Exam 1: Gram positive Staphylococci Flashcards
What does Staphylococcus look like?
gram-positive cocci in clusters like grapes
T/F. Staphylococcus are non-spore forming
T
Is staphyococcus catalase positive or negative
positive
Where is Staphylococcus commonly found?
- Upper resp. tract (nose)
- Lower urogenital tract
- GIT
What are 3 important staphylococcal pathogens?
- S. aureus
- S. pseudintermedius
- S. Hyicus
What is a common staphylococcal opportunistic pathogen?
CoNG staphylococci
What is the pathogenic effect of adhesins?
tissue colonization
What is the pathogenic effect of hemolysins?
Tissue destruction: Cytolytic
What is the pathogenic effect of enterotoxins?
tissue destruction: Heat-Stable toxins
What is the virulence factor that causes food poisoning?
enterotoxins
What is the pathogenic effect of toxic shock syndrome toxins?
Tissue Destruction, superantigen leading to excessive cytokine release
What is the pathogenic effect of Protein A
Immune evasion: Binds Fc portion of IgG and inhibits opsonization
What is the pathogenic effect of leukocidin
Immune evasion: Leucocidal
What is the pathogenic effect of coagulase?
immune evasion: hide bacteria from PMN (polymorphonuclear leukocytes)
Test used to detect most virulent staphylococci
Coagulate test
What is a positive coagulase test?
fibrinogen is converted to fibrin and a visible clot forms
What does CoNS Stand for?
Coagulase- negative staphylococci
What is CoNS?
Cause infection only when immune system is compromised. Commonly causes nosocomial infections and UTIs
What are the 3 species of Staphylococcus of vet. importance.
- Staphylococcus aureus
- Staphylococcus pseudintermedius
- Staphylococcus hyicus
Type of Staphylococcus that causes pyogenic opportunistic infections
Staphylococcus aureus
Bovine Staphylococcal mastitis is also known as:
Contagious mastitis in cattle
When is Staphylococcus aureus seen in cattle?
during lactation
What is the source of infection for staphylococcus aureus in cattle?
infected mammary gland
How is Staphylococcus aureus transmitted in cattle?
- Milking through contaminated milker’s hands
- Teat cup liners
- udder cloths
What are 3 clinical infections associated with Staphylococcus aureus?
- Peracute gangrenous mastitis
- Acute mastitis
- Chronic subclinical mastitis
Describe c/s of peracute gangrenous mastitis caused by Staphylococcus aureus?
Tissue necrosis, udder discoloration, swollen quarters, sore on palpation, fever, depression, anorexia
Describe c/s of Acute mastitis due to staphylococcus aureus
Severe swollen gland, purulent secretion with clots, extensive fibrosis
Describe c/s of Chronic subclinical mastitis caused by Staphylococcus aureus.
Elevated somatic cell count, episodes of bacterial shedding, inflammatory resp., blockage of ducts
How do you prevent contagious mastitis?
- Proper milking technique
- dry cow therapy
- detection of subclinical inf.
- prevent intro of positive cows to herd
Clinical infection of Staphylococcus aureus in horses.
Botryomycosis
What is Botryomycosis?
S aureus infection in horses. rare, chronic granulomatous suppurative disorder with formationof micro-abscessation
How do horses get botryomycosis?
unsanitary castration
how do you treat botryomycosis in horses?
surgical removal and long-term AB tx.
Clinical infection of Staphylococcus aureus in birds.
Bumble foot
What is bumble foot?
S. aureus infection in birds, local chronic pododermatitis of the foot
what species does Staphylococcus pseudintermedius infect?
Dogs and cats
How does Staphylococcus pseudintermedius present in dogs and cats?
local skin dz., otitis externa, infected wounds, UTI, vaginitis, metritis, balanitis, conjunctivitis, bacteremia, abscesses
What is the most common opportunistic pathogen in dogs?
S. Pseudintermedius
What are the main causes of Staphylococcus pseudintermedius in dogs and cats?
- parasites
- food allergies
- foreign bodies
- accumulation of hair
- autoimmune dz.
Bacterial pyoderma is usually triggered by overgrowth of _____
normal resident or transient skin mucosa
T/F. Staphylococcus pseudintermedius is of no zoonotic concern?
F
What is the most important treatment of Staphylococcus pseudintermedius?
ID of underlying problems
T/F. When treating staphylococcus pseudintermedius you should use narrow-spectrum abx?
T
What causes greasy pig disease?
Staphylococcus hyicus
What is greasy pig disease?
infection of staphylcoccus hyicus
Highly contagious exudative epidermitis in suckling and weaned pigs up to 3mo.
If a pig comes into your clinic with signs of excessive sebaceous secretion and exfoliation, anorexia, depression, and fever, what would you expect?
Staphylococcus hyicus
Where can you isolate staphylococcus hyicus on a sow?
vaginal mucosa and skin
How do you treat and prevent greasy pig disease
- early abx therapy and topical tx
- isolation
- disinfection of building
- clipping needle teeth
- good hygiene
Why is it important to clip needle teeth in piglets?
to prevent staphylococcus hyicus because enters through skin through minor abrasions
what are two staphylococcal infections in humans?
- TSS
2. Food poisoning
What is TSS?
Effect of superantigens entering the blood stream
What are c/s of TSS?
fever, headache, vom. diarrhea, skin rash, kidney failure
What is food poisoning?
caused by eating food infected with s. aureus has produced enterotoxins
What are c/s of Food poisoning?
nausea, vom, diarrhea, abdominal cramps, sweating
What are 4 lab. DX tests we can us to detect staphylococcus infection?
- specimines
- direct microscopy
- isolation
- molecular typing with PCR
What are the 2 isolation techniques used for detection of staphylococcal infection?
culturing on blood agar and MacConkey agar
T/F. when dealing with a staphylococcal infection you should always look for possible underlying dz?
T
How do you treat staphylococcal infections?
Tx with antimicrobial agent and eliminate primary cause
What does AMR stand for?
Antimicrobial resistance
What type of AMR is common in Staphylococcal sp.?
B-lactamase- mediated resistance
What is MRSA and MRSP?
Methicillin resistance in S. aureus and S. pseudintermedius
Resistance to beta-lactam abx, also coincides with resistance to other antibacterial drugs. This is known as ____, and common drugs are:
Multidrug resistance
macrolides, aminoglycosides, tetracycline, sulfa drugs
methicillin resistance is mediated by ____ gene resulting in altered penicillin binding proteins.
mecA
What are the 2 types of acquired infections by MRSA?
- hospital acquired infections (HA)
2. Community acquired infections (CO)
