5.1 Gram Positive Aerobic Cocci Flashcards
what are the 3 types of gram positive aerobic cocci
staphylococcus, streptococcus, enterococcus
how is catalase a virulence factor for some gram positive aerobic cocci
prevents oxidative damage by converting hydrogen peroxide to water and oxygen
For the 3 gram positive aerobic cocci, what are the results of the catalase test:
Staphylococcus: positive
Streptococcus: negative
Enterococcus: negative
T/F most staphylococcus species are pathogenic
F: mostly non-pathogenic
where is staphylococcus present
commensal of skin and exposed mm.; also an opportunist
what types of infections does staphylococcus spp. cause
purulent and necrosis
does staphylococcus survive well or poorly in the environment
well
what are the 3 staphylococcus species of interest (pathogenic)
S. aureus; S. pseudointermedius (SIG); S. hyicus
name a disease caused by the following and ID what species:
S. aureus
S. pseudointermedius
S. hyicus
S. aureus: mastitis (cows), bumblefoot (chickens)
S. pseudointermedius: pyoderma, UTI (dogs and cats)
S. hyicus: exudative epidermatitis (greasy pig disease - pigs)
what is the characteristic appearance of S. aureus infection and what is a very common infection
pus, necrosis; UTIs
Is S. aureus zoonotic
Y
S. aureus is responsible for what important condition in humans
toxic shock syndrome
what does MRSA stand for and what does it mean
Methicillin Resistant Staphylococcus Aureus; means that the bacteria is resistant to all β-lactams
what is the major and most common opportunistic pathogen of dogs
S. pseudointermedius
is S. pseudointermedius zoonotic
Y
name some types of diseases caused by S. pseudointermedius in dogs
otitis externa, pyoderma, UTIs, metritis, vaginitis
what does MRSP stand for and what does it mean
Methicillin Resistant Staphylococcus Pseudointermedius; means MULTIRESISTANT, not just to β-lactams….
what is the causative agent of exudative epidermitis in pigs? what age group does it commonly affect
Staphylococcus hyicus; young pigs
what do we use to differentiate the pathogenic strains of Staphylococcus
MALDI-TOF MS
how do we treat and prevent staphylococcus infections
prevention: good hygeine, protocols; asepsis
treatment: perform susceptibility testing to choose an antimicrobial; give antimicrobials and treat primary cause
what is the characteristic appearance of streptococcus
chains of cocci
where is streptococcus
commensal of mucous membranes (NOT skin)
does streptococcus survive well or poorly in the environment
poorly
what kind of infections does streptococcus cause
pyogenic
what are the 5 main species of streptococcus and what species do they have specificity for
1) S. equi (horses)
2) S. zooepidemicus (horses)
3) S. agalactiae (cattle)
4) S. suis (pigs and humans)
5) S. canis (dogs, cats)
what is a key virulence characteristic of streptococcus species
β-hemolysis: lysis of RBCs surrounding the colony
What are the 2 types of hemolysins
O: inactive in presence of oxygen
S: stable in presence of oxygen
what are M proteins and what type of gram positive aerobic cocci contains them
antiphagocytic surface proteins; streptococci
what are the 3 main virulence factors of streptococcus spp.
1) Beta-haemolysis
2) M protein
3) teichoic acid
what are three characteristics of streptococcus infection
1) pus producing
2) spread locally
3) septicemia in immunocompromised
what pathogen causes strangles outbreaks in horses and what is the characteristic appearance
Streptococcus equi; abscesses in lymph nodes of head and neck
how do you treat strangles outbreaks caused by S. equi
- identify guttural pouch carriers and infected horses
- isolation, quarantine, cleaning, disinfection
- treat early with penicillin
- give vaccine
what is “the” cause of opportunistic purulent infections in horses
S. zooepidemicus
what can happen to a foal infected with S. zooepidemicus if no colostrum was given
septicemia (think back to the point that it usually causes local spread but causes sepsis if no antibodies are present)
what does S. canis cause in dogs and cats? what are 2 major conditions caused by S. canis that also can occur in people (from a different pathogen)
opportunistic purulent infections: UTIs, wound infections, otitis externa, mastitis,
necrotizing fasciitis, toxic shock
what is the primary pathogen of the udder of cattle and what does it cause
Streptococcus agalactiae; contagious mastitis and subclinical mastitis
a cow presents with abnormal udders. looking from behind, one quarter is large and one is small. you suspect that ___________, a major subclinical mastitis agent of cows, is present in what quarter
Streptococcus agalactiae; the smaller quarter (it causes fibrosis and atrophy)
where is streptococcus suis found and what type of pathogen is it
in the tonsils; primary pathogen
what age group is most affected by S. suis
weaner pigs
are carriers a problem with S. suis control?
yes - hard to detect
polyserositis, fibrinohaemorrhagic pneumonia, arthritis and endocarditis in weaner pigs is commonly caused by
S. suis
T/F antimicrobial susceptibility testing should be done if you identify streptococcus species but not staphylococcus species
F; other way around; staphylococcus spp. commonly resistant
what is a concern when you want to send a sample of streptococcus to a lab and why
transport media needed; they dont like to dry; they normally live in mucosa of animals
what is a good antimicrobial to choose when you identify an infection caused by streptococcus in an animal
penicillin G
what type of bacteria are enterococcus
facultative anaerobes, low grade opportunist
enterococcus spp. cause diverse infections, such as:
- mastitis
- wound infections
- UTIs
- nosocomial infections
what bacteria is the leading cause of nosocomial infection
enterococcus
what species of enterococci is VRE
vancomycin resistant enterococci refers to E. faecium (NOT E. faecalis or E. ceconium)
T/F resistance is a problem with enterococci spp.
T; they are part of the ESKAPE group
