Staphylococcus

Staphylococcus

Staphylococcus is a genus of Gram-positive bacteria. Under the microscope they appear round , and form in grape-like clusters....

is a genus of Gram-positive

Gram-positive

Gram-positive bacteria are those that are stained dark blue or violet by Gram staining. This is in contrast to Gram-negative bacteria, which cannot retain the crystal violet stain, instead taking up the counterstain and appearing red or pink...

 bacteria

Bacteria

Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...

 which includes several species that can cause a wide variety of infections in humans and other animals through either toxin production or invasion.

Staphylococcal toxins are a common cause of food poisoning

Foodborne illness

Foodborne illness is any illness resulting from the consumption of contaminated food, pathogenic bacteria, viruses, or parasites that contaminate food, as well as chemical or natural toxins such as poisonous mushrooms.-Causes:Foodborne illness usually arises from improper handling, preparation, or...

, as they can be produced in improperly-stored food.

Coagulase-positive

The main coagulase

Coagulase

Coagulase is a protein produced by several microorganisms that enables the conversion of fibrinogen to fibrin. In the laboratory, it is used to distinguish between different types of Staphylococcus isolates. Coagulase negativity excludes S. aureus. That is to say, S...

-positive staphylococcus is Staphylococcus aureus

Staphylococcus aureus

Staphylococcus aureus is a facultative anaerobic Gram-positive coccal bacterium. It is frequently found as part of the normal skin flora on the skin and nasal passages. It is estimated that 20% of the human population are long-term carriers of S. aureus. S. aureus is the most common species of...

.

These bacteria can survive on dry surfaces, increasing the chance of transmission. S. aureus is also implicated in toxic shock syndrome

Toxic shock syndrome

Toxic shock syndrome is a potentially fatal illness caused by a bacterial toxin. Different bacterial toxins may cause toxic shock syndrome, depending on the situation. The causative bacteria include Staphylococcus aureus and Streptococcus pyogenes...

; 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

Staphylococcal scalded skin syndrome

Staphylococcal scalded skin syndrome, SSSS, also known as Pemphigus neonatorum or Ritter's disease, or Localized bullous impetigo is a dermatological condition caused by Staphylococcus aureus.-Pathophysiology:...

, a cutaneous reaction to exotoxin

Exotoxin

An exotoxin is a toxin excreted by a microorganism, like bacteria, fungi, algae, and protozoa. An exotoxin can cause damage to the host by destroying cells or disrupting normal cellular metabolism. They are highly potent and can cause major damage to the host...

 absorbed into the bloodstream. It can also cause a type of septicaemia called pyaemia

Pyaemia

Pyaemia is a type of septicaemia that leads to widespread abscesses of a metastatic nature. It is usually caused by the staphylococcus bacteria by pus-forming organisms in the blood. Apart from the distinctive abscesses, pyaemia exhibits the same symptoms as other forms of septicaemia...

. The infection can be life-threatening. Problematically, Methicillin-resistant Staphylococcus aureus

Methicillin-resistant Staphylococcus aureus

Methicillin-resistant Staphylococcus aureus is a bacterium responsible for several difficult-to-treat infections in humans. It is also called multidrug-resistant Staphylococcus aureus and oxacillin-resistant Staphylococcus aureus...

 (MRSA) has become a major cause of hospital-acquired infections

Nosocomial infection

A nosocomial infection , also known as a hospital-acquired infection or HAI, is an infection whose development is favoured by a hospital environment, such as one acquired by a patient during a hospital visit or one developing among hospital staff...

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

Etymology

The generic name Staphylococcus is derived from the Greek

Greek language

Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...

