Laboratory Diagnosis of Bacterial Infections Flashcards

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1
Q

The diagnosis of a microbial infection begins with an assessment of ________ and _______ features, leading to the formulation of a diagnostic hypothesis.

A

clinical and epidemiologic

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2
Q

Laboratory diagnostic methods

______________ examinations

_______
_________ reactions

______ detection, and _____ detection (______).

____________ assays that allow direct detection of genomic components of pathogens

A

Direct microscopic

Culture; Biochemical

Antigen; antibody; serology

Nucleic acid amplification (NAA)

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3
Q

Site of sampling

Blood

Sterile or non sterile

A

Sterile

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4
Q

Site of sampling

Cerebrospinal fluid (CSF)

Sterile or non sterile

A

Sterile

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5
Q

Site of sampling

Sterile

Body fluids (______ and ______ )

A

Peritoneal and pleural

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6
Q

Site of sampling

Non-sterile (________)
_____tract
Ear, eye and mouth
____(wound and abscess)
______(mid-stream)
Feces

A

normal flora

Respiratory

Skin; Urine

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7
Q

Microscopy

Could be :
• Unstained preparations
• “________ “
Or

•____________ eg for _____

A

Wet prep

Dark-ground illumination ; syphillis

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8
Q

By Microscopy

Could be :
•_______ preparations

• _______ preparations

A

Unstained

Stained

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9
Q

Microscopy
Could be :

• Stained preparations

•______ -stain
•______ stain
• ________

A

Gram

Acid-fast

Fluorescence

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10
Q

Fluorescence (stained microscopy preparation)
Could be :

•______, e.g. _______
Or
•_______

A

Direct; auramine

Immunofluorescence

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11
Q

Types of stains

_______ stains

_______ stains

________ stains

A

Simple

Differential

Structural

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12
Q

Types of stains

Simple stains
-how many dyes are used??
-reveals _____,______, and _____

A

one dye Is used

shape, size, and arrangement

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13
Q

Types of stains

Differential stains
-how many dyes are used??
-to distinguish cell types or parts

-examples: ____ stain, ______ stain, and _____ stain

A

2; uses primary stain and a counter stain

Gram; acid-fast ; endospore

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14
Q

Types of stain

Structural stains
-to __________________________
-eg _______ and _____ stains

A

reveal certain cell parts
not revealed by conventional methods

capsule and flagellar

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15
Q

Gram stain

Gram stain uses a series of stains or dyes, _____ stain eg _____, _____ is added as ____ and _____ with _____ and _____ with ______ or _____.

A

primary; crystal violet

Lugols iodine; mordant

decolorization; acetone

counterstain; saffron or methyl red

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16
Q

Gran stain

Each dye allows to stay for _________ before ______ but ______ is applied as fast as to decolorize.

Then Drain the slide to dry.
Followed by inspection under a light microscope to detect and identify bacteria as Gram-positive or Gram-negative.

A

30-60seconds

gentle washing; acetone

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17
Q

A Gram stain can be done on the ______ , but it is usually done on ________ after transferring a _____ of bacteria from the _______ to a glass microscope slide

A

original sample

cultured bacteria

colony

agar plate

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18
Q

A Gram-positive bacterium appears _____ or _____ due to ______ dye adhering to the cell wall.

A Gram-negative bacterium appears _______, as it is counterstained with a red dye such as ________ or ____

A

blue or purple

crystal violet

red or pink

saffron or methyl red.

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19
Q

The Gram stain also identifies the bacterium’s _____ and ____

A

shape and behaviour.

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20
Q

Cocci are ____ in shape Bacilli are _____-shaped
Some bacteria form clusters whilst others form chains

A

round

rod

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21
Q

Fluorescence Microscope

Is Modified microscope with ____ source and filter.

Uses dyes that ______ when bombarded with ______ rays- fluorescence

Used in diagnosing infections

A

An ultraviolet radiation

emit visible light

shorter UV

22
Q

Culture of pathogenic microbe

Solid media
•________

•_______

A

Agar plates

Slopes

23
Q

Culture of pathogenic microbe

Solid media

• Agar plates
For ________
For ________

• Slopes
For _______culture, e.g. _____________ media for TB

A

Identification; Enumeration

safe long-term ; Lowenstein-Jensen

24
Q

Culture of pathogenic microbe

• Liquid media ( ____ )
• For _______ or ________
• E.g. _____ cultures

A

broth

enrichment or maximum sensitivity

blood

25
Q

Culturing or growing bacteria is most commonly done by inoculating or ____ on ______ from the specimen and exposing them to different conditions.

A

steaking; agar plates

26
Q

Bacteria growth depend on the _____ used to culture the specimen, the ____ for _____, and the amount of _____ available.

A

medium; temperature; incubation

oxygen

27
Q

Comparison of Selective and Differential Media

In a General-purpose nonselective medium , ____________.
In a Selective medium, ________ grows.

