Candida is a group, or genus, of closely related species of yeast that occur naturally in the skin and gastrointestinal tract. They are the major fungal component of human flora—that is, the community of microbes that lives within the human body. If the flora remain in a healthy balance with their human host, then they do not cause disease. But various factors, such as antibiotic use or a weakened immune system, may upset this balance and lead to infection by species within the flora. Infection caused by Candida is known as candidiasis (can-di-DYE-a-sis), and is the most common fungal infection, or mycotic disease, that arises from the human flora. Candidiasis ranges from mild to severe and even life-threatening, depending upon its location. The most common forms of candidiasis affect the mouth, esophagus, vagina, and the bloodstream. Candidiasis does respond to antifungal drugs, although these must be carefully prescribed as some Candida species have developed resistance to specific drugs.
There are over 150 different species of Candida. Most of these do not cause disease. Of those that do, Candida albicans is the most common cause of human mycoses, including blood infections. However, infections from so-called non-albicans Candida (NAC) species, such as C. glabrata and C. krusei, are becoming more common. C. albicans is distinguished from NAC species under the microscope by the appearance of tiny cylindrical projections, called germ tubes, that appear within two to four hours of incubating a sample under investigation.
When the immune system is healthy and the skin and mucous membranes of the gastrointestinal and vaginal tract are intact, the existence of Candida will not cause any health problems. When these conditions do not hold, then Candida may become pathogenic, causing infection and leading to various types of illness.
One of the most important factors causing candidiasis is weakened immunity, which occurs in HIV/AIDS, after cancer chemotherapy (which depletes the white cells that fight infection), and after bone marrow or organ transplantation. Patients having transplants must take medication to stop rejection of the new organ for the rest of their lives. Unfortunately, this also impairs their immune systems and puts them at increased risk of infection, including candidiasis. Other causes of candidiasis include antibiotic use, which can alter the balance of the intestinal flora; the contraceptive pill; pregnancy; old age; malnutrition; and diabetes. In hospitals, the use of intravenous and urinary catheters, which are tubes inserted into the body to deliver fluids and medication and drain the bladder, respectively, often lead to candidiasis. Although Candida can be transmitted via the hands of caregivers and healthcare workers, most cases of candidiasis are endogenous—that is, the patient is infected Candida already present within the body.
The most common sites of candidiasis are the mouth, the esophagus, the skin, the vagina, and the bloodstream. Oral and esophageal candidiasis are often also known as thrush (or oropharyngeal candidiasis [OPC]). Oral thrush is common among people with weakened immunity, especially those with HIV/AIDS. It causes white patches on the tongue and inside the mouth and may be associated with soreness and a burning sensation. Esophageal thrush is also found in HIV/AIDS; it may not cause any symptoms, but some people have difficulty in swallowing, pain, nausea, and vomiting.
Vulvovaginal candidiasis is also very common, affecting three quarters of all women at some stage in their lives. It causes genital itching and burning, with or without a “cottage cheese”-like discharge. Candidiasis can occur when the normal acidity of the vagina changes or with hormonal changes, both of which can encourage the overgrowth of Candida. Risk factors include pregnancy, diabetes, use of broad-spectrum antibiotics, and steroid medications. Men can get a form of the disease— genital candidiasis, which causes an itchy rash on the penis. However, transmission of thrush through sexual intercourse is rare; most infections are endogenous.
WORDS TO KNOW
INTERTRIGO: Intertrigo, sometimes called eczema intertrigo, is a skin rash, often occurring in obese persons on parts of the body symmetrically opposite each other. It is caused by irritation of skin trapped under hanging folds of flesh such as pendulous breasts.
PATHOGENIC: Something causing or capable of causing disease.
FLORA: In microbiology, flora refers to the collective microorganisms that normally inhabit an organism or system. Human intestines, for example, contain bacteria that aid digestion and are considered normal flora.
MYCOTIC DISEASE: Mycotic disease is a disease caused by fungal infection.
NOSOCOMIAL: A nosocomial infection is an infection that is acquired in a hospital. More precisely, the Centers for Disease Control in Atlanta, Georgia, defines a nosocomial infection as a localized infection or one that is widely spread throughout the body that results from an adverse reaction to an infectious microorganism or toxin that was not present at the time of admission to the hospital.
