Insights into the Biology, Infections and Laboratory Diagnosis of Chlamydia

Chlamydia are Gram negative obligate intracellular bacteria of eukaryotic cells and have a unique developmental cycle consisting of formation of infectious particle called elementary body and non-infectious particle called reticulate body. They are included in the order Chlamydiales and the order Chlamydiales belongs to the class Chlamydiae, phylum Chlamydiae, domain bacteria. The genus Chlamydia consists of important species C. muridarum, (affects only mice and hamsters) C. suis (affects only swine) and C. trachomatis (a human pathogen). Chlamydia are Gram-negative obligate intracellular eubacteria. Originally, they were taxonomically categorized into their own order Chlamydiales, with one family, Chlamydiaceae, and a single genus, Chlamydia.1 The genus included four species: C. trachomatis, C. psittaci ,C. pneumoniae and C. pecorum .In 1999, it was proposed by Everett et al 2 that Chlamydia should be divided in two genera, Chlamydia and Chlamydophila, containing altogether nine species (Table 1) in addition to the five new species and three new families (Parachlamydiaceae,