Chla2543

เอกสารประกอบการบรรยายวิชา จุลชีววิทยาทางการแพทยและวิทยา ภูมคุมกัน 2543 เรือ่ ง คลามิดเดีย โดย อาจารยสมชาย แสงอํานาจ เดช MD213

Family: Chlamydiaceae Genus: Chlamydia

Chlamydiae * G (-) bacteria (particles, 200-400 nm or 600-1000 nm) * non-motile (lack of flagella), non-pilated * Obligate intracellular parasites * lack of peptidoglycan in the cell wall * Need host ATP * Stained with Giemsa (poorly stained with Gram’s) * Two forms

Two forms

1. Elementary body (EB)

2. Reticulate body (RB)

* Extracellular

* Intracellular

rigid cell wall; more disulfide cross- * Non-infectious links among major outer mb. * Metabolically active * Infectious (limited metabolic capabilities) * Metabolically inert * Binary fission * diameter; 0.2-0.4 micron * diameter; 0.6-1.0 micron

The Projection and the flower-like structure

The chlamydial developmental cycle

The chlamydial developmental cycle

The chlamydial developmental cycle

RB binary fission

The chlamydial developmental cycle

Chlamydia spp. (differentiate with growth, nucleic acid profile, presence of plasmids, antigen and inclusion morphology.)

1. C. trachomatis 2. C. psittaci 3. C. pneumoniae (originally, TWAR; Taiwan isolates, and acute respiratory isolates)

Characteristics of species of the genus Chlamydia Characteristics

C. trachomatis

C. psittaci C. pneumoniae

1. Inclusion morphology

Oval, vacuolar

Variable, dense

2. EB morphology 3. Folate biosynthesis 4. Glycogen in inclusions

Oval, dense

Round

Round

Pear shaped

Yes

No

No

Presence

Little and do not stain

Absence

Characteristics of species (cont.) Characteristics

C. trachomatis

C. psittaci C. pneumoniae

5. No. of serovars (microimmunofluorsecence test)

12+3

NA

1

6.Sulfonamide sensitivity

Yes

No

No

7. Two 4.4 MDa plasmids 8. Diseases in

Yes, for most strains Mammals?

Yes, for most strains Mammals and avian

No Only human

C. trachomatis 3 biovars; 1.1 TRIC (Trachoma & Inclusion conjunctivitis) 12 serovars (A-K) 1.2 LGV (Lymphogranuloma venereum) 3 serovars (L1-L3) 1.3 MoPn (Murine pneumonitis)

Human diseases caused by Chlamydiae Species, Strains & Serotypes C. psittaci 1. avian strains 2. ovine strains 3. ovine strains

Diseases

1. Ornithosis (Psittacosis) 2. Pneumonia 3. Abortion, Stillbirth

Transmission

Aspiration of bird/animalscontaminated particles (rarely, by direct contact to a pt, or a bite of bird)

Species, Strains & Diseases Serotypes

Transmission

C. trachomatis A, B, Ba, C

Trachoma

D, E, F G, H, I, J, K

Inclusion conjunctivitis (paratrachoma)

direct human contact (fingers), fomite, flies Infants; birth canal infectio Adults; sexual contact, unchlorinated swimming pool

Species, Strains & Diseases Serotypes C. trachomatis

Transmission

D, E, F G, H, I, J, K

Sexual contact

D, E, F G, H, I, J, K D, E, F G, H, I, J, K L, L2, L3

Non-gonorrhea urethritis Post-gonorrhea urethritis Proctitis, Pharyngitis, Cervicitis, Arthritis Lymphogranuloma venereum

Sexual contact Sexual contact Sexual contact

Species, Strains & Diseases Serotypes

Transmission

C. pneumoniae

Human to human (aerosol spread)

Pharyngitis, Pneumonia

Clinical manifestations 1. Ornithosis: * Asymptomatic infection (a transient flu-like illness with malaise, fever, anorexia, rigors, sore throat, severe frontal headache, and photophobia) * Severe illness with typhoidal state, delirium, and even fatal pneumonia. To other organs via blood; meningoencephalitis, arthritis, pericarditis or myocarditis.

