BIOLOGICAL CHARACTERIZATION OF BACTERIOPHAGES AGAINST STREPTOCOCCUS AGALACTIAE.

Streptococcus agalactiae, also known as group B streptococci, was first isolated from cow's milk with mastitis, and it was first identified in 1930 by Rebecca Lancefield. GBS or streptococcus agalacticae is a gram-positive cocci, beta-hemolytic, facultative anaerobic, which is a harmless inhabitant of the normal human microflora. About 30% of the population is an asymptomatic carrier of this microbe. However, it was considered the leading cause of neonatal invasions upon its discovery. GBS is encapsulated in a polysaccharide capsule, which is a major virulence factor, and 10 serotypes of group B streptococci are known for their immunological activity. According to the existing studies, vaginal colonization is most often caused by type Ia, III, and V in other countries of the world. Today number of invasive GBS diseases continues to increase and it remains a significant pathogen among both infants and adults. The use of broad-spectrum antibiotics has certainly played a major role in the fight against infections, although the number of antibiotic-resistant strains has increased and thus modern medicine starts new insights into alternative antibacterials. Bacteriophages are often suggested as an alternative therapeutic agent against bacterial infections. In the present study, our aim was to isolate and study bacteriophages active against group B streptococci. Between March 2019 and March 2020, 257 anovaginal swabs were collected at Nia Oniashvili Tbilisi, Georgia, and Clinic Curatioby using standard bacterial identification procedures, in particular group B streptococcus identification guideline provided by CDC we identified 87 Streptococcus agalactiae strains. We used both standard and modified methods to isolate bacteriophages and study their life cycle, which were developed by the team. In this study, two bacteriophages active against Streptococcus agalactiae were identified: vB_GBS_1 (Syphoviridae) and vB_GBS_2 (Syphoviridae). The biological characteristics, morphology, adsorption, and host range were studied.