Oral Candida Infection

Introduction Oral candidiasis is an oral mucosal disease caused by a fungus, a Candida infection. In recent years, due to the wide clinical application of antibiotics and immunosuppressive agents, the flora imbalance or immunity is reduced, and the visceral, skin and mucous membranes are increasingly infected by fungi, and the incidence of oral mucosal candidiasis is correspondingly increased. . Gruby (1842) isolated yeast-like bacteria from the lesions of patients with aphthous ulcers. Berkhont (1923) confirmed that the bacteria belonged to Candida, Candida albicans, and Candida tropicalis. Among them, Candida albicans is the most important pathogen. Thrush is the most common oral candidiasis.

Cause

1. Toxicity and type of pathogen: Candida albicans is an oval-shaped yeast-like bacterium capable of producing pseudo-mycelium in medium and secretions, which is Gram-positive 2~3m×46m Prolonged bud cells, which are very similar to hyphae. The pseudohyphae form blastospores at the nodules, and sometimes no thick fungus filaments are formed at the end.

The toxicity of Candida depends on the toxic substance metabolites in the digestive tract or the vagina parasitic yeast Candida, which is not pathogenic, and is pathogenic when it develops into a mycelial type. The toxin of Candida albicans has the activity of phospholipase-type A corresponding to the virus. It can be lethal by injecting the suspension of the bacteria into the vein of the animal, so the toxicity and type of the pathogen are closely related to the disease power. The saliva contained in the healthy carrier The amount of bacteria is less than 200/ml, so the general path examination method can not directly find the pathogen in the smear.

Candida albicans has strong adhesion to the oral mucosa epithelium, which is the "foothold" of its pathogenic effect. This adhesion relies on the mannose glycoprotein moiety on the surface of epithelial cells as a surface receptor for cells. Adhesion, and thus the destruction of glycoproteins or similar structures, can inhibit the occurrence of adhesion, which provides a way to explore new therapeutic agents.

2. Host defense function: Human serum contains an anti-fungal component (serum factor) that inhibits the growth of Candida albicans, which is present in newborn infants (1 to 3 months), but lower than the mother, 6~ Adults can reach adulthood at 12 months, so infants who are half-year-old, especially those who are under full moon, are most susceptible to oral mucosal candidiasis. In addition, neutrophil monocytes and eosinophils in the human body also have the function of digesting and killing Candida albicans.

3. The effect of drugs and other factors on the body's defense: The abuse of corticosteroids (SH) often causes Candida infection, SH can weaken the function of the reticuloendothelial system, reduce inflammation and reduce antibody formation; It can increase the activity of fungi, enhance the toxicity of fungi, and the above-mentioned properties of immunosuppressive agents and antimetabolites can cause the proliferation of fungi.

Broad-spectrum antibiotics can cause dysbacteriosis (such as 2% to 3% of patients with oral tetracycline for more than 20 days), destroying the balance of bacteria and fungi in the human digestive tract, and inhibiting some antifungal effects. The growth of Gram-negative bacteria and bacteria capable of synthesizing vitamin B, and the deficiency of vitamin B group can also lead to coenzymes of cell oxidation, which is inhibited to reduce tissue resistance and thus contribute to fungal growth.

4. Host systemic diseases: Inferior immune function: (such as thymus atrophy) receiving large amount of X-ray irradiation without gamma-globulinemia and reticuloendothelial diseases affecting immune function, such as lymphoma Hodgkin's disease leukemia Etc., easily associated with candidiasis, abnormal serum iron metabolism is considered to be one of the causes of candidiasis, which may be caused by iron deficiency and abnormal enzyme system, (iron is a cell-oxidative reduction process related enzymes such as peroxidase cells A component of the pigment) that causes defects in immune function.

Low endocrine function, such as hypothyroidism, Edison disease brain, lower pituitary dysfunction are susceptible to candidiasis.

The pH value of the skin surface of diabetic patients is low, and the sugar content is high, which is conducive to the growth and invasion of Candida albicans. It is also believed that due to the lower fatty acid content of the epidermal keratinized layer of diabetic patients, the ability to inhibit fungi is weakened.

Severe immunodeficiency disease often associated with oral Candida infection

5. Other factors: Environmental factors and working conditions are related to the pathogenesis of Candida albicans, such as working under high temperature and humidity conditions, prone to cutaneous candidiasis.

an examination

Related inspection

Bacterial infection immunoassay for salivary lysozyme in saliva-rich histone saliva

The laboratory diagnostic method for candidiasis is currently considered to be the most reliable to form thick-walled spores on corn medium, and the simplest method is direct microscopic examination of specimens.

Dental doctors often take the pseudomembrane, exfoliated epithelium, clam shell and other specimens of the oral mucosa, placed on the slide, drop a few drops of 10% potassium hydroxide solution, cover the coverslip, and heat with a slight fire to dissolve the keratin. Then, a microscopic examination is performed immediately. If a pseudohyphae or a spore is found, it can be confirmed as a fungal infection, but it must be cultured before it can be diagnosed as Candida albicans.

Acute pseudomembranous candida stomatitis should be differentiated from acute coccidative stomatitis (membrane stomatitis). Membranous stomatitis is caused by cocci infections such as Staphylococcus aureus, hemolytic streptococcus, and pneumococci. It is easy for children and the elderly to suffer from it. It can occur in any part of the oral mucosa. The affected area is congested and edema, and a large amount of fibrinogen is Intravascular exudation, condensation into an off-white or gray-yellow pseudomembrane, the surface is smooth and dense, slightly higher than the mucosal surface. The fake membrane is easily wiped off, leaving a smashed surface and bleeding. Regional lymphadenopathy can be accompanied by systemic reactions. Smear or bacterial culture can identify the major pathogens.

Differential diagnosis

Should be identified with acute coccidulitis (membrane stomatitis). Membranous stomatitis is caused by Staphylococcus aureus. Hemolytic streptococcus. Caused by a cocci infection such as pneumococci. Children and the elderly are prone to suffering. May occur in any part of the oral mucosa. Congestive edema in the affected area is obvious. A large amount of fibrinogen oozes from the blood vessels. Condensed into an off-white or gray-yellow pseudomembrane. The surface is smooth and dense. Slightly higher than the mucosal surface. The fake film is easily wiped off. There is bleeding on the surface and there is bleeding. Regional lymph nodes are enlarged. May be associated with systemic reactions. Smear or bacterial culture can identify the major pathogens.

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