Chlamydia!!! MICROM 442 Deck 13 Flashcards
Elementary body (EB)
-infectious
-EXC spore-like form
-Metabolically inert, non-replicating
Reticulate body (RB)
-Non-infectious
-Intracellular replicating form
-Divide within membrane-bound inclusion
-Osmotically unstable, can’t survive extracellularly
Genome for family chlamydiaceae
Small chromosome
what type of organism is chlyamdia??
obligate & intracellular
what does it secrete?
type III secreted effectors, which both EBs and RBs express
EBs induce epithelial cell internalization
¤ Pre-formed effector protein, Tarp, secreted into target cell
¤ Tarp induces actin polymerization, phagocytosis of EB
RBs secrete Inc proteins: modify the inclusion membrane
Prevent lysosome fusion by blocking SNARE-mediated interactions
C. trachomatis infects mucosal epithelial cells
¤ Secretory antibodies are produced but are not associated with
disease resolution
¤ Infection controlled by T H 1 (interferon-g-associated) immune response
¤ Provokes a low level chronic inflammatory response
¤ Necrosis, epithelial cell proliferation, and scar tissue formation
¤ Scarring responsible for most disease-associated complications
C. trachomatis servoars A-C =
trachoma
C. trachomatis servoars D-K =
¤ Urethritis/Cervicitis
¤ Perinatal infections
¤ Inclusion conjunctivitis
C. trachomatic L1, L2, L3=
Lymphogranuloma venereum (LGV)
LGV serovars specically invade the
lymph nodes where they survive/replicate in phagocytes
A-K serovars are taken up and killed by
phagocytes & invade immune cells
CT infx in men -> urethritis
Dysuria with some urethral discharge
¤ Commonly less purulent (pus-inducing) than
gonorrhea
¤ More likely to be asymptomatic than gonorrhea
¤ Epididymitis is common complication
¤ Frequently unilateral, not associated with infertility
CT infx in women
¤ Dysuria, frequency
¤ Absence of WBC in the urine (in contrast to E. coli UTI)
e.coli vs CT UTI
no WBCs in urine when CT
CT cervicitis
¤ Most infected women are asymptomatic
¤ Mucopurulent cervical discharge
¤ Friability (easily induced bleeding)
¤ Untreated infections persist for months
Chlamydia trachomatis:
Urogenital infections
¤ Pelvic inflammatory disease (PID)
¤ Endometritis (uterine lining)
¤ Salpingitis (fallopian tubes)
¤ Peritonitis (peritoneal cavity)
¤ Symptoms range from none to acute and severe
¤ Discharge, bleeding, fever, abdominal tenderness and pain
¤ Symptomatic PID occurs in ~10-15% of women with endocervical C.
trachomatis infections
CT neonatal infx
inclusion conjunctivitis & pneumonia
CT Dx
-NAAT
-screening
CT stages
1° -> Small ulcer on genital mucosa or
adjacent skin & Few or no symptoms, rapidly heals
2° -> Inguinal lymphadenopathy, fever,
headache, muscle pain
3° -> Chronic procto-colitis mimics inflammatory
bowel diseases
CT A-C pathogenesis
Chronic follicular conjunctivitis -> Ulceration and scarring of cornea, loss of vision
trachoma is most active in
infected children who are a resevoir -> transmission from nasopharyngeal secretions via hands/flies/objects
chlamydia pneumoniae
C. pneumoniae infects and multiplies within a wide range of cell types,
including monocytes/macrophages
C. Pneumonia spread via
respiratory droplets and clinically indistinguishable from other causes of pneumonia
chlaymdophila psittaci
acquired from birds via inhalation
chlaymdophila psittaci prevention
Quarantine and treatment of imported birds
chlaymdophila psittaci dx
Severity ranges from mild febrile disease to fatal
pneumonia
¤ 20% fatality in untreated disease
vax for chlamydia?
NO
abx must be able to
penetrate tissues and enter host cells
