Staph infections or staphylococcal infections refer to the invasions of areas in the body by staphylococcal organisms.
Staphylococcus, also known as staph, is a group of bacteria responsible for causing different kinds of diseases.  It is a genus of gram-positive bacteria that appears spherical when viewed with a microscope and usually arranged into grape-like clusters. There are several species of staphylococcus known, and many of them are known to use humans as their host by colonizing skin and respiratory tracts. Some of these species include: S.aureus, S.auricularis, S.borealis, S.capitis, S.epidermidis, S.haemolyticus, S.leei, S.pasteuri, S.sciuri, S.warneri, S.simulans, and etc. These species can cause different kinds of infections in man. The commonest species usually implicated in these infections is S.aureus.
Staphylococcal organisms may cause diseases by direct invasion or infection or by producing toxins that cause damages within the body tissues and cells. Examples of diseases caused by staphylococcal organisms are cellulitis, impetigo, food poisoning, toxic shock syndrome, boils and so on. 
Diseases caused by these organisms can be very mild or severe and can even be fatal. Infections can lead to sepsis and shock, which can lead to the death of the affected individual. Therefore, staph infections should be treated carefully and completely to avoid complications.
Staphylococcal infections are widespread and occur even in healthcare facilities. Staph infections contracted in hospitals or healthcare facilities usually involve staph organisms that are resistant to antibiotics, and so they are even more difficult to treat. Staphylococcus is one of the leading cause of infections in hospitals and health care facilities, and it is important for health care workers and patients to be educated on how to avoid these infections and necessary precautions they must take in the hospital environment.
Just like other bacterial infections, staph infections are treated using antibiotics. These drugs may act by killing the organisms, preventing their growth and multiplication. Antibiotics should be used as prescribed by the doctor. Treatment regimens should be adhered strictly to prevent the bacteria from developing resistance to the antibiotics, thereby slowing treatment or halting it entirely.
Types of Staph Infections and the Staphylococcus Causing Them
Staphylococcus is one of the leading causes of skin infections in man. Infection of the skin by staphylococcus can manifest itself as cellulitis, which is the inflammation of the connective tissue and deep layers of the skin; impetigo, which is the crusting of the skin. These bacteria can produce harmful toxins that cause a serious skin condition known as Scalded skin syndrome. Another common skin infection caused by staphylococcus in breastfeeding women is Mastitis in which the skin above the breast is infected.
This condition occurs when staphylococcus finds its way into the bloodstream (staphylococcal bacteremia). This is a severe condition and can lead to shock and death. Common symptoms are low blood pressure, fever and chills. The organism that is commonly implicated is Staphylococcus aureus.
Staphylococcus can invade the heart valves and cause inflammation, leading to a condition known as infective/bacterial endocarditis. This is a common cause of heart failure.