Streptococi or Streptococci: How To spell?
The word Streptococi is misspelled against Streptococci, which is plural of "Streptococcus"
Streptococci has double "cc" is mispronounced as "c"Remember double 'CC' in between the strings Streptoco & i which should not be misspelled with single 'C'
Wrong Spelling:  Streptoco-c-i  Correct Spelling:  Streptoco-cc-i 
Find more incorrect spellings of Streptococci to spell right way.