Bacteriology 11: Miscellaneous gram- pathogens Flashcards
Bordetella bronchiseptica
gram?
Main hosts?
Diseases?
Gram - rods
Dogs, Cats, pigs
Canine cough
Tracheobronchitis/Pneumonia
Atrophic Rhinitis
Pseudomonas aeruginosa
Gram?
Main hosts?
Diseases?
Gram- rods
Horses, Dogs, Cats, chinchillas, reptiles
Superinfections
keratitis, dermatitis, burn and wound infections
otitis externa
Stomatitis, septicemia
not good pathogen
What type of bacteria is bordatella?
Gram negative, short rods
OBLIGATE AEROBES
Oxidase positive, motile
Grows on MacConkeys
-Compared to Pasteurella multocida
Species of veterinary importance
-Bordetella bronchiseptica
-Bordetella avium
Where does bordetella come from?
BORETELLA BRONCHISEPTICA
OBLIGATE parasite of ciliated respiratory
epithelium
Maintained in carrier animals (not normal
flora)
Infected or carrier dogs who are “coughing are the main source of infections for naïve dogs”
Occasionally, infections can arise from bacteria present on their own respiratory epithelium (recrudescence)
How is bordetella transmitted?
Factos?
Inhalation is primary mode of transmission through
aerosolized droplets
-Risk Factors
- Introduction of new animals
- Ventilation
- Density of animals
Disease (Canine Cough) is considered to be CONTAGIOUS
Can get “large outbreaks” of disease in housed
animals
How does bordetella cause disease?
Uniquely adapted to set up conditions that allow colonization and disease of the respiratory tract
-Bind to respiratory cilia via fimbriae/pertactin
-Induce ciliostasis, death of cells and subsequent inflammation via dermonecrotic cytotoxin and tracheal cytotoxin
-Also has an osteotoxin which is important in Atrophic Rhinitis
- Decreased phagocytosis and killing of bacteria via other exotoxin
What specific diseases does bordetella cause?
3 specific diseases
Canine Infection Traceobronchitis
- Kennel cough
Tracheobronchitis/Pneumonia
Atrophic Rhinitis
How can you tell if a dog has kennel cough?
Usually see sudden onset of dry, hacking (“goose-honking”) cough that may be productive (common) or non-productive
Cough may be exacerbated by exercise, excitement or pressure of collar
Can also be elicited by tracheal palpation (inconsistent)
Gagging, retching or nasal discharge can also be observed in some cases
Do NOT usually show signs of systemic illness and if they do – should suspect more serious/underlying diseaseCanine Cough - retching
What it the big deal about Canine cough?
respiratory and conclusions after bacterial infection
B. bronchiseptica and/or viruses
can cause the initial damage and
allows secondary invasion by
other bacteria that may enter the
lower respiratory tract
e.g., Klebsiella pneumoniae
Are there other agents involved with Kennel cough?
YES
mycoplasma
Tracheobronchitis and/or Pneumonia description
range?
species?
involvement of other bacteria/viruses?
Wide range of animals (dogs, cats, horses, rodents, people) may be infected
Usually involves other bacteria or
viruses
-Predisposing (e.g., Mycoplasma,
herpesvirus or calicivirus in cats)
-Secondarily (e.g. Klebsiella
pneumoniae, E. coli)
It is the secondary invaders that
cause serious dz (e.g., pneumonia)
Atrophic rhinitis description:
Host?
Diseases?
Sows are the carriers of B. bronchiseptica and transfer infection to piglets
B. bronchiseptica invades initially and causes a mild, transient form of the
disease
-B. bronchiseptica: dermonecrotoxic exotoxin and osteotoxin
Secondary invasion by toxigenic P. multocida (type D) results in a more severe and progressive form of disease (osteolytic)
-P. multocida DERMONECROTIC TOXIN
How do you diagnose bordatella infections?
Canine cough=
-presumptive diagnosis
Tracheobronchitis/ pneumonia=
-nasal swabs, cultured or multiplex PCR
-additional sampling in lungs itself
Atrophic Rhinitis=
-clinical diagnosis and lesions usually sufficient
-swabs of nasopharynx and culture for isolation of B. bronchiseptica and P. multocida
- ELISA and multiplex PCR for detection or toxigenic strains of p. multocida
How do treat bordatella infections?
self limiting infection
Normally it passes over after a week; but if there is infection in the lungs you will want to use antibiotics
Regardless using antibiotics may reduce length of time of coughing and help prevent secondary complications
What are some issues with bordatella?
Some dogs can continue to shed the bacteria for up
to 3 months after cessation of signs!
-So they should not take the dogs near susceptible dogs in this time future
-Relapses may occur if “stressed”
-Treatment may shorten shedding
What kind of bacteria are Pseudomonas?
Gram- rods
Obligate aerobes
Highly motile
Classical colony morphology on blood agar
Oxidase +
ONLY 1 species has significant veterinary importance
IMPORTANT : isolation of ANY other Pseudomonas spp arises from contamination (except fish)
Where does Pseudomonas aeruginosa come from?
UBIQUITOUS in environment
loves water
NOT considered normal flora
Can survive in weird places
- old disinfectants
-sterile water for injection
-medical equipment
What are the Virulence factors of Psudomonas aeruginosa?
PILI
EXOTOXINS
KILLS CELLS
ENDOTOXINS
PYOCYANINS & FLUOROSCEIN
-green coloration
-kills and damages tissue
BIOFILM
How does Psydomonas aeruginosa cause disease?
It is constantly in environment
Therefore they are SECONDARY to compromised host tissues
Need underlying injury or damage to causes disease
OPPORTUNISTIC PATHOGEN
–NEED significant host compromise to cause disease
Superinfection is always involved with P. aeruginosa?
NO
What is superinfection?
First some underlying disease/predisposing factor causes tissue damage (=devitalised/compromised tissues)
This will disrupt the normal flora and allow other (good) pathogens to cause an infection (=primary infection)
The bacterial infection is diagnosed and treated with (often prolonged) antimicrobial therapy & which may kill the 1º bacteria
But underlying disease/predisposing factor NOT addressed in therapy and so still have compromised/damaged tissues
AND P. aeruginosa, although a weaker pathogen, has widespread antibiotic resistance, so it can survive in the face of antibiotic therapy, & therefore can invade & cause 2°infection at this time
What bacteria cause SUPERINFECTIONS?
Pseudomonas aeruginosa
Nocardia spp
Klebsiella pneumoniae
Bacillus cereus
Enterococcus etc
Outline a specific clinical example of SUPERINFECTION?
Endometritis mares
Superinfections key point is?
YOU NEED to treat/cure the underlying process and treat the bacteria causing the superinfection by doing a susceptibility test as they are usually VERY resistant
What disease do Opportunistic infections- Pseudomonas aeruginosa cause?
Corneal ulcers (kereatitis ) many animal species
Dermatitis “Green wool” sheep
Does Pseudomonas aeruginosa cause wound infections?
YES
all species
BURN wounds (a lot of EXUDATION–moisture)
loves moist environments
What kind of hosts or species does Pseudomonas aeruginosa like to cause disease in?
very COMPROMISED/SUSCEPTIBLE hosts/SPECIES
Abscesses/pneumonia/septicemia
-farmed mink/chinchillas
Infectious stomatitis (mouth rot)
-snakes, lizards and turtles
Are Psuedomonas aeruginosa good or bad pathogens?
bad
