Antifungal Susceptibilities of Candida Species Causing Vulvovaginitis and Epidemiology of Recurrent Cases

Abstract

There are limited data regarding the antifungal susceptibility of yeast causing vulvovaginal candidiasis, since cultures are rarely performed. Susceptibility testing was performed on vaginal yeast isolates collected from January 1998 to March 2001 from 429 patients with suspected vulvovaginal candidiasis. The charts of 84 patients with multiple positive cultures were reviewed. The 593 yeast isolates were Candida albicans (n ‫؍‬ 420), Candida glabrata (n ‫؍‬ 112), Candida parapsilosis (n ‫؍‬ 30), Candida krusei (n ‫؍‬ 12), Saccharomyces cerevisiae (n ‫؍‬ 9), Candida tropicalis (n ‫؍‬ 8), Candida lusitaniae (n ‫؍‬ 1), and Trichosporon sp. (n ‫؍‬ 1). Multiple species suggesting mixed infection were isolated from 27 cultures. Resistance to fluconazole and flucytosine was observed infrequently (3.7% and 3.0%); 16.2% of isolates were resistant to itraconazole (MIC > 1 g/ml). The four imidazoles (econazole, clotrimazole, miconazole, and ketoconazole) were active: 94.3 to 98.5% were susceptible at <1 g/ml. Among different species, elevated fluconazole MICs (>16 g/ml) were only observed in C. glabrata (15.2% resistant [R], 51.8% susceptible-dose dependent [S-DD]), C. parapsilosis (3.3% S-DD), S. cerevisiae (11.1% S-DD), and C. krusei (50% S-DD, 41.7% R, considered intrinsically fluconazole resistant). Resistance to itraconazole was observed among C. glabrata (74.1%), C. krusei (58.3%), S. cerevisiae (55.6%), and C. parapsilosis (3.4%). Among 84 patients with recurrent episodes, non-albicans species were more common (42% versus 20%). A >4-fold rise in fluconazole MIC was observed in only one patient with C. parapsilosis. These results support the use of azoles for empirical therapy of uncomplicated candidal vulvovaginitis. Recurrent episodes are more often caused by non-albicans species, for which azole agents are less likely to be effective.Limited data addressing the incidence of vulvovaginal candidiasis suggest approximately two-thirds of women experience at least one episode during their lifetime and nearly 50% of women have multiple episodes (3, 12). The majority of cases of vulvovaginal candidiasis are caused by Candida albicans; however, episodes due to non-albicans species of Candida appear to be increasing (15,22,29). Most non-albicans Candida species have higher azole MICs, and infections they cause are often difficult to treat (10,20,21,26).A possible explanation for more frequent isolation of nonalbicans species from vulvovaginitis patients may be the increased use of topical azole agents-available as over-thecounter preparations in the United States since 1992 (14, 24). Patients who see a physician usually receive empirical therapy; vaginal cultures are not routinely obtained, and susceptibility testing is rarely performed.Surveillance programs for candidemia have demonstrated that fluconazole resistance among C. albicans bloodstream isolates is rare (Յ1%) (16). The majority of studies analyzing yeast isolates from vulvovaginitis patients have also shown the recovery of fluconazole-resistant C. albicans isola...

Candida species isolated from the vaginal mucosa of HIV-infected women in Salvador, Bahia, Brazil

“…Only three isolates had dose-dependent susceptibility or resistance to fluconazole, all of these were C. glabrata present in the vaginal mucosa of HIV-1-infected patients. These data are in agreement with other studies [23][24][25] that described azole refractory vaginitis caused by non-albicans Candida, particularly by C. glabrata. 23 Non-albicans Candida infections frequently require the use of non-azole therapy, including topical therapy with boric acid, Flucytosine, or Amphotericin B.…”

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“…The recommended regimens including induction therapy at times up to two weeks followed by maintenance therapy for up to six months, which have been supported by randomized clinical trials [115], have numerous challenges. The repeated treatments may increase the likelihood of drug resistance as well as shift the spectrum of causative Candida spp [76,89,[95][96][97]. The same has been said with regards to widespread use of azole compounds especially when the diagnosis is not confirmed [14,142].…”

“…The high prevalence of non-albicans Candida spp in RVVC which has been shown to be more common in the developing countries is a worrying situation as C. glabrata has been shown to have high minimum inhibitory concentration (MIC) to azole, and C. krusei is intrinsically resistant to fluconazole [131,144]. Richter et al [89] reported that 67% of C. glabrata from vaginal isolates were not susceptible to azole compounds [89]. Though boric acid is very effective in their treatment its efficacy ends with cessation of treatment [89].…”

“…RVVC is more often due to non-albicans Candida such as C. glabrata which is less susceptible to the azole antifungal agents [89]. Chong et al [90] in their study in Malaysia showed that C. albicans that cause RVVC are less similar to each other than the strains causing sporadic VVC, thus suggesting that the former may represent more virulent sub-types [90].…”

Host Cell Invasion by Medically Important Fungi

“…1999; Willis et al 1999;Richter et al 2005). These infections include oropharyngeal candidiasis, esophageal candidiasis, vulvovaginal candidiasis, and cutaneous candidiasis.…”