Mesrs. or Messrs.: How To spell?
The word Mesrs. is misspelled against Messrs., which is plural of "Monsieur"
Messrs. has double "ss" is mispronounced as "s"Remember double 'SS' in between the strings me & rs. which should not be misspelled with single 'S'
Wrong Spelling:  me-s-rs.  Correct Spelling:  me-ss-rs. 
Explore spell check of Messrs. to spell without errors.