Under a low magnification of 12.5X, this photomicrograph reveals a McCoy cell monolayer culture, and that some of the cells exhibited Chlamydia trachomatis inclusion bodies. The intracellular inclusion body represents the replication phase of the Chlamydia spp. organisms, whereupon, the reorganized reticulate body (RB) multiplies through binary fission into 100-500 new RBs, which mature into elementary bodies (EB). Chlamydia, caused by Chlamydia trachomatis, is the most common bacterial sexually transmitted infection. Using cell cultures from the McCoy cell line is one methods implemented in diagnosing Chlamydia infections.