There are two types of streptococcal infections: group A and group B, states MedlinePlus. The bacteria from group A streptococcal infections cause strep throat, scarlet fever, impetigo and toxic shock syndrome. Group B streptococcal infections cause blood infections, pneumonia and meningitis in newborns.
Group A streptococcal infections spread by contact with mucus from the nose and throats of an infected person or from direct contact with infected wounds or sores on the skin, according to Merck Manual. Group A strep also spreads through contact with people who have the bacteria on their skin or in their throats, reports the Centers for Disease Control and Prevention. The appearance or lack of appearance of group A streptococcal infection symptoms does not affect transmission. However, antibiotic treatment for at least 24 hours usually inhibits the spread of bacteria.
Group B streptococcal infections often spread to newborns through vaginal secretions during childbirth, reports Merck Manual. The transmission of type B streptococcal infection in adults is unknown as of 2015, states the Centers for Disease Control and Prevention. However, group B strep is a common bacteria in the gastrointestinal tract, which may be a contributing factor to the spread of the bacteria.
In order to prevent streptococcal infections, good hand washing is recommended, especially after sneezing and coughing and before preparing food or eating, suggests the Centers for Disease Control and Prevention.