Method for detection of microorganism and kit for detection of microorganism
Live cells of a microorganism in a test sample are detected by the following steps: a) the step of treating the test sample with a topoisomerase poison and/or a DNA gyrase poison, b) the step of extracting DNA from the test sample, and amplifying a target region of the extracted DNA by PCR, and c) the step of analyzing an amplification product.
1. A method for detecting live cells by distinguishing the live cells from dead cells and also from injured cells of microorganisms in a test sample, which comprises the following steps:
a) treating the test sample with two poisons, wherein a first poison is a topoisomerase poison and a second poison is a DNA gyrase poison,
b) extracting DNA from the test sample and amplifying a target region of the extracted DNA by PCR, wherein the length of the target region is 100 to 3000 nucleotides,
c) analyzing a resulting PCR amplification product, and
d) distinguishing the live cells from the dead cells and also from injured cells, wherein the method does not comprise treatment with ethidium monoazide.
2. The method according to claim 1 , wherein the amplification product is analyzed by comparing the product to a standard curve representing the relationship between the amount of the microorganism and the amplification product, prepared by using standard samples of the microorganisms.
3. The method according to claim 2 , wherein the PCR is performed by real-time PCR, and wherein the PCR and the analysis of the amplification product are simultaneously performed.
4. The method according to claim 1 , wherein the test sample is selected from the group consisting of milk, a dairy product, a foodstuff produced from milk or a dairy product as a raw material, a blood sample, a urine sample, a spinal fluid sample, a synovial fluid sample and a pleural fluid sample.
5. The method according to claim 1 , wherein the microorganism is a bacterium.
6. The method according to claim 5 , wherein the target region is the 23S rRNA gene.
7. The method according to claim 6 , wherein PCR is performed by using a primer set of the primers of SEQ ID NOS: 1 and 2, or a primer set of the primers of SEQ ID NOS: 3 and 4.
8. The method according to claim 1 , wherein the microorganism is a pathogenic bacterium.
9. The method according to claim 8 , wherein the target region is a pathogenic gene.
10. The method according to claim 9 , wherein PCR is performed by using a primer set of the primers of SEQ ID NOS: 7 and 8.
11. The method according to claim 1 , wherein the topoisomerase poison is selected from the group consisting of amsacrine, camptothecin, doxorubicin, ellipticine, etoposide, mitoxantrone, saintopin, topotecan and CP-115, 953.
12. The method according to claim 1 , wherein the DNA gyrase poison is selected from ciprofloxacin, ofloxacin, enoxacin, pefloxacin, fleroxacin, norfloxacin, nalidixic acid, oxolinic acid and piromidic acid.
13. The method according to claim 1 , wherein the following step is performed before step a):
a′) treating the test sample with a topoisomerase and/or a DNA gyrase.