PATHOGENIC: Something causing or capable of causing disease.
IN CONTEXT: REAL-WORLD RISKS
The Division of Bacterial and Mycotic Diseases, Centers for Disease Control and Prevention (CDC) warns that “Over-the-counter treatments for yeast infections/Vulvovaginal Candidiasis (VVC) are becoming more available. As a result, more women are diagnosing themselves with VVC and using one of a family of drugs called ‘azoles’ for therapy. However, misdiagnosis is common, and studies have shown that as many as two-thirds of all OTC drugs sold to treat VVC were used by women without the disease. Using these drugs when they are not needed may lead to a resistant infection. Resistant infections are very difficult to treat with the currently available medications for VVC.”
Candidiasis of the skin is sometimes called intertrigo and produces a rash in warm, moist areas such as the armpit, groin, and under the breast. Diaper rash is often a form of candidiasis that affects babies in the area where the diaper comes into contact with the skin. Sometimes, especially in people with HIV/AIDS, candidiasis may also affect the nails. Oral, esophageal, vaginal, and skin candidiasis can all clear up with antifungal treatment, with no lasting effects on health, although they may recur. They may cause some discomfort, even pain, but are relatively mild infections in their own right (although the patient may be suffering from serious disease, such as HIV/AIDS or diabetes, that has allows candidiasis to develop).
Invasive candidiasis, however, can be very serious, even life-threatening. It occurs when Candida invades the bloodstream, and it is dangerous because it may then spread throughout the body, reaching the liver, kidneys, spleen, and other organs. Patients with cancer, depletion of white cells from cancer treatment, or major burns are at risk, as are those who have had organ transplants, abdominal surgery, or broad-spectrum antibiotics. Patients with catheters are also at risk of invasive candidiasis. The death rate from invasive candidiasis can be as high as 50%. Therefore, if Candida is found in a blood culture from a patient, especially if they have fever, then it can be assumed that candidiasis may be spreading through the whole body and prompt treatment is essential.
Candida species cannot be avoided or eliminated, as they occur naturally in the human body. Therefore, prevention depends on dealing with the risk factors that make people vulnerable to candidiasis. For instance, the introduction of the latest treatment for HIV/AIDS (HAART, highly active antiretroviral therapy), has reduced the incidence of esophageal candidiasis in this group. There are also antifungal drugs that can be applied either topically, as a cream or powder, or orally, as a tablet. Vaginal thrush can be treated with antifungal suppositories inserted into the vagina. The main antifungal drugs used in the treatment for candidiasis are amphotericin B, fluconazole, and nystatin, and there are several new drugs at the research stage. Meanwhile, patients with invasive candidiasis must have catheters removed or replaced, as these can be a major source of further infection.
The Division of Bacterial and Mycotic Diseases, Centers for Disease Control and Prevention (CDC), recommends that “because genital candidiasis /Vulvovaginal Candidiasis (VVC) and urinary tract infections share similar symptoms, such as a burning sensation when urinating, it is important to see a doctor and obtain laboratory testing to determine the cause of the symptoms and to treat effectively. Symptoms, which may be very uncomfortable, may persist. There is a chance that the infection may be passed between sex partners.”
IN CONTEXT: REAL-WORLD RISKS
The Division of Bacterial and Mycotic Diseases, Centers for Disease Control and Prevention (CDC) warns that overuse of antifungal medications to treat candidiasis of the mouth and throat (also known as a “thrush” or oropharyngeal candidiasis (OPC), “can increase the chance that they (antifungal medications) will eventually not work (the fungus develops resistance to medications). Therefore, it is important to be sure of the diagnosis from before treating with over-the-counter or other antifungal medications.”
