- How to identify S. epidermidis infection
- How the diagnosis is made
- What is S. epidermidis resistant
- How the treatment is done
Staphylococcus epidermidis , or S. epidermidis , is a gram-positive bacterium that is naturally present on the skin, causing no damage to the body. This microorganism is considered opportunistic, as it is capable of causing disease when the immune system is weakened, for example.
Because it is naturally present in the body, Staphylococcus epidermidis is not widely considered in clinical practice, since most of the time it is isolated in the laboratory, it means contamination of the sample. However, this microorganism is able to grow easily in medical devices, in addition to having been reported to be resistant to several antibiotics, which makes it difficult to treat the infection.
How to identify S. epidermidis infection
The main type of infection by S. epidermidis is sepsis, which corresponds to infection in the blood, since this bacterium can easily enter the body, especially when the immune system is compromised, in addition to being associated with endocarditis. Thus, infection by S. epidermidis can be identified by analyzing the symptoms, the main ones being:
- High fever; Excessive tiredness; Headache; General malaise; Decreased blood pressure; Shortness of breath or difficulty breathing.
S. epidermidis is normally associated with infections in a hospital environment due to its ability to colonize in intravascular devices, large wounds and prostheses, for example, managing to proliferate and resist treatment.
How the diagnosis is made
In the laboratory, the identification of this bacterium is done through tests, the main one being the coagulase test, which differentiates S. epidermidis from Staphylococcus aureus , which has the coagulase enzyme, being called negative coagulase. Among the coagulase negative microorganisms, which are those that do not have the coagulase enzyme, S. epidermidis is the most clinically important.
To differentiate from other species of coagulase-negative staphylococci, novobiocin testing is usually done, which is done with the aim of checking resistance or sensitivity to this antibiotic. S. epidermidis is usually sensitive to this antibiotic, and the treatment is usually indicated by the doctor. However, there are strains of S. epidermidis that already have a resistance mechanism against this antibiotic, which makes treatment difficult.
Often the presence of S. epidermidis in the blood does not necessarily mean infection, since since it is found on the skin, the blood collection process, for example, can cause this bacterium to be identified in the exams. Therefore, the diagnosis of infection by S. epidermidis is made from the analysis of two or more blood cultures. Blood collection is usually done at different locations to avoid false results.
Thus, the diagnosis of infection by S. epidermidis is confirmed when all blood cultures are positive for this microorganism. When only one of the blood cultures is positive for S. epidermidis and the others are positive for another microorganism, it is considered contamination.
What is S. epidermidis resistant
The contamination of the sample by S. epidermidis is often misinterpreted by the laboratories and indicated as infection in the test result, which causes the doctor to indicate the use of antibiotics against "infection". The inappropriate use of antibiotics can favor the formation of resistant bacteria, making treatment difficult.
Currently, infection by S. epidermidis has been frequent in hospitalized patients and, therefore, has gained clinical importance not only due to the indiscriminate use of antibiotics, but also to its ability to form biofilm in medical equipment, which favors the proliferation of this disease. bacteria and resistance to treatments.
How the treatment is done
The treatment for infection with Staphylococcus epidermidis is usually done with the use of antibiotics, however, the antimicrobial of choice varies according to the characteristics of the bacteria, since many have resistance mechanisms. Thus, the use of Vancomycin and Rifampicin, for example, may be recommended by the doctor.
In addition, treatment for S. epidermidis is only indicated when the infection is confirmed. In case of suspected contamination of the sample, new samples are taken to check if there was contamination or if it represents infection.
In the case of colonization of catheters or prostheses by S. epidermidis , it is usually recommended to change the medical device. Currently, some hospitals adopt the use of antiseptic equipment that prevent the formation of biofilm and the development of Staphylococcus epidermidis , preventing infection.
