MICRO Blood/ Fluids/ Anaerobes Flashcards
Normal flora in blood and CSF
None; sterile sites
List potential bacteria isolated in blood cultures
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.
What causes ACUTE bacterial endocarditis ?
- 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.
What causes SUB-ACUTE bacterial endocarditis ?
- normally avirulent viridans group streptococci
- enter bloodstream during dental procedure
Differentiate septicemia vs bacteremia
Septicemia: systemic disease due to persistence of pathogenic organisms OR toxins in blood
Bacteremia: simply presence of bacteria in blood
List potential bacteria isolated in CSF cultures
- N. meningiditis
- S. agalactiae
- S. aureus
- K. pneumoniae and S. pneumoniae
- Haemophilus influenzae
- Listeria monocytogenes
- Pseudomonas aeruginosa
- E. coli
T or F: handling of all lumbar puncture specimens is ALWAYS considered STAT
TRUE; due to seriousness of infections in the nervous system, handling of all lumbar puncture specimens is ALWAYS considered STAT
Which pathogen is common in other sterile bodily fluids but NOT BLOOD OR CSF ?
N. gonorrhoeae
Test Results to ID S. aureus
col morph= wop(h), gop(h)
%= gpc cl
cat= pos
slide/ tube coag= pos
DNAse= pos
TA= R
Which KB disk differentiates MSSA vs MRSA ?
Cefoxitin (FOX)
MSSA= S
MRSA= R
Test results for ID of S. pneumonia
col morph= (wet) alpha
%= gpc prs
TP= S
Bile Sol= pos
Test results for ID of N. gonorrhoeae
col morph= shygy
%= gndc
Ox= pos
CTA sugars:
Dextrose= pos
Maltose, Sucrose, Lactose= neg
Media for N. gonorrhoeae, N. meningitidis
Thayer Martin in CO2, New York City Agar in CO2
Test results for ID of N. meningitidis
col morph= shygy
%= gndc
Ox= pos
CTA sugars:
Dextrose, Maltose= pos
Sucrose, Lactose= neg
NOTE: M for Maltose and Meningitidis
Test results for N. lactamica
col morph= shygy
%= gndc
Ox= pos
CTA sugars:
Dextrose, Maltose, Lactose = pos
Sucrose= neg
NOTE: L for Lactose and Lactamica
List the CTA sugars
Cystine Tryptic Agar:
Base
Dextrose
Maltose
Sucrose
Lactose
How can M. catarrhalis be differentiated from Neisseria sp?
Butyrate esterase (catarrhalis disk)= pos
CTA sugars= neg for all (dextrose, maltose, sucrose, lactose)
Test results to ID S. agalactiae
col morph= small beta
%= gpc ch
cat= neg
PYR= neg
Latex= B
CAMP= pos
TA= R
NOTE: C for Camp and agalaCtiae
Test results to ID K. pneumoniae
MAC= pk
HEK= yel
Orient= blu
TSI= A/Ag
Indole= neg
Lysine= pos
Test results to ID E. coli
%= gnb
MAC= pk
HE= gn
Orient= pk
TSI= A/Ag
Indole= pos
Lys= pos
What is propionibacterium ?
Contaminating flora (anaerobic)
Test results to ID H. influenzae
%= gncb
BAPss= sats
ALA= neg
Test results to ID L. monocytogenes
col morph= beta
%= gpb
cat= pos
BE= pos
TSI= A/A sick
RT Motility= tumbling
37°C Motility= neg
Semi-solid Motility = umbrella pattern
Test results to ID Enterococcus
col morph= ent
%= gpc ch
cat= neg/ wk+
PYR= pos
BE= pos
6.5% NaCl= pos
Test results to ID P. aeruginosa
col morph= sheen
%= gnb
MAC= wh
TSI= K/K
Ox= pos
Nitrate= pos
Motility= pos
42°C =pos
UV= pos
Test results to ID Campylobacter jejuni
Col morph= clr, flt, spr, drop-like
%= gnb, “seagull”
Cat= pos
Ox= pos
Motility= cork-screw
What is the correct additional media OR test to the microscopic morphology: GPCCL
Tube coagulase
Pos = S. aureus
Neg = Staphylococcus sp.
