Candida is a genus of yeasts, or fungi, that naturally exist in your surroundings, on the skin and in the mouth, gastrointestinal tract and vagina. Candida species usually live in a symbiotic relationship with their hosts, mainly because their growth is held in check by bacteria that inhabit the same environments. However, if the normal balance of microorganisms in your body is disrupted -- antibiotics are often the cause -- Candida can grow unchecked, resulting in a yeast infection. Antifungal drugs, such as nystatin, may be needed to treat such infections.
Yeasts Are Different from Bacteria
Although yeasts and bacteria can look the same under a microscope, they differ significantly in their structure, metabolism and reproduction. For example, while yeasts and bacteria both possess cell membranes, the construction of these membranes is dissimilar. According to a 2008 "Journal of Chemical Biology" review, Candida and other yeasts incorporate a molecule called ergosterol into their cell membranes to maintain their flexibility and fluidity. Bacteria use different molecules to achieve the same goal.
Probiotics Are Bacteria
Your gut is the home for trillions of living bacteria that modulate your immune response, produce vitamins and help digestion. Many of these bacterial species are included in commercially available probiotic formulations, and they are found in fermented dairy products, such as yogurt. The World Health Organization defines probiotics as "live organisms which, when administered in adequate doses, confer a benefit on their host."
Nystatin Destroys Yeast, But Not Bacteria
According to the "Physicians' Desk Reference," nystatin is an antifungal agent produced by a bacterium called Streptomyces noursei. In nature, bacteria often produce substances that inhibit the growth of other organisms, thereby reducing competition for nutrients. These substances are often exploited by drug makers for their antimicrobial properties. Nystatin binds to the ergosterol in fungal membranes, essentially punching holes that allow uncontrolled movement of electrolytes and fluids out of the fungal cells. The cell walls and membranes of bacteria are not affected by nystatin.
Considerations
Yeast infections caused by Candida are fairly common, especially following antibiotic treatment. Nystatin, which targets a specific molecule in fungal cell membranes, is frequently used to treat yeast infections. Probiotic supplements are often added to the therapeutic regimen to reestablish a normal population of bacteria. Since nystatin does not affect bacteria, it can be used concurrently with probiotics. If you have a yeast infection that does not respond to treatment, see your doctor.
References
- "Journal of Chemical Biology"; Sterols and Membrane Dynamics; E.J. Dufourc; November 2008
- Report of a Joint FAO/WHO Expert Consultation on Evaluation of Health and Nutritional Properties of Probiotics in Food Including Powder Milk with Live Lactic Acid Bacteria; October 2001
- "Physicians' Desk Reference, 60th Edition: Nystatin"; Lori Murray, Senior Editor; 2006
