Staphylococcal infection

Staphylococcal infection
SEM micrograph of S. aureus colonies; note the grape-like clustering common to Staphylococcus species.
Classification and external resources
Specialty	Infectious disease
MeSH	D013203

A staphylococcus infection or staph infection is an infection caused by members of the Staphylococcus genus of bacteria. These bacteria commonly inhabit the skin and nose where they are innocuous, but may enter the body through cuts or abrasions which may be nearly invisible. Once inside the body, the bacterium may spread to a number of body systems and organs, including the heart, where the toxins produced by the bacterium may cause cardiac arrest. Once the bacterium has been identified as the cause of the illness, treatment is often in the form of antibiotics and, where possible, drainage of the infected area. However, many strains of this bacterium have become resistant to the available regimens of antibiotics— for those suffering these kinds of infection, the body's own immune system is the only defense against the disease. If that system is weakened or compromised, the disease may progress rapidly.^[1]

Types

Other infections include:

• Closed-space infections of the fingertips, known as paronychia.

Coagulase-positive

The main coagulase-positive staphylococcus is Staphylococcus aureus, although not all strains of Staphylococcus aureus are coagulase positive. These bacteria can survive on dry surfaces, increasing the chance of transmission. S. aureus is also implicated^[6] in toxic shock syndrome; during the 1980s some tampons allowed the rapid growth of S. aureus, which released toxins that were absorbed into the bloodstream. Any S. aureus infection can cause the staphylococcal scalded skin syndrome, a cutaneous reaction to exotoxin absorbed into the bloodstream. It can also cause a type of septicaemia called pyaemia. The infection can be life-threatening. Problematically, Methicillin-resistant Staphylococcus aureus (MRSA) has become a major cause of hospital-acquired infections. MRSA has also been recognized with increasing frequency in community-acquired infections.^[7] The symptoms of a Staph Infection include a collection of pus, such as a boil or furuncle, or abscess. The area is typically tender or painful and may be reddened or swollen.^[8]

Coagulase-negative

• S. epidermidis, a coagulase-negative staphylococcus species, is a commensal of the skin, but can cause severe infections in immune-suppressed patients and those with central venous catheters.
• S. saprophyticus, another coagulase-negative species that is part of the normal vaginal flora, is predominantly implicated in uncomplicated lower genitourinary tract infections in young sexually active women.^[9]
• In recent years, several other staphylococcal species have been implicated in human infections, notably S. lugdunensis, S. schleiferi, and S. caprae.

Etymology

The generic name Staphylococcus is derived from the Greek word "staphyle," meaning bunch of grapes, and "kokkos," meaning granule. The bacteria, when seen under a microscope, appear like a branch of grapes or berries.

References