Welcome in H.C.M.
I have gone through your query regarding relapse of throat infection
, infective organism is strep and you are already taking antibiotic.
Here I would like to clear you that correct or most effective antibiotic for throat infection is choosed according to culture and sensitivity of throat swab. This paricular test tells us about the causative organism and a long list of antibiotics with comparative effect, which may be use in this paricular case. Once an antibiotic is given in full course for recomanded duration usually clears the infection but some times erradication of infection is not complete due to emergencr of resistant mutants. Therefore after copletion of course wait for 72 hours and than again repeat the culture , if infection is there that should be treated untill sterile culture is reported.
Probably you got the answer of your query.