Biotechnological Applications of Two Novel Lytic Bacteriophages of Streptococcus mutans in Tooth Decay Bio-Controlling

Abstract

Recently the prevention of bacterial infections using their specific viruses, bacteriophages, is challenging. In this research two water samples of Caspian sea were gathered and filtered through 0.45 μm membrane filters. The filtrates were added to Streptococcus mutans culture media in their logarithmic phase, cultivated on brain heart infusion agar and incubated at 37°C and 5% CO2 until bacteriophage plaques were appeared. Transmission electron microscopy of purified plaques revealed two types of lytic bacteriophages. The first phage had hexagonal head measured 74 nm and was most probably related to Cystoviridae family of bacteriophages. The second lytic bacteriophage contained a bottle-shaped mantle measuring 55×125 nm that was most probably related to Ampullaviridae family of bacteriophages. The microtiter plate assay showed the addition of bacteriophages to Streptococcus mutans after 0, 6, 12 and 18 h of culturing the host strain in microtiter plates prevented the biofilm formation up to 99, 69, 41 and 26%, respectively. In conclusion this is the first report of two novel Cystovirus and Ampullavirus that had lytic effects on Streptococcus mutans. These lytic bacteriophages could be considered as specific agents for phage therapy of tooth decay.