Any pregnant woman with a vaginal discharge or inflamed vulvovaginal area should be evaluated for Candida. Candida vulvovaginitis is the second most common cause of vaginitis after bacterial vaginosis. Many women are asymptomatic, but the classic signs are a profuse, pruritic, thick, white, curdlike discharge associated with dysuria, dys-pareunia, and pruritus ani. The diagnosis of Candida vulvovaginitis is a clinical diagnosis that is confirmed by culture and microscopic detection of the yeast. A drop of the cervicovaginal fluid should be immersed in a 10% potassium hydroxide (KOH) preparation on a glass slide with a coverslip for microscopic examination. Sometimes, this slide is heated before examining it under the microscope. The presence of ovoid budding yeast cells 3-7 ^m in diameter, seen sometimes with pseudohyphae, can make a presumptive diagnosis. The diagnosis is confirmed by isolating Candida from the cervicovaginal secretions cultured on Sabouraud's dextrose agar, which is commercially available. If bacterial contamination of the specimen is expected, then chloramphenicol should be used in the culture medium. Cycloheximide, which prevents fungal overgrowth, should not be used because it may inhibit some strains of Candida.
Candida is an unlikely pathogen in the immunocompetent pregnant woman. If the mother is immunosuppressed or has other risk factors for systemic candidiasis and is symptomatic, a workup should be initiated. If a pregnant woman who is immunocom-petent has signs of systemic infection, such as fever, shock, or respiratory distress, or focal signs, a full sepsis work should be done. This would include multiple blood cultures, midstream clean catch or catheterized urine sample for urinalysis and culture, complete blood cell count and differential, liver function tests, and chest x-ray. Attempts to isolate Candida from blood and any other affected areas, such as cerebrospi-nal fluid, joint fluid abscess formation, bone marrow, bronchial alveolar lavage washings, skin lesions, tissue biopsy specimens, urine, and placenta should be made.
The isolation of Candida from urine, sputum, or bronchial washings does not always confirm the diagnosis. Candida isolated from respiratory and urinary cultures, especially in the presence of bacteria, may reflect contamination from oral or vaginal flora. Quantitative urine cultures are not helpful.
The lysis-centrifugation blood culture method (Isolator system), which is the most sensitive method for detection of bacteria in blood cultures, can detect almost all clinically significant yeast isolates. Therefore, Candida can be easily detected and isolated from routine blood cultures. Blood isolation may take from 24 to 72 hours. On the agar plate, Candida colonies are white or cream-colored colonies, with filamentous extensions coming from the edges of the colonies indicating the formation of pseudohyphae. C. albicans may undergo a transformation when placed in human serum for several hours. These new forms, chlamydospores, have cylindrical extensions called germ tubes. Because this is unique to C. albicans, a positive germ tube test confirms the diagnosis of C. albicans infection. Determining which Candida species has been isolated is important in invasive disease because of possible resistance. For example, C. krusei is known to be resistant to fluconazole. Routine susceptibility testing is not recommended. These tests are not always done in hospital laboratories, may not be reliable, and may be difficult to interpret.
Because the yield from cultures may be low in patients who are immunocompromised, tissue diagnosis may be required to confirm the diagnosis. The presence of yeast cells or pseudohyphae on histologic sections helps to confirm the diagnosis. The presence of pseudohyphae suggests tissue invasion rather than colonization; however, blastospores or yeast cells can be virulent as well. Diagnosis should be made in conjunction with the clinical picture and other diagnostic tests, such as urinalysis, radiographic imaging of the lungs or kidneys, or endoscopy, to rule out esophagitis or tissue biopsy. The isolation of Candida from cultures and histological detection of Candida in tissue specimens confirms the diagnosis. The pregnant woman should be treated for vaginal or invasive candidiasis. Preliminary studies do not justify the use of antifungal chemopro-phylaxis to prevent invasive candidiasis in the newborn. Whether chemoprophylaxis is beneficial needs further study.
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