bacteriology 11 Flashcards
bordetella
gram negative, short rods
obligate aerobes
oxidase positive
motile
grows on macconkey and blood
bordetella species of veterinary importance
bordetella bronchispetica
where is bordetella found
obligate parasite of ciliated respiratory epithelium
maintained in carrier animals not nf
couching are the main source of infection for naive dogs
how is bordetella transmitted
inhalation
contagious
large outbreaks
how does bordetlla cause disease
adapted to set up conditions that allow colonization and disease of repiratory tract
can predispose to more serious disease
specific diseases does bordetlla cause
canine infectious tracheobronchitis-canine cough, kennel cough
tracheobronchitis/pneumonia
atrophic rhinitis-pigs
canine cough/kennel cough
dry hacking that may be productive or non productive
can be exacerbated by exercise, excitement or pressure of the collar
can also be elicited by tracheal palpation
gagging, retching or nasal discharge
not usually show signs of systemic illness
can cause initial damage and allow secondary invasion by other bacteria that may enter the LRT
tracheobronchitis and or pneumonia
wide range of animals
dogs, cats, horse, rodents, people
usually involves other bacteria or virues
secondary invader that causes serious dz
atrophic rhinitis
pigs
sows are carrier
invades initially
diagnose bordetella
canine cough-presumptive diagnosis
tracheobronchitis/pneumonia-not part of normal flora of URT, no nasopharyngeal swabs may be ok, samples can be cultured or multiplex PCR and collect samples from LRT
atrophic rhinitis-clinical signs and lesions usually sufficient
swabs of the nasopharynx and culture for isolation
treat bordetella
self limiting infection and may resolve on own
antibiotic therapy may reduce length of time of coughing and help prevent secondary complication
treat if suspect bronchopneumonia
not predictably susceptible so should do culture and susceptibility testing if-animals not responding, dogs are very ill or if cat is involved
pseudomonas
gram negative rods
obligate aerobes
highly motile
metallic sheen and smell fruity
oxidase positive
only veterinary species of importance
pseudomonas aeruginosa
isolation of any other pseudomonas spp arise from contamination
where do you find pseudonmonas
ubiquitous
saprophyte-live in soil and water
transitorily-in feces, skin and mucus membranes or normal animals
can survive in weird places
pseudomonas virulence factors
pili-adherence to host cells
exotoxin-kill cells especially phagocytes
endotoxin
pyocyanins and fluoroscein-kills cells and damage tissue and causes green coloration of colonies
collagenase, elastase-breaks down collagen and damages blood vessels
biofilm production-aids in coloization, resist phagocytosis and antimicrobial tolerance
pathogenesis of pseudomonas
environmental exposure is constant
infections are secondary to compromised host tissue-need underlying injury or damage to get disease
opportunistic pathogen but needs significant host compromise to cause disease
steps in superintection
first some underlying disease/predisposing factor causes tissue damage
this will disrupt the normal flora and allow other good pathogens to cause infection
the bacterial infection is diagnosed and treated with antimicrobial therapy which may kill the first bacteri
but underlying disease not addressed in therapy so still have compromised/damaged tissue
what bacteria cause super infection
pseudomonas aeruginosa
nocardia spp
klebsiella pneumoniae
bacillus cereus
enterococcus
there are a number of bacteria which may be involved in superinfection which have a similar pathogensis
key points to superinfection
unless the underlying factor allowing disease to occur is resolved you will not resolve the superinfection
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
opportunistic infection-pseudomonas aeruginosa
corneal ulcers (keratitis)-many animal species
dermatitis(green wool)-sheep-skin infection with wet conditions
wound infection-all species, especially burn wounds, love moist environments and burn wounds have a lot of exudation
superinfections-pseudomonas aeruginosa
can be involved in superinfections in all situation
there are some other situations where P aeruginosa may be involved
infection-pseudomonas aeruginosa
compromised host or susceptible species
abscesses/pneumonia/septicemia
infectious stomatitis
how to diagnose pseudomonas aeruginosa
frequently a contamination during sample collection
isolation alone does not necessarily mean that it is significant
careful: review of history and clinical signs
application of the appropriate rule for interpretation
repeat isolation if uncertain
treat pseudomonas aeruginosa
with difficulty
often respond poorly to antimicrobial therapy
intrinsic antimicrobial resistance
acquired resistance in some strains
therefore must do susceptibility testing and use appropriate antibiotics
underlying host compromise also important
very important to address host factors if you will for resolution of disease-diagnose and treat underlying disease, getting rid of necrotic tissue, and drying out-remove excess exudation
