Respiratory Pathogens 2 Flashcards
What are the general characteristics of Rhodococcus equi bacteria
- Gram (+)
- Facultative intracellular organism
What are the virulence factors of Rhodococcus equi bacteria
- Virulence
o Mycolic acids (inhibit phagocytosis and complement – allow survival in macrophages and form granulomas)
o VapA protein (surface protein – interfere with phagolysosome formation to allow intracellular survival)
What is the pathogenesis of Rhodococcus equi bacteria
- Pathogenesis
o Inhale soil dust = resp infection
o Infective droplets/swallowing infected sputum = enteric disease
o Local or disseminated infection – spread via hemo-lymphatic (systemic)
What are the lesions of Rhodococcus equi bacteria
- Lesions
o Resp: pyogranulomatous bronchopneumonia
o Enteric: ulcerative enterocolitis and typhlitis
o Systemic disease (pyogenic)
How is Rhodococcus equi diagnosed
- Dx: c/s +/- cytology via BAL or TTW
What is CIRD?
Canine Infectious Resp Disease
* Multifactorial: primary and secondary bacteria/virus (many cause) + stress
* Progress to bronchopneumonia
List 3 common CIRD pathogens and the sequelae of each? What species does it affect?
- Streptococcus equi subsp. Zooepidemicus: shelter outbreak = suppurative or necrotizing hemorrhagic pneumonia
- Streptococcus canis: shelter cat resp pathogen
- Mycoplasma cynos: primary lower resp disease in dogs
What are the general characteristics of Bordatella bronchiseptica bacteria
- Gram negative
- Obligate aerobe and obligate pathogen
- Commensal in upper resp
What is the main virulence factor associated with Bordatella bronchiseptica
- Virulence
o Tracheal cytotoxins (damage ciliated resp epithelium = increase mucous/vasoconstriction)
o Also fimbriae/LPS
What is the pathogenesis of Bordatella bronchiseptica
- Pathogenesis very contagious
o Attach to ciliated epithelium
o Ciliostasis
o Colonize
o Alter resp epithelium function
o Excess mucous secretion
o Impair innate immune
o Predispose to secondary infection
Commonly occurs with Adenovirus and parainfluenza
What are 2 clinical presentations of Bordatella bronchiseptica infection
o Mild upper resp infection
o Pneumonia
What is FIRD
Feline Infectious Respiratory Disease
* Multifactorial: primary and secondary bacteria/virus (many cause) + stress
* Clinically
o Rhinosinusitis/conjunctivitis/oral or nasal ulcers/pneumonia
What is the causative agent for Psittacosis
Chlamydia psittaci (Psittacosis)
What are the general characteristics of Chlamydia bacteria
Chlamydia
* Obligate intracellular
* Acid fast
* Affinity for ciliated cells of resp/conjunctiva
How is chlamydia transmitted
- Transmit: aerosol/droplet/dust
What are the 2 main virulence mechanisms of Chlamydia
- Virulence (lots – 10% genome)
o Secretion systems (secrete effectors that help with cell invasion)
o Cytotoxins – slows cell cycle (control when cell dies)
What is a new and concerning pathogen emerging in cats? What is the clinical presentation
- Streptococcus canis: emergent pathogen in cats causing fatality
o S. canis as sole causative agent
o Skin ulcer/resp infection/necrotizing sinusitis/meningitis/necrotizing fasciitis
What are 2 major considerations to have when dealing with Chlamydia psittaci
- Zoonotic (parrot fever = human)
- Wild and domestic birds = carriers
o serotypes that affect wild birds and turkeys - Provincially notifiable in B and reportable in US
How is Chlamydia psittaci transmitted
- Transmit; resp discharge/feces/airborne particles
o fecal oral
o inhale
o vertical
What are 4 clinical presentations of Chlamydia psittaci
- Clinical presentation:
o subclinical
o severe/systemic
o acute
o chronic + intermittent shedding
What are the clinical signs of Chlamydia psittaci
o Nasal/ocular discharge
o Conjunctivitis
o Diarrhea
o Fever
What are the 3 forms of chlamydia? What are their respective functions and features
- Elementary body: infectious + spore like + enviro resistant
- Reticulate body: survive in lysosome + non infectious
- Aberrant body: non replicative + cause persistence
What are the 8 steps of Chlamydia lifecycle in the body
- Elementary body bind cell surface
- Endocytose
- Elementary body form inclusion body
- Transition to reticulate body – metabolically activity
- Reticulate body replication
- Convert to aberrant body or back to elementary body
- Elementary body escapes via lysis or extrusion
What are the 2 main lesions of Chlamydia psittaci
o Fibrinous polyserositis
o Hepatitis
What is one main consideration when diagnosing Chlamydia psittaci?
- Dx; cannot be grown on agar – require embryonated eggs/cell cultures
o Also CBC/Biochem/Rad/serology/PCR/histo
Why is identifying resp pathogens in reptiles harder to find
- Challenge:
o Limited display of clinical signs
o Clinical signs may only appear in advanced disease = because very high spare lung capacity
What does Resp sounds/open mouth breaking/increase resp rate indicate in reptiles
- Resp sounds/open mouth breaking/increase resp rate = VERY bad
What common resp disease is found in snakes
- Snake: pharyngitis/tracheitis common
What common resp disease is found in tortoises
- Tortoise: nasal secretion common
What are some challenges when diagnosing a bacterial infection in reptiles
- Normal microflora = large range of aerobic bacteria and fungi
- Makes results difficult to interpret
- Most bacterial infections due to primary viral infection/toxin/chronic illness/husbandry related
What are the features of Mycoplasma agassizii bacteria
Mycoplasma agassizii
* Gram (-)
What type of disease does Mycoplasma agassizii cause in tortoises and what is a major risk factor
- Upper resp infection
- Risk factor: stress
How is Mycoplasma agassizii transmitted in tortoises
- Transmit: direct (nasal discharge)
very contagious
What are the clinical signs of Mycoplasma agassizii in tortoises
o Non specific (anorexia/weight loss/dyspnea)
o Rhinitis/conjunctivitis
o Erosion and deformation of beak
How to diagnose Mycoplasma agassizii in tortoises and what samples can you take
- Sample: blood/nasal swab/lavage
- Dx: CBC/Biochem/PCR
What disease does Pasturella multicida cause in rabbit
Pasturella multicida (pasturellosis/snuffles)
- Type A = most toxigenic
- Serious disease + very contagious
What are the 4 clinical manifestation of respiratory disease in rabbits
o Rhinitis/snuffles
o Otitis media/interna
o Conjunctivitis
o Acute sepsis and sudden death (no prior clinical signs)
What is the clinical manifestation of Pasturella multicida cause in rabbit
o Mild upper resp signs – sepsis
o Can have healthy subclinical carrier (30-90%)
List 5 potential bad tx for Pasturella multicida cause in rabbit and why
Ampicillin
Amoxicillin
Amox-clav
Penicillin
Clindamycin
(+/- GI adverse)
