Chlamydiaceae 2 genera 1 Chlamydia 1 2 Chlamydia

Chlamydiaceae

2 genera 1. Chlamydia 1. 2. Chlamydia trachomatis Chlamydophila 1. 2. Chlamydophila psittaci Chlamydophila pneumoniae

Chlamydiaceae n Small enough to pass through 0. 45 mm filters n Obligate intacellular parasites Are they viruses?

They are bacteria. . : Possess inner and outer membranes (as Gram- negative bacteria) Cell wall + n DNA & RNA n Prokaryotic ribosomes n Synthesize their own proteins, nucleic acids, lipids n Susceptible to numerous antibacterial antibiotics n Cell wall but no peptidoglycan!! n

Chlamydiaceae/ Physiology & structure n Exist in morphologically distinct forms Elementary body 1. n n n infectious Resistant to harsh environmental conditions No replication in this form Reticulate body 2. n n n Noninfectious Metabolically active fragile

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Cell wall n The major outer membrane protein (MOMP) q n Different for each species. Variable regions in the gene encoding this protein are found in C. trachomatis and are responsible for serologic variants (called serovars-serotypes).

Chlamydia trachomatis biovars exist n 1. 2. Trachoma LGV (lymphogranuloma venereum) These have been further divided into 19 serotypes q Trachoma: A, B, Ba, C, D, Da, E, F, G, Ga, H, I, Ia, J, K q LGV: L 1, L 2 a, an L 3

Chlamydia trachomatis/ Diseases n n n Trachoma Adult inclusion conjunctivitis Neonatal conjunctivitis Infant pneumonia Ocular lymphogranuloma venereum Urogenital infections q n Urethritis, cervicitis, endometritis, salpingitis, . . Lymphogranuloma venereum

Epidemiology n n n Most common sexually transmitted bacteria in United States Ocular trachoma primarily in North and sub. Sahara Africa, the Middle East, southern Asia, South America LGV highly prevalent in Africa, Asia, and South America

Chlamydia trachomatis/pathogenesis & immunity n Infects nonciliated, cuboidal or transitional epithelial cells in Mucous membranes of the urethra, endocervix, endometrium, fallopian tubes, anorectum, respiratory tract, conjunctivae

Chlamydia trachomatis/epidemiology Pulmonary infection n in newborns n a diffuse interstitial pneumonia in 20 % 10 -

Chlamydia trachomatis/ epidemiology “C. trachomatis is thought to be the most n common sexually transmitted disease in US” 4 million new cases /year, 50 million new cases/year, worldwide n most with serotypes D-K with N. gonorrhoeae, most common cause of epididymitis in sex. act. men n 15% of the cases of proctitis in ½ men

Chlamydia trachomatis/epidemiology LGV n is a chronic STD n C. trachomatis serotypes L 1, L 2 a, L 3 n sporadic in N. America, Australia, Europe n highly prevalent in Africa, Asia, S. America n in US, male homos. being the major reservoir

Chlamydia trachomatis/Clinical Diseases n n Trachoma serovars A, B, Ba, C follicular conjunctivitis scarred conjunctiva eyelids turn inward in-turned eyelashes abrade corneal ulceration, scarring, pannus formation LOSS OF VISION

Chlamydia trachomatis/Clinical Diseases n n n Urogenital infections I most GTI in women are asymptomatic 80 % may become symptomatic clinical manifestations: q n cervicitis, endometritis, urethritis, salpingitis, bartholinitis, perihepatitis A mucopurulant discharge and hypertrophic ectopy are seen in symptomatic patients

Chlamydia trachomatis/Clinical Diseases n n n Urogenital infections II most genital infections in men are symptomatic ( 75%) 35 -50 % NGU are caused by Ct dual infections with N. gonorrhoeae not uncommon

Chlamydia trachomatis/Clinical Diseases Urogenital infections III Reiter’s syndrome n urethritis, conjunctivitis, polyarthritis, and mucocutaneous lesions n caused by Chlamydia trachomatis !! ? ?

Chlamydia trachomatis/Clinical Diseases Lymphogranuloma venereum n n 1 -4 weeks of incubation primary lesion q q n penis, urethra, glans, scrotum, vaginal wall, cervix, vulva often overlooked: small, “painless”, heals rapidly secondary stage q q q inflammation and swelling of the lymph nodes inguinal nodes, most commonly involved buboes

Chlamydia trachomatis/Laboratory diagnosis n symptomatic infections are easier to n n n diagnose than asymp. infc. the quality of the specimen is important intracellular bacteria a specimen of pus or urethral exudate is inadequate ( 30 % of specimens submitted for study in patients with suspected Chlamydia infection are inappropriate)

Diagnosis n Molecular amplification tests are the most sensitive and specific tests currently available

Chlamydia trachomatis/Laboratory diagnosis Serology q detection of specific Ig. M antibodies in infants with chlamydial pneumonitis

Chlamydia trachomatis/Laboratory diagnosis Serology n can be helpful in the diagnosis of LGV

Chlamydia trachomatis/Prevention & Control n Prevention difficult population with endemic disease (limited access to medical care) n Chlamydia conjunctivitis and genital infections safe sexual practices

Chlamydophila pneumoniae n First isolation from the conjunctiva of a child in Taiwan TW-183 (related to AR 39) TWAR Chlamydia pneumoniae Chlamydophila

Chlamydophila pneumoniae/Epidemiology n It’s a human pathogen n n important cause of bronchitis, pneumonia, and sinusitis transmission: person-to-person by respiratory secretions common: 200 000 -300 000 cases annually >50 % of people have serologic evidence of past infections

Chlamydophila pneumoniae/Clinical Diseases most infections are asymptomatic or mild n persistent cough and malaise n cannot be differentiated from other atypical pneumonias n Is there a role of C. pneumoniae in the pathogenesis of atherosclerosis ? n

Chlamydophila pneumoniae/Laboratory diagnosis n n NA techniques serology!!

Chlamydophila psittaci n n n The cause of psittacosis “parrot fever” (psittakos is “parrot” in Greek) The natural reservoir is any species of bird q Ornithosis, ornithos= bird

Chlamydophila psittaci/epidemiology n Infection in: q n n Humans, sheep, cows, goats In: blood, tissues, feces and feathers of infected birds Infection occurs by means of the respiratory tract (RES of the liver & spleen blood)

Chlamydophila psittaci/epidemiology n Transmission: q q Inhalation of dried bird excrement, urine or respiratory secretions “Most infections result from exposure to psittacine birds” (parrots (a tropical bird with a curved beak, which is often kept as a pet and can be trained to copy the human , parakeetsa small parrot with a long tail, macaws(a brightly coloured bird of the parrot family found in Central and South America), cockatiels) voice)

Chlamydophila psittaci/epidemiology n Person-to-person transmission is rare q Veterinarians, q Zookeepers q Pet shop workers q Employee of poultryprocessing plants “are @ increased risk”

Chlamydophila psittaci/clinical disease n Incubation: 5 -14 days n n Pulmonary signs CNS involvement is common (death may occur) GIT symptoms. . .

Chlamydophila psittaci/Laboratory diagnosis n n Based on serologic findings: antibody detection Species specific MIF test

Chlamydophila psittaci/Prevention and control n n Psittacosis can only be prevented through the control of infections in domestic and imported pet birds No vaccine!