Complex sentence: Chlamydophila abortus was previously classified as Chlamydia psittaci along with all chlamydiae except Chlamydia trachomatis, based on a lack of evident glycogen production and on resistance to the antibiotic sulfadiazine.
Split into simpler sentences: Chlamydophila abortus was previously classified as Chlamydia psittaci along with all chlamydiae except Chlamydia trachomatis. This was based on a lack of evident glycogen production and on resistance to the antibiotic sulfadiazine.