RESUMEN
The quantification of pathogens is important for assessing water safety and preventing disease outbreaks. Culture-independent approaches, such as quantitative PCR (qPCR) and digital PCR (dPCR), are useful techniques for quantifying pathogens in water samples. However, since pathogens are usually present at low concentrations in water, it is necessary to concentrate microbial cells before extracting their DNA. Many existing microbial concentration methods are inefficient or take a long time to perform. In this study, we applied a coagulation and foam separation method to concentrate environmental water samples of between 1000 and 5000 mL to 100 µL of DNA (i.e., a 1-5 × 104-fold concentration). The concentration process took <1 h. The DNA samples were then used to quantify various target pathogens using dPCR. One gene, the Shiga toxin gene (stx2) of Shiga toxin-producing Escherichia coli, was detected at 32 copies/100 mL in a river water sample. The coagulation and foam concentration method followed by dPCR reported herein is a fast, sensitive, and reliable method to quantify pathogen genes in environmental water samples.
Asunto(s)
Agua Dulce/microbiología , Reacción en Cadena de la Polimerasa/métodos , Agua Dulce/química , Reacción en Cadena de la Polimerasa/instrumentación , Sensibilidad y Especificidad , Toxina Shiga/genética , Toxina Shiga/metabolismo , Escherichia coli Shiga-Toxigénica/genética , Escherichia coli Shiga-Toxigénica/aislamiento & purificación , Escherichia coli Shiga-Toxigénica/metabolismoRESUMEN
Chronic myelogenous leukemia (CML) is a myeloproliferative disorder characterized by the presence of the Philadelphia chromosome. Although the major BCR/ABL transcript is present in majority of CML patients, the minor BCR/ABL transcript is rarely reported as an additional chromosomal abnormality related to the progression of CML. We describe the case of a 37-year-old woman who had CML and pain in the extremities. She was diagnosed with lymphoid blast crisis of CML on the basis of the following findings: presence of promyelocytes, myelocytes, and metamyelocytes in peripheral blood smear; detection of major and minor BCR/ABL transcripts by polymerase chain reaction analysis; proliferation of lymphoblastic cells with abnormal B-cell phenotype; and aberrant expression of myeloid antigens in the bone marrow. The patient underwent one course of idarubicin and cytosine arabinose therapy combined with imatinib followed by daunorubicin/cyclophosphamide plus vincristine and prednisone/L: -asparaginase (DNR/COP/L: -ASP) therapy, high-dose cytosine arabinose, and CHOP therapy (cyclophosphamide, doxorubicin, vincristine, and prednisolone). Subsequently, the patient underwent high-dose chemotherapy (total body irradiation and cyclophosphamide) followed by allogeneic bone marrow stem cell transplantation from a human leukocyte antigen (HLA)-matched unrelated donor. After these treatments, the patient was disease-free for 19 months. Our case suggests that these treatments may be feasible, safe, and effective for the treatment of patients with blast crisis CML expressing the minor BCR/ABL transcript.