Antifungal resistance of Candida genital isolates on the increase

By Helen Albert, Senior medwireNews Writer

Resistance to antifungal therapy of genital-infection causing Candida species may be an increasing problem, suggests research presented at the European Academy of Dermatology and Venereology annual congress in Prague, Czech Republic.

"It is very important to monitor the azole susceptibility profile of genital isolates for Candida species because the ability to acquire resistance has an obvious impact on clinical practice," presenter Carmen Lisboa Silva (Hospital de São João, Faculty of Medicine of Porto, Portugal) told medwireNews.

Lisboa Silva and colleagues enrolled 113 men with balanitis and 61 women with vulvovaginitis attending a sexually transmitted disease clinic in Porto between 2005 and 2007 to assess levels of antifungal resistance in the various infection-causing species of Candida involved.

Overall, the researchers obtained 208 Candida genital isolates from the participants. The most common infection was with C. albicans (54.3%), followed by C. parapsilosis (24%), C. guilliermondii (12%), and C. glabrata (4.8%).

The overall susceptibilities of all the different isolates to the antifungal drugs fluconazole, itraconazole, voriconazole, posaconazole, amphotericin B, and caspofungin were 89.4%, 63.4%, 91.8%, 93.8%, 100% and 94.0%, respectively.

Seventeen patients had multi-drug-resistant infections. The researchers classified these as being resistant to two (n=7; two C. albicans, two C. guilliermondii, two C. utilisis, and one C. glabrata), three (n=2; two C. albicans), or four azoles (n=6; five C. albicans, one C. guilliermondii), or resistant to three azoles plus caspofungin (n=2; two C. albicans).

The researchers note that itraconazole resistance was particularly common in non C. albicans species.

"What we found was that the majority of the Candida genital isolates were in fact susceptible to azole treatments," said Lisboa-Silva, "but we found some Candida isolates had itraconazole resistance phenotype."

She added that "although we didn't find any association between resistance and some clinical data and outcomes, it is very important to continue to monitor this pattern of susceptibility of Candida because it's a very frequent clinical situation and nowadays the use of antifungals is also very frequent so we have to know what the impact of this practice is in our clinic."

She said that the problem could be more common, although she conceded that more studies in more patients are needed to make strong conclusions about this.

In a similar fashion to the way in which resistance to antibiotics following extensive use has arisen in recent years, Lisboa Silva believes a similar problem could occur with antifungals. "In the future if you need antifungals we need to ask if there is any resistance already before using them," she said.

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