TABLE 3.

Comparison of the isolation of viable lactobacilli and bifidobacteria by the culture method and the detection of lactobacilli and bifidobacteria DNA by PCR using species-specific primers in breast milk samples (n = 66)

	No. positive samples
Species	Only by culture	By both culture and PCR	Only by PCR
Lactobacillus	1	26	24
L casei	1		3
L fermentum		7	12
L gasseri		6	9
L gastricus	2	—*	—*
L plantarum		1	6
L reuteri		3	5
L rhamnosus	1		6
L salivarius		9	16
L vaginalis	2	—*	—-*
Bifidobacterium	1	6	12
B breve		5	4
B lactis			2
B longum	2		2
	No. negative samples
	Only by culture	By both culture and PCR	Only by PCR
	36	15	1

PCR = polymerase chain reaction.

^*L gastricus and L vaginalis could not be detected by PCR because L gastricus- and L vaginalis-specific primers were not available.