1.02 Bacterial Cultivation & Identification

Question 1

Provides preliminary information about a

bacteria

Answer 1

MICROSCOPY: Gram Stain

Question 2

Required for definitive identification and

characterization

Answer 2

CULTURE: Agars, Broth, Slants

Question 3

Process of growing microorganisms in culture by taking bacteria from the infection site

Answer 3

Cultivation

Question 4

Predictable pattern of growth for bacteria as observed in a closed system or culture

Answer 4

THE GROWTH CURVE/CYCLE

Question 5

Phase where bacteria are newly streaked in the culture medium

Answer 5

Lag Phase

cells in lag period are typically synthesizing RNA, enzymes and intermediates that might be missing from their new environment

Question 6

Cells are in a steady state. Exponential growth of living bacterial cells.

Answer 6

Logarithmic/Exponential Phase

Question 7

Exponential Phase is stopped by which 2 events?

Answer 7

▪ Depletion of nutrition or oxygen

▪ Toxic metabolic by-products accumulate and inhibit growth

Question 8

There is a plateau in number of living bacterial cells

Answer 8

Maximum Stationary Phase

Rate of cell division and death are roughly equal

Question 9

There are more than dead bacteria than alive ones

Answer 9

Death/Decline Phase

Question 10

Nutritional needs of bacteria?

Answer 10

▪ Gases
▪ Water
▪ Ions
▪ Nitrogen
▪ Carbon

Question 11

Bacteria sources of energy?

Answer 11

▪ Carbohydrates

▪ Proteins

Question 12

These are bacteria that have very complex needs and exceptional media components

Answer 12

Fastidious

Question 13

These are common or clinically important bacteria whose needs are relatively basic and straightforward

Answer 13

Non-fastidious

Question 14

These are bacteria that use inorganic material such as: H2O, inorganic salts and CO2

Answer 14

Lithotrophs/Autotrophic

Question 15

Bacteria that needs “organic form” of carbon (glucose or other sugars)

Answer 15

Organotrophs/Heterotrophic

Question 16

These are bacteria that require oxygen and grows well in room air

Answer 16

Obligate Aerobes

Question 17

These are bacteria that need low oxygen tension to survive.

Oxygen tension needed?

Answer 17

Microaerophilic bacteria

5%

Question 18

They do not require oxygen to survive

What are the enzymes that they lack?

What are their means of energy production?

Answer 18

Obligate anaerobes

superoxide dismutase & catalase

Fermentation

Question 19

Capable of surviving with or without oxygen

Answer 19

Facultative anaerobes

Question 20

Temperature that pathogenic bacteria grow best?

Answer 20

37 ̊C

Question 21

Psychrophilic temperature requirement?

Answer 21

-5 to 30 ̊C

Question 22

What is the commonly encountered human pathogenic bacteria in the clinical laboratory, and what are their temperature requirements?

Answer 22

Mesophilic

10 to 45 ̊C

Question 23

Thermophilic temperature requirement?

Answer 23

25 to 80 ̊C

Question 24

Optimum pH for pathogenic bacterial growth?

Answer 24

NEUTRAL - 7.2-7.6

Question 25

Acidophilic pH?

Answer 25

pH 6.5 to 7.0

Question 26

The pH most clinically significant from pathogenic bacterial growth? pH?

Answer 26

Neutrophilic pH 7.5 to 8.0

Question 27

Alkalophilic pH?

Answer 27

8.4 to 9.0

Question 28

Nutrients are dissolved in water. Growth is indicated in this media by?

Answer 28

Broth medium change in the broth’s appearance from CLEAR to TURBID

Question 29

Combination of a solidifying agent added to the nutrients and water.

Answer 29

Solid Medium

Question 30

The most common solidifying agent. Where is it extracted from?

Answer 30

Agarose seaweed

Question 31

Agaribose: Melting temperature? Solidifies at what temperature?

Answer 31

≥95 ̊C ≤50 ̊C