Methods and compositions for detecting and identifying species of Candida

    公开(公告)号:US20080102449A1

    公开(公告)日:2008-05-01

    申请号:US11321984

    申请日:2005-12-29

    IPC分类号: C12Q1/68 C12P19/34

    CPC分类号: C12Q1/6895 C12Q1/689

    摘要: Methods and compositions useful in the detection and identification of species of Candida are disclosed. These species include Candida albicans, Candida glabrata, Candida parapsilosis, and Candida tropicalis, each of which is a causative agent for vaginal candidiasis. The compositions of the invention are combinations of oligonucleotides. These oligonucleotides include pairs of forward and reverse primers for polymerase chain reactions, wherein each primer pair is capable of priming the synthesis of an amplicon specific to one of Candida albicans, Candida glabrata, Candida parapsilosis, and Candida tropicalis, but preferably is not capable of priming the synthesis of an amplicon specific to any of the other three species. In preferred embodiments, the forward primers of the primer pairs have identical sequences, while each reverse primer of the primer pairs has a unique sequence relative to all of the other reverse primers; or the reverse primers of the primer pairs have identical sequences, while each forward primer of the primer pairs has a unique sequence relative to all of the other forward primers. These unique primer sequences account for the species specificity of the resultant amplicons. The oligonucleotides also include probes capable of detecting these amplicons, and sequencing primers for determining, in primer extension reactions, the nucleotide sequences contained within the amplicons. In preferred methods of the invention, a biological sample is tested for the presence of at least one isolate of Candida albicans, Candida glabrata, Candida parapsilosis, and Candida tropicalis by isolating nucleic acid from the sample, attempting a polymerase chain reaction in a mixture containing this nucleic acid and a plurality of these primer pairs, ascertaining whether any amplicon is produced in the mixture using an oligonucleotide probe, and determining the sequence of any resultant amplicon using the sequencing primers. The detection of an amplicon indicates that the sample contains at least one isolate of Candida albicans, Candida glabrata, Candida parapsilosis, or Candida tropicalis, and the nucleotide sequence data is used to determine which of these four Candida species is present.