In a General-purpose nondifferential medium, ________________

In a Differential medium, _____________________

A

All species grow

Only one species grow

All species have a similar appearance.

All species grow but may show different reactions.

28
Q

Coagulase test

Coagulase is an enzyme produced by certain bacteria that converts ______ to _____ and is observed as _______ in plasma.

The coagulase test differentiates _________ from _______

A

fibrinogen to fibrin; clumping of cells

coagulase- positive Staphylococcus aureus from coagulase- negative staphylococci.

29
Q

Catalase test

Catalase is an enzyme that degrades _______ into _______ and _______ .

The bacterial sample is added to a test tube of _______.

The production of _____(____) indicates a positive result.

The catalase test differentiates ___________ from ________

A

hydrogen peroxide into hydrogen and oxygen.

hydrogen peroxide

bubbles (oxygen)

catalase-positive staphylococci and micrococci from catalase-negative streptococci

30
Q

Antibiotic Sensitivity Testing

Antibiotic sensitivity testing determines ______________________________

A

which antibiotics inhibit the growth of the bacteria that have been cultured.

31
Q

Antibiotic susceptibility testing

This information allows the selection of the most suitable antibiotic to treat a particular infection.

T/F

A

T

32
Q

Antibiotic susceptibility testing is used to determine:

1) The ______ of particular antibiotics against particular bacteria

2) Whether the bacteria are ______ to selected antibiotics

3)To identify __________________

A

effectiveness

resistant

bacterial antibiotic resistance patterns.

33
Q

Antimicrobial susceptibility testing

___________ test is a standard procedure for assessing antimicrobial activity
While

_________ zones are used to determine an organisms susceptibility to an antimicrobial agent

A

Disk diffusion

Inhibition

34
Q

Antimicrobial susceptibility testing

The ____________ procedure is used to assess antibiotic susceptibility with regard to various concentrations

A

Minimum inhibitory concentration ( MIC)

35
Q

Serology

Is a branch of immunology dealing with study of ______ interactions in(vivo or vitro?) by different serological tests.

A

Ag –Ab

Vitro

36
Q

Serological identification
A-_______ serological tests:
-B- ______ serological tests:

A

Direct

Indirect

37
Q

Serological identification
A-Direct serological tests:
- ____________ of unknown organism
-Detection of ________ by using _________
-_________ and _________ of isolated organism

A

Identification

microbial antigens; specific known antibodies

Serogrouping and serotyping

38
Q

Serological identification

B-Indirect serological tests:
-Detection of ___________ and _________ ———— (___ and ___ ) by using _____ or ______

A

specific and non specific antibodies

IgM& IgG

antigens or organisms

39
Q

Uses of serological identification

•Where organism _________
•To confirm ______
•To measure ______
•Where disease is _________
•To confirm _____

A

cannot be culture

an isolation

vaccine response

sequelae of infection

PCR

40
Q

Characteristics of serological identification

(Increased or Reduce?) reliance on culture Faster
(More or Less?) sensitive
(More or Less?) definitive
(More or Less?) discriminating
Techniques adaptable to (all or some?) pathogens

A

Reduce
More
More
More
All

41
Q

Various types of serological identification

include:

List 6

A

Precipitation
Agglutination
Complement fixation
immunofluorescence
Elisa
Western blot

42
Q

Serum Separation

What is serum ?
Serum : _______ - ______
Plasma : ____-____

A

Blood- cells and clotting factors; blood – cells

43
Q

Serum separation:
Use _____ tube (_______ ), Leave blood for ______ at room temp. Then _______ before you Centrifuge at ____ for _____.

A

plain; no anticoagulant; 1 hour ; room; Separate the clot; 3000rpm; 10 min

44
Q

Agglutination
Passive Agglutination
• The agglutination of _____________ that have been ________ or ______ to cells or insoluble particles (e.g., _____,_____)

A

soluble antigens or antibodies ; adsorbed or chemically coupled ; latex beads, charcoal

45
Q

Reactions of passive agglutination can be up to ___ times more sensitive than _________ tests

A

five; direct agglutination

46
Q

ELISA can test for specific organisms either by ____________ during an infection or _________.

A

detecting bacterial antigen; antibacterial antibody

47
Q

ELISA

The detection of the antibody confirms __________ but it is not necessarily the ________

A

contact with an organism at some time; reason for a current infection.

48
Q

ELISA is (Specific or non-specific?) , (sensitive or non sensitive?) , (simple or complex?) , (expensible or inexpensible?) & (reproducible or irreproducible?)

A

Specific; sensitive; simple; inexpensible and reproducible

49
Q

ELISA is Used extensively to detect either ____ or ___ .

A

Ag or Ab

50
Q

ELISA can not detect small quantities of Ag

T/F

A

F
It also detects small quantities of Ag