Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Microbiology > Micrococcaceae > Flashcards

Micrococcaceae Flashcards

You may prefer our related Brainscape-certified flashcards:
Biology 101 flashcards
1
Q

Micrococcaceae

A

staphylococcus and micrococcus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Staphylococcus species

A

S. aureus, S. epidermidis, S. hemolyticus, S. saprophyticus, S. intermedius

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Micrococcaceae general characteristics

A
  • Gram-positive cocci, catalase positive, singly, pairs or in clusters
  • Colony morphology: cream-colored, buttery on BA or CNA, some produce Beta hemolysis
  • aerobic or falcultative anaerobes, non motile, non spore forming, non encapsulated
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

exceptions to general characteristics

A

S. saprophyticus is an obligate anaerobe

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Micrococcus luteus

A
  • Gram-positive, catalase positive, coagulase negative
  • morphology: distinct yellow colony
  • non-pathogen
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

coagulase

A

staphylocoagulase enzyme clots plasma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

coagulase positive staphylococci

A
  • S. aureus (human pathogen)

- S. delphini, S. intermedius, S. lutrae, S. hyicus (animal pathogens)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

coagulase negative staphylococci (CoNS)

A
  • S. epidermidis (nosocomial infections)

- S. saprophyticus (UTI’s in young, sexually active females)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Staphylococcus aureus

A
  • exist in carrier state in 20-30% of population
  • most virulent staph species
  • superficial to systemic infections
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Virulence factors of S. aureus

A
  • enzymes: coagulase, hyaluronidase, lipase
  • enterotoxins, toxins A-E and G-I, exfoliative toxins, cytolytic toxin
  • Protein A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

hyaluronidase

A

hydrolyzes the hyaluronic acid present in connective tissue and helps spread infection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

lipase

A

breaks down the fats and oil created by sebaceous glands on skin surfaces

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

enterotoxins

A

heat-stable exotoxins that cause diarrhea and vomiting

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

toxins A-E and G-I

A
  • resistant to gastric acid and associated with food poisoning
  • A, B, and D associated with staph food poisoning
  • toxic shock syndrome toxin-1 (TSST-1)
  • TSST-1, B, C, G, and I are superantigens
  • causes toxic shock syndrome
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

exfoliative toxin (epidermolytic toxin)

A

causes epidermal layer of skin to slough off; causes Scalded Skin Syndrome and bullous impetigo

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

cytolytic toxins

A

alpha, beta, and gamma hemolysin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

alpha hemolysin

A

destroys platelets and tissues

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

beta hemolysin

A
  • acts on the sphingomyelin of RBC membranes, causing lysis

- hot-cold lysin because works at 37 and 4 degrees C

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

gamma hemolysin

A
  • also called Panton-Valentine leukocidin (PVL)
  • exotoxin kills polymorphonuclear leukocytes to help prevent phagocytosis
  • typically associated with community-acquired infections
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Protein A

A
  • binds the fragment crystallizable (Fc) portion of an antibody to avoid phagocytosis by masking it immunogenic proteins with host proteins to look like “self”
  • negates the protective effects of IgG
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Transmission of Staph. aureus

A
  • colonizes nares (20-30% carriers)
  • axillae, vagina, pharynx, other skin surfaces
  • nosocomial
  • fomites, poor hygiene
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Clinical cases of Staph. aureus include

A

localized (pyogenic) skin infections, impetigo

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Scalded Skin Syndrome

A
  • extensive exfoliative dermatitis, most likely to occur in renal failure patients and ICP’s
  • localized lesion to profuse peeling
  • 2-4 days, can be fatal in adults, spontaneous recovery in children
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

toxic shock syndrome

A
  • associated with super-absorbent tampons
  • high fever, rash of the trunk/extremeties, watery diarrhea, vomiting, dehydration, leads to hypotension
  • Disseminated intravascular coagulation (DIC),
  • increase in blood urea nitrogen (BUN) and creatinine
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

toxic epidermal necrolysis (TEN)

