ERG11 mutations associated with azole resistance in Candida albicans isolates from vulvovaginal candidosis patients

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% and4.2% were resistant to fluconazole, itraconazole and voriconazole, respectively. In total,27 missense mutations were detected in ERG11 genes from resistant/susceptible dosedependent isolates. Among them, Y132 H, A114 S, and Y257 H substitutions were most prevalent and were known to cause fluconazole resistance. G464 S and F72 S 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 azoleresistant 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.

Analysis of var genes cloned from a Plasmodium falcivarum isolate in China

Objective:To analyse the rar gene repertoire and characterise the rhondroitin sulphate A (CSA)-binding activity of the Duffy-binding like(I)BI.) domains encoded by the var2csa gene of a Plasmodium falciparum(P.falciparum) isolate in Hainan Province,China.Methods:The sequences of var DBL1 regions were PCR-amplified,sequenced and the sequence characteristics was bioinformalically analysed.Recombinant proteins encoded by the var2csa genes were expressed and purified.The binding activities of the recombinant proteins to CSA receptor was detected by ELISA assays.Results:Fifty six unique DBI.a sequences were obtained,and the sequences represented similar diversity to the var genes of the genome parasite 3D7.There are two var2csa genes in the P.falciparum isolated from Hainan Province.Unlike in other falciparum parasites such as HB3,the two var2csa genes are more diverged.The receptor-binding capacity of DBL-5εand DBI.-6 e domains of HN var2CSA was studied.Conclusions:This work represented the diversity of rar genes of a P.falciparum isolate in China.