Staphylococcus epidermidis characteristics, morphology

1532
Egbert Haynes

Staphylococcus epidermidis it is a gram positive bacterium that is part of the usual bacterial flora on the body surface. It was first described by Friedrich Rosenbach in 1884.

Generally it remains harmless, without causing any type of harm to human beings. However, when an imbalance occurs in that normal microbiota and an injury or wound also occurs, it is likely that the bacteria enter the body and generate certain discomforts that can become serious..

Stahylococcus epidermidis. Source: Pixnio.com

The Staphylococcus epidermidis It is considered an opportunistic pathological agent, since it affects people who have a compromised immune system, so the cells in charge of attacking any foreign pathogen do not work properly.

This bacterium is a very common germ in the hospital area, since it is frequent in the case of people with a catheter for a long time, as well as in people who have some type of prosthesis.

If the infection is detected early and treatment is followed correctly, a cure is very likely. On the contrary, carelessness and negligence can be fatal.

Article index

  • 1 Taxonomy
  • 2 Morphology
  • 3 General characteristics
  • 4 Diseases
    • 4.1 Abscesses
    • 4.2 Phlebitis
    • 4.3 Septicemia
    • 4.4 Endocarditis
  • 5 Treatment
  • 6 References

Taxonomy

The taxonomic classification of Staphylococcus epidermidis is as follows:

Domain: Bacterium

Edge: Firmicutes

Class cocci

Order: Bacillales

Family: Staphylococcaceae

Gender: Staphylococcus

Species: Staphylococcus epidermis.

Morphology

As the name implies, the Staphylococcus epidermidis It is a bacterium that has a rounded shape, with a size of 0.5 - 1.5 microns in diameter. When observed under the microscope, they are seen in pairs or tetrads (accumulations of 4 bacterial cells).

When culturing, small, white or grayish colonies are seen. They have an approximate diameter of 2.5 to 4 mm. The culture initially has a cloudy appearance, to later become clear with a mucoid-looking deposit.

The cell surface does not present any type of extensions such as flagella or cilia.

Like all bacteria, it has a cell wall. In the case of Staphylococcus epidermidis, this structure is made up of peptidogicane. Similarly, it contains glycerol teichoic acid, which is evidenced in the glucosyl residues in the cell wall..

General characteristics

It is gram positive

The Staphylococcus epidermidis It is a bacterium that, when subjected to the Gram staining process, acquires a characteristic violet color. This is due to the structure of the cell wall, in which some particles of the dye remain fixed..

It is Gamma hemolytic

One of the properties studied in bacteria is the ability to hemolyze when grown on blood agar. This means causing the destruction of red blood cells..

In the case of Staphylococcus epidermidis, it is unable to achieve hemolysis of blood cells. Because of this, it belongs to the group of gamma hemolytic bacteria..

It is facultative aerobic

The Staphylococcus epidermidis It is a bacterium that can develop both in environments with ample availability of oxygen and in those in which there is none.

It is mesophilic

This bacterium has a growth temperature of between 30 ° C and 37 ° C, the latter being the optimum temperature.

It is catalase positive

The Staphylococcus epidermidis synthesizes the enzyme catalase, which is capable of splitting the hydrogen peroxide molecule (HtwoORtwo) in water and oxygen. This is an important characteristic, as it allows us to differentiate staphylococci from streptococci..

Metabolism

This bacterium has a fairly active metabolism. It is capable of producing acid from the following molecules: maltose, glucose, fructose, sucrose, galactose, mannose, lactose and glycerol.

Habitat

Bacteria are an important part of the normal flora on the body surface. It is naturally found in the skin and mucous membranes.

It is coagulase negative

Coagulase is an enzyme that promotes the transformation of fibrinogen into fibrin. This property constitutes a criterion for differentiation between the different bacteria that belong to the genus Staphylococcus..

Likewise, according to some studies, coagulase negative bacteria are more susceptible to the action of the immune system of the organisms they infect.

It is urease positive

Being urease positive, it is capable of hydrolyzing urea into ammonia and carbon dioxide, with the intervention of water..

