Day 1: Question 1 - Preliminary ID Flashcards

1
Q

What are the basic characteristics for staphylococcus
(6)

A

No haemolysis
No odour
Catalase positive*
Oxidase negative
KoH negative

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2
Q

What Preliminary ID test results indicate Staphylococci

A

Cocci

Gram positive

Catalase positive

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3
Q

How do you know a GP and catalase cocci is a staphylococcus and not a micrococcus?

A

Micrococcus are extremely small
Staphylococcus are so much more common

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4
Q

What five tests would you do to speciate staphylococci?

A

DN’ase test

Mannitol salt agar

SAIDE agar -> Chromid S.aureus ELITE agar

Novobiocin susceptibility test

Coagulase test -> Staphaurex P test -> protein A test

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5
Q

What are the three classifications of streptococci

A

Alpha haemolytic

Beta haemolytic

Gamma haemolytic

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6
Q

What are the basic characteristics for streptococci
(4)

A

Could be alpha, beta or gamma haemolyisis

Gram positive

Aerobe

Catalase negative*

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7
Q

What tests would you carry out for streptococci?
(6)

A

Lancefield grouping (b) (g)

Bacitracin (b)

Optochin (a)

MacConkey (g)

Bile Aesculin (g)

Vancomycin (g)

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8
Q

What are the basic characteristic test results for enterococci?
(4)

A

Cocci*

Gram positive*

Aerobe*

Catalase negative *

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9
Q

What’s the most important step when identifying streptococci/enterococcus?

A

If you have a gram positive, aerobe, catalase negative cocci, you need to be able to identify haemolysis

Only certain tests carried out for each type of haemolysis

Gamma haemolysis usually means an enterococcus

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10
Q

What are the basic characterisation results for Neisseria or Moraxella?

A

Cocci
Gram negative
Diplococci
KOH positive
Catalase positive
Oxidase negative

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11
Q

What tests do you carry out for presumptive Neisseria or Moraxella?
(3)

A

TAXO

DN’ase

Catarrhalis test (M. Catarrhalis)

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12
Q

How could you distinguish Moraxella from Neisseria on an agar plate?

A

Moraxella is pushable

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13
Q

What are the basic characteristic test results for Haemophilus

A

Gram negative*

Aerobe*

Coccobacilli*

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14
Q

List the tests used to confirm haemophilus

A

Factor X, V, XV test

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15
Q

What are the basic characteristic test results for bacillus species?

A

Bacilli

Gram positive

Aerobe

Sporing

Catalase

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16
Q

What tests should you carry out for bacillus
(2)

A

PEMBA

Motility

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17
Q

What are the basic characteristic test for Corynebacteria?
(5)

A

Bacilli

Gram positive

Aerobe

Non sporing

Catalase positive

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18
Q

What are the tests for corynebacteria
(3)

A

Trehalose

Urease

Tinsdale

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19
Q

What are the basic characterisation test results for enterobacterales?
(5)

A

Bacilli

Gram negative

Aerobe

Rod

Oxidase negative*

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20
Q

What tests should you carry out for enterobacterales

A

Biochemical testing -> with MacConkey purity plate

Brilliance chromogenic agar

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21
Q

Why is the MacConkey plate so important in the biochemical test for enterobacterales?

A

Enterobacterales are classified based on their ability to ferment lactose -> pink colonies = lactose fermenter, yellow colonies = non lactose fermenter

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22
Q

What are the lactose fermenter enterobacterales?

A

Escherichia

Enterobacter

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23
Q

What are the non lactose fermenter enterobacterales?

A

Salmonella

Proteus

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24
Q

What are the basic characterisation tests for pseudomonas?
(5)

A

Bacilli

Gram negative

Aerobic

Rod

Oxidase positive

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25
Q

What tests are used for pseudomonas
(2)

A

Growth at different temperatures -> 42 degrees and 4 degrees

Kings A medium

26
Q

What are the basic characteristic test results for clostridium

A

Bacilli*
Gram positive*
Anaerobe*
Sporing*

27
Q

What are the tests for clostridium
(4)

A

Metronidazole and anaerobic growth

Egg yolk

Naglar

Lactose-gelatin

28
Q

How can you distinguish between moraxella and neisseria?

A

Moraxella have larger pushable colonies

29
Q

What are the three clinically significant staphylococci?

A

Aureus

Epidermidis

Saprophyticus

30
Q

What are the five clinically significant strains of streptococci?

