Staphylococcus 1 Flashcards

1
Q

What are the major points to understand about Pathogenic Streptococcus spp?

A

tend to be species-adapted

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2
Q

With staphylococcus what test is used to determine if its Staphylococcus aureus or other type of Staph?

A

coagulase test - S. aureus is coagulase pos

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3
Q

Transmission of Staphylococcus spp. can occur how?

A

via exogenous or endogenous spread

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4
Q

What factors would predispose and animal to Staphylococcus?

A

Compromise in the integrity of skin or mucous membrane
Impairment in some other host defense
Presence of a foreign body - e.g. catheter, suture, prosthesis

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5
Q

What are the cell associated virulence factors of Staphylococcus?

A

capsule, protein A, adhesions

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6
Q

What is the purpose of protein A virulence factor?

A

avoid phagocytosis

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7
Q

Exotoxins are a virulence factor for Staphylococcus. What is their pathogenic effect?

A

Food poisoning in humans

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8
Q

What are the three Staphylococcus species of veterinary importance?

A

S. auerus, S. pseudointermedius, S. hyicus

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9
Q

Of the three veterinary importance Staphylococcus which ones are coagulase positive?

A

S. aureus
S. pseudintermedius

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10
Q

Clinical conditions due to S. aureus in sheep are:

A

Tick pyemia, mastitis, dermatitis

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11
Q

S. aureus causes what in horses?

A

Scirrhous cord - botryomycosis of the spermatic cord

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12
Q

S. pseudintermedius in dogs causes what?

A

Pyoderma, endometritis, cystitis, otitis externa and other suppurative conditions

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13
Q

If we are culturing Staphylococcus what would we see on blood agar?

A

Observe for colony morphology

Hemolysis

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14
Q

What biochemical tests are used for diagnosing staphylococcus spp?

A

Catalase
Coagulase
DNase
Latex agglutination tests

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15
Q

T or F Staphylococcus spp. are non-fastidious.

A

True - grow on non-enriched media

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16
Q

What do staphylococcus colonies look like on medium?

A

yellowish/golden (especially S. aureus)

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17
Q

What type of test would you utilize to distinguish between S. aureus and S. epidermidis?

A

Tube coagulase test

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18
Q

Methicillin-resistance (MR) is the major cause of antibiotic resistance with Staphylococcus. What encodes for this resistance? Which antibiotic is it resistant against?

A

mec A/C gene, resistance to beta-lactam antibiotics

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19
Q

Due to multidrug resistance staphylococcal infections in animals, what antibiotics are veterinarians left with for treatment?

A

rifampicin, chloramphenicol, aminoglycosides, newer antimicrobial agents

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20
Q

What are the three major points to understand about Staphylococcus spp?

A

major opportunistic pathogen, associated pyogenic infections, mainly involved in skin and soft tissue infections

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21
Q

T or F Some Enterococci are of emerging importance because of innate resistance to most common antimicrobials

A

TRUE

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22
Q

What test do we use to determine if its staphylococcus or streptococcus?

A

staph is catalase positive, step and enterococcus are catalase negative

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23
Q

Staphylococcus are Gram () that form clusters

A

Gram (+)
irregular clusters that resemble a bunch of grapes

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24
Q

Staphylococcus spp. are resistant to what enzyme?

A

lysozyme

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25
Q

What type of infection to Staphylococcus spp. cause?

A

pyogenic infections (via opportunistic pathogens)

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26
Q

T or F Staphylococcus spp. are only a cause of secondary infection.

A

False can be primary or secondary infection

27
Q

Staphylococcus spp. virulence factor capsule has what pathogenic effect?

A

Anti-phagocytic

28
Q

Adhesins allow Staphylococcus to not only bind to host cells but is important for formation of what?

A

Biofilms

29
Q

What staphlococci exotoxin is a superantigen in humans?

A

Toxic Shock Syndrome Toxin

30
Q

What causes desquamation as an exotoxin?