A
  • causes: drug induced, infections, vaccines
  • similar to Staph. Scaleded Skin Syndrome (SSSS), except steroids can be effective
  • high mortality rate
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q
  • Gram-positive cocci, catalase positive, singly, pairs or in clusters
  • Colony morphology: cream-colored, buttery on BA or CNA, some produce Beta hemolysis
  • aerobic or falcultative anaerobes, non motile, non spore forming, non encapsulated
A

Micrococcaceae general characteristics

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q
  • Gram-positive, catalase positive, coagulase negative
  • morphology: distinct yellow colony
  • non-pathogen
A

Micrococcus luteus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q
  • exist in carrier state in 20-30% of population
  • most virulent staph species
  • superficial to systemic infections
A

Staphylococcus aureus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

hydrolyzes the hyaluronic acid present in connective tissue and helps spread infection

A

hyaluronidase

30
Q

breaks down the fats and oil created by sebaceous glands on skin surfaces

A

lipase

31
Q

heat-stable exotoxins that cause diarrhea and vomiting

A

enterotoxins

32
Q

causes epidermal layer of skin to slough off; causes Scalded Skin Syndrome and bullous impetigo

A

exfoliative toxin (epidermolytic toxin)

33
Q

destroys platelets and tissues

A

alpha hemolysin

34
Q
  • acts on the sphingomyelin of RBC membranes, causing lysis

- hot-cold lysin because works at 37 and 4 degrees C

A

beta hemolysin

35
Q
  • also called Panton-Valentine leukocidin (PVL)
  • exotoxin kills polymorphonuclear leukocytes to help prevent phagocytosis
  • typically associated with community-acquired infections
A

gamma hemolysin

36
Q
  • binds the fragment crystallizable (Fc) portion of an antibody to avoid phagocytosis by masking it immunogenic proteins with host proteins to look like “self”
  • negates the protective effects of IgG
A

Protein A

37
Q
  • extensive exfoliative dermatitis, most likely to occur in renal failure patients and ICP’s
  • localized lesion to profuse peeling
  • 2-4 days, can be fatal in adults, spontaneous recovery in children
A

Scalded Skin Syndrome

38
Q
  • associated with super-absorbent tampons
  • high fever, rash of the trunk/extremeties, watery diarrhea, vomiting, dehydration, leads to hypotension
  • Disseminated intravascular coagulation (DIC),
  • increase in blood urea nitrogen (BUN) and creatinine
A

toxic shock syndrome

39
Q
  • causes: drug induced, infections, vaccines
  • similar to Staph. Scaleded Skin Syndrome (SSSS), except steroids can be effective
  • high mortality rate
A

toxic epidermal necrolysis (TEN)

40
Q

food poisoning

A
  • enterotoxins A, B, and D, from enterotoxin-producing strains contaminating rich foods and inadequate refrigeration
  • toxin causes the sickness, 2-8 hrs after ingestion, lasts 24-48 hrs, nausea, vomiting, abdominal pain, cramping
41
Q
  • enterotoxins A, B, and D, from enterotoxin-producing strains contaminating rich foods and inadequate refrigeration
  • toxin causes the sickness, 2-8 hrs after ingestion, lasts 24-48 hrs, nausea, vomiting, abdominal pain, cramping
A

food poisoning

42
Q

Other infections caused by staph species

A

secondary pneumonia, bacteremia and endocarditis, osteomyelitis, arthritis (if bacteria in joints)

43
Q
  • predominately nosocomial infections (skin flora introduced in catheters, CSF shunts and heart valves)
  • produces a slime layer to adhere to prosthetics and avoid phagocytosis
  • common cause of hospital-acquired UTI’s
A

Staph. epidermidis

44
Q
  • causes UTI’s in young, sexually active females
  • increased adherence to epithelial cells of urogenital tract
  • found in urine cultures
A

S. saprophyticus

45
Q
  • coagulase negative staph that mimics S. aureus infection

- pathogen of infective endocarditis, septicemia, meningitis, skin and soft tissue infections, UTI’s, and septic shock

