MICRO Blood/ Fluids/ Anaerobes Flashcards

1
Q

Normal flora in blood and CSF

A

None; sterile sites

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2
Q

List potential bacteria isolated in blood cultures

A

NOTE: may be a skin contaminant OR pathogen

S. aureus
S. pneumoniae (β strep)
Haemophilus sp.
Listeria monocytogenes
Bacteroides sp. (anaerobes)
Pseudomonas sp.
Enterococcus sp.
Campylobacter sp.
Enterobacteriaceae
Candida sp.

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3
Q

What causes ACUTE bacterial endocarditis ?

A
  • develops within 2 months after implantation of prosthetic heart valve
  • S. aureus, S. epidermidis
  • S. pneumoniae, N. meningitidis, S. pyogenes, N. gonorrhoeae, P. aeruginosa, and Enterobacteriaceae sp.
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4
Q

What causes SUB-ACUTE bacterial endocarditis ?

A
  • normally avirulent viridans group streptococci
  • enter bloodstream during dental procedure
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5
Q

Differentiate septicemia vs bacteremia

A

Septicemia: systemic disease due to persistence of pathogenic organisms OR toxins in blood

Bacteremia: simply presence of bacteria in blood

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6
Q

List potential bacteria isolated in CSF cultures

A
  • N. meningiditis
  • S. agalactiae
  • S. aureus
  • K. pneumoniae and S. pneumoniae
  • Haemophilus influenzae
  • Listeria monocytogenes
  • Pseudomonas aeruginosa
  • E. coli
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7
Q

T or F: handling of all lumbar puncture specimens is ALWAYS considered STAT

A

TRUE; due to seriousness of infections in the nervous system, handling of all lumbar puncture specimens is ALWAYS considered STAT

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8
Q

Which pathogen is common in other sterile bodily fluids but NOT BLOOD OR CSF ?

A

N. gonorrhoeae

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9
Q

Test Results to ID S. aureus

A

col morph= wop(h), gop(h)
%= gpc cl
cat= pos
slide/ tube coag= pos
DNAse= pos
TA= R

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10
Q

Which KB disk differentiates MSSA vs MRSA ?

A

Cefoxitin (FOX)

MSSA= S
MRSA= R

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11
Q

Test results for ID of S. pneumonia

A

col morph= (wet) alpha
%= gpc prs
TP= S
Bile Sol= pos

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12
Q

Test results for ID of N. gonorrhoeae

A

col morph= shygy
%= gndc
Ox= pos

CTA sugars:
Dextrose= pos
Maltose, Sucrose, Lactose= neg

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13
Q

Media for N. gonorrhoeae, N. meningitidis

A

Thayer Martin in CO2, New York City Agar in CO2

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14
Q

Test results for ID of N. meningitidis

A

col morph= shygy
%= gndc
Ox= pos

CTA sugars:
Dextrose, Maltose= pos
Sucrose, Lactose= neg

NOTE: M for Maltose and Meningitidis

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15
Q

Test results for N. lactamica

A

col morph= shygy
%= gndc
Ox= pos

CTA sugars:
Dextrose, Maltose, Lactose = pos
Sucrose= neg

NOTE: L for Lactose and Lactamica

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16
Q

List the CTA sugars

A

Cystine Tryptic Agar:

Base
Dextrose
Maltose
Sucrose
Lactose

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17
Q

How can M. catarrhalis be differentiated from Neisseria sp?

A

Butyrate esterase (catarrhalis disk)= pos
CTA sugars= neg for all (dextrose, maltose, sucrose, lactose)

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18
Q

Test results to ID S. agalactiae

A

col morph= small beta
%= gpc ch
cat= neg
PYR= neg
Latex= B
CAMP= pos
TA= R

NOTE: C for Camp and agalaCtiae

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19
Q

Test results to ID K. pneumoniae

A

MAC= pk
HE= yel
Orient= blu
TSI= A/Ag
Indole= neg
Lysine= pos

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20
Q

Test results to ID E. coli

A

%= gnb
MAC= pk
HE= gn
Orient= pk
TSI= A/Ag
Indole= pos
Lys= pos

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21
Q

What is propionibacterium ?

