Chlamydia Filename: Chlamydia.ppt 1 4/13/2015 Chlamydia 2 4/13/2015 Chlamydia Obligate intracellular coccoid parasites contain DNA and RNA, and ribosomes lack ATP, biosynthetic pathways cell wall but peptidoglycan absent – use disulfide bonds 3 non motile 4/13/2015 Obligate Parasites Obligate intracellular parasites of mammals and birds – not transmitted by arthropods. – incorrectly called the PLT viruses or Bedsonia or basophilic viruses, Multiply in the cytoplasm of the host cell. – generally epithelial cells – Basophilic inclusions 4 4/13/2015 Similar to Viral Infections The methods used to study Chlamydia are those of the virologist rather than the bacteriologist. The clinical features, pathogenesis, pathology and epidemiology of chlamydial infections are similar to those of viral infections. 5 4/13/2015 Energy Parasites The cells can synthesize DNA, RNA and protein. No flavoproteins or cytochromes. lack of ATP-generating ability need to obtain ATP from the host cell. 6 4/13/2015 Three species: C. trachomatis C. psittaci C. pneumoniae 7 4/13/2015 Ecology Chlamydia form two main ecological groups. Infect only humans – Subgroup A – trachoma, inclusion conjunctivitis, and lymphogranuloma venereum Zoonotic Infections – Subgroup B – Respiratory tract infections 8 4/13/2015 Zoonotic Infections transmitted to man About 100 species of birds are naturally infected with chlamydia. – 71 species of parrots – finches, pigeons, chickens, ducks, turkeys and seabirds. 9 4/13/2015 C trachomatis Trachoma conjunctivitis proctitis urethritis salpingitis Lymphogranuloma venereum C psittaci & C pneumoniae Upper respiratory infection Bronchitis Pneumonia 10 4/13/2015 Chlamydial Morphologies Elementary body – 0.25 - 0.3 um diameter – electron-dense nucleoid – Released from ruptured infected cells. Human to human – & bird to human. Reticulate Body – Intracytoplasmic form 0.5 - 1.0 um – Replication and growth. ( Inclusion body ) – without a dense center. 11 4/13/2015 Developmental Cycle of Chlamydia 12 4/13/2015 13 C trachomatis elementary bodies 4/13/2015 C trachomatis inclusions Glycogen Inclusions 14 4/13/2015 Subgroups Subgroup A Mammalian parasites Compact inclusions Glycogen synthesized Folates synthesized – Sensitive to D-cycloserine 15 Restricted host range Chlamydia trachomatis Subgroup B Primarily bird parasites Diffuse inclusions Glycogen not synthesized Folates not synthesized – Resistant to D-cycloserine Broadening of host range Chlamydia psittaci 4/13/2015 Evolution of Chlamydia Gram-negative cocci Facultative intracellular parasites of mammals Obligate intracellular parasites Host range restricted to rodents Restricted virulence (compact inclusions) Folates synthesized (sulfonamide susceptible) Glycogen synthesized and deposited in inclusions 16 4/13/2015 Conjunctivitis Inclusion conjunctivitis: – Transmitted by infectious secretions of the genitourinary tract – autoinoculation Infantile conjunctivitis: – Acquired in the birth canal -- 5-12 days after birth – most common type of conjunctivitis 17 Antibiotic prophylaxis: erythromycin, tetracycline. 4/13/2015 Chlamydial Infection of Ocular Conjunctiva 18 4/13/2015 Trachoma infection of conjunctival epithelial cells. – subepithelial infiltration of lymphocytes. – Infected epithelial cells contain cytoplasmic inclusion bodies – Cell infiltrations to cornea cause clouding 19 Trichiasis: abnormal inward growth of eyelashes. 4/13/2015 Predisposing factors: climate - hot , dry shortage of water standards of hygiene low Transmitted by flies, dirty towels, fingers, cosmetic eye pencils. Initial infection in childhood mostly by 1015 years of age. 20 4/13/2015 Trachoma 21 Almost six million people have become blind and another 540 million almost 10% of the world’s population are at risk 4/13/2015 Trachoma Incidence 22 4/13/2015 Chlamydia trachomatis Clinical disease lymphogranuloma venereum nongonoccal urethritis (NGU) epididymitis salpingitis mucopurulent cervicitis pelvic inflammatory disease (PID) Reiter's syndrome neonatal chlamydia 23 4/13/2015 Chlamydia: Rates by Gender 24 4/13/2015 Chlamydia Symptoms In Men 25 Symptoms usually appear between 7 and 28 days after infection, usually with mild burning when urinating, a more frequent need to urinate, and a white discharge from the penis. Occasionally, blood may appear in the urine. The symptoms occur most frequently in the morning. 