Staphylococcal infection

Staphylococcal infection
Classification and external resources
SEM micrograph of S. aureus colonies; note the grape-like clustering common to Staphylococcus species.
MeSH	C013203

Staphylococcus is a Gram-positive bacteria which includes several species that can cause a wide variety of infections in humans and other animals through infection or the production of toxins. Staphylococcal toxins are a common cause of food poisoning, as they can be produced in improperly-stored food. Staphylococci are also known to be a cause of bacterial pink eye.

Coagulase-positive

Further information: Staphylococcus aureus#Role in disease

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 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, and is being recognized with increasing frequency in community-acquired infections.

Etymology

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

Main Staphylococcus aureus infections
Type	Examples
Localized skin infections	Stye and other small, superficial abscesses in sweat or sebaceous glands Subcutaneous abscesses (boils) around foreign bodies Large, deep, infections (carbuncles) possibly causing bacteremia
Diffuse skin infection	Impetigo
Deep, localized infections	Acute and chronic osteomyelitis Septic arthritis
Other infections	Acute infective endocarditis Septicemia Necrotizing pneumonia
Toxinoses	Toxic shock syndrome Gastroenteritis Scalded skin syndrome
Unless else specified in boxes, then reference is

Other infections include:

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

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 genitourinary tract infections in sexually-active young women.

• In recent years, several other staphylococcal species have been implicated in human infections, notably S. lugdunensis, S. schleiferi, and S. caprae.