Prepare antigenic streptococcal hemolysin and cultivate the streptococci prior to serological groupings with Thermo Scientificâ„¢ Oxoidâ„¢ Todd-Hewitt Broth (Dehydrated). Todd-Hewitt Broth is an easily reconstituted, dehydrated modification of the medium originally described by Todd and Hewitt1 for the production of antigenic streptococcal haemolysin. Streptococci are facultatively anaerobic, catalase-negative, gram-positive cocci that occur as pairs or chains. They cause a wide variety of clinical diseases including pharyngitis, scarlet fever, otitis media, impetigo, meningitis, neonatal sepsis, pneumonia, endocarditis, osteomyelitis, and necrotizing fasciitis. One of the most useful phenotypic characteristics of streptococci is the hemolytic reaction, generally classified as alpha, beta or gamma according to the appearance of zones around colonies growing on Blood Agar.Todd Hewitt Broth is recommended for the cultivation of group A haemolytic streptococci used for serological studies.Well-buffered: the medium is well buffered by sodium phosphate and sodium carbonate to neutralize the acid produced during glucose fermentation.Todd-Hewitt Broth can be employed as an alternative to serum broth or horse-flesh digest broth, for the cultivation of streptococci prior to serological grouping2.Not all products are available for sale in all territories. Please inquire.Remelâ„¢ and Oxoidâ„¢ products are now part of the Thermo Scientific brand.