A

Staph. lugdunensis

46
Q

Opportunistic staphs

A
  • S. warneri, S. capitis, S. simulans, S. hominis, S. schleiferi
  • normal flora that can cause endocarditis and septicemia
  • CoNS
47
Q
  • common CoNS found in wounds, bacteremia, endocarditis and UTI’s
  • may have resistance to vancomycin
A

S. haemolyticus

48
Q

Isolation of Staphs

A
  • grow well on blood agar and thioglycolate
  • if contaminated specimen, can be selected for on mannitol salt agar, Columbia colistin-nalidixic acid agar (CNA), PEA, CHROMagar
49
Q

Thioglycolate broth

A
  • pancreatic digest of casein, soy broth and glucose

- supports anaerobes, aerobes, microaerophilic and fastidious organisms

50
Q
  • colistin, nalidixic acid, and 5% sheep blood

- selects for isolation of gram-positive cocci

A

Columbia colistin-nalidixic acid agar (CNA)

51
Q
  • peptone base, mannitol, 7.5% salt, phenol red indicator
  • selective isolation for staph.
  • turns yellow if mannitol is hydrolyzed (S. aureus)
A

Mannitol salt agar

52
Q

CHROMagar

A

MRSA colonies show up magenta

53
Q

Identification methods

A

oxidative-fermentative glucose medium, modified oxidase, catalase, coagulase, PYR, Bacitracin disk test, Novobiocin, antimicrobial susceptibility

54
Q

Oxidative-fementative glucose medium

A

most Staph. ferment glucose, while Micrococci don’t

55
Q

modified oxidase

A

microdase disk will be positive for Micrococci and negative for most Staphylococci

56
Q

Catalase test

A
  • hydrogen peroxide becomes water and oxygen gas in the presence of enzyme catalase
  • bubbling is positive, staph. are positive
57
Q

coagulase

A

clumping factor that causes agglutination in plasma

58
Q

coagulase test

A
  • mix water or saline with organism and rabbit plasma
  • if it clumps, it’s positive
  • if negative, tube test must be run
  • hallmark test for S. aureus (other staph can be pos. too)
59
Q

extracellular free coagulase

A
  • extracellular enzyme that clots plasma

- tube test: check for clotting 4 hrs and 24 hrs after inoculation

60
Q

PYR

A

negative for S. aureus, but positive for other coagulase positive staph

61
Q

Groups of Coagulase-positive staph

A

S. aureus group, S. hyicus group, S. intermedius group

62
Q

PYR test

A
  • detection of pyrrolidonyl arylamidase helps differentiate streptococci and enterococci
  • color change to red if positive
63
Q

Bacitracin disk test

A
  • differentiates Micrococcus from CoNS
  • Micrococcus luteus is susceptible
  • CoNS are resistant (sapro, epidermidis)
64
Q

Novobiocin test

A
  • presumptive differentiation of CoNS
  • if resistant, S. saprophyticus
  • if susceptible, likely S. epidermidis
65
Q

Rapid Identification

A

BBL staphloslide, Staphaurex, Bactistaph, Plasma-carrier coated particles detect clumping factor and protein A, PCR for MRSA and MSSA, qualitative nucleic acid hybridization assays, MALDI-TOF mass spectrometry

66
Q

antimicrobial susceptibility

A
  • most S. aureus are resistant, so you need to do Beta-lactamase test
67
Q

MRSA

A
  • community-acquired MRSA, health care-associated/community onset MRSA, hospital associated MRSA
  • infection control by barrier protection, contact isolation and handwashing
  • treat w/ vancomycin (susceptibility test with cefoxitin disk)
68
Q

Borderline oxacillin-resistant S. aureus (BORSA)

A

can separate from MRSA on oxacillin salt agar plate

69
Q

mecA gene

A

gene in MRSA that encodes penicillin-binding proteins (PBPs); very few express phenotype

70
Q

Gold standard

A

mecA gene detected by PCR

71
Q

VRSA

A

Vancomycin resistant staph. aureus

72
Q

Macrolide resistance

A
  • resistance to clindamycin may not be obvious
  • if resistance to clindamycin and erythromycin are not the same, do a D test
  • induced resistance if forms a D (on clindamycin side)

Microbiology (26 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions