Is serratia marcescens as serious as what im reading online? my throat culture came back with that. after a week on antibiotic, my throat is still hurting just as much as it was 2 months ago. could this bacteria be the cause?

Serratia marcescens isn't a common growth when throat culture is done but it's still possible. These bacteria can often be treated with oral antibiotic(s) unless you get the resistant bug which can be identified by the antibiogram with that throat culture. If the bacteria is sensitive to the prescribed antibiotic but you throat condition isn't improved then re-evaluation is recommended. Take care.