A

Contaminating flora (anaerobic)

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22
Q

Test results to ID H. influenzae

A

%= gncb
BAPss= sats
ALA= neg

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23
Q

Test results to ID L. monocytogenes

A

col morph= beta
%= gpb
cat= pos
BE= pos
TSI= A/A sick
RT Motility= tumbling
37°C Motility= neg
Semi-solid Motility= umbrella pattern

24
Q

Test results to ID Enterococcus

A

col morph= ent
%= gpc ch
cat= neg/ wk+
PYR= pos
BE= pos
6.5% NaCl= pos

25
Q

Test results to ID P. aeruginosa

A

col morph= sheen
%= gnb
MAC= wh
TSI= K/K
Ox= pos
Nitrate= pos
Motility= pos
42°C =pos
UV= pos

26
Q

Test results to ID Campylobacter jejuni

A

Col morph= clr, flt, spr, drop-like
%= gnb, “seagull”
Cat= pos
Ox= pos
Motility= cork-screw

27
Q

What is the correct additional media OR test to the microscopic morphology: GPCCL

A

Tube coagulase

Pos = S. aureus
Neg = Staphylococcus sp.

28
Q

What is the correct additional media OR test to the microscopic morphology: GPCCH, α-hem on BAP

A

Ethyl hydrocupreine hydrocholride (Optochin /TP)

TP R = Viridans
TP S = S. pneumoniae

29
Q

What is the correct additional media OR test to the microscopic morphology: GNDC

A
  • Thayer-Martin
  • New York city agar

Growth = Neisseria sp.
No growth = Moraxella sp.

30
Q

What is the correct additional media OR test to the microscopic morphology: Box-square GPB

A

Egg yolk agar

Lecithinase pos (white precipitate) = C. perfringens

Lipase pos (pearly iridescent) = C. sporogenes*

*NOTE: lipids are shiny, and so are spoons

31
Q

Which of the following statements is true about the collection of blood culture specimens?

a.
If coagulase negative Staphylococci isolated it is due to poor collection technique

b.
Should be collected after the fever has subsided and the patient is feeling better

c.
Should always collect 2 sets; one with two anaerobic vials and the second set with one aerobic vial

d.
Collection should occur from 2 separate sites in case skin contamination occurs from one of the sites

A

d.
Collection should occur from 2 separate sites in case skin contamination occurs from one of the sites

32
Q

Which of the following organisms are susceptible to SPS?

a.
N. gonorrhoeae

b.
S. pneumoniae

c.
H. influenzae

d.
All of the above

A

a.
N. gonorrhoeae

33
Q

Which of the following stains is used to examine for the presence of bacteria in a blood culture after the gram stain reveals no bacteria seen?

a.
Acridine Orange

b.
Auramine Rhodamine

c.
Ziehl-Neelsen

d.
Calcofluor White

A

a.
Acridine Orange

34
Q

Which of the following methods is / are useful for direct viral examination?

Select all that apply:

a.
ELISA

b.
Western blot

c.
PCR

d.
Electron microscopy

A

a.
ELISA

c.
PCR

d.
Electron microscopy

35
Q

Which of the following terms best describe an organism which prefers an environment with oxygen present but which functions well without oxygen?

a.
Aerobe

b.
Microaerophilic

c.
Aerotolerant

d.
Facultative anaerobe

A

d.
Facultative anaerobe*

*NOTE: “can be” an anaerobe

36
Q

Which of the following organisms is associated with transient bacteremia?

a.
Coagulase negative staphylococci

b.
Diphtheroids

c.
Staphylococcus aureus

d.
Neisseria gonorrhoeae

A

a.
Coagulase negative staphylococci

37
Q

The following results are recorded for a tissue specimen:

Direct Smear Results:
4+ WBC
3+ RBC
3+ GPB

Culture Results:
BAPO2: no growth
BAP*: large translucent colony with two zones of hemolysis
MAC: no growth

Which of the following descriptors would best match the Gram stain result?

a.
Thin Gram positive bacilli with terminal spore

b.
Thick Gram positive bacilli with blunt ends and no spores

c.
Short Gram positive bacilli, almost coccoid in shape

d.
Short Gram positive bacilli, palisading

A

b.
Thick Gram positive bacilli with blunt ends and no spores

NOTE: C. perfringens

38
Q

The following results are recorded for a tissue specimen:

Direct Smear Results:
4+ WBC
3+ RBC
3+ GPB

Culture Results:
BAPO2: no growth
BAP*: large translucent colony with two zones of hemolysis
MAC: no growth

Which of the following terms best describe the atmospheric requirements of the organism?

a.
Facultative anaerobe

b.
Capnophilic organism

c.
Microaerophilic organism

d.
Obligate anaerobe

A

d.
Obligate anaerobe

39
Q

Which of the following organisms is resistant to kanamycin, vancomycin, and colistin?

