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Staphylococci correspond to a group of gram-positive bacteria that have a round shape, are found grouped in clusters, similar to a bunch of grapes and the genus is called Staphylococcus.
These bacteria are naturally present in people without any sign of illness. However, when the immune system is poorly developed, as in the case of newborns, or is weakened, due to chemotherapy treatment or old age, for example, bacteria of the genus Staphylococcus they can enter the body and cause disease.
Main species
Staphylococci are small, immobile bacteria arranged in clusters and can be found naturally in people, especially on the skin and mucous membranes, not causing any kind of disease. Most staph species are facultative anaerobic, that is, they are able to grow in an environment with or without oxygen.
The species of Staphylococcus can be classified into two groups according to the presence or absence of the coagulase enzyme. Thus, the species that have the enzyme are called positive coagulase, the Staphylococcus aureus the only species in this group, and species that do not have it are called coagulase negative staphylococci, whose main species are Staphylococcus epidermidis and Staphylococcus saprophyticus.
1. Staphylococcus aureus
O Staphylococcus aureus, or S. aureus, is a kind of staphylococcus normally found in the skin and mucosa of people, mainly in the mouth and nose, causing no disease. However, when the immune system is weakened, the S. aureus it can enter the body and cause infections that can be mild, such as folliculitis, or severe, such as sepsis, for example, which can put a person's life at risk.
This bacterium can also be easily found in a hospital environment, and can cause serious infections that are difficult to treat due to the acquired resistance of the microorganism to various antibiotics.
O Staphylococcus aureus it can enter the body through wounds or needles, especially in the case of hospitalized people, who use injectable drugs or who need to take penicillin injections regularly, for example, but it can also be transmitted from person to person through direct contact or through droplets of air from coughing and sneezing.
The identification of infection by Staphylococcus aureus it is done through microbiological tests that can be performed on any material, that is, secretion of wound, urine, saliva or blood. In addition, the identification of the S. aureus can be made through coagulase, since it is the only species of Staphylococcus that has this enzyme and is therefore called positive coagulase. See more about identifying S. aureus.
Main symptoms: Symptoms of infection by S. aureus vary according to the type of infection, form of infection and condition of the person. Thus, there may be pain, redness and swelling in the skin, when the bacteria proliferates on the skin, or high fever, muscle pain, headache and general malaise, which is usually indicative that the bacteria is present in the blood.
How the treatment is done: The treatment of infection by Staphylococcus aureus varies according to your sensitivity profile to antimicrobials, which may vary according to the person and the hospital you are in, if this is the case. In addition, the doctor takes into account the patient's health status and the symptoms presented by the patient, in addition to other infections that may exist. Usually the doctor recommends using Methicillin, Vancomycin or Oxacillin for 7 to 10 days.
2. Staphylococcus epidermidis
O Staphylococcus epidermidis or S. epidermidis, as well as the S. aureus, is normally present on the skin, not causing any kind of infection. However, the S. epidermidis it can be considered opportunistic, since it is capable of causing disease when the immune system is weakened or underdeveloped, as in the case of newborns, for example.
O S. epidermidis it is one of the main microorganisms isolated in hospitalized patients, since it is naturally present in the skin, and its isolation is often considered as contamination of the sample. However, the S. epidermidis have been linked to a large number of infections in the hospital environment due to their ability to colonize intravascular devices, large wounds, prostheses and heart valves, and can be associated with sepsis and endocarditis, for example.
The ability to colonize medical equipment makes this microorganism resistant to several antibiotics, which can make the treatment of the infection more complicated and endanger the person's life.
Confirmation of infection by S. epidermidis happens when two or more blood cultures are positive for this microorganism. In addition, it is possible to differentiate the S. aureus of S. epidermidis through the coagulase test, in which the Staphylococcus epidermidis does not have the enzyme, being called negative coagulase. Understand how the identification of the Staphylococcus epidermidis.
Main symptoms: Symptoms of infection by Staphylococcus epidermidis they usually only appear when the bacteria is in the bloodstream, and there may be a high fever, headache, malaise, shortness of breath or difficulty in breathing and low blood pressure, for example.
How the treatment is done: The treatment of the infection by S. epidermidis varies according to the type of infection and characteristics of the isolated microorganism. In case the infection is related to the colonization of medical devices, for example, the replacement of the devices is indicated, thus eliminating the bacteria.
When the infection is confirmed, the doctor may also indicate the use of antibiotics, such as Vancomycin and Rifampicin, for example.
3. Staphylococcus saprophyticus
O Staphylococcus saprophyticus, or S. saprophyticus, as well as the S. epidermidis, is considered a coagulase-negative staphylococcus, requiring further tests to differentiate these two species, such as the novobiocin test, which is an antibiotic that S. saprophyticus is normally tough and the S. epidermidis and sensitive.
This bacteria can be found naturally on the skin and genital region, causing no symptoms. However, when there is an imbalance in the genital microbiota, the S. saprophyticus and cause urinary tract infection, especially in women, since this bacterium is able to adhere to the cells of the urinary system of women of reproductive age.
Main symptoms: Symptoms of infection by S. saprophyticus they are the same as for a urinary tract infection, with pain and difficulty urinating, cloudy urine, feeling of not being able to empty the bladder and persistent low fever, for example.
How the treatment is done: The treatment of infection by S. saprophyticus it is done with the use of antibiotics, such as Trimethoprim. However, treatment with antibiotics should only be indicated by the doctor in the presence of symptoms, otherwise it may favor the emergence of resistant bacteria.