Laboratory Diagnosis, Specimen Collection & Serologic Test 2 Flashcards
1
Q
Important specimen if the infection is a disseminated type
A
BLOOD
2
Q
temp and storage of blood
A
30 deg C up to 21 days
2
Q
in Lysis centrifugation technique, for pathogenic fungal elements, it is best incubated for as long as
____ days
A
10-15
3
Q
- Contains both solid and liquid media
- If bottle is inverted, specimen will be inoculated on the solid media
A
Biphasic broth-agar system
3
Q
in Lysis centrifugation technique, As fast as ___ days of incubation, fungal elements can be already be detected on the plated media
A
4
4
Q
this clinical specimen use culture media with cycloheximide
A
RESPIRATORY SECRETIONS
4
Q
respiratory secretions examples
A
Sputum
Bronchoalveolar lavage (BAL)
Bronchial washings
Tracheal aspirate
4
Q
- Optimal for isolation of H. capsulatum & filamentous fungi
- Centrifugation of concentrates is best before culture
A
Lysis centrifugation technique
5
Q
Collection is not done by medical technologists
A
Lumbar tap
6
Q
csf must be kept at what temp, and why not be refrigerated
A
37 deg C, it might kill any fungal elements present in the specimen
7
Q
Almost all body fluids are abundant except for
A
synovial fluid
8
Q
Both clinical specimens may be processed as blood culture
A
BONE MARROW AND STERILE BODY FLUIDS
9
Q
ideal urine specimens
A
Midstream
clean-catch
Early morning
10
Q
how many swabs are required for vaginal and cervical discharges, and what are those for
A
2 swabs: KOH test and culture
11
Q
urine specimens must be processed by how many hours
A
2hrs (at RT) or refrigerate
12
Q
subcutaneous samples
A
Lesions
abscesses
tissues
13
Q
what techniques must be done to collect subcutaneous specimens
A
Needle aspiration or biopsy
14
Q
machine used to macerate or mash the tissue
A
Stomacher
15
Q
where can you get muco-cutaneous specimens
A
tongue
throat
16
Q
how many swabs should be used for muco-cutaneous and what are those for
A
2 swabs: culture and smear
17
Q
most common clinical specimen
A
CUTANEOUS
18
Q
suspected organisms for cutaneous
A
dermatophytes
19
Q
allows the visualization of fluorescence which could aid in collecting the correct hair specimen
A
Woods lamp
19
Q
culture media perfect for recovery of dermatophytes
A
Mycosel agar
20
incubation period of skin
30 deg C (21 days)
21
culture media must include
Amino acids or urea
Glucose
22
antimicrobials
Cycloheximide + Chloramphenicol
Gentamicin + Chloramphenicol
Ciprofloxacin
23
TYPES OF CULTURE MEDIA
Plated and Tubed
24
permit the growth of virtually all clinically relevant fungi
Non-selective
24
tailored to isolate specific pathogenic fungi of interest
Selective
25
- Recovery of (1) saprobic & (2) pathogenic fungi
- Sufficient for recovery of dermatophytes
- Initially without antibiotics to isolate C. neoformans,
candida & aspergillus
- they are sensitive to Cycloheximide & chloramphenicol
SABOURAUD DEXTROSE AGAR
26
- (contains 2% dextrose)
- enhances typical sporulation
- provides more characteristic colony morphology
Emmons modification
27
- For the primary recovery of (1) saprophytic and (2)
dimorphic fungi
BRAIN-HEART INFUSION AGAR
28
for tissue specimen w/ dimorphic fungi
BHI with sheep blood + antibiotics
29
widely used as an INITIAL CULTURE media from collection
BHI broth
30
Primary recovery/ isolation of (1) saprophytic and
(2) dimorphic fungi, particularly fastidious strains.
