Staphylococcus is a round-shaped, gram-positive species of bacteria. The bacteria got its name from Greek words “staphyle” and “kokkos” that mean “a bunch of grapes”, because these species is mostly found in clusters when viewed through microscope. Staphylococcus bacteria was identified and named by Rosenbach, in 1884. There are different strains of Staphylococcus bacteria that are classified into one of the two main groups, coagulase-positive and coagulase-negative, depending on their ability to produce coagulase, proteins responsible fro blood clotting. Staphylococcus aureus is the most pathogenic coagulase-positive strain, which is responsible for most infections in humans. Staphylococcus epidermidis is coagulase-negative strain, not highly virulent but usually associated with implanted devices such as catheters.
Diseases Caused by Staphyloccocus
Staphylococcus bacteria can infect different tissues in the body. Most infections are caused by Staphylococcus aureus, which usually first affects the skin. But if it enters the bloodstream, other organs can be infected too. Infections in the skin usually occur when the skin is damaged due to cuts, abrasions or burns. Skin infections are commonly localized such as boil, furuncle, carbuncle and sty. However, staphylococcus aureus infection can affect large areas of the skin resulting in impetigo, cellulites or folliculitis. When the bacteria reach the bloodstream it can cause infections in many body organs. These include: blood infection (sepsis), lung infection (pneumonia), heart valve infection (endocarditis) and bone infection (osteomyelitis). These are severe conditions that can be fatal. Staphylococcus aureus can also cause scalded skin syndrome that affects infants, mastitis that affects breastfeeding women and toxic shock syndrome that affects menstruating women due to the use of certain type of tampons. Finally, staphylococcus aureus can cause septic shock and food poisoning because of toxins produced by the bacteria. Staphylococcus epidermis strain rarely causes infection. However, people with weakened immunity and implanted medical devices are susceptible to S.epidermidis infection.
Symptoms of Staph InfectionLocalized skin infections like boils and furuncles are characterized by red, painful and swollen area with the drainage of pus. Impetigo is an infection of surface of the skin, featured by painful rash and large blisters. Cellulitis is an infection of the connective tissue under skin that causes swelling and redness of the affected area. Symptoms of scalded skin syndrome include fever, rash and sloughing of the top layer of the skin. Blood poisoning is accompanied with persistent fever, chills and low blood pressure. Toxic shock syndrome causes symptoms like: high fever, headache, muscle aches and seizures. Food poisoning is accompanied with nausea, vomiting, diarrhea and abdominal cramps. Staphylococcus epidermidis infection is featured by the presence of redness, tenderness and pus on the area where catheter is introduced.