1 Phage typing of Streptococcus agalactiae

TLDR: This chapter discusses the development of a phage-typing system for Group B streptococci, one of the major pathogenic groups for man, which has been studied much less intensively than staphylococcal bacteriophages and Gram-negative bacilli.

Abstract: Publisher Summary This chapter discusses the development of a phage-typing system for Group B streptococci. The application of Lancefield's serological method to the haemolytic streptococci has led to the recognition of some major pathogenic groups for man, including Groups A, B, C, D, and G. Groups A, B, and C can be equated with species described on the basis of biochemical characteristics: Streptococcus pyogenes (Group A), S. agalactiae (Group B), and S. equisimilis (Group C). Group D streptococci can be subdivided into three main species: S. bovis , S. faecalis, and S. faecium , which all possess the same group antigen. To trace the spread of these organisms or relate strains to particular diseases, further identification of the organisms beyond the species is required. An ideal typing system should reproducibly identify related strains as being the same and unrelated strains as being different. However, factors such as genetic variation and experimental conditions influence the reproducibility of any typing method. Phage typing has been used in the construction of discriminatory systems for some common pathogens—notably, S. aureus —but streptococcal bacteriophages have been studied much less intensively than staphylococcal bacteriophages and Gram-negative bacilli. Phage sensitivity has been used as an additional means of subdividing certain types of Group A streptococci and lysotyping schemes have been proposed for Groups A, C, and D.