 bacteria called group a streptococcus can cause many different infections invasive group a strep igas infections include necrotizing fasciitis and streptococcal toxic shock syndrome the most common igas outbreaks investigated in the united states are those occurring in long term care ltc facilities healthcare associated igas clusters can also involve postpartum and post surgical infections gas is spread by respiratory droplets direct contact with mucus or secretions of an infected person or by contact with infected or colonized wounds outbreaks and clusters of healthcare associated igas often require urgent public health action even a single case of igas usually warrants investigation and follow up to rule out a larger problem 