SOURCE: Division of Bacterial and Mycotic Diseases, Centers for Disease Control and Prevention
Infections acquired in hospitals, also known as nosocomial infections from the Greek word for hospital (nosocomium), are an increasing public health problem. Those affected are often already very sick and are unable to fight an infection the way a healthy person would, because their immune system is weak. Added to this, many organisms that cause nosocomial infections are becoming resistant to antibiotics, so treatment may be ineffective. Candida, which is normally either harmless or the cause of only mild infection, is the fourth leading cause of nosocomial bloodstream infection, according to the Centers for Disease Control and Prevention (CDC). Such infections occur at a rate of five to ten per 10,000 hospital admissions and carry a mortality rate of 40–50%. Even if a patient survives, hospital stays are prolonged and this involves significant extra health care costs, which may run to thousands of dollars. Once found mainly in cancer and bone marrow transplant units, nosocomial infections, including Candida, now appear in all parts of the hospital and are on the increase. An aging population, more frequent use of invasive therapies involving catheters, and overuse of antibiotics are among the contributing factors.
Gates, Robert. Infectious Disease Secrets, 2nd ed. Philadelphia: Hanley & Belfus, 2003.
Centers for Disease Control and Prevention (CDC). “Division of Bacterial and Mycotic Diseases: Candidiasis.” Oct 6, 2005. <http://www.cdc.gov/ncidod/dbmd/diseaseinfo/default.htm> (accessed Jan 27, 2007).
Candidiasis is an infection caused by a species of the yeast Candida, usually Candida albicans. This is a common cause of vaginal infections in women. Also, Candida may cause mouth infections in people with reduced immune function, or in patients taking certain antibiotics. Candida can be found in virtually all normal people but causes problems in only a fraction. In recent years, however, several serious categories of candidiasis have become more common, due to overuse of antibiotics, the rise of AIDS, the increase in organ transplantations, and the use of invasive devices (catheters, artificial joints and valves)—all of which increase a patient's susceptibility to infection.
Over one million women in the United States develop vaginal yeast infections each year. It is not life-threatening, but it can be uncomfortable and frustrating.
This disorder, also known as thrush, causes white, curd-like patches in the mouth or throat.
Deep organ candidiasis
Also known as invasive candidiasis, deep organ candidiasis is a serious systemic infection that can affect the esophagus, heart, blood, liver, spleen, kidneys, eyes, and skin. Like vaginal and oral candidiasis, it is an opportunistic disease that strikes when a person's resistance is lowered, often due to another illness. There are many diagnostic categories of deep organ candidiasis, depending on the tissues involved.
Causes and symptoms
Most women with vaginal candidiasis experience severe vaginal itching. They also have a discharge that often looks like cottage cheese and has a sweet or bread-like odor. The vulva and vagina can be red, swollen, and painful. Sexual intercourse can also be painful.
Whitish patches can appear on the tongue, inside of the cheeks, or the palate. Oral candidiasis typically occurs in people with abnormal immune systems. These can include people undergoing chemotherapy for cancer, people taking immunosuppressive drugs to protect transplanted organs, or people with HIV infection.
Deep organ candidiasis
Anything that weakens the body's natural barrier against colonizing organisms—including stomach surgery, burns, nasogastric tubes, and catheters—can predispose a person for deep organ candidiasis. Rising numbers of AIDS patients, organ transplant recipients, and other individuals whose immune systems are compromised help account for the dramatic increase in deep organ candidiasis in recent years. Patients with granulocytopenia (deficiency of white blood cells) are particularly at risk for deep organ candidiasis.
Often clinical appearance gives a strong suggestion about the diagnosis. Generally, a clinician will take a sample of the vaginal discharge or swab an area of oral plaque, and then inspect this material under a microscope. Under the microscope, it is possible to see characteristic forms of yeasts at various stages in the lifecycle.
Fungal blood cultures should be taken for patients suspected of having deep organ candidiasis. Tissue biopsy may be needed for a definitive diagnosis.
RACHEL FULLER BROWN (1898–1980)
Rachel Fuller Brown was born on November 23, 1898 in Springfield, Massachusetts. Brown was the oldest of two children born to Annie (Fuller) and George Hamilton Brown. In 1912, her father left their family in Missouri and her mother moved the family back to Springfield. Brown double majored in history and chemistry at Mount Holyoke, receiving her A.B. degree in 1920. She also earned her M.A. degree from the University of Chicago. Brown began her doctoral studies at the University, but she experienced financial difficulties and took a job before she received her Ph.D. She worked at the Division of Laboratories and Research of the New York State Department of Health as an assistant chemist for seven years and finally returned to Chicago and completed her Ph.D.
