27 – Moraxella and Chlamydia Flashcards
Microbial characteristics: Moraxella
- Biocontainment level 2
- Gram negative
- STRICT anaerobes
Microbial characteristics: Chlamydia
- Biocontainment level 2 or 3
- Obligate intracellular parasites
o Genome reduction: rely on host metabolic machinery rather than having their own - Biphasic development
Chlamydia ‘lifecycle’
- Elementary bodies bind to cell surface
- Endocytosis occurs, formation of inclusion bodies
- Organisms becomes metabolically active
- Reticulocyte bodies divide
- Reticulocyte bodies then differentiated back into elementary bodies
- Elementary bodies escape by lysis or extrusion and infect other cells
What is the natural host or habitat of Moraxella?
- Found on mucous membranes of mammals
- Don’t survive well outside of host
- May be transmitted by insects
What is the natural host or habitat of Chlamydia?
- Elementary bodies somewhat resistant to environmental conditions
- Can survive for several days outside host
- Avian GIT=natural site for C. psittaci
- Asymptomatic infections are common (BIG PROBLEM!)
Virulence factors of Moraxella
- Type IV pilli
- Cytotoxin
- Transferrin and lactoferrin binding proteins
Virulence factors of Chlamydia
- *Virulence genes comprise 10% of their gene
- Various secretion systems
- Cytotoxin
What does Moraxella bovis cause in cattle?
- Infectious bovine keratoconjunctivitis (pink eye)
- Incubation period of 2 days to 3 weeks
What are the clinical signs of Moraxella bovis in cattle?
- Copious watery lacrimation
- Blepharospasm, photophobia
- Opacity may develop in center of cornea which may ulcerate
- Most cases recover
- In severe cases: eyes rupture=blindness
How is Moraxella bovis in cattle transmitted?
- Mechanical vectors: INSECTS
- *cattle are the reservoir
How do you treat Moraxella bovis in cattle?
- Early infections: respond to topical antimicrobials
o Can be administered topically, parenterally - Adjunctive therapy includes protecting animals from LIGHT
o Housing indoors or eye patches
How do you control Moraxella bovis in cattle?
- Fly control may help
- NO effective vaccine available
What does Chlamydia psittaci cause in birds?
- Psittacosis
What are the clinical signs of psittacosis in birds?
- Nasal and ocular discharges
- Conjunctivitis
- Green-yellow feces
- Inactivity
- Weight loss
- *diffuse fibrinous airsacullits and pericarditis
In acute lesions there may be more profound gross and histological lesion of psittacosis in birds
- Hepatomegaly
- Serofibrinous polyserositis
- Petechial hemorrhages on liver and spleen
How is Chlamydia psittaci in birds transmitted?
- Fecal-oral
- Vertical
Chlamydia psittaci in birds
- Can be seen in gallinaceous birds (ex. chickens)
- *resistant to drying
o Can remain infectious for several months - *reportable disease in US, not CANADA
How do you treat Chiamydia psittaci in birds?
?
How do you control Chlamydia psittaci in birds?
- No effective vaccine
Chlamydia psittaci in people
- IMPORTANT ZOONOSES
- Infection through exposure to aerosolized organisms
- Pneumonia is most common presentation
o Mild to severe acute and fulminant
o Culture negative endocarditis
Who are the people at risk for Chlamydia psittaci?
- Pet birds/pigeon owners
- Vets
- Zoo keepers
- Farmers
- Those working in poultry industry
What does Chlamydia abortus cause in sheeps?
- Enzootic abortion in ewes (“EAE”)
- *abortion typically occurs without prior signs
o Last month of pregnancy
o Infection remains until 3-4 months into pregnancy for ewes - Vaginal discharge for up to 3 weeks following abortion
Chlamydia abortus in sheep prevalence
- Common in UK and USA
- Can affect up to 60% of animals in naïve flocks
How do you control Chlamydia abortus in sheep?
- Isolate aborting animals and clean up abortuses
What does Chlamydia pneumoniae cause in people?
- Respiratory tract infections
o Laryngitis, pharyngitis, fever, headache
o May or may not cause pneumonia
o 2-5% of individuals have asymptomatic infections
Who are at highest risk of Chlamydia pneumoniae?
- Crowded settings
- *but affects people of all ages
Chlamydia pneumoniae in koalas:
- Severe conjunctivitis in koala
o Reddening and lacrimation - Trying to get a vaccine
- ‘pee’ leaking out
What does Chlamydia suis cause in pigs?
- Associated with infections of reproductive and respiratory tract
o Conjunctivitis, rhinitis, pneumonia
o Return to estrum, inferior seme quality
Chlamydia suis in pigs
- Pigs are ONLY KNOWN host
- *can survive up to 30 days in environment
How do you treat Chlamydia suis in pigs?
- Antimicrobials
o TETRACYCLINES first choice followed by macrolides or fluroquinolones
How do you control Chlamydia suis in pigs?
- NO vaccines available
- Cleaning and good management important
o REDUCE ENVIRONEMTNAL RESERVOIR
Chlamydia trachomatis in humans
- Primarily a human pathogen
o Has been isolated from animals - Sexually transmitted disease
- Transmitted from mothers to newborns
o Conjunctivitis, pneumonia - *requires close contact=reduced transmission during pandemic
Chlamydia trachomatis: sexually transmitted disease
- Often no overt clinical signs
o Can cause reproductive system damage and lead to INFERTILITY - Burning on urination or discharge
How do you treat Chlamydia trachomatis in people?
- *Azithromycin and doxycycline
Moraxella sample collection and handling
- Swabs of lacrimal secretions
Chlamydia sample collection and handling
- Blood for serology: paired acute + convalescent
- Abortion: smears from placenta or vagina
- Polyarthritis: joint fluid
- Conjunctivitis: swab
- Systemic infection: lung and abdominal viscera
- *for culture: specialized transport media
- Can keep at +4 or -70!
o FREEZE THAW CYCLES KILL!
Lab ID of Moraxella
- Culture on blood agar
Lab ID of Chlamydia
- Antigen capture ELISA
- Serology
- Microscopic examination of tissues
- PCR based assays
- Culture: research only
Chlamydia and zoonotic/interspeices transmission
- Broad host range
- C. psittachi is one of the 10 most common laboratory acquired infections
- *C. abortus is a potential zoonoses
o Abortion in women=avoid lambing ewes
Treatment options for Moraxella and Chlamydia
- No standardized methods for determining antimicrobial susceptibility
- *impossible for Chlamydia
What is Moraxella catarrhalis (human pink eye) intrinsically resistant to?
- TRIMETHOPRIM
o Avoid it as a monotherapy in vet med - People: commonly beta-lactamase producers
