Clostridia Spore bearing, obligate anaerobes and gram positive organisms. Reside normally in GI tract; although they have the propensity to cause fulminant bacteremia, but it is rare. In this question, pt. is well after an acute episode of illness; rules out fulminant course. So, a transient self-limited bacteraemia due to transient gut translocation could occur mostly during an episode of gastroenteritis and doesn't require treatment and fuher workup. So, among the given options returning for penicillin therapy is the best answer.