Chlamydia

Bacteriology CHLAMYDIA GENERAL CHARACTERISTICS 1. Obligate intracellular bacterial parasite infecting birds, mammals, and humans 2. Two distinct species a. Chlamydia trachomatis i. Inhibited by sulfonamides ii. Demonstrates iodine-staining inclusions b. Chlamydia psittaci i. Not inhibited by sulfonamides ii. Lacks iodine-staining cytoplasmic inclusions 3. Human diseases caused by chlamydia a. Trachoma b. Inclusion conjunctivitis c. Lymphogranuloma venereum (LGV) d. Psittacosis 4. Developmental cycle-3 major stages a. Attachment and penetration of elementary body into host cell cytoplasm b. Development of elementary body with reticulate body c. Formation of elementary body progeny; maturation of reticulate body Laboratory identification a. All chlamydia infect chick embryo b. Tissue cell culture lines i. McCoy cells ii. Hela cells c. Infection in mice except causative agents of trachoma and inclusion conjunctivitis Antigenic structure a. Group-specific antigen, associated with cell wall, detects by complement-fixation testing b. Species-specific and stain-specific antigens c. Elementary body outer membrane protein d. Frei test i. Intradermal skin test for lGV using Iygranum antigen from infected chick embryo yolk sac material ii. Examine 48-72 hours after injection for formation of subcutaneous nodule iii. Not specific for lGV, and less sensitive than complement fixation test e. 19 or more antigenic types based on immunofluorescence i. Types A, B, and C, from patient's eyes with trachoma in trachoma endemic locations ii.Types D through M, from patient's eyes from non-endemic trachoma areas and adult genital tracts CHLAMYDIA TRACHOMATIS 1. Develop glycogen-containing microcolonies or inclusions called Halberstadter-Prowazek bodies 2. Ocular trachoma a. Leading cause of blindness in underdeveloped world b. In U.S. occurs most frequently in American Indians c. 4 major stages of disease i. Stage I, incipient trachoma (a) Relatively asymptomatic (b) Keratitis may be present ii. Stage II, establishes trachoma (a) Papillary and follicular hypertrophy

(b) Corneal infiltration, pannus iii. Stage III, cicatricial complications (a) Conjunctival scarring (b) Trichiasis, entropion, pannus iv. Stage IV, healed trachoma (a) No active inflammation (b) May be asymptomatic d. Protedive immunity to repeated infections poor e. Diagnosis by microimmunofluorescence of type-specific antibody or visualization of inclusions by Giemsa stain f. Treatment and prevention i. Topical or systemic antibiotics to limit complications and bacterial superinfection (e.g.,tetracycl i nes) ii. Systemic vaccine may exacerbate disease 3. Inclusion conjunctivitis, genital trachoma a. Infantile i. Associated with maternal genital infection ii. Symptoms occur within first week of birth b. Neonatal pneumonia i. Become ill with pneumonitis 4-16 weeks after birth ii. Conjunctivitis may precede ii. Eosinophilia common c. Adult disease i. Usually sporadic but epidemic in persons swimming in unchlorinated swimming pools ii. Ocular disease often associated with genital disease iii. Genital infection in males accounts for 20% of nongonococcal urethritis iv. Causes chronic cervicitis and urethritis in women 4. lymphogranuloma venereum (LGV) a. More common in males, blacks b. Organisms cause death when infected intracerebrally in mice c. Three antigenic types-I, II, III d. Venereal disease of which humans are only known host e. 1-4 week incubation period, culminating in headache, myalgia, and fever f. Primary lesion painless, vesicular, small g. Large, matted, painful, inguinal and femoral lymph nodes h. Women may experience elephantiasis of vulva (esthiomene) i. Other manifestations i. Diarrhea, tenesmus, abdominal pain ii. Rectal stricture, perforation j. Laboratory findings i. Hyperglobulinemia ii. Positive rheumatoid factor and cryoglobulins Diagnosis i. Compatible clinical findings ii. Isolation of organism-most definitive iii. Rising LGV-complement fixation test iv. Reactive intradermal Frei test Treatment i. Sulfadiazine ii. Tetracycline iii. Penicillin

CHLAMYDIA PSITTACI 1. Develop severe febrile disease, named according to transmitting animal a. Psittacosis, disease transmitted from psittacine birds (parrots, parakeets) b. Ornithosis, disease transmitted from nonpsittacine birds 2. Intracellular microcolonies a. Do not stain with iodine b. Inclusions called LCL (Leventhal-Cole-Lillie) bodies, staining with Giemsa c. Development of inclusives not inhibited by sulfadiazine or cycloserine 3. Epidemiology a. Occurs more often in autumn b. May be transmitted by inhalation of organisms from infected birds and their droppings and humans i. Parrots, parakeets ii. Turkeys, ducks, chickens iii. Pigeons, wild birds c. Infected animals may range from asymptomatic carriers to clinically ill 4. Clinical manifestations a. Clinical severity varies; may resemble influenza with initial constitutional symptoms b. Pulmonary symptoms i. Nonproductive cough, rales, consolidation ii. May recur if untreated iii. Chest x-ray suggests "atypical pneumonia" or bronchopneumonia c. CNS manifestations i. Severe frontal headache ii. Toxic encephalitis may occur leading to death d. Other less common manifestations i. Subacute bacterial endocarditis ii. Hepatitis iii. Erythema nodosum iv. Carditis v. Follicular keratoconjunctivitis vi. Biologic false positive VDRL 5. Treatment a. Tetracycline b. Erythromycin