In 1948, Brown and Elizabeth Hazen began researching fungal infections found in humans due to antibiotic treatments and diseases. Some of the antibiotics they discovered did indeed kill the fungus; however, they also killed the test mice. Finally, Hazen located a microorganism on a farm in Virginia, and Brown's tests indicated that the microorganism produced two antibiotics, one of which proved effective for treating fungus and candidiasis in humans. Brown purified the antibiotic which was patented under the name nystatin. In 1954, the antibiotic became available in pill form. Brown and Hazen continued their research and discovered two other antibiotics. Brown received numerous awards individually and with her research partner, Elizabeth Hazen. Rachel Brown passed away on January 14, 1980.
In most cases, vaginal candidiasis can be treated successfully with a variety of over-the-counter antifungal creams or suppositories. These include Monistat, Gyne-Lotrimin, and Mycelex. However, infections often recur. If a women has frequent recurrences, she should consult her doctor about prescription drugs such as Vagistat-1, Diflucan, and others.
This is usually treated with prescription lozenges or mouthwashes. Some of the most-used prescriptions are nystatin mouthwashes (Nilstat or Nitrostat) and clotrimazole lozenges.
Deep organ candidiasis
The recent increase in deep organ candidiasis has led to the creation of treatment guidelines, including, but not limited to, the following: Catheters should be removed from patients in whom these devices are still present. Antifungal chemotherapy should be started to prevent the spread of the disease. Drugs should be prescribed based on a patient's specific history and defense status.
Home remedies for vaginal candidiasis include vinegar douches or insertion of a paste made from Lactobacillus acidophilus powder into the vagina. In theory, these remedies will make the vagina more acidic and therefore less hospitable to the growth of Candida. Fresh garlic (Allium sativum ) is believed to have antifungal action, so incorporating it into the diet or inserting a gauze-wrapped, peeled garlic clove into the vagina may be helpful. The insert should be changed twice daily. Some women report success with these remedies; they should try a conventional treatment if an alternative remedy isn't effective.
Although most cases of vaginal candidiasis are cured reliably, these infections can recur. To limit recurrences, women may need to take a prescription anti-fungal drug such as terconazole (sold as Terazol) or take other anti-fungal drugs on a preventive basis.
These infections can also recur, sometimes because the infecting Candida develops resistance to one drug. Therefore, a physician may need to prescribe a different drug.
Deep organ candidiasis
The prognosis depends on the category of disease as well as on the condition of the patient when the infection strikes. Patients who are already suffering from a serious underlying disease are more susceptible to deep organ candidiasis that speads throughout the body.
Because Candida is part of the normal group of microorganisms that co-exist with all people, it is impossible to avoid contact with it. Good vaginal hygiene and good oral hygiene might reduce problems, but they are not guarantees against candidiasis.
Biopsy— The removal and examination of tissue from a live body.
Colonize— To become established in a host.
Granulocytopenia— A condition characterized by a deficiency of white blood cells.
Nasogastric— Tube inserted through the nasal passages into the stomach.
Opportunistic— Infection caused by microorganisms that are usually harmless, but which can cause disease when a host's resistance is lowered.
Systemic— Afflicting an entire body system or the body in general.
Because hospital-acquired (nosocomial) deep organ candidiasis is on the rise, people need to be made aware of it. Patients should be sure that catheters are properly maintained and used for the shortest possible time length. The frequency, length, and scope of courses of antibiotic treatment should also be cut back.
Greenspan, Deborah, and John S. Greenspan. "HIV-Related Oral Disease." The Lancet 348 (September 14, 1996): 729-734.
Candidiasis is an infection caused by a species of the yeast Candida, usually the Candida albicans fungus. Candida is found on various parts of the bodies of almost all normal people but causes problems in only a few. Candidiasis can affect the skin, nails, and mucous membranes throughout the body including the mouth (thrush), esophagus, vagina (yeast infection), intestines, and lungs.