Diseases

The staphylococcus epidermidis it is a bacterium that is generally not pathogenic, since it is part of the usual bacterial flora of the skin and certain mucous membranes.

However, there are times when the natural balance of this bacteria is disrupted, so they begin to proliferate uncontrollably, causing injuries and damage to people's tissues..

A common element of infections caused by Staphylococcus epidermidis is that it occurs in people who have a synthetic device such as a catheter, artificial heart valves, osteoarticular prostheses, as well as cerebrospinal fluid shunts. From this it can be inferred that most cases occur in the sanitary environment..

Among the most frequent pathologies that can cause Staphylococcus epidermidis there are abscesses, septicemia and endocarditis.

Abscesses

An abscess is defined as a lump on the skin, which is often filled with pus. It is caused by the presence of Staphylococcus epidermidis in any injury or wound.

Characteristic symptoms include:

  • Fever
  • Edema at the injury site
  • Presence of ulcer
  • The affected area may be red and warm
  • Discharge of pus and bloody substances.

Phlebitis

Phlebitis is the inflammation of a vein. In the hospital environment, it usually occurs when there is a catheter.

The most common symptoms of bacterial phlebitis are:

  • Pain in the area
  • Fever
  • Redness of the area
  • Edema of the area
  • There may be pus discharge.

Septicemia

Septicemia is also known as "blood poisoning." The main cause is the passage of certain bacteria into the bloodstream, with its consequent spread throughout the body. This can occur when local infections are not properly cared for in time..

This being the case, bacteria, in this case Staphylococcus epidermidis, can cause damage to the brain, heart, lungs, muscles and bones.

Among the most representative symptoms of septicemia are:

  • Increased respiratory rate
  • incrise of cardiac frecuency. Above 90 beats per minute.
  • Excessive increase or decrease in body temperature
  • Acne
  • Delirium or confusion

Endocarditis

As its name implies, endocarditis is inflammation of the innermost membrane of the heart or other elements of the heart. It occurs when the bacteria, in this case, the Staphylococcus epidermidis, passes into the bloodstream and reaches the heart.

There it mainly colonizes the atrioventricular valves. If the valves are synthetic, the risk of developing endocarditis is higher.

The symptoms of bacterial endocarditis are:

  • High fever
  • Fatigue
  • Incrise of cardiac frecuency
  • Weightloss
  • Excessive sweating.

Treatment

As in any infection caused by bacteria, the treatment to be followed includes the administration of antibiotics, either through the oral or intravenous route. The doctor is the one who, according to the diagnosis made by culture, will determine the drug to use.

The Staphylococcus epidermidis is methicillin resistant and sensitive to vancomycin and novobiocin.

References

  1. Brooks G., Carroll K., Butel J., Morse S., Mietzner T. Medical Microbiology. 25th edition. Mc Graw Hill Interamericana. 2010.
  2. Microbiological etiopathogenesis. Obtained from: hygiene.edu.uy
  3. Fernández, A., García, E., Hernández, A., Canteras, M., Ruiz, J. and Gómez, J. (2012). Bacteremia due to coagulase negative Staphylococcus: analysis of prognostic factors and influence of antibiotic treatment. Spanish Journal of Chemotherapy. 25 (3). 199-205
  4. García, C., Pardo, J. and Seas C. (2003, October). Bacteremia due to Staphylococcus epidermidis and soft tissue abscess in a post-operated patient: a case report. Herediana Medical Journal. 14 (4).
  5. Staph infections. Retrieved from: mayoclinic.org
  6. Otto, M. (2017). Staphylococcus epidermidis: a major player in bacterial sepsis ?. Future Microbiology. Retrieved from: id-hub.com
  7. Patrick, C., Plaunt, M., Sweet, S., and Patrick G. Defining Staphylococcus epidermidis cell wall proteins. (1990). Journal of Clinical Microbiology. 28 (12). 2757-2760
  8. Staphylococcus epidermidis bacteria. Retrieved from: prod.hopkins-abxguide.org
  9. Staphylococcus epidermidis. Retrieved from: microbewiki.kenyon.edu
  10. Staphylococcus epidermidis. Retrieved from: tgw1916.net

Yet No Comments