Survival of streptococcus after my scarlet fever
The Streptococci are a part of the normal human flora.


  The streptococci are widely distributed in nature and frequently form part of the normal human flora (seeTable 29-1). Approximately 5-15% of humans carry S pyogenes or S agalactiae in the nasopharynx. 


Please see:http://www.ncbi.nlm.nih.gov/books/NBK7611/#!po=51.4706 for more details on epidemiology of streptococci.

As 5-15% humans have it in their nasopharynx, it is not really possible to maintain streptococci free environment. It will get repopulated quickly.

Usually the reason you get infected is because of some alteration in your normal flora.


  S pneumoniae and, to a lesser extent, S pyogenes are part of the normal human nasopharyngeal flora. Their numbers are usually limited by competition from the nasopharyngeal microbial ecosystem and by nonspecific host defense mechanisms, but failure of these mechanisms can result in disease. More often disease results from the acquisition of a new strain following alteration of the normal flora. (From the same article, under pathogenesis)


So basically disinfecting wont help much as humans have the streptococci as a part of their normal flora. And it is very likely that the people you live with or come in contact with regularly have the streptococci already in their flora (either they got it from you or they originally had it themselves).