chlamydia Flashcards
Chlamydia species
Chlamydia trachomatis, Chlamydia psittaci, and Chlamydia pneumoniae.
Chlamydia structure
Gram negative cocci or coccobacilli. Cell wall is atypical (peptidoglycan does not contain N-acetylmuramic acid). Small genome
Chlamydia growth characteristics
obligate intracellular bacteria. Cant synthesize ATP or oxidize NADP (they depend on host cell for energy).
chlamydia visualization
visualized by staining infected cells with Giemsa’s stain. Individual bacteria are not observed, but characteristic intracellular inclusions forming compact masses can be observed near the nucleus. Lugols iodine stains C. trachomatis inclusions brown b/c glycogen matrix
Infectious form of Chlamydia
Elementary bodies are the infectious form- they have a condensed chromosome with electron-dense centers.
Vegetative form of chlamydia
Reticulate bodies- multiply intracellularly
Describe the life cycle of Chlamydia
Binary fission. Biphasic life cycle. Elementary bodies enter cell by endocytosis > Ebs are sequestered in inclusion > Differentiation into reticulate body > RBs develop in membrane bound vacuole via metabolic changes and reorganization of chromosome > RBs replicate for 24-72 hrs via binary fission > RBs reorganize and condense to form new EBs > host cell ruptures and frees EBs which infect other host cells
Chlamydia antigens
LPS is common to all chlamydia. Specific outer membrane proteins (e.g., MOMP, 61 kD, 33 kD, 14 kD) are used to serotype the Chlamydia, and each serotype is associated with a particular disease
chlamydia pathogenosis
Adhesins allow for attachment. Inhibit phagolysosome fusion. May cause latent infection
Transmission of C. trachomatis
direct personal contact among humans (e.g. sexual transmission)
Transmission of C. Psittaci
transmitted to humans by inhalation of bacteria in droplets or dust from birds and fowl
Transmission of C. pneumoniae
transmitted by aerosols from person to person
Chlamydia toxins
A heat-labile toxin is produced by infectious Chlamydia. The toxin is lethal to mice when injected intravenously. The specific role of the toxin in pathogenesis is unknown. Each serotype of Chlamydia produces a specific toxin
Chlamydia latency
C. trachomatis may exist in a latent condition and be reactivated if an individual becomes immunosuppressed
List the diseases caused by C. trachomatis and the serovariant
Serovariant A-C: trachoma, conjunctivitis. D-K: STDs, infant conjunctivitis, and pneumonia. L1-L3: lymphogranuloma venereum.