicillin, which are usually taken orally if the infection is localized. Drug-resistant Staphylococcus infections, on the other hand, are resistant to penicillin and other antibiotics in the same chemical class. If a doctor suspects a Staph infection, bacteria from the infection will be cultured and tested for drug resistance. If the bacteria are drug-resistant, they can still be treated with some types of antibiotics. More advanced infections that have spread may need to be treated with intravenous antibiotics in the hospital.
About S. aureus
Staphylococcus aureus is the Staph species most commonly responsible for human disease. A large proportion of the population harbors the bacteria, which normally causes no harm. In rare cases, it can cause infections of varying severity. MRSA is a growing problem in hospitals and group care facilities, but it is also present in some communities. While there are fewer antibiotics that can be used to treat MRSA than non-drug-resistant S. aureus, MRSA is still very treatable in the early stages of the infection.