27 – Moraxella and Chlamydia Flashcards

1
Q

Microbial characteristics: Moraxella

A
  • Biocontainment level 2
  • Gram negative
  • STRICT anaerobes
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2
Q

Microbial characteristics: Chlamydia

A
  • Biocontainment level 2 or 3
  • Obligate intracellular parasites
    o Genome reduction: rely on host metabolic machinery rather than having their own
  • Biphasic development
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3
Q

Chlamydia ‘lifecycle’

A
  1. Elementary bodies bind to cell surface
  2. Endocytosis occurs, formation of inclusion bodies
  3. Organisms becomes metabolically active
  4. Reticulocyte bodies divide
  5. Reticulocyte bodies then differentiated back into elementary bodies
  6. Elementary bodies escape by lysis or extrusion and infect other cells
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4
Q

What is the natural host or habitat of Moraxella?

A
  • Found on mucous membranes of mammals
  • Don’t survive well outside of host
  • May be transmitted by insects
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5
Q

What is the natural host or habitat of Chlamydia?

A
  • 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!)
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6
Q

Virulence factors of Moraxella

A
  • Type IV pilli
  • Cytotoxin
  • Transferrin and lactoferrin binding proteins
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7
Q

Virulence factors of Chlamydia

A
  • *Virulence genes comprise 10% of their gene
  • Various secretion systems
  • Cytotoxin
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8
Q

What does Moraxella bovis cause in cattle?

A
  • Infectious bovine keratoconjunctivitis (pink eye)
  • Incubation period of 2 days to 3 weeks
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9
Q

What are the clinical signs of Moraxella bovis in cattle?

A
  • Copious watery lacrimation
  • Blepharospasm, photophobia
  • Opacity may develop in center of cornea which may ulcerate
  • Most cases recover
  • In severe cases: eyes rupture=blindness
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10
Q

How is Moraxella bovis in cattle transmitted?

A
  • Mechanical vectors: INSECTS
  • *cattle are the reservoir
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11
Q

How do you treat Moraxella bovis in cattle?

A
  • 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
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12
Q

How do you control Moraxella bovis in cattle?

A
  • Fly control may help
  • NO effective vaccine available
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13
Q

What does Chlamydia psittaci cause in birds?

A
  • Psittacosis
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14
Q

What are the clinical signs of psittacosis in birds?

A
  • Nasal and ocular discharges
  • Conjunctivitis
  • Green-yellow feces
  • Inactivity
  • Weight loss
  • *diffuse fibrinous airsacullits and pericarditis
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15
Q

In acute lesions there may be more profound gross and histological lesion of psittacosis in birds

A
  • Hepatomegaly
  • Serofibrinous polyserositis
  • Petechial hemorrhages on liver and spleen
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16
Q

How is Chlamydia psittaci in birds transmitted?

A
  • Fecal-oral
  • Vertical
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17
Q

Chlamydia psittaci in birds

A
  • Can be seen in gallinaceous birds (ex. chickens)
  • *resistant to drying
    o Can remain infectious for several months
  • *reportable disease in US, not CANADA
18
Q

How do you treat Chiamydia psittaci in birds?

A

?

19
Q

How do you control Chlamydia psittaci in birds?

A
  • No effective vaccine
20
Q

Chlamydia psittaci in people

A
  • IMPORTANT ZOONOSES
  • Infection through exposure to aerosolized organisms
  • Pneumonia is most common presentation
    o Mild to severe acute and fulminant
    o Culture negative endocarditis
21
Q

Who are the people at risk for Chlamydia psittaci?

A
  • Pet birds/pigeon owners
  • Vets
  • Zoo keepers
  • Farmers
  • Those working in poultry industry
22
Q

What does Chlamydia abortus cause in sheeps?

A
  • 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
23
Q

Chlamydia abortus in sheep prevalence

A
  • Common in UK and USA
  • Can affect up to 60% of animals in naïve flocks
24
Q

How do you control Chlamydia abortus in sheep?

A
  • Isolate aborting animals and clean up abortuses
25
Q

What does Chlamydia pneumoniae cause in people?

A
  • Respiratory tract infections
    o Laryngitis, pharyngitis, fever, headache
    o May or may not cause pneumonia
    o 2-5% of individuals have asymptomatic infections
26
Q

Who are at highest risk of Chlamydia pneumoniae?

A
  • Crowded settings
  • *but affects people of all ages
27
Q

Chlamydia pneumoniae in koalas:

A
  • Severe conjunctivitis in koala
    o Reddening and lacrimation
  • Trying to get a vaccine
  • ‘pee’ leaking out
28
Q

What does Chlamydia suis cause in pigs?

A
  • Associated with infections of reproductive and respiratory tract
    o Conjunctivitis, rhinitis, pneumonia
    o Return to estrum, inferior seme quality
29
Q

Chlamydia suis in pigs

A
  • Pigs are ONLY KNOWN host
  • *can survive up to 30 days in environment
30
Q

How do you treat Chlamydia suis in pigs?

A
  • Antimicrobials
    o TETRACYCLINES first choice followed by macrolides or fluroquinolones
31
Q

How do you control Chlamydia suis in pigs?

A
  • NO vaccines available
  • Cleaning and good management important
    o REDUCE ENVIRONEMTNAL RESERVOIR
32
Q

Chlamydia trachomatis in humans

A
  • 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
33
Q

Chlamydia trachomatis: sexually transmitted disease

A
  • Often no overt clinical signs
    o Can cause reproductive system damage and lead to INFERTILITY
  • Burning on urination or discharge
34
Q

How do you treat Chlamydia trachomatis in people?

A
  • *Azithromycin and doxycycline
35
Q

Moraxella sample collection and handling

A
  • Swabs of lacrimal secretions
36
Q

Chlamydia sample collection and handling

A
  • 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!
37
Q

Lab ID of Moraxella

A
  • Culture on blood agar
38
Q

Lab ID of Chlamydia

A
  • Antigen capture ELISA
  • Serology
  • Microscopic examination of tissues
  • PCR based assays
  • Culture: research only
39
Q

Chlamydia and zoonotic/interspeices transmission

A
  • 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
40
Q

Treatment options for Moraxella and Chlamydia

A
  • No standardized methods for determining antimicrobial susceptibility
  • *impossible for Chlamydia
41
Q

What is Moraxella catarrhalis (human pink eye) intrinsically resistant to?

A
  • TRIMETHOPRIM
    o Avoid it as a monotherapy in vet med
  • People: commonly beta-lactamase producers