Candida: Infection, Transmission & Diseases

Candida is a genus of yeast. The best known representative of this genus is the fungus Candida albicans.

What is Candida?

Candida are yeasts from the division of tubular fungi. Several species of the genus are potential pathogens for humans. They are also known as pathogenic Candida. These include Candida stellatoidea, Candida famata, Candida glabrata, Candida krusei or candida dubliniensis. However, the best known and most common representative of Candida is Candida albicans. It is the causative agent of candidiasis. Candidiasis is an infectious disease that can cause sometimes drastic symptoms, especially in people with a weakened immune system. The fungus is also found in three quarters of all healthy people. However, in this case it belongs to the transient flora. This means that it is ingested with food, passes through the intestinal tract and is then excreted. It lives on the mucous membranes of the mouth, throat and in the digestive tract. It also feels at home in the genital area, between the fingers and toes and on the fingernails as well as toenails. Candida albicans is a facultative pathogen. Normally, it lives in a state of equilibrium with the human immune defense system and the other microorganisms in the digestive tract. However, colonization can result in serious symptoms.

Occurrence, distribution, and characteristics

Candida yeasts are found almost everywhere. It is almost impossible for humans not to come into contact with Candida. Primarily through food, humans ingest large amounts of fungi daily in a normal diet. Especially plant-based food components are naturally contaminated with Candida. For example, the German Society for Hygiene and Microbiology allows up to 100,000 colony-forming units of fungi per gram on dried herbs and spices. Fresh raw vegetable salads also often contain Candida in large quantities. For ready-to-eat salads, such as those available at salad counters in supermarkets, guideline values of up to 5,000,000 colony-forming units per gram apply. Thus, in a meal containing 200 grams of raw salad, several million fungi can easily enter the body. Candida is relatively resistant to gastric acid, so many of the ingested yeast fungi pass into the intestinal tract. In the intestine, killing of many fungi by digestive enzymes normally occurs. However, with intact colonization resistance in the intestine, the fungi usually do not have the opportunity to multiply further in the intestine. Also, prolonged adherence or further colonization in the intestine is not possible with intact intestinal flora.

Diseases and complaints

In contrast, when candida fungi in the human intestine encounter an impaired barrier system, opportunists can proliferate and colonize the intestine. Thus, a minor candida colonization initially becomes a superficial infection of the intestinal walls. In the intestine, candida yeasts can develop various pathogenic mechanisms. For example, they can form filaments that bore deeply into the intestinal mucosa. Activation of cyclic proteases also damages the intestinal mucosa. With the aid of these pathogenic mechanisms, the yeasts can penetrate deep into the intestinal wall. This initially results in deep mycoses. Later on, it is also possible for the yeasts to enter the body’s bloodstream, resulting in a generalized distribution of the yeasts. Already in the intestine, the yeasts can cause numerous symptoms. Due to the rapid multiplication of the fungi in the intestine, there is naturally also an increased number of dead fungal and intestinal cells. These decay and release so-called antigens. The antigens are partially absorbed by the intestinal mucosa and enter the blood via damaged mucosal barriers. In the case of an allergic predisposition, the antigens can cause corresponding allergic reactions. It is even suspected that rheumatoid manifestations, which are common in intestinal mycoses, are due to circulating immune complexes. Yeasts have been used to produce alcoholic beverages for many centuries. During the decomposition of carbohydrates, they produce ethanol and fusel oils. Similar processes occur in the intestines when candida is present. In particular, the liver suffers from the permanently produced fusel alcohols in the case of a prolonged fungal load. Chronic intestinal mycoses can thus cause severe liver damage.Since the yeasts partially displace the local flora when they attach to the intestinal mucosa, the barrier function of the intestine is also impaired. Intestinal mycosis can thus cause the so-called leaky gut syndrome. In leaky gut syndrome, the intestinal mucosa is permeable, allowing various antigens and microorganisms to enter the bloodstream. Allergic skin symptoms or skin diseases such as neurodermatitis can be the result. Candida, however, can spread not only in the intestine but also in the oral cavity. Candidiasis of the oral cavity is also called thrush or stomatitis candidomycetica. A whitish coating can be seen on the reddened mucous membranes of the mouth. This can be wiped off. Candidiasis of the vagina is called vaginal mycosis or vaginal fungus. Here, too, the causative agent is almost always Candida albicans. Vaginal thrush is usually caused by weakened defenses, hormonal fluctuations, improper intimate hygiene, or sexual intercourse. Characteristic symptoms of vaginal fungal infection are itching and discharge. The discharge is white and of a friable consistency. Unlike the discharge in bacterial infections, the discharge in vaginal thrush is almost odorless. In addition, white, wipeable coatings may appear on the mucosa of the vagina. Erosions of the sensitive mucous membranes are also possible. Depending on the extent of the disease, painful lesions may also spread to the inner thighs.