Leptospira spp.

Leptospira spp.

Leptospira are spiral-shaped, right-handed helix with hooked ends. One medically important species is L. interrogans which causes human leptospirosis.

Borrelia

Borrelia

Borrelia is gram-negative spirochetes, measuring around 3-30 μm x 0.2-0.5 μm. Lyme’s disease is caused by B. burgadorferi (transmitted by hard-shelled tick).

Coxiella burnetii

Coxiella burnetii

Coxiella burnetii is poorly Gram-stained so stained with Giemsa stain. It causes Q fever, an acute system infection primarily affects the lungs and is zoonotic.

Rickettsia rickettsii

Rickettsia rickettsii

Rickettsia rickettsii is a gram-negative, obligate intracellular bacillus that is non-sporing, non-motile, non-capsulated, aerobic.

Rickettsia prowazekii

Rickettsia prowazekii

Rickettsia prowazekii is the causative agent of epidemic/louse-borne typhus and relapsing louse-borne typhus. It infects vascular endothelial cells, producing widespread vasculitis.

Mycoplasma pneumoniae

Mycoplasma pneumoniae

Mycoplasma pneumoniae causes respiratory tract diseases- primary atypical pneumonia or walking pneumonia. It can also cause pericarditis, hemolytic anemia, arthritis, nephritis, Bell’s palsy, and meningoencephalitis.

Mycobacterium tuberculosis

Mycobacterium tuberculosis

Mycobacterium tuberculosis causes tuberculosis (TB) which was one of the most infectious diseases in human history. They are obligate aerobes and infect lungs and were first identified by Robert Koch in 1882.

Chlamydia trachomatis

Chlamydia trachomatis

Chlamydia trachomatis is a gram-negative bacterium that causes chlamydia, a common sexually transmitted infection (STI).

Treponema pallidum

Treponema pallidum

Treponema pallidum, the causative agent of Syphilis, is transmitted congenitally (placenta), contact with an active lesion, infected blood transfusion but is mostly transmitted by sexual contact with infected lesions.