Bacteriology - Pyogranulomas Flashcards
What type of cells will be seen in acute inflammation?
neutrophils
Pyogenic bacteria causes suppurative inflammation primarily acting as __________
extracellular bacteria
Underlying disease process is usually of one ________ and ________
suppuration and abscess formation
What are the 4 main types of pyogenic bacteria?
staphylococci
streptococci
cornyebacteria
trueperella
Which bacteria are a mixture of acute and chronic inflammation?
pyogranulomatous
How do pyogranulomatus cause inflammation?
by acting both extra and intracellularly
How can pyogranulomatus avoid being killed?
evading intracellular destruction
How can we overcome bacteria evading intracellular destruction?
through cell mediated immunity which can be achieved by vaccines
What are the rules of thumb regarding Gram positive rods
less frequent isolated than other groups of bacteria
tend to cause syndromes - can give presumptive diagnosis
if more information is needed definitive diagnosis is needed
What are the 3 main types of actinomycetes?
actinomycetes
nocardia
dermatophilus
What is an important diptheroid gram positive bacteria?
rhodococcus
What are the oxygen requirements of
Actinomycetes
Nocardia
Dermatophilus
A - FA or ANO2
N - strict aerobes
D - strict aerobes
What are the 3 main characteristics of pyogranulomatous
gram +
filamentous
branching rods
What are distinguishing features of rhodococcus?
gram +, short club shaped rods
What is meant by actinomyces being an opportunistic disease?
requires something to allow access of organism into diseased sit and disease is NEAR where they are normal flora
Most species of actinomyces are normal flora of what two areas?
oral cavity and GIT
Which Actinomycetes is considered to be a saprophyte? What does this mean?
Saprophytes
found in soil and decaying vegetation
While nocardia is considered to be opportunistic, it is considered to be a ______ pathogen. What does this mean?
poor
requires significant compromise
Which Actinomycete is considered to be an obligate parasite of the skin but can survive in the environment for a long time
dermatophilus congolensis?
Who is considered to be a reservoir to dermatophilus congolensis?
carrier animals or fomites
Which Actinomycete requires alteration of the skin for invasion, typically wetting?
Dermatophilus congolensis
How can dermatophilus be transferred from an infected/carrier animal to a susceptible one?
rub against each other (contagious)
transferred by insects (flies, ticks)
by contaminated fomites (scabs, sheep dips, brushes)
Where do Rhodococci equi come from?
saprophytes
found in soil
secondary in GIT of horses
animal manure
inhalation or ingestion
What are the virulence factors of nocardia?
mycolic acid and cell wall lipids
What are the virulence factors of dermatophilus?
motile zoospores aid invasion
What are the virulence factors of Rhodococcus?
plasmid mediated, VapA
Which two of the Actinomycetes are facultative intracellular parasites?
nocardia
Rhodococcus
What “syndrome” does actinomyces bovis cause? In what species?
Lumpy Jaw in cattle
What does lumpy jaw require to cause disease?
some alteration to mucusa/skin to allow access of organism into site of disease production
What are some examples of mucosal/skin alteration that allows actinomyces bovis to gain access into organism?
grass awns
sharp feed
impacted feed
What does Lumpy Jaw result in?
chronic pyogranulomatous osteomyelitis of the mandible or maxilla
What clinical signs are seen with lumpy jaw? What are the signs caused by?
hard, non-painful lumps on the head of cattle caused by impairment of function
What 3 “syndromes” will actinomyces spp cause? (Including Actinomyces bovis)
lumpy jaw
abscesses
serositis
What are abscesses?
pyogranulomatous lesions
What do abscesses occur secondary to?
bite or traumatic injury
What flora are involved in abscesses?
mixed
What is serositis? What is it caused by? What species is it often seen in?
inflammation of serous membrane seen in dogs and cats caused by direct instillation such as trauma or fighting
What 3 “syndromes” are seen in nocardia spp.
pyothorax/peritonitis
abscesses
bovine mastitis
What is a distinguishing histological feature of nocardia?
beading or branching filaments
Who does pyothorax/peritonitis affect?
dogs and cats who are immunocompromised
What is bovine mastitis associated with? Is it curable?
intramammary infusions
poor prognosis - cull
What syndrome does D. congolensis cause?
dermatophilosis - rain scald, greasy heel, lumpy wool, strawberry footrot
What species is affected by dermatophilosis?
mostly ruminants and horses
When does dermatophilosis commonly occur?
prolonged wet conditions causing skin maceration which allows organisms to invade epidermis
What is the basic lesion of dermatophilosis?
exudative dermatitis with thick scab formation
Explain the life cycle of dermatophilus
motile cocci (zoospores) elongate into rods, divide into multiple planes, motile cocci (zoospores)
What 2 main diseases do rhodococcus equi cause?
rattles
cellulitis/lymphadentis
What is rattles?
pyogranulomatous bronchopneumonia of foals causing significant morbidity and mortality
What disease can be associated with type III hypersensitivity?
rattles
What is cellulitis/lymphadentis?
pyogranulomatous lesions that spread to lymph nodes in cats
What are 4 steps to diagnose infections?
- signalment, history, clinical signs
- obtain sample from lesions
- perform a gram stain/diff quik
- suspect either actinomyces of nocardia
What are 3 ways to treat infections?
- surgical debridement, excision, or drainage
- topical therapy
- antibiotics
What are the drugs of choice for actinomyces and dermatophilus?
penicillin +/- streptomycin or tetracyclines
Penicillin +/- streptomycin are not the drugs of choice for nocardia or rhodococcus. Why?
They are intracellular - those antibiotics do not go into the cell
What is the drug of choice for rhodococcus?
macrolides AND rifampin
Why is susceptibility testing recommended for nocardia?
unpredictable
