There are some bifidobacteria-selective media you can use. They contain lactobacilli inhibitory substances (lithium salts, propionate, the antibiotic mupirocin) and/or bifidobacteria-promoting carbon sources (raffinose, galactooligosaccharides).

Jakub Grzesiak I have tried BSM and mupirocin and they still survive and outgrow my bifidobacterium. I can try some of the other pieces you have mentioned. Thanks

I have used Reinforced clostridial agar supplemented with lithium mupirocin. TOS-propionate agar supplemented with lithium mupirocin is another option. Anaerobic incubation for 48 to 72 hours.

"Primers with less than 20 specific bases may not anneal with sufficient specificity, even at higher temperatures. While a touchdown PCR with temperatures up to 46°C could be attempted, a more effective solution would be to design primers with longer regions of homology, incorporating degenerate bases if necessary@