ENHANCEMENT OF LYSOZYME TRYPSIN-MEDIATED DECAY OF INTESTINAL BIFIDOBACTERIA AND LACTOBACILLI

Lysozyme-mediated lysis of Bifidobacteria and Lactobacilli was studied in in vitro tests using the agar gel plate and turbidometric Micrococ cus luteus (lysodeikticus) procedure as a standard. Suspensions of the strains Bifidobacterium infantis, B. infantis liberorum, B. breve, B. longum, B. ssp, and Lactobacillus acidophilus proved to be resistant to egg white lysozyme and human milk lysozyme when incubated at 37 deg rees C in concentrations of 5, 50, and 500 mg lysozyme/L, respectively , through 30 and 60 min. Heat treatment at 100 degrees C for 1 h and p retreatment with ether, acetone, ascorbic acid, and hydrogen peroxide failed to incline the bacteria to the lytic effects of lysozyme. Conse cutive incubation of the lysozyme-pretreated bacteria with trypsin res ulted in a significantly enhanced bacteriolysis in all strains of bact eria, with the exception of B. longum. The mode of action of lysozyme and proteolytic enzymes on Bifidobacteria and Lactobacilli offers an e xplanation for the release of microbial building blocks and their colo nic absorption and retention in the breast-fed baby.