In situ identification of C. pneumoniae in HeLa 229 cells by FISH using Cy5-labeled probe Cpn-974, specific for C. pneumoniae (A) (showing an infra-red fluorescence, assigned to blue color); FLUOS-labeled probe Chlae-574, which targets all members of the family Chlamydiaceae (B) (green); and Cy3-labeled probe Chls-523, which hybridizes to all chlamydiae and chlamydia-like bacteria (C) (red). (D) Due to the overlap of colors, the chlamydial inclusions, which bound all three probes, appear white in the composite image. Bar, 10 μm.