The bacteria that causes strep throat also causes group-A strep. In extremely rare instances, it can result in a secondary infection like flesh-eating disease, though the majority of cases are not as severe. Swelling, redness, a bad odour, fever, and swelling are symptoms to watch out for. The doctor explained that a type of bacteria known as group A Streptococcus (group A strep) can result in numerous infections. According to the CDC, these infections range from minor illnesses to very serious and fatal diseases.