L21 Chlamydia, Mycoplasma and Q Fever Flashcards
Clinical Significance of Chlamydia?
STIs
Ocular Infections
Respiratory Tract Infections
Life Cycle of Chlamydia
Exists in 2 form:
Elementary Bodies (EB) - Infectious Form
Infectious
Spore like
Extracellular: Exists outside of cell
Rigid cell wall w/ crosslinked disulfide bonds
Protects bacteria
Reticulate Body (RB) - Reproductive Form
Non-Infectious
Metabolically active
Replicates in this form
Fragile cell membrane
Life Cycle of Chlamydia
Elementary Bodies (EB) - Infectious Form
Spore like
Extracellular: Exists outside of cell
Rigid cell wall w/ crosslinked disulfide bonds - Protects bacteria
Reticulate Body (RB) - Reproductive Form
Non-Infectious: Replicates in this form
Metabolically active
Fragile cell membrane
Chlamydia Trachomatis Serovars
Site of infections?
Conditions?
Diagnosis?
Treatment
STI?
Chlamydia Trachomatis Ocular Diseases?
Chronic Disease: Serotype A-C => Chronic Follicular Keratoconjunctivitis
Acute Disease : Serotype D-K => Inclusion Conjunctivitis
C. Trachomatis (A-C) = ______________
Condition Associated?
Manifestation?
Spread?
C. Trachomatis (A-C) = Trachoma
Chronic Follicular Keratoconjunctivitis
Infection of conjunctival epithelial cells → follicle development
=> Multiple re-infections disrupt the frictionless movement of the eyelid over the cornea
=> Conjunctival scarring and corneal damage
=> blindness
MOST COMMON cause of preventable blindness
Primarily in developing countries: Asia, Middle East, Asia
Person to person spread via: Contact, Droplets, Flies
Trachomatous TRICHIASIS: eyelashes rub against the cornea
MOST COMMON cause of preventable blindness?
Chronic Follicular Keratoconjunctivitis
Caused by Chlamydia A-C
C. Trachomatis (D-K): __________________________
Conditions Associated?
Sites Infected?
Treatment?
C. Trachomatis (D-K): Inclusion Conjunctivitis and STIs
Chlamydia Inclusion Conjunctivitis
STI of adults
- Most have concurrent genital tract infection
- Acute infection (not chronic like Trachoma)
- Not purulent
No corneal scarring or blindness!!
Neonatal Inclusion Conjunctivitis
Transmitted from genital infection at delivery- Mother has chlamydia (can also occur from Caesarean section)
Occurs 5 days to 6 weeks after delivery
Acute watery then mucopurulent discharge
Can lead to infant pneumonia syndrome
Treatment oral erythromycin
Sexually Transmitted Genital Tract Infections
Cervicitis: females
Urethritis: Males
Epididymitis
Pharyngeal Infection
Pelvic Inflamatory Disease
C. Trachomatis (L1-L3): _____________________
Sites of infection
Epidemiology?
C. Trachomatis (L1-L3): Lymphogranuloma Venereum (LGV)
More aggressive and invasive infection
L= Lymphotropic: Infection of lymphatics, lymph nodes and anorectal tissues = proctitis
Genital and colorectal tissues affected
Epidemiology:
Tropical and subtropical areas
Outbreaks in men who have sex with men
Highly associated w/ HIV infection
70% of MSM with LGV have HIV in Ireland
Diagnosis of Chlamydia Trachomatis?
Depends on Serotype/Site of infection
Trachoma: Clinical, clearly distinct signs esp. in endemic region
NAAT (nucleic acid amplification test)
D-K: Urethritis/cervicitis: genital tract specimen or urine
L1-L3: LGV
Treatment of Chlamydia Trachomatis
NOT CULTURABLE due to intracellular nature (Want therapy with good intracellular penetration)
Trachoma (A-C): Erythromycin or Doxycycline
D-K:
Urethritis / cervicitis: Doxycycline
Neonatal conjunctivitis: Erythromycin
LGV (L1-3) : Doxycycline
Chlamydophila Psittaci
Transmission?
Manifestation?
Diagnosis?
Treatment?
Chlamydophila Psittaci
Zoonotic infection: Psittacosis (parrot fever)
Transmission via Inhalation of respiratory secretions or droppings from infected birds
Acute pneumonia, often bilateral and severe
Serology for diagnosis
Treatment
– Doxycycline
– Don’t forget to treat the bird!
What is repsonsible for Psittacosis (parrot fever)
Chlamydophila Psittaci
Chlamydophila Pneumoniae
Transmission?
Clinical features?
Diagnosis?
Treatment?
Chlamydophila Pneumoniae
Transmission
– Droplet spread person-to-person
– Children and adolescents
Clinical features
– Upper respiratory tract infection – flu like
– Pneumonia with atypical features, often hoarse voice.
– Often have co-infection
– No seasonal variation
Diagnosis
– Serology
– PCR respiratory tract specimen
Treatment
Doxycycline
Macrolides
Mycoplasma Pneumoniae:
Significance?
Anaerobe/Aerobe?
Microbe Characteristics?
Culture Characteristics?
Mycoplasma Pneumoniae
Smallest free-living micro-organism
Generally facultative anaerobes (Except M.pneumoniae - aerobe)
Intracellular infection
No rigid cell wall
– Cells bound by sterol containing membrane
– Stain poorly in lab
Require specialized media for laboratory culture– Not routinely performed
“Fried egg” colonies on specialized agar plates after several days of incubation
Diagnosis of Mycoplasma Pneumoniae?
No cell wall => does not take up Gram stain
Fastidious growth requirements => difficult to culture from sputum
Serology: Presence of M. pneumoniae IgM (more reliable in children and teenagers)
Molecular analysis: Direct PCR for M. pneumoniae DNA on respiratory sample
Cold Agglutinins
Supportive only, not diagnostic
IgM antibodies form against I antigen on erythrocyte membranes
Agglutination of RBCs at low temperatures => hemolysis
Hemolysis is not usuall_y clinically significant except in Sickle Cell_
