Chapter 46: Chlamydia and Chlamydophila

CHLAMYDIA PSITTACI

Causes ORNITHOSIS-disease of bird that can be transmitted to humans Usually causes flulike symptoms Rarely nonrespiratory conditions are observed Individuals who handle animals are at the greatest risk of infection Transmitted via inhalation of aerosols or contact with infected material or a pet bird Difficult diagnosis since symptoms similar to other respiratory infections

Major outermembrane protein (chlamydiaceae)

(MOMP) in the cell wall is an important structural component of the outer membrane and is unique for each species

Trachoma (CHLAMYDIA TRACOMATIS)

2 BIOVARS: TRACHOMA AND LGV (LYMPHOGRANULOMA VENEREUM). THE BIOVARS HAVE BEEN FURTHER DIVIDED INTO SEROVARS ON THE BASIS OF ANTIGENIC DIFFERENCES IN THE MAJOR OUTER MEMBRANE PROTEIN (MOMP) LEADING CAUSE OF PREVENTABLE BLINDNESS ADULT INCLUSION CONJUCTIVITIS --> 18-30 YRS OLD AND GENITAL INFECTION PROBABLY PRECEDES EYE INVOLVEMENT NEWBORN INCLUSION CONJUNCTIVITIS --> AN INFECTION ACQUIRED DURING PASSAGE OF THE INFANT THROUGH THE BIRTH CANAL INTERSTITAL PNEUMONIA --> PULMONARY INFECTION W/ C. TRACHOMATIS ALSO OCCURS IN NEWBORNS.... 10-20% EXPOSED AT BIRTH DEVELOP MOST COMMON SEXUALLY TRANSMITTED DISEASE IN US TRACHOMA IS A CHRONIC DISEASE CAUSED BY SEROVARS A, B, VA AND C. INITIALLY, PATIENTS HAVE FOLLICULAR CONJUCTIVITIS NEONATAL CONJUNCTIVITS: INFANTS EXPOSED TO C. TRACHOMATIS AT BIRTH INFANT PNEUMONIA: DISTINCTIVE STACATTO COUGH PROCTITIS IS COMMON IN WOMEN WITH LGV Bacteria multiply in the conjunctival cells, scarring The scarring causes the eyelashes to turn inwards and abrade the eye; may eventually result in blindness. Cornea will develop vascularization... what causes blindness Indistinguishable from gonococci Typically a disease of children who have been infected during birth Transmitted eye-to-eye by droplet, hands, contaminated clothing, and eye-seeking flies Infection of the eye with bacteria from the genitalia can also result in disease

Lymphogranuloma venereum (Chlamydia trachomatis)

Chronic sexually transmitted disease Occurs sporadically in USA Characterized by a transient genetal lesion and swollen, painfully inflamed, inguinal lymph nodes Occurs in three stages: 1) Initial stage -Produces a lesion at the infection iste that is small, painless, and heals rapidly 2) Second stage: -Buboes develop at the infection site (Buboes are swollen lymph nodes) 3) Third stage -Only some cases progress to this stage -Characterized by genital sores, constriction of the urethra and gential elephantitis (Genital area (not bubo) becomes enlarged)

ENZYME-LINKED IMMUNOSORBENT ASSAYS

ELISAs an assay that relies on an enzymatic conversion reaction and is used to detect the presence of specific substances (such as enzymes or viruses or antibodies or bacteria) NOUN

CHLAMYDIEA PNEUMONIAE (Chlamydia)

HUMAN PATHOGEN Causes bronchitis, pneumonia & sinusitis Most infections don't require hospitalization Severe cases can resemble primary atypical pneumonia caused by mycoplasma pneumoniae Prevention is difficult because C. pneumoniae is ubitquitous (very confused with mycroplasma pneumonia (walking pneumonia) )

RETICULATE BODIES

METABOLICALLY ACTIVE, NONINFECTIOUS FORMS

ELEMENTARY BODIES

METABOLICALLY INACTIVE INFECTIOUS FORMS LPS -- WEAK ENDOTOXIN ACTIVITY MOMP (MAJOR OUTER MEMBRANE PROTEIN)