4/13/2015 Erythematous meatus and urethra with balanitis Hyperlink to original 26 4/13/2015 Chlamydial Urethritis in Males 27 4/13/2015 Nongonococcal urethritis (NGU) Reiter's syndrome Swollen, painful right knee in which needle aspiration for synovial fluid was performed (yellow discoloration from the betadine prep) Hyperlink to original site 28 4/13/2015 Lymphogranuloma venereum LGV 200 reported cases per year. Incubation period is 5 to 20 days. Lesion: Transient vesicles on penis or vagina that are often unnoticed and patients do not usually seek medical advice. 29 4/13/2015 Bilateral inguinal adenopathy with overlying erythema 30Roberts MD R 4/13/2015 LGY: "Groove sign" Pompart's ligament is preserved despite the involvement of multiple inguinal nodes R Roberts MD 31 4/13/2015 LGV: Microscopy lymph node shows both necrosis and granulomatous reaction (dimorphic necrotizing granulomatous reaction) R Roberts MD 32 4/13/2015 Chlamydia pneumoniae This bacterium was first recognized in 1983 as a respiratory pathogen, after isolation from a college student with pharyngitis. Pneumonia or bronchitis, gradual onset of cough with little or no fever. Less common presentations are pharyngitis, laryngitis, and sinusitis. 33 4/13/2015 Incidence 34 Each year an estimated 50,000 adults are hospitalized with pneumonia in the United States. The overall incidence is unknown. 4/13/2015 35 4/13/2015 Transmission Person-to-person transmission by respiratory secretions. Risk Groups All ages at risk but most common in schoolage children. By age 20 years, 50% of population have evidence of past infection. Reinfection throughout life appears to be common. 36 4/13/2015 C. pneumoniae Associations Associated with Heart Disease infection may be associated with – atherosclerotic vascular disease Proposed Associations – Alzheimer's diseases, asthma, and reactive arthritis 37 4/13/2015 Treatment Chlamydia 38 Adults Conjunctival, urethral, cervical, rectal: – Azithromycin 1 gm x 1 dose – Doxycycline 100 mg BID for 7 days – Ofloxacin 300 mg po BID for 7 days – Erythromycin 500 mg QID for 7 days – Amoxacillin 500 mg TID 7-10 days Children < 45 kg, urogenital & rectal: – erythromycin 50 mg/kg/day in 4 doses for 10-14 days Neonates (ophthalmia, infants born to infected mothers): – erthromycin 50 mg/kg/day in 4 doses for 10-14 days 4/13/2015 Chlamydia Antigens Antigens: group specific & species specific Major outer membrane protein (cysteine-rich) Eucaryotic cell binding protein Host response: damage to specific tissues 39 4/13/2015 Laboratory Diagnosis Isolate the organism from infected tissue. – Inoculate the yolk sac of seven-day chick embryos – Inoculate McCoy human cells. 40 Characteristic cytoplasmic inclusion bodies in infected cells. 4/13/2015 Immunofluorecent tests Microimmunofluorescent tests – patients with eye infections – Check tears for the presence of antichlamydia antibody. Direct immunofluorescence – of conjunctive cells with fluorescein conjugated monoclonal antibody is sensitive and specific. – In neonatal conjunctivitis and early trachoma 41 4/13/2015 Serological diagnosis: Immunofluorecent tests Delayed Type Skin Reaction Antibodies to Family antigen 42 4/13/2015 FREI Test 43 Delayed-type skin reaction to killed organisms in genitourinary infections 4/13/2015 Antibodies to Family antigen Rising titer of antibody against the chlamydial family antigen in lung infections. – Complement fixation test – Fluorescent antibody test. 44 4/13/2015 DONE!!! 45 4/13/2015