Complex sentence: Antibiotic resistance in gonorrhea has been noted by beginning in the 1940s, when gonorrhea was treated with penicillin, but doses had to be progressively increased in order to remain effective.
Split into simpler sentences: Antibiotic resistance in gonorrhea has been noted beginning in the 1940s. Gonorrhea was treated with penicillin, but doses had to be progressively increased in order to remain effective.