Micro - Bacterial Pathogens

Question 1

Symptoms of bacterial vs viral infections (mouth)

Answer 1

Only Bacterial:
White spots
Gray furry tongue
Swollen uvula

Bacterial and Viral:
Red throat
Red swollen tonsils

Question 2

Basic characteristics of bacteria

Answer 2

Prokaryotes

circular chromosomes

Can also be extra-chromosomal - plasmids

Question 3

Gram positive characteristics

Answer 3

\+
Thick 
TA & LTA
Promote attachment to mammalian cells
Low endotoxin activity
external to cell membrane

Question 4

Gram staining

Answer 4

Crystal violet
Grams iodine
Decolonize
Counterstain with Safranin red

Purple is Positive

Question 5

Classification of bacteria based on shape

Answer 5

Coccus
-spherical

Bacillus
-rod shaped

Coccobacillus
-between spherical and rod shaped (ovalish?)

Vibrio
-banana

Spirillum
-~~~~

Spirochete
- more spiral and thinner than spirillum

Question 6

Classification of bacteria based on growth requirement

Answer 6

Aerobic
Anaerobic

Facultative-can grow in the presence OR absence of oxygen

Fastidious-special growth requirement

Non-fastidious-simple growth requirement

Capnophilic-requires CO2

Halophilic-salt loving

Question 7

Teichoic and Lipoteichoic acid are important for ___

Answer 7

Viability
Virulence
Serotyping

The only difference between the two is that LTA starts from the plasma membrane

Question 8

Encapsulated bacteria benefits:

What is the capsule made of?

Answer 8

Promotes adherence
Anti-phagocytic
Poor antigen

*capsules are unnecessary for growth but important for virulence

Loose Polysaccharide layer of protein layer

Question 9

Endospores

Answer 9

Produced by some gram + bacteria

Non-replicating
Thick coat
Contain DNA

Toughest life form
Can germinate back into vegetative cells

Question 10

Bacterial flagella

Answer 10

H-antigens

Propellers that confer motility towards food and away from poisons

Assist in bacterial attachment to human cells -virulence factor

Question 11

Flagella classification

Answer 11

Monotrichous
-one flagella

Lophotrichous
-multiple flagella originating from one side

Amphitrichous
-two flagella originating from opposite sides

Peritrichous
-flagella all over

Question 12

Bacterial Fimbriae

Answer 12

Pili

F-antigens

Hair-like projections
Thinner and shorter than flagella
Originate in plasma membrane
Protrude through cell wall
Can act as adhesins 
Major virulence factors

Question 13

Gram negative bacteria characteristics

Answer 13

Thin

Between inner and outer membrane

Permeability barrier for large molecules

Protects from adverse conditions

Asymmetric bilayer (normal inner leaflet, outer leaflet is primary LPS)

Question 14

Bacterial Lipopolysaccharides (LPS)

Answer 14

Characteristic of gram - bacteria

Integral part of outer membrane

Released after cell death

When host senses LPS it turns on every defense at its disposal

Question 15

Acid-fast bacteria

Answer 15

PG layer is surrounded by wax-like lipid coat
-contains mycolic acid, cord factor, wax D, sulfolipids

Lipid coat is responsible for virulence
Lipid coat is antiphagocytic

Question 16

What determines acid fastness?

Answer 16

C-chain length

Question 17

Sites with low numbers of bacteria

Answer 17

Bladder
Uterus
Parts of digestive tract (Stomach-acid)
Parts of respiratory tract

Question 18

Normally sterile sites (no bacteria)

Answer 18

Blood
Lymph
CSF 
Synovial fluid
Sub-epidermal tissue

Question 19

How can we use the fact that bacterial ribosomes are different from human cells?

Answer 19

Makes it easy to target and kill them

Protein synthesis inhibitors serve better in toxigenic diseases than cell wall inhibitors

Question 20

Are most normal flora in the GI tract gram + or - ? Why?

Answer 20

-

They have an outer membrane that protects them

Question 21

How long does the lag phase typically last?

Answer 21

60-90 minutes

Question 22

During the exponential phase, the bacterial population ____ every ___ minutes

Answer 22

Doubles

20

Question 23

During which phase of bacterial growth are antimicrobials most effective?

Answer 23

Exponential phase

Question 24

Phases of bacterial growth

Answer 24

Lag
Exponential
Stationary
Death

Question 25

Obligatory steps for infections

Answer 25

1. Acquisition/colonization
2. Immune evasion/infection
3. Replication/proliferation
4. Dissemination/disease
5. Treatment

1 is epidemiology
2-4 is virulence
5 is identification