The use of a mimic to detect polymerase chain reaction-inhibitory factors in feces examined for the presence of XXXX .

@entity1707 @entity294 @entity18375 @entity1681
@entity18375 is an intracellular organism that causes @entity1681 in @entity1707 . This bacterium is difficult to culture, and antemortem demonstration of the microbe is therefore often performed on fecal samples by polymerase chain reaction (PCR). Polymerase chain reaction is sensitive and specific, but inhibitory factors in feces might cause false-negative results. This article describes the construction and use of an internal standard, a mimic. The mimic is amplified by the same primers as those used for @entity18375 DNA and thus could indicate false-negative results in clinical samples. The amplicon was clearly visible when as few as 10 mimic molecules were added per amplification reaction and when no inhibitors werepresent. When fecal samples were spiked with the mimic, the detection limit was 10(2) molecules per PCR. Sixty clinical samples, 20 from @entity1707 , 20 from growing @entity1707 with @entity294 , and 20 from @entity1707 without @entity294 , were prepared by a boiling procedure and subjected to PCR together with 10(3) mimic molecules. Nine samples were positive, of which 7 originated from @entity1707 with @entity294 and 2 from @entity1707 without @entity294 . In 14 samples from @entity1707 , in 8 samples from @entity1707 without @entity294 , and in 3 samples from @entity1707 with @entity294 , neither the mimic nor the target DNA was visible. This indicated the presence of inhibitors in these samples. It is concluded that the mimic can be used as an internal control in the diagnosis of @entity18375 to indicate inhibition of PCR.
