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Introduction:Candida albicansis one of the most important aetiological agents causing vaginal candidiasis in pregnant women.Most women will experience at least one episode during their reproductive years. Antifungal resistance is a particular problem with Candida infections. Some types of Candida are increasingly resistant to the first-line and second-line antifungal medications.Objective:To investigate the azole susceptibility of Candida albicans(C. albicans) from pregnant vulvovaginal candidiasis patients and to detect ERG11gene in these azole resistance isolates.Methods:Forty-one clinical isolates of C. albicanswere collected. Azole susceptibility was tested in vitrousing microdilution techniques.The ERG11genes of 27 isolates of C. albicans(All resistant to azoles) were amplified using PCR method
ABSTRACT
Objective:To investigate the azole susceptibility of Candida albicans (C. albicans) from vulvovaginal candidosis patients and to analyze the relationship between ERG11 gene mutations in these isolates and azole resistance. Methods:Three hundred and two clinical isolates of Candida species were collected. Azole susceptibility was tested in vitro in microdilution studies. The ERG11 genes of 17 isolates of C. albicans (2 susceptibles, 5 dose-dependent resistants and 10 resistants) were amplified and sequenced. Results:Of the 302 isolates collected, 70.2%were C. albicans, of which 8.5%, 3.8%and 4.2%were resistant to fluconazole, itraconazole and voriconazole, respectively. In total, 27 missense mutations were detected in ERG11 genes from resistant/susceptible dose-dependent isolates. Among them, Y132H, A114S, and Y257H substitutions were most prevalent and were known to cause fluconazole resistance. G464S and F72S also has been proved to cause fluconazole resistance. Two novel substitutions (T285A, S457P) in hotspot regions were identified. Conclusions:Twenty seven mutations in the ERG11 gene were identified in azole-resistant C. albicans isolates, which indicated a possible relation with the increase in resistance to azole drugs and the recurrence of vulvovaginal candidosis. The relationship of two novel substitutions (T285A, S457P) with fluconazole resistance needs to be further verified by site-directed mutagenesis.
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Objective: To investigate the azole susceptibility of Candida albicans ( C. albicans) from vulvovaginal candidosis patients and to analyze the relationship between ERG11 gene mutations in these isolates and azole resistance. Methods: Three hundred and two clinical isolates of Candida species were collected. Azole susceptibility was tested in vitro in microdilution studies. The ERG11 genes of 17 isolates of C. albicans (2 susceptibles, 5 dose-dependent resistants and 10 resistants) were amplified and sequenced. Results: Of the 302 isolates collected, 70.2% were C. albicans, of which 8.5%, 3.8% and 4.2% were resistant to fluconazole, itraconazole and voriconazole, respectively. In total, 27 missense mutations were detected in ERG11 genes from resistant/susceptible dose-dependent isolates. Among them, Y132H, A114S, and Y257H substitutions were most prevalent and were known to cause fluconazole resistance. G464S and F72S also have been proved to cause fluconazole resistance. Two novel substitutions (T285A, S457P) in hotspot regions were identified. Conclusions: Twenty seven mutations in the ERG11 gene were identified in azole-resistant C. albicans isolates, which indicated a possible relation with the increase in resistance to azole drugs and the recurrence of vulvovaginal candidosis. The relationship of two novel substitutions (T285A, S457P) with fluconazole resistance needs to be further verified by site-directed mutagenesis.
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Objective To investigate the point mutation of the open reading frame of cytochrome P-450 lanosterol 14-? demethylase gene ERG11. Methods In order to identify such alterations, the DNA was extracted by enzyme lysis methods and the PCR was performed. The PCR products were purified and cloned into PBS vector, then transformed into DH5? and sequenced. Results Twenty nine point mutations were identified in this 15 resistant isolates, most of which were different from susceptible strains. The mutations included 12 missense substitutions: F72L, D81G, D116E, K128T, Y132H, E266D, D294G, S361P, M374V, P386L, H400R, and Q474K, of which 6 had not been described previously (D294G, S361P, M374V, P386L, H400R, and Q474K). The other mutations included a frameshift, and 17 silent mutations. Conclusions The point mutation of resistant isolate is different from that of the susceptible isolate. It is suggested that the drug resistance is related with by the newly found alterations, including D294G, S361P, M374V, P386L, H400R, Q474K, and a frameshift.