Moraxella and Chlamydia

Question 1

Moraxella characteristics

Answer 1

-gram negative, strict aerobes
-biocontainment level 2

Question 2

Chlamydia characteristics

Answer 2

-obligate intracellular parasites
**they have genome reduction, rely on host metabolic machinery rather than having their own

-biphasic development

-different species range from biocontainment level 2 to 3

Question 3

Chlamydia lifecycle steps

Answer 3

1. elementary bodies bind to cell surface
2. Endocytosis occurs, formation of inclusion bodies
3. Organism becomes metabolically active
4. Reticulocyte bodies divide
5. Reticulocyte bodies differentiate back into elementary bodies

6.Elementary bodies escape by lysis or extrusion and infect other cells

Question 4

Moraxella habitat

Answer 4

-found on mucous membranes of mammals
-dont survive well outside host
-may be transmitted by insects

Question 5

Chlamydia habitat

Answer 5

-elementary bodies somewhat resistant to environmental conditions
-can survive for several days outside host
-asymptomatic infections common

-Avian GI tract for C. psittaci

Question 6

Moraxella virulence factors

Answer 6

-Type IV pilli
-Cytotoxin
-Transferring and lactoferrin binding proteins

Question 7

Chlamydia virulence factors

Answer 7

-virulence genes comprise 10% of their genome

-various secretion systems (type II, III, V)- secretion of effector molecules involved in cell invasion

-cytotoxin- slows down cell cycle, the organism wants to control when the cell dies/ruptures

Question 8

Moraxella bovis cause incubation time and transmission

Answer 8

-causes infectious bovine keratoconjunctivitis (pink eye)

-incubates 2 days to 3 weeks; cattle reservoir

-transmission via mechanical vectors (insects)

Question 9

Clinical signs of Moraxella bovis

Answer 9

-copious watery lacrimation
-Blepharospasm, photophobia
-Opacity of center of cornea, which may ulcerate
-severe cases: eye rupture= blindness

**most cases recover

Question 10

Treatment of Moraxella bovis

Answer 10

-early infections respond to topical antimicrobials

-adjunctive therapy includes protecting animals from light (housing indoors or eye patches)

-Fly control

**no vaccines present

Question 11

Chlamydia psittaci

Answer 11

-causes psittacosis

-Clinical: nasal and ocular discharge, conjunctivitis, green-yellow feces, inactivity, weight loss

-Acute: hepatomegaly, serofibrinous polyserositis, petechial hemorrhages on liver and spleen

Question 12

Chlamydia psittaci transmission and control

Answer 12

Transmission: fecal oral or vertical
**resistant to drying, will stay infectious for several mths

Treatment/control:
-no vaccines
-reportable disease in US but not Canada

Question 13

Chlamydia psittaci in humans

Answer 13

-important zoonoses
-infection through aerosolized organisms

-presents commonly as pneumonia (mild to severe, acute to fulminant)
>culture negative endocarditis

-risk for people with pet birds, vets, farmers, zoos

Question 14

Chlamydia abortus in sheep

Answer 14

Causes enzootic abortion of ewes (EAE)
-abortions often without prior signs; occurs in last month of pregnancy
-vaginal discharge for up to 3weeks following abortion

-common in UK and USA
-naive flocks

-control: isolate aborting animals and clean up abortuses

Question 15

Chlamydia pneumoniae in humans

Answer 15

-respiratory tract infections (laryngitis, pharyngitis, fever, headache, sometimes pneumonia)
-some have asymptomatic signs

-affects all ages, crowded settings at high risk

Question 16

Chlamydia pneumoniae in koalas

Answer 16

-causes conjunctivitis
Redding and lacrimation

Question 17

Chlamydia suis in pigs

Answer 17

-Only in pigs
-infections of reproductive and respiratory tract (conjunctivitis, rhinitis, pneumonia; return to estrus and inferior semen quality)
-can survive up to 30 days in environment

Question 18

Treatment and control of Chlamydia suis

Answer 18

-Antimicrobials= tetracuclines, macrolides, fluoroquinolines

-no vaccines

-cleaning and good management important, reducing environmental reservoir

Question 19

Chlamydia trachomatis

Answer 19

-primarily human pathogen although it has been isolated from animals

-STD

-often no overt clinical signs and can cause reproductive system damage and lead to infertility
-sometimes burning on urination or discharge
-newborns can show conjunctivitis and pneumonia

Question 20

Transmission and treatment of Chlamydia trachomatis

Answer 20

Transmission:
-STD
-mother to newborns
-need close contact; pandemic shut downs reduced transmission

Treatment:
-Azithromycin
-doxycycline

Question 21

Sample collection of Moraxella

Answer 21

swabs of lacrimal secretions

Question 22

Sample collection for Chlamydia

Answer 22

-Blood for serology= paired acute and convalescent

-Abortion- smears from cotyledons, placenta or vagina

-polyarthritis- joint fluid

-conjunctivitis- swab

-systemic infection- lung and abdominal viscera samples

-culture- need special transport media

**Temp at either 4 degrees or -70 degrees BUT no freeze thaw cycles (they kill)

Question 23

Lab ID of Moraxella

Answer 23

-culture on blood agar

Question 24

Lab ID of chlamydia

Answer 24

-antigen capture on ELISA

-serology

-microscopic exam of tissues

-PCR

-culture for research only (embryonated eggs, cell culture)

Question 25

Zoonoses

Answer 25

Chlamydia has broad host range

1.C. psittaci is one of the most common lab acquired infections

2. C. abortus- can cause abortion in women; pregnant women should avoid lambing ewes

Question 26

Treatment of Moraxella and Chlamydia

Answer 26

-no standard methods for antimicrobial susceptibility testing
*not possible in chlamydia due to life cycle

Question 27

Resistant in Moraxella catarrhalis

Answer 27

1. Intrinsic resistance to trimethoprim
   **avoid for vet Moraxella
2. Avoid beta-lactams in humans because they may also produce beta-lactamases