 word "staphyle" meaning a bunch of grapes, and "kokkos" means berries. 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 Stye An external stye or sty , also hordeolum , is an infection of the sebaceous glands of Zeis at the base of the eyelashes, or an infection of the apocrine sweat glands of Moll. External styes form on the outside of the lids and can be seen as small red bumps. Internal styes are infections of the...  and other small, superficial abscesses in sweat Sweat gland Sweat glands, or sudoriferous glands, are small tubular structures of the skin that produce sweat. There are two kinds of sweat glands:...  or sebaceous gland Sebaceous gland The sebaceous glands are microscopic glands in the skin that secrete an oily/waxy matter, called sebum, to lubricate and waterproof the skin and hair of mammals... s Subcutaneous abscesses (boil Boil A boil, also called a furuncle, is a deep folliculitis, infection of the hair follicle. It is always caused by infection by the bacterium Staphylococcus aureus, resulting in a painful swollen area on the skin caused by an accumulation of pus and dead tissue... s) around foreign bodies Large, deep, infections (carbuncles) possibly causing bacteremia Bacteremia Bacteremia is the presence of bacteria in the blood. The blood is normally a sterile environment, so the detection of bacteria in the blood is always abnormal....
Diffuse skin infection	Impetigo Impetigo Impetigo is a highly contagious bacterial skin infection most common among pre-school children. People who play close contact sports such as rugby, American football and wrestling are also susceptible, regardless of age. Impetigo is not as common in adults. The name derives from the Latin impetere...
Deep, localized infections	Acute and chronic osteomyelitis Osteomyelitis Osteomyelitis simply means an infection of the bone or bone marrow... Septic arthritis Septic arthritis Septic arthritis is the purulent invasion of a joint by an infectious agent which produces arthritis. People with artificial joints are more at risk than the general population but have slightly different symptoms, are infected with different organisms and require different treatment. Septic...
Other infections	Acute infective endocarditis Septicemia Necrotizing pneumonia
Toxinoses	Toxic shock syndrome Toxic shock syndrome Toxic shock syndrome is a potentially fatal illness caused by a bacterial toxin. Different bacterial toxins may cause toxic shock syndrome, depending on the situation. The causative bacteria include Staphylococcus aureus and Streptococcus pyogenes... Gastroenteritis Gastroenteritis Gastroenteritis is marked by severe inflammation of the gastrointestinal tract involving both the stomach and small intestine resulting in acute diarrhea and vomiting. It can be transferred by contact with contaminated food and water... Scalded skin syndrome Staphylococcal scalded skin syndrome Staphylococcal scalded skin syndrome, SSSS, also known as Pemphigus neonatorum or Ritter's disease, or Localized bullous impetigo is a dermatological condition caused by Staphylococcus aureus.-Pathophysiology:...
Unless else specified in boxes, then reference is

Other infections include:

• Closed-space infections of the fingertips, known as paronychia
  Paronychia
  The nail disease paronychia , commonly misidentified as a synonym for whitlow or felon, is an often-tender bacterial or fungal hand infection or foot infection where the nail and skin meet at the side or the base of a finger or toenail...
  
  .

Capitalization

As with all genus (generic) names in binomial nomenclature

Binomial nomenclature

Binomial nomenclature is a formal system of naming species of living things by giving each a name composed of two parts, both of which use Latin grammatical forms, although they can be based on words from other languages...

, Staphylococcus is capitalized when used alone or with the species. It is also properly italicized. However, it is not capitalized or italicized when used in adjectival forms (as in a staphylococcal infection), or as the plural (staphylococci or when writing of one of several types of staphylococcus).

Coagulase-negative

• S. epidermidis
  Staphylococcus epidermidis
  Staphylococcus epidermidis is one of thirty-three known species belonging to the genus Staphylococcus. It is part of human skin flora, and consequently part of human flora. It can also be found in the mucous membranes and in animals. Due to contamination, it is probably the most common species...
  
  , a coagulase
  Coagulase
  Coagulase is a protein produced by several microorganisms that enables the conversion of fibrinogen to fibrin. In the laboratory, it is used to distinguish between different types of Staphylococcus isolates. Coagulase negativity excludes S. aureus. That is to say, S...
  
  -negative staphylococcus species, is a commensal of the skin
  Skin
  -Dermis:The dermis is the layer of skin beneath the epidermis that consists of connective tissue and cushions the body from stress and strain. The dermis is tightly connected to the epidermis by a basement membrane. It also harbors many Mechanoreceptors that provide the sense of touch and heat...
  
  , but can cause severe infections in immune-suppressed
  Immunosuppression
  Immunosuppression involves an act that reduces the activation or efficacy of the immune system. Some portions of the immune system itself have immuno-suppressive effects on other parts of the immune system, and immunosuppression may occur as an adverse reaction to treatment of other...
  
   patients and those with central venous catheters.

• S. saprophyticus
  Staphylococcus saprophyticus
  Staphylococcus saprophyticus is a coagulase-negative species of Staphylococcus bacteria. S. saprophyticus is often implicated in urinary tract infections. S. saprophyticus is resistant to the antibiotic novobiocin, a characteristic that is used in laboratory identification to distinguish it from S...
  
  , another coagulase
  Coagulase
  Coagulase is a protein produced by several microorganisms that enables the conversion of fibrinogen to fibrin. In the laboratory, it is used to distinguish between different types of Staphylococcus isolates. Coagulase negativity excludes S. aureus. That is to say, S...
  
  -negative species that is part of the normal vaginal flora
  Vaginal flora
  The bacteria that colonize the vagina, collectively referred to as the vaginal microbiome, were discovered by the German gynecologist Albert Döderlein in 1892. The amount and type of bacteria present have significant implications for a woman's overall health...
  
  , 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
  Staphylococcus lugdunensis
  Staphylococcus lugdunensis is a coagulase-negative member of the genus Staphylococcus, consisting of Gram-positive bacteria with spherical cells that appear in clusters.-History:...
  
  , S. schleiferi, and S. caprae
  Staphylococcus caprae
  Staphylococcus caprae is a Gram positive, coccus bacteria and a member of the genus Staphylococcus. S. caprae is coagulase-negative. It was originally isolated from goats but members of this species have also been isolated from human samples.-Clinical importance:S...
  
  .