high ASO titre tells that you had streptococcal infection
in the past , its level more than 200 unit per ml in adults is concerned significant and it is used to direct antibiotics addministration.it can de due to rheumatic fever
, scarlet fever
or even other infection of strepto.your arthritis
can be the a result of rheumatic fever by this bacteria, for this anntibiotic is advisable for the prevention of any further complication caused by this bacteria. so you must follow your doctor and should continue your treatment.
i think i have answered you completelt.
thanks for consulting HCM