Diagnostic Microbiology Flashcards

Question

Syphilis:

Answer 1

Try to irritate the surface of the wound, the Chancre, with acetone or ether. Then, observe the development of some fluid coming out, which is the one collected and used for examining Treponema pallidum. Organisms will be inside the lesion.

Answer 2

The large majority of human normal flora are anaerobes, and when they are displaced from their normal sites, they produce disease.

Answer 3

``` SUGGEST ANAEROBIC INFECTIONS 1. Often contiguous with the mucosal surface 2. Tend to involve many organisms, which these organisms are the anaerobes plus the aerobes; a multi-etiology. 3. Tend to form closed-space infections either as discrete abscess (e.g. Lungs, brain, pleura, peritoneum, pelvis) or by burrowing through tissue layers 4. Pus with a foul odor 5. Favored by the reduced blood supply ```

Answer 4

``` ○ Swabs are not used ○ For closed abscesses, aspirate aseptically, avoid entry of air by sealing the needle after the procedure ○ Use appropriate transport media when the specimen has to be brought to a distant laboratory. ```

Answer 5

Inoculation, incubation, isolation, Inspection, and Identification

Answer 6

providing nutrients in the laboratory

Answer 7

○ Nutrient broth - liquid medium containing beef extract & peptone ○ Nutrient agar - solid media containing beef extract, peptone & sugar

Answer 8

- a complex polysaccharide isolated from red algae. - Solid at room temperature, liquifies at boiling (100℃), does not resolidify until it cools to 42℃) - Provides a framework to hold moisture & nutrients - Not digestible for most microbes

Answer 9

liquid, semisolid and solid

Answer 10

Synthetic- pure inorganic or organic Complex/non-syn- non chemically defineable ingredient General-purpose media - grows a broad range of microbes, usually nonsynthetic Enriched media - contains complex organic substances such as blood, serum, hemoglobin or special growth factors required by fastidious microbes

Answer 11

● The most common enriched media is blood agar. ● The organism in plate A produces hemolysis ● Chocolate agar is a variation of blood agar plate. It is blood agar which is heated, it turns to a brown color.

Answer 12

● Contains one or more agents that inhibit growth of some microbes and encourage growth of the desired microbes ● Example: Salmonella/Shigella agar medium- will only allow the growth of Salmonella species and Shigella species

Answer 13

● Allows growth of several types of microbes and displays visible differences among desired and undesired microbes ● A good example of this is the MacConkey agar. It will allow the growth of organisms that can ferment lactose and organisms that do not ferment lactose

Answer 14

Reducing medium - contains a substance that absorbs oxygen or slows penetration of oxygen into medium; used for growing anaerobic bacteria Carbohydrate fermentation medium - contains sugars that can be fermented, converted to acids, and a pH indicator to show the reac

Answer 15

ability to enlarge objects

Answer 16

ability to show detail; the higher the resolving power, the higher the ability to see the details of the particular object being examined

Answer 17

● The oil makes it possible for the organism being examined to be seen more clearly in the microscope. ● The rays of light are concentrated to the point of examination and bounce back to the eyes. Without oil, you lose some of the light waves.

Answer 18

The most widely used, the specimen is | darker than the surrounding field

Answer 19

brightly illuminated specimens surrounded by darkfield; a special type of light microscope whereas instead of seeing the field to be brightly illuminated, what you will see is a background of black and only the ones that you want to see are illuminated. So they will stand out. This is the one used for Treponema pallidum and also for Leptospirosis

Answer 20

transforms subtle changes in light waves passing through the specimen into differences in light intensity, best for observing intracellular structures

Answer 21

Modified compound microscope with an the ultraviolet radiation source and a filter that protects the viewer’s eye Useful in diagnosing infections-For example, Treponema pallidum (Syphilis), you can tag the antibodies against the T. pallidum with special dye

Answer 22

Forms an image with a beam of electrons that can be made to travel in wavelike patterns when accelerated to high speeds. ● Electron waves are 100,000X shorter than the waves of visible light.

Answer 23

``` ○ Transmission electron microscope (TEM) - transmits electrons through the specimen; darker areas represent thicker, denser parts and lighter areas indicate more transparent, less dense parts ○ Scanning electron microscope (SEM) - provides detailed three- dimensional view. SEM bombards the surface of a whole, metal- coated specimen with electrons while scanning back and forth over it. ```

Answer 24

● In bacteriology, staining procedures are very important because one staining procedure gave us a very big classification of the bacteria. The Gram staining classified the bacteria into two types of microorganism-- the gram positive organism and the gram negative organism. Their cell walls are responsible for their classification.

Answer 25

allow examination of characteristics of live cells: motility, shape, & arrangement; you examine the specimen as is

Answer 26

are made by drying & heating a film of specimen. This smear is stained using dyes to permit visualization of cells or cell parts.

Answer 27

○ Cationic dyes - basic, with positive charges on the chromophore ○ Anionic dyes - acidic, with negative charges on the chromophore ○ Positive staining - surfaces of microbes are negatively charged and attract basic dyes; the cell wall will be stained ○ Negative staining - microbe repels dye & it stains the background; an example of this is when you want to see the capsulated microorganism,

Answer 28

one dye is used

Answer 29

use a primary stain and a | counterstain to distinguish cell types or parts. Gram stain Acid- fast stain

Answer 30

``` - India ink capsule stain of Cryptococcus neoformans. You use the India ink so what you see is the Cryptococcus’ very thick capsule. - Flagellar stain. The red ones are the flagellar stains ```

Diagnostic Microbiology Flashcards

(54 cards)