CHLAMYDIAE

 

INTRODUCTION:  These organisms belong to the order Chlamydiale which contains one family Chlamydiaceae.  The family comprises of one genus Chlamydia in which three species have been recognised.  These are C. trachomatis, C. psittaci and C. pneumoniae.  It comprises of the strains which were earlier designated as TWAR strains.  The acronym TWAR was derived from initial letters of the designation of early isolates from Taiwan (TW) and acute respiratory (AR) infection.  Respiratory tract infections

MORPHOLOGY:  Chlamydiae exist in two forms known as reticulate body (RB) which was earlier known as initial body and the elementary body (EB).  The RB is the noninfective vegetative form which is rich in ribosomes.  The reticulate body of C. trachomatis gives basophillic appearance when stained with Giemsa.

PATHOGENESIS AND IMMUNITY:  Chlamydiae do not produce demonstrable exotoxin. The cell envelope of these organisms, though similar to other gram-negative bacteria does not possess endotoxic activities. But they do have several properties of significance in pathogenesis, one of which is toxicity of live elementary body preparation. Hypersensitivity has also been incriminated as playing an important role in influencing clinical severity of infection. Individuals who had prior exposure to chlamydial antigen, on reinfection show severe clinical symptoms.

RELATED;

1.  PATHOGENESIS OF MICROBES

2.  BACTERIOLOGY

2.  MEDICAL MICROBIOLOGY