Author: Silvia Marinova, PhD student in the Genomic Stability Laboratory at BAS

The Candida fungus under an electron microscope. Credit: Edgerton Lab, State University of New York at Buffalo

Fungal diseases are considered a serious health problem especially in people with weakened immunity. The most widespread [ref.1] such infection is candidiasis, also known as candidal colpitis and thrush.

It is caused by a fungus of the genus Candida and only develops under certain conditions. There are high-risk factors that lead to Candida infection, including antibiotics.

 

What causes candidiasis

Candida is a genus of fungi, some members of which can provoke the disease candidiasis in humans. Candida albicans is the most common pathogenic species, but nevertheless other members of the genus [ref.2] are often isolated recently, such as C. glabrata, C. tropicalis, C. parapsilosis, C. krusei, C. famata, C. guilliermondii and C. lusitaniae, especially in immunodeficiency people with AIDS.

Along with other microorganisms, this type of fungus is normally part of the human microflora. They live in the digestive tract, skin and vagina, without causing infections and unpleasant symptoms under normal conditions.

However, sometimes their natural environment can change and this may create conditions in which the Candida fungus begins intensive reproduction. In these cases, candidiasis may develop, and in the absence of treatment, it is possible to develop into invasive candidiasis, which is a life-threatening condition.

 

Parts of the body that may be affected by Candida

Body parts that may be affected include:

  • Mouth - when the fungus overgrows in the mouth the disease is called thrush. This affects the moist places around the lips, tongue, the inside of the cheeks. Whitish adhesives appear on the mucous membranes.

Candidiasis of the tongue in a child after taking antibiotics. Credit: James Heilman, MD

  • Esophagus - there may be difficulty swallowing.

  • Skin - skin redness appears in places where the skin is moist.

  • Vagina - there may be burning and pain during sexual intercourse, unusual discharge, itching and pain in the area of the vagina. Vaginal candidiasis is rarely sexually transmitted.

  • Internal organs and blood - in this condition, the fungus enters the bloodstream, reaching and infecting internal organs. Most often it occurs in underweight newborns and people with severely weakened immunity due to disease or due to aggressive therapy with medications. In these cases the fungus can enter the bloodstream through surgical wounds, intubation and others. This condition is called invasive (deep) candidiasis and is the most common nosocomial infection [ref.2].

 

Taking antibiotics often leads to fungal infections, including candidiasis

The human microflora, or microbiome, consists of various microorganisms, which inhabit the skin and mucous membranes of the nasal and oral cavity, colon, vagina, eyes, etc. Their population inhabits them constantly and is called "normal" microflora and differs in composition in each individual [ref.3].

It performs various functions. It has a role in digestion, metabolism and immunity and in general in recent years there is an increasing emphasis on the relationship between the overall health of the body and the presence of "normal" and balanced microflora.

Mixed colony of Candida albicans on a nutrient medium. Credit: Garnhami, Wikipedia

Let's take the vaginal microflora as an example. Its composition is normally dominated by one or two types of bacteria such as lactobacils [ref.4]. Their role is to create slightly acidic conditions in the vagina. Thus, they protect it from the entry of disease-causing microorganisms. This environment is sufficient to keep the growth of Candida fungi under control.

When this fine balance maintained by the body is disturbed due to the impact of internal or external factors, then favorable conditions are created for the development of diseases such as candidiasis, due to increased reproduction of the fungus.

The cause may be the prolonged use of broad-spectrum antibiotics, which have been prescribed to treat diseases caused by certain bacteria, such as sinusitis, bronchitis or cystitis. Often antibiotics destroy not only disease-causing bacteria, but also part of the "normal".

This leads to an imbalance of microflora. In our sample case, this can lead to a decrease in the amount of lactobacils in the vagina. This means that they will not be able to maintain an acidic environment there, which in turn is the exact prerequisite for increasing the growth and resealing of the fungus of the Candida genus. Then the appearance of symptoms begins and candidiasis develops.

 

How to prevent infection

One of the main things you need to know is that when taking antibiotics it is desirable to also take probiotics, and even better is the combination of probiotics and prebiotics (nutrients for beneficial bacteria). They import large amounts of the "good" bacteria and thus help maintain their balance.

Read more in the article Fermented foods - natural probiotics for good health.

Often your attending physician will also prescribe drugs that have an antimycotic (antifungal) effect. They prevent the development of fungal infections and should be taken according to your prescribed scheme.

Antibiotics should never be used without a doctor's prescription, because this poses many risks, including the development of antibiotic resistance.

Besides taking antibiotics, there are other risk factors that increase the likelihood of candidiasis, such as the change in the normal environment due to external factors. It is good to observe some simple hygiene habits that reduce the risk:

  • wear breathable cotton underwear;

  • change wet swimsuit as soon as possible;

  • avoid too hot baths or showers;

  • use a special intimate soap and not the usual one;

  • do not overwash the skin and vagina;

  • do not wear too tight trousers that lead to sweating;

  • use communal swimming pools, saunas and public baths with caution.

 

What is the treatment of candidiasis

To begin a treatment, it is necessary to first have a diagnosis. This is usually done by taking a secretion from the affected place and its examination for the presence of the candida fungus.

However, positive samples do not always mean infection, since candida sometimes represents a normal part of the microbiome, as mentioned above. It is also necessary to present the corresponding symptoms for the diagnosis of candidiasis.

Candidiasis is generally susceptible to treatment. Various antifungal preparations are used, the exact method of administration or application is determined by the affected site. It is necessary to strictly follow the course of treatment appointed by a doctor. In some cases, it is possible that the fungus may prove resistant [ref. 5] to the discharged medication, and then another one should be appointed.

It is important not to neglect the symptoms and that treatment be timely and adequate to avoid complicating ordinary infection to invasive candidiasis, since it is a life-threatening condition.

 

Read more:

What is the difference between a bacterium and a virus and what exactly is the cell

What you need to know about herpes

 

References:

  1. Candida albicans infection inhibits macrophage cell division and proliferation. Fungal genetics and biology: FG & B. 2012
  2. Candida Infections and Therapeutic Strategies: Mechanisms of Action for Traditional and Alternative Agents. Front. Microbiol., 2018
  3. Structure, function and diversity of the healthy human microbiome. Nature. 2012
  4. The vaginal microbiome: new information about genital tract flora using molecular based techniques. BJOG: an international journal of obstetrics and gynaecology. 2011
  5. Antifungal Resistance. www.cdc.gov/fungal/antifungal-resistance.html

 

The author:

👩 🔬 Silvia Marinova has a BSc in Molecular biology (Sofia University, Bulgaria), and a MSc in structural biology (Grenoble, France). She is currently a doctoral student at the Laboratory of Genomic Stability at IMB, BAS. Her research interests are in the field of DNA repair, microscopy and biophysics. She loves photography, painting and sports.