Researchers first described Mycobacterium xenopi in 1959 after isolating it from skin lesions of the South African toad Xenopus laevis. M xenopi, a slow-growing, nontuberculous mycobacterium, is often considered to be a saprophyte or an environmental contaminant. It grows optimally at 45°C (113°F) and has been found, occasionally in large numbers, in hospital hot water supplies at the outlet valves of water heaters
A real-time polymerase chain reaction (real-time PCR,or qPCR) is a laboratory technique of molecular biology based on the polymerase chain reaction(PCR). It monitors the amplification of a targeted DNA molecule during the PCR(i.e.,in real time),not at its end,as in conventional PCR.
Two common methods for the detection of PCR products in real-time PCR are(1)non-specific fluorescent dyes that intercalate with any double-stranded DNA and (2)sequence-specific DNA probes consisting of oligonucleotides that are labelled with a fluorescent reporter,which permits detection only after hybridization of the probe with its complementary sequence.