Assays for fungal infection

Abstract

Methods and kits are described for testing for the presence or absence of any fungus in a sample. Examples of fungi that can be detected include, but are not limited to, those belonging to the genera Candida, Aspergillus and Pneumocystis . The methods include obtaining a sample suspected of containing fungal nucleic acid, including at least one universal region of fungal nucleic acid, and testing for the presence or absence in the sample of the at least one universal region of fungal nucleic acid. Samples may be biological or non-biological.

We claim: 
     
       1. A method for detecting the presence or absence of any species of a fungus belonging to the genus  Candida  in a sample, comprising:
 i. obtaining a sample suspected of containing fungal nucleic acid from the genus  Candida , and 
 ii. testing for the presence or absence in the sample of an identifying region of fungal nucleic acid comprising SEQ ID NO: 5, the complement or transcript thereof, or a sequence having 80% or more sequence identity with SEQ ID NO: 5, the complement or transcript thereof, said identifying region being present in species of the genus  Candida  but not those of the genus of  Aspergillus  or  Pneumocystis , wherein the testing includes contacting the sample with a molecular beacon probe comprising SEQ ID NO: 8, and 
 wherein the presence of said identifying region of fungal nucleic acid indicates the presence of any species of a fungus belonging to the genus  Candida  in the sample, and the absence of said identifying region of fungal nucleic acid in the sample indicates the absence of any species of a fungus belonging to the genus  Candida  in the sample. 
 
     
     
       2. The method of  claim 1  further comprising amplifying the identifying region of fungal nucleic acid by contacting the sample with a pair of primers including SEQ ID NO: 6 and SEQ ID NO: 7. 
     
     
       3. The method of  claim 2  in which the amplifying step is carried out in the presence of one or more internal PCR amplification controls. 
     
     
       4. The method of  claim 3  in which the one or more internal PCR amplification controls comprise a non-fungal sequence. 
     
     
       5. The method of  claim 3  in which the amplifying step is carried out in the presence of a cloned or synthesized tRNA-LEU intron region, which is then added to the amplification mixture in a predetermined amount to rule out the presence of inhibitors or other defective amplification steps. 
     
     
       6. The method of  claim 5  in which the tRNA-LEU intro region comprises a portion of the Maize ( Zea mays ) tRNA-LEU intron region. 
     
     
       7. The method of  claim 5  in which the tRNA-LEU intron region includes SEQ ID NO: 9. 
     
     
       8. The method of  claim 7  further comprising detecting the presence of a nucleic acid include SEQ ID NO: 10. 
     
     
       9. The method of  claim 8  in which the detecting step comprises contacting the sample with a pair of oligonucleotide primers including SEQ ID NO: 11 and SEQ ID NO: 12 and a molecular beacon probe including SEQ ID NO: 13. 
     
     
       10. The method of  claim 1  in which the nucleic acid comprises DNA. 
     
     
       11. The method of  claim 1  in which the nucleic acid comprise RNA. 
     
     
       12. The method of  claim 1  in which the sample is obtained from a biological source. 
     
     
       13. The method of  claim 12  in which the sample comprises a biological fluid, tissue, or combination thereof. 
     
     
       14. The method of  claim 12  in which the sample is a biological sample obtained from a non-biological source. 
     
     
       15. The method of  claim 14  in which the non-biological source comprises a piece of a vehicle, watercraft, aircraft, building, or dwelling. 
     
     
       16. The method of  claim 1  in which the source is obtained from an environment. 
     
     
       17. The method of  claim 16  in which the sample comprises an air sample, a water sample, a soil sample, or combinations thereof. 
     
     
       18. The method of  claim 1  in which the testing step further comprises contacting the sample with an oligonucleotide probe comprising a nucleic acid capable of hybridizing to at least one universal region of fungal nucleic acid under stringent conditions. 
     
     
       19. The method of  claim 18  in which the probe includes a detectable label. 
     
     
       20. The method of  claim 1 , wherein said method is used for the diagnosis of a fungal infection belonging to the genus  Candida  in a patient, and the sample is from said patient.