TABLE 3.

Effect of inhibition by carcass rinse from chicken on PCR amplification with different DNA polymerases in a Y. enterocolitica PCR assay

DNA polymerase	Rinse sample (%)a	Result with Y. enterocolitica concen (CFU/25-μl reaction tube)d
		Conventional PCRb				Real-time PCRc
				5 × 103	5 × 102	5 × 101	5 × 100	5 × 103	5 × 102	5 × 101	5 × 100
Taq polymerase	Water	++	++	++	+−	++	++	++	−−
	20	−−	−−	−−	−−	−−	−−	−−	−−
	2	+−	−−	−−	−−	++	−−	−−	−−
	0.2	+−	++	+−	−−	++	++	++	−−
Tth polymerase	20	−−	−−	−−	−−	−−	−−	−−	−−
	2	++	++	++	−−	++	++	++	−−
	0.2	++	++	++	−−	++	++	++	−−
DyNAzyme II	20	−−	−−	−−	−−	−−	−−	−−	−−
	2	−−	++	−−	−−	++	++	−−	−−
	0.2	++	++	++	+−	++	++	++	−−

^aCarcass-rinse sample from neck skin of chicken in physiological saline.

^bTwo independent PCR results confirmed by gel electrophoresis.

^cTwo independent PCR results confirmed by melting-curve analysis in a LightCycler instrument.

^dOvernight culture of Y. enterocolitica Y79 in Tris-buffered saline with CFU determination by plating on TGE plates. Dilutions of the cell suspensions were made in physiological saline and added to the PCR mixture to a final amount of 20% (vol/vol).