Overview Coccobacillus Haemophilus influenzae H. ducreyi Chlamydia trachomatis Bordetella pertussis Pasteurella multocida Brucella spp. Branching filamentous Actinomyces Nocardia (weakly acid fast) Pleomorphic Rickettsiae Chlamydiae (use Giemsa stain) Spiral (spirochetes) Leptospira Borrelia (use Giemsa stain) Treponema No cell wall Mycoplasma