Candida may cause yeast mouth infections (also known as thrush) in children with reduced immune function or in children taking certain antibiotics . Antibiotics may upset the balance of microorganisms in the body and allow an overgrowth of Candida. The use of inhaled steroids for the treatment of asthma has also been shown to cause oral candidiasis. Many infants acquire candidiasis from their mothers during the process of birth, when the baby comes in contact with naturally existing Candida found in the mother's vagina. Candidiasis is not considered harmful to infants unless it lasts more than several weeks after birth. These yeast mouth infections cause creamy white, curd-like patches on the tongue, inside of the mouth, and on the back of the throat. Under the whitish material, there are red lesions that may bleed.
Candida also may infect an infant's diaper rash , as it grows rapidly on irritated and moist skin. Children who suck their thumbs or other fingers may also develop candidiasis around their fingernails, causing redness on the nail edges.
Candida is a common cause of vaginal infections in adolescent girls, especially when the normal populations of the bacteria Lactobacilli have been reduced due to antibiotic use, allowing the overgrowth of Candida. A candidiasis infection in the vagina results in itching , burning, soreness, and a thick, white vaginal discharge.
Other risk factors for candidiasis include obesity , heat, and excessive sweating that result in the formation of moist skin areas where the yeast organism can grow.
In the early 2000s, several serious categories of candidiasis have become more common, due to overuse of antibiotics, the rise of AIDS , the increase in incidence of organ transplantations, the use of chemotherapy in cancer treatment, and the implantation of invasive devices (e.g., nasogastric tubes, catheters, and artificial joints and valves) into the body—all of which increase a patient's susceptibility to infection. Diabetics are especially susceptible to candidiasis, as they have high levels of sugar in their blood and urine and a low resistance to infection, both of which are conditions that favor the growth of yeast. Also known as invasive candidiasis, deep organ candidiasis is a serious systemic infection that can affect the esophagus, heart, blood, liver, spleen, kidneys, eyes, and skin. Like vaginal and oral candidiasis, it is an opportunistic disease that strikes when a child's resistance is lowered, often due to another illness. Children with granulocytopenia (deficiency of white blood cells) are particularly at risk for deep organ candidiasis. There are many diagnostic categories of deep organ candidiasis, depending on the tissues involved.
In the past candidiasis was referred to as moniliasis.
Candidiasis is an extremely common infection. Thrush occurs in approximately 2–5 percent of healthy newborns and occurs in a slightly higher percentage of infants during their first year of life.
Over 1 million adult women and adolescent girls in the United States develop vaginal yeast infections each year. It is not life-threatening, but the condition can be uncomfortable and frustrating.
Causes and symptoms
Candidiasis is caused by a species of the yeast Candida, usually the Candida albicans fungus.
In oral candidiasis, the disease is characterized by whitish patches that appear on the tongue, inside of the cheeks, or on the palate. Pain or difficulty in swallowing may indicate a fungal infection in the throat, which is a potential complication of AIDS. Most adolescent girls with vaginal candidiasis experience severe vaginal itching and have a discharge that often looks like cottage cheese and has a sweet or bread-like odor. The vulva and vagina can be red, swollen, and painful. The infected skin in diaper rash that includes infection with Candida appears fiery red with areas that may have a raised red border.
Effects of deep organ or systematic candidiasis include meningitis , arthritis, fungemia (fungi in the blood, causing fever and possibly leading to sepsis), endocarditis (heart infection), endophthalmitis (infection and scarring in the eye that can affect vision), and renal or bladder bezoars (colonization and blockage of the urinary tract by Candida, which can cause urinary tract infections and kidney failure.
Often clinical appearance and visual examination give a strong suggestion about the diagnosis. Generally, a doctor takes a sample of the vaginal discharge or swabs an area of oral or skin lesions, and then inspects this material under a microscope, where it is possible to see characteristic forms of yeasts at various stages in the lifecycle.
Fungal blood and stool cultures for detection of the Candida organism should be taken for patients suspected of having deep organ candidiasis. Tissue biopsy may be needed for a definitive diagnosis.