C. TRACHOMATIS CULTURE

MOST SPECIFIC, BUT INSENSITIVE

Chlamydias

OBLIGATE INTRACELLULAR PARASITES OMP 2, A SECOND, HIGHLY CONSERVED OUTER MEMBRANE PROTEIN IS SHARED BY ALL MEMBERS OF CHLAMYDIACEAE. CYSTEINE RICH... DISULFIDE CROSS-LINKS ACCOUNTS FOR STABILITY IN ELEMNTARY BODIES ENERGY PARASITES: USE HOST CELL ADENOSINE TRIPHOSPHATE FOR THEIR ENERGY REQUIREMENTS. SOME STRAIN MAY ALSO DEPEND ON THE HOST TO PROVIDE SPECIFIC AMINO ACIDS. Do not have cell walls Have two membranes without peptidoglycan between them Were previously described as viruses due to their size Have DNA and RNA even though they have two membranes Grow and multiply only within the vesicles of host cells Unique developmental cycle with two forms: elementray bodies and reticulate bodies. Both forms can occur within the phagosome of a host cell.

INCLUSION

PHAGOSOME WITH ACCUMULATED RETICULATE BODIES

Chlamydia trachomatis

Pathogenesis and epidemiology: -has a limited host range -one strain infects mice; all others infect humans -Infects the conjunctiva and various mucous membranes -Enters the body through abrasions and lacerations -Most common reportable sexually transmitted disease in U.S. -Clinical manifestations due to cell destruction and inflammatory response Reticulate bodies begin growing about 10 hours after infection... inside endosome prevent fusion with lysosome Same with erlichiosis prevent fusion with lysosome Diseases: 1) Sexually transmitted diseases -Lymphogranuloma venereum -Nongonococcal urethritis -Proctitis 2) Trachoma -Ocular disease -Leading cause of nontraumatic blindness in humans -Infection typically occurs during childbirth When endosome is filled iwth RV's... inclusion body 21 hours later... elementary bodies again 19 hours later.... exocytose 10 hours after infection eb's become rb's Elementary bodies are the infective stage 21 hours after infection rbs become again ebs 19 hours after Diagnosis: -Demonstrate bacteria inside cells from the site of infection (direct immunofluorescence staining; enzyme-linked immunosorbent assay (ELISA) (fluoresence) Treatment: -Antibiotics can be administered for genital (doxycycline) and ocular (erythromycin for children & preg women) infections -Surgical correction of deformities from trachoma may prevent blindness Prevention: -Abstinence to prevent sexually transmitted infections -Blindness prevented with prompt use of antibacterial agents

Developmental forms and life-cycle of Chlamydia

Reticulate bodies begin growing about 10 hours after infection... inside endosome prevent fusion with lysosome Same with erlichiosis prevent fusion with lysosome When endosome is filled iwth RV's... inclusion body 21 hours later... elementary bodies again 19 hours later.... exocytose 10 hours after infection eb's become rb's Elementary bodies are the infective stage 21 hours after infection rbs become again ebs 19 hours after Real life cycle: 1) EB attaches to receptor on host cell (0 hr) 2) EB enters host cell via endocytosis 3) EB converts into RB in vesicle (10 hours) 4) RB divides rapidly resulting in multpile RBs in an inclusion body 5) Most RBs convert back into EBs (21 hours) 6) EBs are released from host cell (40 hours)

SEROVARS

SEROLOGICAL VARIANTS

NUCLEIC ACID AMPLIFICATION TESTS (NAATS)

Test of choice for C. Trachmatis infection.More sensitive (generally reported to be 90%-98% sensitive. First amplify a specific sequence of genetic information and then detect it with a species-specific probe.

DIRECT IMMUNOFLUORESCENCE STAINING

WITH FLUORESCEIN-CONJUGATED MONOCLONAL ANTIBODIES

NUCLEIC ACID PROBE TEST

most commonly meausure for the presence of a species=specific sequence of 16s ribosomonal rna (in c. trachomatis)

LPS of family chlamydiaceae

only weak endotoxin activity