Staphylococcus capitis belong to the superordinate bacterial group of cocci and, as communal, colonize human skin and the mucous membranes of the nose. For healthy people, contact with Staphylococcus capitis is no longer tragic. However, immunocompromised patients can develop symptoms of poisoning and even endocarditis due to the bacteria contracting into the interior of the body.
Staphylococci are spherical bacteria with gram-positive properties. Staphylococci is a slang term. The scientific generic name is Staphylococcus.
Some staphylococci have the ability to produce free coagulase. In this context, a distinction is made between coagulase-positive and coagulase-negative staphylococci within the species. Staphylococcus capitis are a species within the genus of coagulase-positive staphylococci.
Although bacteria of the species Staphylococcus capitis are a natural element of the human skin flora, they can be dangerous for immunocompromised patients. This is especially true when the bacteria invade the body. In connection with the skin flora, the bacteria are known as commensals and do not harm humans because they do not feed parasitically on substances that humans themselves need to survive. In connection with immunodeficient patients, however, there is no longer talk of a communal relationship, but rather of pathological properties.
Bacteria of the Staphylococcus capitis species can therefore be associated with disease value for humans, although physiologically they colonize the skin of healthy people without any disease value. All staphylococci belong to the higher group of cocci.
Bacteria of the species Staphylococcus capitis prefer to live on the skin and in the mucous membranes of humans or other warm-blooded animals. Warm-blooded animals offer them a particularly suitable environment in which to grow, as the optimum temperature for the bacteria to multiply is between 30 and 37 degrees Celsius. On the skin, they are tolerated by the human immune system because they behave inconspicuously.
The bacteria are not rod-shaped bacteria, but spherical cells with a diameter between 0.5 and 1.5 µm. The staphylococci are arranged individually, in pairs or in grape-like clusters and have no ability to actively move.
All staphylococci grow facultatively anaerobically. This means that they can metabolize even in the absence of oxygen. However, your metabolism also works if there is oxygen in your environment. In addition to the skin and mucous membranes of warm-blooded animals, the bacteria also colonize the environment and are found, for example, in the air, in water or in food.
Their energy metabolism is mostly oxidative and is referred to as fermentative. In this context, they convert organic substances enzymatically. Instead of oxidase, they have catalase: an enzyme that converts hydrogen peroxide into oxygen and water to generate energy. The bacteria do not form spores and are not equipped with capsules.
The transmission from one individual to a second individual occurs in most cases via smear infection. This means that skin contact is the decisive factor. Not only skin contact with contaminated people, but also with contaminated objects can spread the bacteria into the body, especially in connection with food.
Since the bacteria colonize different skin areas as communal, self-infection can also take place. For example, an individual can spread the microorganisms from a colonized area of skin to other areas and thus promote colonization of the inside of the body. As a rule, the bacteria inside the body are not tolerated by the immune system and cannot spread any further. In people with a weak immune system, however, the contract into the interior of the body can take place without a defense reaction of the immune system and in this context causes pathological clinical symptoms.
As long as staphylococci are outside the human body, they have no effect on humans. Pathological phenomena only appear when the bacteria are tolerated inside the body through smear infection or self-infection. In healthy people, the immune system counteracts such an event. Infections with staphylococci are possible, especially in people with a weakened immune system. The species Staphylococcus captis is sometimes referred to as a hospital germ because it is estimated that 90 percent of hospital staff are infected with the bacteria.
Infections express themselves in immunodeficient patients in particular in the form of poisoning. The bacteria excrete enterotoxins as metabolites into the surrounding substrate. These toxins are protein-like structures that can cause certain symptoms of intoxication. Above a certain dose, enterotoxins mainly cause vomiting. The enterotoxins act in the abdominal organs on sympathetic fibers in the brain that are connected to the vomiting center. The toxins also act on the kidneys, liver, lungs, and gastrointestinal tract.
In the early phase of infection, the enterotoxins cause increased salivation, which, in addition to vomiting, is associated with nausea, gagging and diarrhea. In particularly severe, albeit rare, cases, there are states of shock or mucus and blood in the stool and vomit. Hypokalemic muscle paralysis may occur in the late phase. The patients often have a body temperature below average. Fever is rarely observed.
Endocarditis can also occur in connection with an infection. This is an inflammation of the inner lining of the heart, which is often associated with the symptoms of valvular or ischemic heart failure and also sometimes causes kidney damage.