When to call the doctor
The doctor should be called if a child exhibits any symptoms of the various types of candidiasis.
Treatment of candidiasis is primarily accomplished through the use of antifungal drugs. Oral candidiasis is usually treated with prescription lozenges or mouthwashes. Some of the most-used prescriptions are nystatin mouthwashes (Nilstat or Nitrostat) and clotrimazole lozenges. Skin infections can be treated with topical antifungal creams. Highly inflamed skin lesions can also be treated with corticosteroid creams.
For infants with oral candidiasis, pacifiers should be sterilized or discarded. Bottle nipples should be discarded and new ones used as the infant's mouth begins to heal.
The risk of diaper rash complicated with candidiasis can be reduced by preventing irritating dermatitis through the use of absorbent diapers and prevention of excessive exposure to urine or feces through frequent changing of diapers. The use of plastic pants that do not allow air circulation over the diaper area is not recommended. Children may still attend child care; however, childcare providers should follow good hygienic practices, including thorough hand washing and disposal of materials that may contain nasal and oral secretions of infected children, in order to prevent transmitting the infection to other children.
In most cases, vaginal candidiasis can be treated successfully with a variety of over-the-counter antifungal creams or suppositories, including Monistat, Gyne-Lotrimin, and Mycelex. However, infections often recur. If an adolescent girl has frequent recurrences, she should consult her doctor about prescription drugs such as Vagistat-1, Diflucan, and others.
The early 2000s increase in deep organ candidiasis has led to the creation of treatment guidelines, including, but not limited to, the following:
- Catheters should be removed from children with candidiasis.
- Antifungal therapy may be used during chemotherapy to prevent candidiasis.
- Drugs should be prescribed based on a child's specific history and immune defense status (this is especially critical for children with AIDS). Stronger antifungal drugs, such as ketoconazole or fluconazole, may be necessary.
- Diabetes mellitus should be controlled with appropriate medication and dietary changes.
Home remedies for vaginal candidiasis include vinegar douches or insertion of a paste made from Lactobacillus acidophilus powder into the vagina. In theory, these remedies make the vagina more acidic and, therefore, less hospitable to the growth of Candida. Fresh garlic (Allium sativum ) is believed to have antifungal action, so incorporating it into the diet or inserting a gauze-wrapped, peeled garlic clove into the vagina may be helpful. The insert should be changed twice daily. Some women report success with these remedies; however, they should try a conventional treatment if an alternative remedy is not effective.
Oral and skin candidiasis, though painful, are usually cured with the use of antifungal medications. However, in premature infants, in children with poor or compromised immune systems, or in children with deep organ or systematic infections, eradication of the infections may be more difficult to achieve. Mortality in low birth-weight premature infants with systemic candidiasis may reach 50 percent.
Often candidiasis can be prevented through good sanitation procedures, such as keeping the body cool and dry, wearing natural fabric underclothes, changing underclothes frequently, wiping from front to back after bowel movements, and washing hands often. For children who are susceptible to candidiasis because of immune deficiencies, the regular use of antifungal drugs to prevent infections may be required.
Parents need to practice good hygienic procedures as they care for their children, in order to prevent the development of candidiasis.
Biopsy —The surgical removal and microscopic examination of living tissue for diagnostic purposes or to follow the course of a disease. Most commonly the term refers to the collection and analysis of tissue from a suspected tumor to establish malignancy.
Granulocytopenia —A condition characterized by a deficiency of white blood cells.
Nasogastric tube —A long, flexible tube inserted through the nasal passages, down the throat, and into the stomach.
Opportunistic —Infection caused by microorganisms that are usually harmless, but which can cause disease when a host's resistance is lowered.
Systemic —Relating to an entire body system or the body in general.
Martin, Jeanne Marie, and Rona P. Soltan. Complete Candida Yeast Guidebook: Everything You Need to Know about Prevention, Treatment, and Diet. New York: Prima Lifestyles, 2000.
The Official Patient's Sourcebook on Invasive Candidiasis. San Diego, CA: Icon Health Publications, 2002.