SABOURAUD HEART INFUSION
31
- Usually used for research
- Primary recovery of dimorphic pathogenic fungi
INHIBITORY MOLD AGAR
32
- General purpose BASAL MEDIUM for the cultivation of yeasts & molds
- Stimulates sporulation and pigmentation
- Aids in cultivating and differentiating pathogenic and non-pathogenic fungi
- Commonly used in finding out fungal organisms from food and beverages
- To control the growth of the contaminating bacterial
agent
POTATO DEXTROSE AGAR
33
PDA: serves as growth stimulant and carbohydrate source
Dextrose
34
PDA: provides a nutrient base for luxuriant growth of fungi
Potato infusion
35
PDA: ___ it may be added to lower the pH to about ___
10% sterile tartaric acid
pH 3.5
36
- Primary recovery of (1) saprophytic and (2) dimorphic fungi, particularly fastidious and slow-growing strains
- Cultivation, isolation, & induction of sporulation
(Spore formation) of fungi from clinical specimens
POTATO FLAKE AGAR
36
Recommended for the cultivation of yeasts and
molds
V-8 AGAR
37
V-8 AGAR: provides essential growth nutrients
Yeast extract
38
V-8 AGAR: Source of amino acids
L-asparagine
39
V-8 AGAR: Source of energy
Glucose
39
V-8 AGAR: supplies the trace ingredients needed to
stimulate the growth of fungal elements
that are found in the specimen.
V-8 juice
40
- Highly selective for dermatophytes
- For isolation of pathogenic fungi from non-sterile
materials
MYCOSEL/MYCOBIOTIC AGAR
41
Recommended for selective isolation of pathogenic
fungi (dermatophytes) from cutaneous sources
DERMATOPHYTE TEST MEDIUM
42
For use in the cultivation of fungi and for the inducement of chlamydospore formation by
Candida albicans
CORN MEAL AGAR w/ TWEEN 80
43
Allows the growth of the organism vertically so it would lessen the surface tension on the agar; very helpful for candida so that from the base of the agar
they will go out on the surface.
Tween 80
43
Chlamydospore formation is best seen when the
organisms are incubated
25 deg C
44
C. neoformans are able to release the enzyme
phenoloxidase
44
ROUTINE CULTURE MEDIA for fungi but is perfect
for aspergillus
CZAPEK AGAR
44
NS: serves as a substrate for the detection of
phenoloxidase
Caffeic acid
44
Identification of C. neoformans
NIGER SEED/ BIRD SEED AGAR
44
NS: enhances melanization of some strains of
C. neoformans
Creatinine
45
The action of phenoloxidase to caffeic acid results in the production of
MELANIN
46
- Conversion of Blastomyces dermatitidis from mold
to yeast form
- Used for dimorphic fungi so that we could
see their other form
COTTONSEED CONVERSION AGAR
47
For differentiation of yeasts by means of their typical chlamydospores and on basis of micromorphological criteria
RICE EXTRACT AGAR
47
- For isolation and differentiation of major clinically
significant Candida species
- allows each Candida spp. to produce its characteristic colonies and pigmentation.
CHROMAGAR CANDIDA
48
- Differential media used in the presumptive
identification of Trichophyton species based on
nutritional requirements
TRICHOPHYTON AGARS
48
- Detection of C. neoformans
- Differentiates T. mentagrophytes vs T. rubrum
- Detection of Trichosporon spp.
UREA AGAR
49
This method allows the medical technologists to
obtain information regarding the morphology of the
organism
DIRECT MICROSCOPIC METHOD
50
- Directly gather sample from the infected sample site
- useful for cutaneous specimens
WET MOUNT
50
destroy keratin layer particularly the hydroxide component
KOH (10%)
51
- Not a direct method; sample used is the one that is
used in the culture
- a.k.a. AMAN’S MEDIUM
LACTOPHENOL COTTON BLUE
51
LPCB: serve as a preservative
Lactic acid
52
LPCB: antimicrobial agent; can kill any live organisms in the specimen
Phenol
53
method used in LPCB
Basic Tease Mount
53
LPCB: a stain with affinity to CHITIN and fungal
cell walls
Cotton blue
54
- Can be used by itself, but it is more effective with
KOH
- Uses a non-specific fluorochrome that binds to
CHITIN and CELLULOSE in cell wall of organisms
CALCOFLUOR WHITE + KOH
54
method for rapid detection of yeast, fungal elements and parasites
Fluorescent staining
54
- Negative staining method
- Perfect for encapsulated organisms
- Capsules appear as clear halo against dark background
INDIA INK
55
swabs when collecting the sample.