A

Exfoliative toxin

31
Q

What is the pathogenic effect of hemolysins and leukocidin?

A

hemolysin: Destroy red blood cells

leukocidin: Kills polymorphonuclear leukocytes

32
Q

What exoenzymes pathogenic effect is the break down of hydrogen peroxide?

A

catalase

33
Q

Which exoenzymes pathogenic effect is to promotes clotting; may lead to walling off the infection site?

A

coagulase

34
Q

How many species are there of Staphylococcus?

A

over 50

35
Q

Staphylococcus pseudintermedius is isolated from what species?

A

dogs and cats

36
Q

S. aureus can be hosted in what species?

A

cattle, sheep, horses, and poultry

37
Q

Clinical conditions due to S. aureus in cattle are:

A

Mastitis

38
Q

S. aureus causes what in poultry?

A

bumblefoot

39
Q

S. hyicus in pigs causes what?

A

Exudative epidermitis (greasy-pig disease)

40
Q

S. equorum is a commensal in what species?

A

horse

41
Q

S. felis is a commensal in what species?

A

cats

42
Q

S. equorum and S. felis are coagulase ___?

A

negative

43
Q

What specimens can be used for diagnosis of Staphylococcus?

A

Pus, milk or other suitable specimens

44
Q

When culturing Staphylococcus, what medium do we use?

A

Blood agar and selctive medium

45
Q

If we are culturing a sample and suspect Staphylococcus, which selective media would be used?

A

MSA and Purple Agar

46
Q

PCR is used to detect what with Staphylococcus spp?

A

To detect MRSA, MLST

47
Q

What type of oxygen content do Staphylococcus require?

A

Facultative anaerobes

48
Q

T or F Staphylococcus species are mostly salt tolerant, catalase (+), non-motile, and non-spore forming

A

TRUE

49
Q

How quickly do Staphylococcus grow on medium?

A

Rapid growth in 18-24 hours at 37°C

50
Q

hemolysis on blood agar can be variable with Staphylococcus. What does this mean?

A

Depends on species can be non-hemolytic, single hemolysis, or double hemolysis

51
Q

S. aureus and S. pseudintermedius produce what type of hemolysis on blood agar

A

Produce double haemolysis on sheep blood agar

52
Q

The use of Mannitol Salt Agar (MSA) is used to differentiate between what spp?

A

Differentiates staphylococci from coliforms and streptococci

53
Q

What staph spp. causes yellow fermentation on purple agar?

A

S. aureus - this is due to fermenting the maltose

54
Q

Since Staphylococcus spp are normal commensals, where are they found on the body?

A

skin, mucous membranes, URT, lower urogenital tract, trasient flora of GIT

55
Q

Which type of staphylococci (coagulase positive or negative) can cause infections?

A

both

56
Q

Staphylococcus spp. can be cultured on what agar?

A

blood agar

57
Q

What are the common clinical conditions seen in dogs and cats due to Staphylococcus spp?

A

pyoderma, otitis externa, mastitis, osteomyelitis, wound infection

58
Q

Why are Methicillin-resistant staphylococcal infections important to understand in vet med?

A

Difficult to treat, may display multidrug resistance

59
Q

T or F Staphylococci are catalase-negative

A

False - they are positive

60
Q

T or F Only coagulase-positive staphylococci are pathogenic

A

False: both can cause infections

61
Q

T or F Staphylococcus hyicus is non-hemolytic

A

TRUE

62
Q

T or F Staphylococcus aureus and Staphylococcus pseudintermedius are non-hemolytic

A

False: they are both hemolytic

63
Q

T or F Staphylococcus aureus is responsible for greasy pig disease/exudative epidermitis

A

False: S. hyicus via exfoliative toxin

64
Q

What virulence factors of Staph are the exoenzymes?

A

Catalase -Lipase -Elastase -Hyaluronaidase