Lab 1

Question 1

Aims of bacterial culture

Answer 1

• Isolation of causative agents
• AB susceptibility test
• Vacc. prod.
• Industry

Question 2

Types of detection of bacteria in a sample

Answer 2

1. Direct: smear, impression smear or PCR

2. Indirect: animal trial or inoculation of sample into a medium

Question 3

Composition of media

Answer 3

• Water
• C-sources
• N-sources
• Vitamins and other additives
• Osmotic pressure: 0,9% NaCl sol.
• pH: 7.2-7.4

Question 4

Classification of media

Answer 4

Accordring to:

1. Origin: natural/artificial/synthetic
2. State: liquid/semi-solid/solid
3. Aim of culture: common (basic nutrient)/selective/differential (indicator)

Question 5

Natural media examples

Answer 5

Potato slide, blood, serum, milk, bile, urine

Question 6

Common media is

Answer 6

Capable of sustaining growth of bacteria

Question 7

Selective media is

Answer 7

Contain inhibitory substances that prevent growth of unwanted bacteria sp.

Question 8

Differential media is

Answer 8

• Give a presumptive ID of bacteria

- Often contain sugar + pH-indicator (colour change)

Question 9

Semi-solid medium examples

Answer 9

• Motility tests

- Oxidation/fermentation

Question 10

Solid medium examples

Answer 10

• Blood agar
• Nutrient agar
• Mac Conkey´s agar

Question 11

Liquid medium examples

Answer 11

-Carbohydrate broths

Question 12

Blood agar is

Answer 12

Solid, artificial, differential medium

Question 13

Nutrient agar is

Answer 13

Solid, artificial, common medium

Question 14

Carbohydrate broths is

Answer 14

• Mannitol/Dextrose/Lactose/Sucrose
• Liquid, artificial, differential medium
• pH-indicator: phenol-red

Question 15

Mac Conkey´s agar is

Answer 15

• Solid, artificial, selective, differential medium
• Lactose + (e-coli) or - (salmonella)
• Inhib. materials: bile salts, crystal violet
• pH-indic: neutral red

Question 16

Salt-Mannitol agar is

Answer 16

• Selective
• 10% NaCl, Mannitol, Phenol red
• Isolation of staphylococcyl

Question 17

Chocolate agar is

Answer 17

-Heat treated (80´C, 20min) blood agar

Question 18

Chocolate agar bacterias

Answer 18

• Avibacterium paragalinarum
• Haemophilus parasuis
• Taylorella equigenitalis
• Histophilus somni

Question 19

Pure culture is

Answer 19

• Descendants of the same bacterium

- Same geno- + phenotype

Question 20

Obligate aerobe bacteria

Answer 20

• Grow in presence of O2 only
• Gram+: bacillus, dermatophilus, micrococcus, nocardia, phrodococcus
• Gram-: brucella, bordetella bronchiseptica, francicella, moraxella, pseudomonas
• Ziehl-Neehlsen +: myobacterium

Question 21

Obligate anaerobe bacteria

Answer 21

• Can´t tolerate O2 at all
• Gram+: conynebacterium, erysipelothrix rhusiopathiae, listeria, staphylococcus, streptococcus
• Gram-: actinobacillus, aeromonas, enterobacterium, haemophilus, pasteurella, vibrio

Question 22

Microaerophile bacteria

Answer 22

• 4-6% O2 pressure, 10% CO2 pressure needed
• Gram+: several actinomyces sp., lactobacillus
• Gram-: campylobactes

Question 23

Capnophile bacteria

Answer 23

• Need 5-10% CO2
• Gram+: Actinomyces viscous, dermatophiles congolensis
• Gram-: brucella abortus B.ovis, campylobacter jejuni C.fetus, avibacterium paragallinarum, histophilus somni, taylorella equigenitalis

Question 24

Anaerobic culture methods

Answer 24

• Candle jar method
• Biological O2-binding
• Chemical: pirogallic acid+KOH/H2+palladium catalisator/Na-borohidrid+NaHCO3+ascorbic acid+H2O/other
• Evaluation of air w. vacuum pump
• Anaerobic broth
• Deep agar
• Pre-reduced media

Question 25

Light microscope 1. Visible light 2. Resolving power 3. Magnification

Answer 25

1. 400-700nm 2. 0,2-0,4macrometer 3. 1200-1500x

Question 26

Dark field microscope exam

Answer 26

Bacterial motility