2 0 ▁M ▁prote ins ▁are ▁identified . ▁These ▁M ▁prote ins ▁are ▁encoded ▁by ▁ 2 3 4 ▁types ▁em m ▁gene ▁with ▁greater ▁than ▁ 1 , 2 0 0 ▁alle les . ▁ ▁L ys ogen y ▁▁ ▁All ▁stra ins ▁of ▁S . ▁py ogen es ▁are ▁poly ly s ogen ized , ▁in ▁that ▁they ▁carry ▁one ▁or ▁more ▁b acter i oph age ▁on ▁their ▁genom es . ▁Some ▁of ▁the ▁' ph ages ▁may ▁be ▁defect ive , ▁but ▁in ▁some ▁cases ▁active ▁' ph age ▁may ▁compens ate ▁for ▁defect s ▁in ▁others . ▁In ▁general , ▁the ▁gen ome ▁of ▁S . ▁py ogen es ▁stra ins ▁isolated ▁during ▁disease ▁are ▁> 9 0 % ▁identical , ▁they ▁differ ▁by ▁the ▁' ph age ▁they ▁carry . ▁ ▁Vir ul ence ▁factors ▁▁ ▁S . ▁py ogen es ▁has ▁several ▁vir ul ence ▁factors ▁that ▁enable ▁it ▁to ▁attach ▁to ▁host ▁t issues , ▁e va de ▁the ▁imm une ▁response , ▁and ▁spread ▁by ▁pen etr ating ▁host ▁t issue ▁layers . ▁ ▁A ▁car bo h yd rate - based ▁b acter ial ▁caps ule ▁composed ▁of ▁h yal ur onic ▁acid ▁surr ounds ▁the ▁b acter ium , ▁protect ing ▁it ▁from ▁ph ag oc yt osis ▁by ▁neut roph ils . ▁In ▁addition , ▁the ▁caps ule ▁and ▁several ▁factors ▁embedded ▁in ▁the ▁cell ▁wall , ▁including ▁M ▁protein , ▁lip ote ich o ic ▁acid , ▁and ▁protein ▁F