Qiaamp ultraclean production pathogen mini kits

DNA was isolated from 1.5 mL of breast milk from each mother and from one Salivette saliva collection swab from each child. Before DNA isolation, Salivette cotton swabs were transferred to ClotSpin Baskets (Qiagen, Valencia, CA), thawed at room temperature, and centrifuged for 3 minutes at 2095 ×g to withdraw saliva into the ClotSpin Basket reservoir. Recovered saliva volumes ranged from 0.2 mL to over 1.5 mL. For those samples with greater than 1.5 mL recovered volume, only 1.5 mL was used for DNA isolation. Samples were subjected to a mechanical “bead beating” pretreatment using Pathogen Lysis Tubes (Qiagen, Valencia, CA) to disrupt Gram-positive bacterial cell walls according to the manufacturer’s protocol. Fat from breast milk samples was removed along with liquid supernatant after pelleting by centrifugation and before bead beating. DNA isolation from mechanically-lysed breast milk and saliva samples was completed using QIAamp Ultraclean Production Pathogen Mini Kits (Qiagen, Valencia, CA) according to the manufacturer’s protocol.