What is Candida?

Candida is a type of fungus that causes infections commonly known as Candidiasis, or yeast infections. Candida normally exists within the body in a form that does not cause problems for the host. In particular, Candida lives in the mouth and gut of its host, and is considered a normal part of the digestive flora which are always present within the digestive tract. Candida also lives within the vagina in women, and in its usual form is undetectable by the host and causes no problems. Candida can also be found on the skin, around the nail beds, within the respiratory tract, and in or around the anus.

A delicate balance exists between Candida and various types of bacteria, which feed upon it and therefore keep the fungus under control. However, if conditions are right Candida will mutate and multiply, and a yeast infection will result.

Two Forms of Candida

In its asymptomatic form, which does not cause problems for the host, Candida exists as unicellular yeast. These are single celled organisms which feed upon sugars inside the host, playing a role in digestion and participating in the complex ecosystem of microscopic organisms normally present in healthy individuals.

When environmental conditions are right, the Candida cells can be activated and switch over to multicellular, filamentous structures called hyphae. Once activated and morphed into this multicellular form, Candida can grow quickly unchecked by the host, and becomes invasive and harmful. In its hypha form, Candida is capable of invading tissues of the body and causing damage to them. This is the form which causes the symptoms of a yeast infection.

What Causes the Transformation

Several different environmental factors can cause unicellular Candida organisms to transform into the infectious, multicellular hypha form. Changes in the pH levels of the environment (the host’s body) can trigger the transformation. One example of this is seen in pregnant or menopausal women. When hormone levels shift, pH levels also change and signal Candida to shift into its hypha form.

In many cases, overuse of antibiotics is the culprit. While antibiotics are helpful in combating bacterial infections, they also tend to kill off the bacteria which normally prevent the growth of Candida. Immunosuppressive medications, such as those used to treat cancer, also play a role by limiting the host’s natural ability to control infections. Candida appears to be an opportunistic organism; when the conditions are beneficial it will quickly take advantage of the situation and multiply.

Mutation and Adaptation

One of the main factors which causes difficulty in treating yeast infections is the organism’s ability to mutate and adapt quickly. This is the cause of multiple, recurring infections that become progressively difficult to treat. Candida multiplies rapidly, and can implement changes to its DNA code in order to thwart its host’s attempts to kill it or limit its growth. The organism accomplishes this through contracting or expanding repeats in its DNA structure, chromosomal translocation, chromosomal deletion, or trisomy in which a third chromosome is added to a pair.

Possessing a variety of strategies to alter its own DNA quickly means Candida is easily capable of responding to an assault by developing a resistance to medications. When a particular medication is introduced into the host environment, it may appear to work at first. Quickly, however, Candida begins to alter its DNA so that it becomes less vulnerable to the effects of the drug. This adaptation means a medication that was once helpful in controlling infection may become useless for future infections. As with most adaptive mutations, these changes help Candida to flourish and become stronger within the host environment. A person with recurring yeast infections will usually find each subsequent infection to be more stubborn and difficult to treat, and symptoms may become more severe as well.