Analysis Of ERG3Gent Mutation And High Expression In Drug Resistance Of Candida Albicans

BackgroundIn recent years,with the increase of risk factors of invasive fungal infection,morbidity and mortality of infections are rising.Candida albicans is the most common form of conditional pathogenic bacteria.Because of the wide and long use of antifungal drugs,the development of drug resistance increased.We explored mechanism of drug resistance in candida albicans to guide drug use in clinic.It had important significance.ObjectiveWe studied the common antifungal drug resistance in candida albicans.The ERG3gene of clinical candida albicans was measured by extraction,amplification,sequencing and bioinformatics analysis for DNA and real-time quantitative analysis for mRNA to investigate the relationship of the mutation and high expression of ERG3to antifungal drug resistance in candida albicans.MethodsWe collected36candida albicans strains of clinical patients and identified the type of strains by using KOH microscopy, ShaShi medium,CHROMagar candida color medium and API20CAUX identification system.36candida albicans strains were tested by drug sensitivity in vitro.DNA was extracted.PCR was carried out to amply the full-length ERG3.The purified ERG3compared with known standard sequences in genbank (AF069572) through BLAST analysis.The mRNA expression of ERG3was determined by Reverse Transcription-Polymerase Chain Reaction(RT-PCR).Results(1)Of the36Candida albicans,the rate of strains susceptible to5-flucytosine and amphotericine B was superior,the rate of strains resistant to itraconazole,voriconazole and fluconazole was50.06%,72.22%and58.33%.(2)19appeared synonymous-mutations,including T51C,T432C, T381C,C438T,T1044C.They didn’t cause the change of amino acids.Two strains appeared missense mutations,including C1052T.They caused alanine to change into valine. Missense mutations strains appeared mult-drug resistance. (3)High expression rate of ERG3mRNA of18FCA-resistant candida albicans strains was94.4%and the rate of16FCA-sensitive strains was50.0%.We discovered multi-drug resistance and cross resistance in high expression strains.Only1strain occurred missense mutation. Other parts of strains occurred synonymous mutations.Conclusions(1)Candida albicans had a higher sensitivity for5-fluorine cytosine,amphotericin B and of fluconazole,itraconazole and voriconazole had different levels of drug resistance.The drug resistance of itraconazole and voriconazole was higher than fluconazole’s.It had occurred mult-drug resistance and cross-resistance.(2)The mutation and high expression of ERG3genes increased antifungal drug resistance.Meanwhile,variety of regulating mechanism participate in the formation of drug resistance in candida albicans.