Practical Exam Review Flashcards
Ascaris ova
Ascaris ova
Ascaris ova
Ascaris
Aspergillus
Aspergillus
Aspergillus
Aspergillus
Aspergillus
Dematiacious
Aspergillus
C. neoformans bird seed
C. neoformans budding yeast
C. neoformans encapsulated yeast
C. neoformans sab dex
C. neoformans
C. albicans
C. albicans
C. albicans
Positive Germ Tube
C. albicans yeast
Chlamydoconidia
Clamodochlymdia pseudohyphae
Coccidiodes immitis
Coccidiodes immitis
Coccidiodes immitis
Coccidiodes immitis
Coccidiodes immitis
Coccidiodes immitis
Conidia
C. neoformans
Cryptosporidium oocyst
Cryptosporidium oocyst
Cryptosporidium parvum
E histolytica
E. histolytica troph
E histolytica
E histolytica
Enterobius ova
epithelial cell
and gram pos or gram variable rod
epithelial cells and GPC underdecolorized
few epi cells many gram neg rod many budding yeast
few WBC few epis, many gram pos diplo
few gram neg rod
Positive Flurochrome Stain
Germ tube
Giardia cyst troph
Giardia cyst
Giardia troph
Giardia
GPC clusters
Gram negative coccobacilli
Gram neg rods
Gram pos cocci in pairs epithelial cells and WBC
Gram pos cocci chains
Gram pos rods
Hyline mold
Hyphae
LJ agar
many WBC many gram deg diplo
MGIT
Microsporum canis
Negative flurochrome stain
Negative kinyoun stain
Penicillium Lactophenol
Penicillium Lactophenol
Penicillium Sab dex
Penicillium
Pinworm
Plasmodium Giemsa Stain
Positive Calcafluor stain
Positive Fluorochrome Stain
Positive Fluorochrome Stain
Positive FTA-ABS
Positive Germ Tube
Positive Kinyoun
Positive Kinyoun
Pseudohyphae
RBC gram neg rods
Shistosoma ova
Shistosoma ova
T. trichuria ova
Taenia
T. trichuria ova
T. trichuria ova
Trophozoite
Trypanasoma cruzi
Trypanasoma cruzi
Trypanasoma cruzi
Unacceptable sputum screen
WBC and gram neg diplo
WBC and gram pos rods
WBC gram neg rods
WBC gram pos cocci some intracellular gram neg rods
Name 2 methods of measuring the turbidity of the inoculum
Match with McFarland Standard using unaided eye
Use of commercial instrument - densitometer, colorimeter
Name 2 criteria for selection of antimicrobials agents to be tested?
Site of infection
method
avaliability (formulary)
Known resistance patterns
Give the class and spectrum of activity for the following:
Ampicillin
Beta lactam, gram pos and gram neg
Give the class and spectrum of activity for the following:
Cefazolin
beta lactam
gram pos, gram neg
Give the class and spectrum of activity for the following:
Clindamycin
Lincosamide
gram pos (rarely gram neg)
Give the class and spectrum of activity for the following:
Levofloxacin
quinolone
gram pos and neg
Give the class and spectrum of activity for the following:
Piperacillin
beta lactam
gram pos and neg
Give the class and spectrum of activity for the following:
Ticarcillin/Clavulanic Acid
beta lactam combo
gram pos and neg
Give the class and spectrum of activity for the following:
Trimethoprim/sulfa
combo
gram pos and neg
What are the possible problems and what measures should be taken if the following are observed when performing quality control:
Several E. coli zones are too large
check inoculum
medium depth
medium pH
What are the possible problems and what measures should be taken if the following are observed when performing quality control:
Small colonies within the zone of Tetracycline with S. aureus
mixed culture - reisolate
resistant mutants
What are the possible problems and what measures should be taken if the following are observed when performing quality control:
Gentamycin zone too small with P. aeruginosa
Ca and/or Mg level too high in medium
What is the relationship between MIC and zone size?
see regression graph pg 195
MIC breakpoints plotted against zone sizes, regression line is drawn
DD breakpoints are where lines intersect
An organism with an increased MIC value will be expected to have an increased or decreased zone size?
decreased
Name the 3 weekly QC organisms used for the Kirby Bauer method
E. coli 25922
P. aerug 27853
S. aureus 25923
Describe the action of the (amoxicillian or ticarcillin)/clavulanic combination
2 beta lactams
beta lactam/beta lactamase inhibitor
Inhibitor renders B-lactamase incapable, beta lactam drug
An oxacillin disk is used to test S. pneumoniae for penicillin
Why?
Due to increased resistance observed with penicillin, OX is more sensitive and reliable indicator
An oxacillin disk is used to test S. pneumoniae for penicillin. What should be done if the interpretation is resistant or <20mm
Perform MIC for confirmation
Define empiric antimicrobial therapy
Therapy that is started before knowing organism or susceptibility profile
If you mistakenly adjusted the organism inoculum suspension to be equal to a number 1 McFarland turbidity standard, would the results be falsely resistant, sensitive, or not altered
Resistant
Why should you not incubate the disk diffusion plate in a CO2 enriched incubator
It will alter the pH and affect the zone sizes
Small colonies are observed at the inner edge of the zone of inhibition around the oxacillin disk when S. aureus is tested. The outer zone size corresponds to an interpretation of susceptible, and the small colonies are growing in the resistant range. How do you interpret the results?