a.
Peptostreptococcus sp

b.
Bacteroides fragilis

c.
Clostridium sp

d.
Veillonella sp

A

b.
Bacteroides fragilis

40
Q

Which of the following results best match the CSF from a patient with bacterial meningitis?

a.
PMNs, elevated glucose, elevated protein

b.
Lymphocytes, normal glucose, elevated protein

c.
PMNs, low glucose, elevated protein

d.
Lymphocytes, low glucose, elevated protein

A

c.
PMNs, low glucose, elevated protein

PMN - Polymorphonuclear leukocytes

41
Q

A patient is diagnosed with peritonitis after bowel surgery. Which of the following organisms is most likely to be isolated in the peritoneal fluid?

a.
Campylobacter jejuni

b.
Shigella dysentariae

c.
Bacteroides fragilis

d.
Salmonella enterica Serovar typhi

A

c.
Bacteroides fragilis
- an anaerobe

42
Q

The following results are recorded for a tissue specimen:

Direct Smear Results:
4+ WBC
3+ RBC
3+ GPB

Culture Results:
BAPO2: no growth
BAP*: large translucent colony with two zones of hemolysis
MAC: no growth

Which of the following tests will help identify the pathogen?

a.
KVC disks

b.
SPS disk

c.
Room temperature motility

d.
Reverse CAMP

A

d.
Reverse CAMP

NOTE: C. perfringens = pos

43
Q

The following results are recorded for a tissue specimen:

Direct Smear Results:
4+ WBC
3+ RBC
3+ GPB

Culture Results:
BAPO2: no growth
BAP*: large translucent colony with two zones of hemolysis
MAC: no growth

Which of the following conditions is often associated with this pathogen?

a.
Gas gangrene

b.
Otitis media

c.
Spontaneous abortion

d.
Pseudomembranous colitis

A

a.
Gas gangrene

NOTE: C. perfringens

44
Q

The following results are recorded for an isolate:

Gram stain: GPB large
Catalase: negative
Egg Yolk:
Lecithinase negative
Lipase positive
Reverse CAMP: negative

Which of the following organisms best fit the results?

a.
Clostridium sporogenes

b.
Actinomyces israelii

c.
Bacillus cereus

d.
Clostridium perfringens

A

a.
Clostridium sporogenes

NOTE: Lipase positive, Reverse CAMP negative

45
Q

Which of the following organisms is considered a Risk Group III organism?

a.
Francisella tularensis

b.
Pasteurella multocida

c.
Bordetella pertussis

d.
Neisseria meningitidis

A

a.
Francisella tularensis

46
Q

Principle of Plate Bile Solubility. What is a positive result ?

A

Principle:
Presence of bile salts accelerate activity of autolytic enzyme

Positive: flattened/ dissolved colonies after 15 min

47
Q

Chemical name for TP

A

(Optochin)/ Ethyl hydrocupreine hydrochloride

48
Q

Principle of PYR test. What is a positive result ?

A

Principle:

Detects PYRase= hydrolyzes L-pyrrolidonyl-beta-beta-naphthylamide (PYR)

Positive: pink color within 1 minute

49
Q

Test to differentiate Micrococcus from S. aureus

A

Bacitracin/ TA:

Micrococcus = S
S. aureus = R

50
Q

T or F: Tube coagulase detects free coag, while slide coag detects bound coagulase

A

TRUE; Tube coagulase detects free coagulase

51
Q

List HACEK group. What are they known for ?

A

Haemophilus
Aggregatibacter
Cardiobacterium
Eiknella corrodens
Kingella

= ENDOCARDITIS

52
Q

Ideal ratio of blood: media in BACTEC vials

A

1:5

53
Q

Test results for ID of Bacteroides fragilis

A

%= gncb
cat= pos
BBEA= pos
KVC= RRR

BBEA= Bacteroides Bile Esculin Agar

54
Q

How is susceptibility performed for anaerobic organisms ?

A
  • E-test (modified KB)
  • microbroth dilution
55
Q

Principle of reverse CAMP. What is a positive result ?

A

Principle:

  • STB (S. agal) is streaked down the centre of BAP*
  • Test organisms are inoculated at a right angle

Positive: C. perfringens will produce an open arrowhead (>) = synergistic hemolysis

56
Q

Test results for ID of C. perfringens

A

col morph= dzh
%= gpb boxcars
cat= neg
reverse CAMP = pos
lecithinase= pos

57
Q

Test results for ID of C. sporogenes

A

col morph= rhz
%= gpb spores
cat= neg
reverse CAMP= neg
lipase= pos