Greenberg, Michael E. "Candidiasis." eMedicine, September 1, 2004. Available online at <www.emedicine.com/ped/topic312.htm> (accessed December 7, 2004).
Judith Sims Richard H. Lampert
Candidiasis is an infection that is caused by members of the fungal genus Candida.
The two most common species associated with Candidiasis are Candida albicans and Candida glabrata. Less commonly, but still able to cause the infection, are Candida tropicalis, Candida parapsilosis, Candida guilliermondi, and Candida krusei.
The fungus is a normal resident of the body, typically in the mouth and the gastrointestinal tract. In these habitats, the microorganism normally colonizes the cell surface. In healthy people in the United States, Candida species colonize more than half of these individuals. The presence of the fungus is beneficial. Invading bacteria are recognized by the Candida cells and are destroyed. Thus, the fungi complement the immune system and other defenses of the body against infection.
When the body is in proper balance with respect to the microbial flora, the fungi exist as a so-called yeast form. These are not capable of invasion. However, Candida can infect areas of the body that are warm and moist. These include the eye (conjunctivitis), fingernails, rectum, folds in the skin, and, in infants, the skin irritation in infants known commonly as diaper rash. Typically, such infections are more of an inconvenience than a dangerous health concern.
However, in people whose immune systems are compromised in some way, or when the normal balance of the microbial flora has been disrupted by, for example, antibiotic therapy, Candida can establish an infection. For example, an infection of the mouth region, which is referred to as oropharyngeal infection, was a very common infection in those whose immune system was deficient due to infection with the Human immunodeficiency virus . More aggressive antiviral therapy has reduced the incidence of the infection.
Such infections are associated with the change from the Candida cells from the yeast form to a so-called mycelial fungal form. The mycelia produce long, root-like structures that are called rhizoids. The rhizoids can penetrate through the mucous cells that line the inside of the mouth and vagina, and through the epithelial cells that line the intestinal tract. This invasion can spread the infection to the bloodstream. As well, the microscopic holes that are left behind in the cell walls can be portals for the entry of toxins, undigested food, bacteria, and yeast.
In countries around the world where fungal infections are widespread in the populations, Candida species have over-taken Cryptococcus species as the most common cause of infections that affect the central nervous system of immunocompromised people.
Besides the oropharyngeal infection, Candida can also commonly cause a vaginal infection. Both infections are evident by the development of a fever and chills that, because of the fungal genesis of the infections, are unaffected by antibacterial therapy. Visually, white patches appear on the surface of the cells lining the mouth and oral cavity and the vagina. More rarely, the infections may spread to the bloodstream. Examples of the infections that can result include the kidney, spleen, nerve cells (meningitis ), heart (endocarditis). Arthritis may even develop. Immunocompromised individuals are especially susceptible to these infections.
The contamination of the bloodstream by Candida occurs most commonly in the hospital setting, where a patient is being treated for Candidiasis or other malady. Indeed, this type of bloodstream infection is the fourth most common cause of hospital-acquired bloodstream infections in the United States. The death rate from the infection can approach 40 per cent.
Treatment for Candida infections consist of the administration of antifungal drugs. Examples of the drugs of choice include amphotericin B, fluconazole, ketoconazole, and nystatin. The real possibility of the development of irritative side effects makes monitoring during therapy a prudent precaution.
See also Fungi; Immunodeficiency
Candidiasis (thrush, monilia infection) is caused by a fungus that most commonly infects the mouth (usually of infants or persons with weakened immune systems), or the vagina (yeast infection). Another form of candidiasis causes painful inflammation under the fingernails (paronychia). It also occurs as an opportunistic infection in the late stages of HIV/AIDS (human immunodeficiency virus/acquired immunodeficiency syndrome), as a nosocomial infection after catheterization; and it can invade the spinal canal and meninges, where it is obviously much more serious.
Candidiasis is transmitted by close contact of an infected with an uninfected mucous membrane. Infants acquire it as they pass through the birth canal. Topical application of antifungal paint or ointment can usually eliminate the infection and thus prevent transmission. Management is more difficult in debilitated and immunocompromised patients, in whom the condition can be very stubborn.
John M. Last
(see also: Fungal Infections; Fungicides )