What is the correct additional media OR test to the microscopic morphology: GPCCH, α-hem on BAP
Ethyl hydrocupreine hydrocholride (Optochin /TP)
TP R = Viridans
TP S = S. pneumoniae
What is the correct additional media OR test to the microscopic morphology: GNDC
- Thayer-Martin
- New York city agar
Growth = Neisseria sp.
No growth = Moraxella sp.
What is the correct additional media OR test to the microscopic morphology: Box-square GPB
Egg yolk agar
Lecithinase pos (white precipitate) = C. perfringens
Lipase pos (pearly iridescent) = C. sporogenes*
*NOTE: lipids are shiny, and so are spoons
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
d.
Collection should occur from 2 separate sites in case skin contamination occurs from one of the sites
Which of the following organisms are susceptible to SPS?
a.
N. gonorrhoeae
b.
S. pneumoniae
c.
H. influenzae
d.
All of the above
a.
N. gonorrhoeae
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.
Acridine Orange
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.
ELISA
c.
PCR
d.
Electron microscopy
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
d.
Facultative anaerobe*
*NOTE: “can be” an anaerobe
Which of the following organisms is associated with transient bacteremia?
a.
Coagulase negative staphylococci
b.
Diphtheroids
c.
Staphylococcus aureus
d.
Neisseria gonorrhoeae
a.
Coagulase negative staphylococci
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
b.
Thick Gram positive bacilli with blunt ends and no spores
NOTE: C. perfringens
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
d.
Obligate anaerobe
Which of the following organisms is resistant to kanamycin, vancomycin, and colistin?
a.
Peptostreptococcus sp
b.
Bacteroides fragilis
c.
Clostridium sp
d.
Veillonella sp
b.
Bacteroides fragilis
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
c.
PMNs, low glucose, elevated protein
PMN - Polymorphonuclear leukocytes
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
c.
Bacteroides fragilis
- an anaerobe
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
d.
Reverse CAMP
NOTE: C. perfringens = pos
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.
Gas gangrene
NOTE: C. perfringens
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.
Clostridium sporogenes
NOTE: Lipase positive, Reverse CAMP negative
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.
Francisella tularensis
Principle of Plate Bile Solubility. What is a positive result ?
Principle:
Presence of bile salts accelerate activity of autolytic enzyme
Positive: flattened/ dissolved colonies after 15 min
Chemical name for TP
(Optochin)/ Ethyl hydrocupreine hydrochloride
Principle of PYR test. What is a positive result ?
Principle:
Detects PYRase= hydrolyzes L-pyrrolidonyl-beta-beta-naphthylamide (PYR)
Positive: pink color within 1 minute
Test to differentiate Micrococcus from S. aureus
Bacitracin/ TA:
Micrococcus = S
S. aureus = R
T or F: Tube coagulase detects free coag, while slide coag detects bound coagulase
TRUE; Tube coagulase detects free coagulase
List HACEK group. What are they known for ?
Haemophilus
Aggregatibacter
Cardiobacterium
Eiknella corrodens
Kingella
= ENDOCARDITIS
Ideal ratio of blood: media in BACTEC vials
1:5
Test results for ID of Bacteroides fragilis
%= gncb
cat= pos
BBEA= pos
KVC= RRR
BBEA= Bacteroides Bile Esculin Agar
How is susceptibility performed for anaerobic organisms ?
- E-test (modified KB)
- microbroth dilution
Principle of reverse CAMP. What is a positive result ?
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
Test results for ID of C. perfringens
BAP* = dzh
%= gpb boxcars
cat= neg
reverse CAMP = pos
lecithinase= pos
Test results for ID of C. sporogenes
col morph= rhz
%= gpb spores
cat= neg
reverse CAMP= neg
lipase= pos