In a syphilis patient, site which does not help in isolation of organism:-
T. pallidum is very difficult to demonstrate in Gumma (Teiary syphilis). Infectivity of a patient to the sexual paner is maximum during primary, secondary and early latent stage. During these stages spirochetes are abundant in the lesions.
Gumma
Primary chancre
Mucosal patch
Maculopapular rash
Systemic Bacteriology (Haemophilus, Yersinia, Spirochaetes, Ricketssia, Chlamydia, Mycoplasma and Miscellaneous Bacteria)