Resistant
While reading a disk diffusion susceptibility test, you notice a faint haze of growth to the edge of the sulfmethoxazole disk and a more pronounced zone that measures in the sensitive range. Is the drug S, I, or R?
Sensitive
Your Mueller Hinton agar is 3.5mm in depth. How will this affect the results? Will they be falsely sensitive or falsely resistant? Will the zones be too large or too small?
Sensitive
Too large
In recording the results of a microdilution tray, you notice that a slight haze is present in all the trimethoprim-sulfamethoxazole wells. Will you record the result as susceptible or resistant?
Susceptible
What is being detected in the serum of patients with a reactive RPR?
Antilipid antibodies (reagin)
Name 2 tests that may be used to confirm a reactive RPR?
FTA-ABS, MHA-TP - treponemal tests
Why is the room temperature where the testing occurs important?
Too cold <73 = decreased reactivity
Too hot >85 = increased reactivity
What is the clinical value of performing a quantitative test on a reactive sample?
4 fold rise = infection, reinfection or treatment failure
4 fold decrease = adequate therapy
Describe the prozone effect and what should be done if it is observed?
Specimen will be more reactive when diluted. Any reactive specimen should be titered.
Does a non reactive RPR rule out Syphillis? If not, why?
May be primary syphilis, secondary with prozone effect or late syphallis
Describe the colony of Candida albicans (yeast) on Sab dex agar
Moist, creamy, white
Describe the colony and reverse of Aspergillus on Czapek dox agar
Colony - fluffy, white, blue green, grey green
Reverse - tan
Describe the colony and reverse of Trichophyton mentagrophytes on Mycobiotic agar
White powdery colony, tan reverse
How will a dematiaceous mold appear on sab dex agar?
dark grey, dark green to black
Give 2 examples of dematiaceous molds
Alternaria, phialophora, cladosporium, exophiala, etc.
What is the difference between a germ tube and pseudohyphae?
Germ tube - no constriction between yeast cell and hyphal structure
Pseudohyphae - has constriction
What is the interpretation of a positive germ tube?
Diagnostic for Candida albicans
Which media is most useful to determine microscopic chacteristics of yeast?
Corn meal agar
What is the most reliable method for ID of molds?
Microscopic identification
What is the ID of the organism on the front page of blackboard?
Penicllium spp.
What is the primary Kinyoun stain and its function?
Carbolfuchsin - stains the mycobacteria
What is the Kinyoun counterstain and its function?
Methylene blue - stains background and other bacteria - not acid fast
What is present in the cell wall that contributes to acid-fastness
Mycolic acids
How will mycobacteria appear on a gram stain?
poorly stained, beaded gram pos bacilli, gram neutral or ghosts
Which stain is more sensitive Kinyoun or Flurochrome?
Fluorochrome
Why is quantitation of the AFB important?
indicates the extent of the patient’s infectiousness
How many oil fields should be observed before calling a smear negative
300 oil fields
What factors may contribute to a false positive smear?
Cross-contamination of slides, using tap water in staining, not wiping oil immersion between slides
What must be done to prepare a sputum or fluid specimens for AFB staining?
Decontamination, concentration by centrifugation, heat-fixing
Which fixative is appropriate for:
Trichrome
SAF, PVA
Which fixative is appropriate for:
Acid fast stains
SAF or formalin
Which fixative is appropriate for:
Fluorescent stains
Formalin, SAF
Which fixative is appropriate for:
Recovery of helminth eggs
formalin
Counterstain in modified acid fast stain
Methlyene blue
Giemsa stain is appropriate for which organisms (2 example)
Plasmodium and Trypansoma
Is thick or thin smear used for ID?
Thin
On trichrome, nuclei of E. coli should stain
red or purple
Name 2 microscopic structures associated with C. albicans
Clamidochlamidia, germ tube
Fungal elements on calcafluor will appear
blue/white or yellow green
A positive well on API 20 will appear
cloudy/turbid
Basic principle of the 20C system
ID of yeast, carbohydrate utilization
Disk diffusion testing for S. aureus will use which media?
Mueller hinton
Zone sizes must be interpreted using _____?
CLSI standards/tables
Name 3 common AST quality control organisms?
E. coli
S. aureus
P. aeruginosa
Give two reasons for zones too large on E. coli
medium depth
medium pH
Kinyoun primary stain is _____?
Carbolfuchsin
Fluorochrome counterstain is _____?
Potassium permanganate
What is the appearance of a positive MGIT tube?
Fluoroscence
1-9 AFB org/field on kinyoun stain will be reported as?
3+
Serum that agglutinates with the cardiolipin reagent may be reported as?
reactive or weakly reactive
