Candida species are ubiquitous fungi and are the most common fungal pathogens that affect humans. The growing problem of mucosal and systemic candidiasis reflects the enormous increase in the pool of patients at risk and the increased opportunity that exists for Candida species to invade tissues normally resistant to invasion. Candida species are true opportunistic pathogens that exploit recent technological advances to gain access to the circulation and deep tissues.
Historically many earlier studies made clear the infectious potential of the Candida organism to invade a wide variety of human tissues and cause human disease. Unfortunately many physicians consider the role of Candida in chronic disease processes to be strictly limited to clearly definable instance of tissue invasion and infection. However, the organism has a much broader role in causing chronic illness by virtue of its ability to stimulate tissue sensitivity to the organism and/or its byproducts.
Candida is a common inhabitant of the intestinal tract, the oral mucus membranes and the vaginal tract. Isolation from the mouth, vaginal secretions and feces is higher in hospitalized patients than normal subjects, although both can usually yield significant colonization rates. There are about 79 species of Candida and 6 have been implicated definitively in human disease. Candida albicans, the most common human pathogen, is found only in human and animal carriers so its acquisition from the environment is unlikely. There is clinical support for the sensitivization potential of Candida since protein antigens from the outer capsule have been shown to stimulate histamine release from rat cell tissue cultures. The organism has been known to be a pathogenic factor in selected cases of asthma, hives (urticaria), irritable bowel disease, and psoriasis.
Signs might include yeast overgrowth in the mouth, intestines, vaginal tract and esophagus. Women may suffer fatigue, premenstrual syndrome and loss of libido. In males fatigue and low grade depression and irritability are particularly common complaints. Children may complain of bowel disturbances, thrush, diaper rash and other signs. Common symptoms to all groups would include: abdominal bloating and gas and sugar cravings; impaired immunity; nutritional factors (lack of vitamin A, iron and folic acid); diabetes; medications (cimetidine or Tagamet, antibiotics, birth control pills, cortisone) and malignancies all predispose to candidiasis.
Research has shown cross reactions between antibodies to Candida. and healthy ovarian tissue. Thyroiditis is seen in candidiasis patients in a greater degree than in the general population. Mitral valve prolapse has also been seen in a close relationship with candidiasis and thyroiditis. Antibodies to T-helper lymphocytes have also been detected in candidiasis patients. It is this subpopulation of lymphocytes that becomes disturbed in AIDS and chronic Epstein-Barr viral infections. It has been suggested that the candidiasis seen in AIDS patients may not simply be another opportunistic infection, but rather a direct contributor to the development of the disease.
ABH non-secretors have a higher incidence of oral candidiasis, Lewis (a+b-) more than Lewis (a-b-). Oral carriage of Candida is also significantly associated with blood group O (p less than 0.001) and independently, with non-secretion of blood group antigens (p less than 0.001), with the trend towards carriage being greatest in group O non-secretors. (3)
Although non-secretors make up only about 26% of the population, they are significantly over represented among individuals with either oral or vaginal Candida infections, making up almost 50% of affected individuals. (1) The inability to secrete blood group antigens in saliva also appears to be a risk factor in the development of, or persistence of chronic hyperplastic Candidosis. In one study, the proportion of non-secretors of blood group antigens among patients with chronic hyperplastic Candidosis was 68%. (2)
Non-diabetic individuals who are non-secretors of blood group antigens are prone to superficial infections by Candida albicans. In this study, 216 patients with diabetes mellitus who were denture wearers were examined for the presence or absence of denture stomatitis. There was an overall trend for non-secretors to be prone to denture stomatitis compared with secretors. Stepwise linear discriminant analysis was used to dissect the contribution of secretor status and other variables to the development of the disease. Secretor status was found to be a contributory factor among patients with non-insulin dependent diabetes but not among those with insulin-dependent diabetes.
Oral candidiasis shows a higher incidence of group O over other ABO groups. (3)
The neutrophils and monocytes of most patients with deseminated candidiasis have been found to lack detectable levels of the enzyme Myeloperoxidase (MPO). This rarely affects phagocytosis of the organism, but markedly decreases intracellular destruction, resulting in the organism persisting as intracellular inclusion. This perhaps affords an explanation to the persistance of some health care practitioners in employing questionable superoxide therapies in candidiasis. MPO synthesis is dependent on adequate tissue levels of both iodine and ascorbate, the therapeutic employment of which offers a more sound and safe approach.
1. Thom SM, Blackwell CC, MacCallum CJ, et al. Non-secretion of blood group antigens and susceptibility to infection by Candida species. FEMS Microbiol Immunol 1989 Jun;1(6-7):401-
2. Lamey PJ, Darwazeh AM, Muirhead J, et al. Chronic hyperplastic candidosis and secretor status. J Oral Pathol Med 1991 Feb;20(2):64-7
3. Burford-Mason AP, Weber JC, Willoughby JM. Oral carriage of Candida albicans, ABO blood group and secretor status in healthy subjects. J Med Vet Mycol 1988 Feb;26(1):49-56
4. Epidemiol Infect 1991 Apr;106(2):355-363 Chronic atrophic oral candidiasis among patients with diabetes mellitus--role of ABH secretor status. Aly FZ, Blackwell CC, MacKenzie DA, Weir DM, Elton RA, Cumming CG, Sofaer JA, Clarke BF