dacron/rayon swabs
55
result in CALCOFLUOR WHITE + KOH
apple-green/bluish-white: fungi and parasites
reddish-orange: other materials
56
may intensely fluorescent in Calcofluor white
Cotton fibers
57
stain used in Mycelia and Conidia
Gridley’s
57
stain used in Black Cell Wall
Gomori’s/ Grocott Methenamine Silver
57
stain used in stains hyphae of molds & some yeast
Periodic Acid Schiff
58
stain used in Fungi are weakly G (+) but poorly stained and Useful for Candida
- Kinyoun’s AFS
- Hucker’s Gram Stain
- H&E
58
stain used in Better demo of B. dermatitidis than wet mounts
Papanicolau
58
stain used in detecting intracellular H. capsulatum in blood smears.
Giemsa and Wright’s stain
58
stain used in Dematiaceous hyphae
Fontana-Masson
59
incubation period
yeast:
molds:
30 d Celsius and 22-25 d Celsius for 21 days
59
Allows the medical technologists to see actual
colonies growing in the culture media and take
note the microscopic details that would help in
identifying the organism
CULTURE METHOD
59
added to liquefy highly viscous samples & facilitate plating on agar media
Mucolytic agents
59
If delayed, the specimen can be refrigerated for a
short time except
blood
CSF
skin
hair
nails
59
what level: Inoculations & manipulation of mold
colonies
BSL 2
59
desired humidity to prevent the agar from drying out
40-50%
60
what level: dimorphic fungi
BSL 3
61
Clean surfaces of BSCs and incubators regularly
use 70% ethanol or bleach
62
rate of growth of yeast
24hrs to 4 days
63
rate of growth of molds
4 days to several weeks
64
- Most accurate method to preserve & observe
fungi
- Fungi are preserved in original state
- Requires more skill & time than tease mount
- NOT FOR DIMORPHIC FUNGI because it is too
open and because the MOT for this is respiratory
except for Sporothrix
SLIDE CULTURE
65
- Used to differentiate between fungal or bacterial
organisms
- Its procedure is similar to COAGULASE TEST
- To differentiate Candida albicans from other
Candida spp
GERM TUBE TEST
66
- test to identify T. mentagrophytes
- Can also utilize soil
hair baiting
67
hair baiting incubation period
25 deg C for 10 to 14 days
68
CHO Assimilation Test For Yeast
BIOCHEMICAL TEST
69
positive results in REDUCTION OF NITRATE TO NITRITE
change in color (red) = positive
If negative add Zinc dust
No change in color = positive
70
For PRELIMINARY ID of C. neoformans
RAPID UREASE TEST
71
- Provides enough information to name the
species of the fungal organism
- Provide key elements that needed to improve
management of invasive fungal infections
SEROLOGICAL TEST
72
- Time consuming; mold cultures grow after
several weeks
- It has low sensitivity due to the low concentration of the organism in the samples infested.
Culture methods
73
- Detection of specific host immune responses to fungal antigens using immunological reagents
- Detection and quantitation of specific fungal metabolite byproducts
Non-culture methods
74
- Good for Cryptococcosis
- Detect polysaccharide antigen
- Qualitative & semi-quantitative
LATEX AGGLUTINATION
75
Look for antibodies of specific antigens
IMMUNODIFFUSION
76
Precipitation Band in Active infection
M and H
77
Precipitation Band in Early/Chronic Infection
M only
78
- Microbroth dilution breakpoint test
- Allows us to identify which concentration of drugs is susceptible
FungiTest
