VMC 311: Systematic Veterinary Bacteriology and Mycology (2+1)

SYSTEMATICS

Domain	Bacteria
Phylum	Chlamydiae
Class	Chlamydiae
Order	Chlamydiales
Family	Chlamydiaceae
Genus	Chlamydia Chlamydophila

• Chlamydia are derived from the characteristic appearance of the inclusion bodies produced by these agents, which are seen close to the nuclei of infected cells as a cloak or mantle (chlamys meaning mantle).
• Chlamydiae are obligate intra cellular parasites, filterable, requiring living system for multiplication.
• They differ from viruses in
  • They possess cell wall, resembling Gram-negative bacteria but lacking muramic acid
  • Do not have an eclipse phase following an infection.
  • Produce basophilic intracytoplasmic inclusion bodies in infected cells (Hence, referred as basophilic virus).
  • Pocesses both DNA and RNA
  • Multiply by binary fission.
  • Sensitive to antibiotics.
• Therefore, they occupy a position intermediate between rickettsia and viruses.
  • Chlamydiae are more dependant on host cell for high energy compounds such as ATP. Hence, they are called as energy parsites.
  • C.psittaci causes variety of infections in animals such as gastritis, diarrhoea, pneumonia, enzootic abortion in ewes, abortion, orchitis, epididymitis, seminal vesiculitis, feline pneumonitis, sporadic bovine encephalomyelitis (BUSS disease), conjuctivitis, rhinitis, hepatitis, and polyserositis and poly arthritis.
  • Chlamydia infection in psittacine birds such as parrots called as psittacosis and this infection in non-psittacine birds such as pigeons, sparrows, turkey and domestic poultry called as ornithosis.