Albicans

Oral treatment offers the advantage of bringing all the lesions at all sites under control, in addition to the absence of unpleasant cosmetic effects. In certain cases, it may be preferable to use oral treatment for C. albicans vaginitis and for extensive and persistent pityriasis versicolor, a skin disorder caused by Pityrosporum orbiculare. In the case of onychomycosis, a combination treatment, topical plus systemic, is required. It is preferable to use oral treatment for deep and systemic mycoses, though intravenous or intrathecal treatment is sometimes required. 

In addition to tolnaftate and cetylpytidinium chlotide, the ointment also contains poly(ethylene glycol). This piepaiation is not active against C. albicans. 

Miconazole. Miconazole nitrate [22832-87-7] (Fig. 2), the 1-phenethyl-imidazole derivative first described in 1969, interferes at low doses with the cytochrome P-450 dependent ergosterol biosynthesis in yeasts and fungi. The result is accumulation of C-14 methylated sterols on the one hand and reduction of the ergosterol levels in the membranes on the other hand (12). Analogous to clotrimazole, this leads to a disturbance in the membranes it results in inhibition of ceU repHcation, mycelium development (in C. albicans) and finally, ceU death. High concentrations of miconazole, which may be achieved with topical use, disturb the orientation of phosphoHpids in the membranes, which produces leaks (13). 

Like the a2ole derivatives, it inhibits the biosynthesis of ergosterol. However, naftifine [65472-88-0] does not inhibit the cytochrome P-450 dependent C-14-demethylase, but the epoxidation of squalene. Squalene epoxidase cataly2es the first step in the conversion of squalene via lanosterol to ergosterol in yeasts and fungi or to cholesterol in mammalian cells. The squalene epoxidase in C. albicans is 150 times more sensitive to naftifine, C2 H2 N, than the en2yme in rat fiver (15). Naftifine is available as a 1% cream. 

Flucytosine. Flucytosine (17) or 5-fluorocytosine (4-amino-5-fluoro-2-pyrimidone, 5-FC), C H FN O, is a pyrimidine derivative, that is efficient against Candida albicans Cryptococcus neoformans and Torulopsis glabrata. 

Flucytosine-resistant strains can develop very rapidly. These mutants may have a disturbed 5-FC-metabohsm, or a compensatory mechanism for the disturbed nucleic acid functions. No cytosine permease was found in a resistant Cyptococcus neoformans strain, whereas cytosine deaminase was absent in resistant C. albicans strains. A deficiency of uridine monophosphate pyrophosphorylase occurs frequently in resistant C. albicans strains (1). 

Miconazole. Miconazole (Fig. 2, 7a) is also available as a sterile solution for intravenous infusion. Miconazole has a therapeutic effect on systemic mycoses due to C albicans A.spergillusfumigatus Cyptococcus neoformans Blastomyces dermatitidis Histoplasma capsulatum Coccidioides immitis Paracoccidioides brasiliensis and Petriellidum boydii. 

Silicone reliners are supplied as either a one-component system that cures in the presence of moisture or heat, or a two-component system containing base and catalyst. Both types adhere poody to denture base and carmot be polished satisfactorily. Some silicones support propagation of bacteria such as Candida albicans. Acrylic-based sifloxane monomers and resins have been proposed for overcoming these deficiencies (211). 

Fenticonazole (106), on the other hand, is used topically to combat a wide variety of dermatophytes and yeasts, particularly Candida albicans. It can be synthesized from 2,4-dichlo-rophenacyl chloride (104) by reduction with borohydride and subsequent displacement with imidazole to give 105. This last undergoes ether formation with p-thiolphenylbenzyl chloride mediated by NaH to produce fcnticonazole (106) [37]. 

The superficial mycotic infections occur on the surface of, or just below, the skin or nails. Superficial infections include tinea pedis (athlete s foot), tinea cruris (jock itch), tinea corporis (ringworm), onychomycosis (nail fungus), and yeast infections, such as those caused by Candida albicans. Yeast infections or those caused by C. albicans affect women in the vulvovaginal area and can be difficult to control. Women who are at increased risk for vulvovaginal yeast infections are those who have diabetes, are pregnant, or are taking oral contraceptives, antibiotics, or corticosteroids. 

CORTICOSTEROID INHALANTS. The inhalers, particularly die corticosteroid or mast cell aerosols, may cause tiiroat irritation and infection with Candida albicans. The nurse instructs the patient to use strict oral hygiene, cleanse die inhaler as directed in die package directions, and use die proper technique when taking an inhalation. These interventions will decrease die incidence of candidiasis and help to soodie die throat. Occasionally an antifungal drug may be prescribed by die primary health care provider to manage the candidiasis. 

Lopez-Berestein, G., Metha, R., Hopfer, R. L., Mills, K., Kasi, L., Metha, K., Fainstein, V., Luna, M., Hersh, E. M., and Juliano, R. L. (1983). Treatment and prophylaxis of disseminated infection due to Candida albicans in mice with liposome-encapsulated amphotericin B, J. Infect. Pis.. 147, 939-945. 

Altered tissue distribution of amphotericin B by liposomal encapsulation Comparison of normal mice and mice infected with Candida albicans. Cancer Drug Deliv., 1, 199-205. 

Another form of switching is well-known in C. albicans. This is the phenomenon of phenotypie switching (Soil 1992) whereby colony morphologies vary dramatieally (e.g. white, opaque, fiizzy, wrinkled.) These may seem trivial to the pharmacist or physician, but the variability extends far beyond the mere appearance of the colonies. It ean eneompass a vast array of bioehemical alterahons, anhgenicities and drug... 

Fig. 2.7 Germ tube formation by Candida albicans. For simplicity the diagram merely illustrates the nuclear content of the parental yeast cell and the developing germ tube. In real life there is a complex rearrangement of cytoplasmic constituents which results in all parts except the apex becoming highly vacuolated.

Sanjuan R., Zueco J., Stock R., Font de Mora J. Sentandreu R. (1995) Identification of glucan-mannoprotein complexes in the cell wall of Candida albicans using a monoclonal antibody that reacts with a (l,6)-/3-glucan epitope. Mzcroftzo/ogy, 141, 1545-1551. 

Soil D.R., Galask R., Isley S. et al. (1989) Switching of Candida albicans during recurrent episodes of recurrent vaginitis. 7 C/mM/craftzo/, 27, 681-690. 

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