A

Strep pneumonia

Strep pyogenes

Strep viridans

Strep mutans

Strep agalactiae

31
Q

How can you tell a strep is strep pneumoniae from how is appears on a blood agar plate and under a microscope

A

Alpha haemolysis

Draughtsman colonies or mucoid colonies

Lanceolate -> flame shaped cocci

32
Q

What strep strains have alpha haemolysis

A

S pneumoniae (most likely)

S viridians

33
Q

What strep strains have beta haemolysis

A

S pyogenes (most likely)

S agalactiae

34
Q

What strep strains have gamma haemolysis

A

S. bovis however any gram positive cocci which are catalase negative and don’t have haemolysis are more than likely enterococcus than strep

35
Q

Which are the most significant Lancefield grouping?
(4)

A

Group A = Strep pyogenes

Group B = Strep agalactiae

Group C = Strep equi or strep equisimilis

Group D = Enterococcus faecalis or Strep bovis

36
Q

What are the three clinically significant species of Enterococcus

A

E. faecalis

E. faecium

E. durans

37
Q

What should you do if you ID an enterococcus?
(2)

A

Suggest vancomycin susceptibility as some strains are resistant

Suggest chromogenic VRE Medium

38
Q

How could you identify Neisseria before carrying out tests
(3)

A

Seen in pairs

Often kidney shaped cocci

Grown on chocolate agar

39
Q

How could you identify moraxella before carrying out tests
(3)

A

Cocci in pairs

Tend to resist decolorisation

Grown on chocolate agar

40
Q

List the six clinically significant strains of Neisseria

A

N. gonorrhoeae

N. meningitidis

N. pharyngitis

N. lactamica

N. flavescens

N. sica

41
Q

List the clinically significant strains of Bacillus species
(4)

A

Bacillus anthracis

Bacillus cereus

Bacillus subtilis

Bacillus thuringenesis

42
Q

What would indicate B. anthrax in a case study?
(3)

A

Food poisoning from eating contaminated fried rice

Contact with animals

Anthrax -> skin (blister), lung, intestine, injection

43
Q

How could you identify B. anthrax from a gram stain?
(3)

A

Medusa head -> large tangled chains of bacilli

Large, grey-white colonies

No haemolysis

44
Q

What species of Bacillus have B-haemolysis

A

Bacillus cereus

Bacillus thuringenesis

45
Q

What species of Bacillus have alpha-haemolysis

A

B.anthrax (usually no haemolysis)

B. subtilis (definitely alpha)

46
Q

What are the clinically significant species of Corynebacteria

A

C. diptheria

C. ulcerans

C. pseudotuberculosis

Diptheroids

47
Q

How would you know if you have a corynebacteria and not a listeria species

A

Corynebacteria grow on Tinsdale but listeria wont

48
Q

What are the clinically significant species of Clostridium

A

C. botulinum

C. difficile

C. perfringens

C. tetani

49
Q

Where is C. botulinum found and what infections does it cause?
(2)

A

Its an organism that produces a toxin in food/wound

It causes botulism

50
Q

Where is C. difficile found and what infections does it cause?

A

Often overgrows commensals in the gut during antibiotic therapy and can cause pseudomembranous colitis

51
Q

What infection does C. tetani cause

A

Tetanus

52
Q

How do you differentiate pseudomonas from enterobacterales

A

Pseudomonas is oxidase positive

53
Q

List the five clinically significant species of Haemophilus

A

H. influenzae

H. parainfluenzae

H. ducreyi

H. aegyptius

H. aphrophilus

54
Q

What species of proteus are clinically significant

A

Proteus mirabilis

Proteus vulgaris

55
Q

How can you identify proteus on an agar plate

A

Swarming colonies

56
Q

What are the clinically significant strains of pseudomonas

A

P. aeruginosa

P. fluorescence

57
Q

List the genera that make up the family bacteroidaceae
(4)

A

Bacteroides

Poryphyromonas

Prevotella

Fusobacterium

58
Q

What are the three clinically significant species of bacteroides?

A

B. fragilis

B. oralis

B. ureolyticus

59
Q

What are the five strains of fusobacterium

A

F. nucleatum

F. necrophorum

F. periodonticum

F. mortiferum

F. necrophorum

60
Q

What is the only clinically significant strain of pasteurella

A

P. multocida

61
Q

What is the only clinically significant strain of prevotella?

A

Pr. melaninogenica