A fungal culture will assist your doctor in determining whether or not fungi exist in a certain part of your body and, if so, what type they are. Not all of the fungi in your body are hazardous, infection-causing fungus. Your body naturally produces some types of fungi that live in and on you without causing any problems. However, if the amounts become too high or their type changes (for example, from benign to harmful), then it may be necessary to treat the problem. Fungi are easy to grow in laboratory conditions. By exposing a sample of your blood, urine, or other tissue to special nutrients, the fungus will thrive and grow into several colonies. The doctor can use this information to help diagnose your condition and prescribe an appropriate treatment plan. There are three main classes of antifungals: azoles, polyenes, and echinocandins. All have similar effects on fungi, but they work by dealing with the structure of the fungus differently. Azoles inhibit an enzyme in the fungus' cell membrane called 14α-lanosterol demethylase, which results in increased levels of toxic substances within the cells. Polyenes bind to membranes of the fungus cell wall, altering its permeability to chemicals.