Question | Answer |
Characteristics of both Chlamydia and Rickettsia | They both use ATP |
Chlamydia trachomatis | Obilgate intracellular parasite. Require the biochemical resources of eukaryotic host cell to growth and replicate |
What is the characteristic inclusion of Chlamydia trachomatis? | Reticulate bodies RB - replicative form |
What is the infective form of inclusion bodies? | Elementary bodies - look like a bacillus. They are extracellular and inert |
Developmental cycle of Chlamydia trachomatis | The Ebs bind cells and are phagocytized. In the cell Ebs become RBs. RBs replicate and inclusion may contain 100-500 bodies |
What is the outer layer of the Chlamydia trachomatis cell wall? | lipopolysaccharide membrane - no peptidoglycan |
Lab diagnosis of Chlamydia trachomatis | cytology - detect inclusions in epithelial cells and fluorescent antibody techniques/ Cell cultures of McCoy cells/ NAATs (most common)/ Serology |
What are serovars? | serological variants, equivalent to serotypes |
Subtypes A, B, Ba, C of Chlamydia trachomatis | cause Trachoma - inflammation of conjunctiva --> blindness |
Subtypes L1, L2, L3 of Chlamydia trachomatis | cause Lymphogranuloma venereum a sexually transmitted disease |
Subtypes D-K of Chlamydia trachomatis | cause Urethritis, infant pneumonia |
Most common STD? | C.trachomatis - also major cause of PID |
Natural habitat for C.trachomatis | humans: 25% men and 70-80% women |
Transmission of C. trachomatis | sex or mother to infant during birth |
Diagnosis of C. trachomatis | Cell cultures, DFA, EIA, NAAT |
What is DFA? | scraping that is examined microscopically with a direst fluorescent test to detect inclusion bodies |
Chlamydophila psittaci | Infects birds and infect humans by aerosol inhalation. Chills, fever, malaise and progression to pneumonia |
Chlamydophila pneumoniae | Human pathogen causes pneumonia, sinusitis, and pharyngitis. |
Rickettsia | Obligate, intracellular parasite. Infect endothelial cells lining small blood vessels. Multiply intracellularly. Can synthesize protein, nucleic acids and ATP. Have "leaky membranes" |
Morphology of Rickettsia | Gram negative, pleomorphic |
Transmission of Rickettsia | Vectors: fleas, ticks, and the human body louse. |
Diagnosis of Rickettsia | Weil-Felix test - Whole cell agglutination assay that uses Proteus cell surface antigens to detect cross-reactive rickettsial antibodies. |
where can Rickettsia be grown? | Tissue cells and embroyonated eggs - level 3 pathogen |
R.rickettsii infection: | Rocky Mountain Spotted fever. From tick vector. Maculopapular rash beginning on extremities. Use immunohistology with tissue biospies and fluorescent stain or PCR |
Orentia tsutsugmushi infection: | Scrub typhus |
Drug of choice for Rickettsial Infections | Tetracycline or Chloramphenicol |
Triad of Rickettsial Infections | fever. headache, and rash |
R.prowazekii | typhus - from human body louse. Rash develops |
Coxiella burnetti | Q fever - inhalation or ingestion of unpasteurized milk. Detected with serology. Gram negative coccobaccilli. obligate intracellular parasite. Forms spores to survive. |
Dichlorodiphenyltrichloroethane, DDT | Was effective in WWII against the mosquito that spread malaria and lice with typhus. |
Brill-Zinsser Disease | occurs decades after initial Rickettsial Infection, treat with tetracycline |
Q Fever | systemic infection that primarily affects the lung-granuloma formation. Occupational illness. treat with tetracycline |
Ehrlichia chaffeensis | Zoonotic disease. from ticks. Cause monocytes infection |
Morulae | cytoplasmic vacuoles containing enriched Ehrlichia that are found in Giemsa - or Diff-Quikâstained buffy coat smears from infected patients. |
Anaplasma phagocytophilum | causes human granulocytic anaplasmosis |
Similarities of Ehrlichia chaffeensis and Anaplasma phagocytophilum | infect leukocytes. ID'd by serology. Treated with Doxycycline |