2. Chlamydial urethritis and cervicitis * Asymptomatic, in females, the organism may be at cervix (1) infect ascending organs (endometritis, salpingitis, Pelvic inflammatory disease (PID) tubal damage, ectopic pregnancy, infertility) (2) Offspring (3) Partners * Symptoms; muco-purulent discharge, homosexual males have symptoms of rectum; (pain, bleeding, discharge, diarrhea)

3. Inclusion conjunctivitis

(Paratrachoma) * benign, self-limited, suppurative conjunctivitis, but not lead to blindness * inclusions in the exudates are identical with those of trachoma

* in the new born - 5-12 days after birth - swelling of the eyelids, hyperaemia, sticky exudate and conjunctivitis - 2nd bacterial infection blindness

Occular damage or

- untreated, develop pneumonia - May have ear infection, rhinitis (mucopurulent)

4. Trachoma * chronic suppurative eye disease with follicular conjunctivitis * One of the leading global causes of blindness.

Progression of trachoma (5 stages) 1. Medium trachomatis inflammation in the conjunctiva with follicular inflammation 2. Intense inflammation with diffuse thickening of the conjunctiva 3. Scarring of tarsal conjunctiva 4. Inturned eyelashes 5. Corneal opacity

5. Lymphogranuloma venereum (LGV) * males (majority) & females * tropics &subtropics. * begin with a genital ulcer, followed by lymphadenopathy of the regional lymph nodes (enlargement of inguinal and femoral lymph nodes) * females: proctitis; b/c the lymphatic drainage from the vagina is perirectal.

6. Respiratory infection * C. pneumoniae * human to human via aerosol * The 3rd most common pneumonia after Streptococcus pneumoniae & Haemophilus influenzae in North America.

Non-human infections * source of infection to human * important economically * the organism in the dust from the dried bird’s nasal secretions and droppings can survive for months. * sheep droppings, milk, placenta, fleece

Lab. diagnosis 1. Specimen collection Remove exudates or discharges Vigorously swabbing or scraping to obtain columnar epithelial cells immediately Place in a transport medium (4 C) processed within 48 hr, otherwise stored at -70 C (BSA may be added)

2. Tests 2.1 Direct cytopathologic examination * Iodine staining for glycogen-containing inclusions of C. trachomatis. * most useful in dx of neonatal inclusion conjunctivitis (many inclusions are produced), but in adults. * simple, inexpensive, rapid for screening, but poor sensitivity, and unreliable b/c glycogen is present only during certain periods in the growth cycles.

2.2 Antigen detection methods * Direct fluorescent antibody staining (FA) - require experience, not for large no. * Enzyme immunoassays (EIA) - minimal training, automated for large no. of samples, quantitative results. * Monoclonal Ab-based membrane culture-EIA **FA and EIA; sensitivity & specificity equivalent to cell culture

* DNA hybridization technique - probe to chromosomal DNA and plasmids; sensitivities vary, depending on hybridization and probe-labeling conditions, less sensitive than isolation methods. - probe to conserved sequence of rRNA giving high specificity and sensitivity comparable to FA, EIA & culture. * Polymerase chain reaction

2.3 Isolation of Chlamydiae * inoculation into 1) Embryonated eggs (inclusion formed 6-8 days, impractical, tedious, time-consuming, less sensitive) 2) Experimental animals (less sensitive than 1 and 3) 3) Tissue cultures ****most sensitive & specific method for the isolation and identification of Chlamydia. ****Cell lines: McCoy, HeLa229, RBK-21, L929& Buffalo green monkey kidney cells.

2.4. Serological test * Complement-fixation test (CF) - use genus-specific Ag (LPS) - for dx; C. psittaci, C. pneumoniae, LGV strains of C. trachomatis (little value for trachoma & genital infection dx)

* Microimmunofluorescence technique (Micro-IF) - more sensitive than CF - for dx; Ocular & genital infection, method of choice for infantile pneumonia - measure specific Ab (to 15 serovars) - not available widely

Treatment and control Antibiotics: Tetracyclins (Adults), Erythromycin (babies) Penicillin, should not be used b/c it is chlamydiastatic. (improved, but relapsed with pneumonia) CAP eye drop (chlamydiastatic) develop pneumonitis ** Tx at least 7 days (b/c of the prolonged replication cycle) (3 wks recommended, esp. for ascending & complicated genital infection in women.) ** Tx the partner