Lec 1 Intro

Question 1

3 different major types of shapes used to distinguish bacteria?

Answer 1

• cocci [rounded]
• rods or bacilli [rod shape]
• spirochetes or spirilla [coarse shape]

Question 2

3 different major staining characteristics used to distinguish bacteria?

Answer 2

• gram positive vs gram negative
• acid fast
• non-staining

Question 3

Is mycoplasma staining or non-staining?

Answer 3

non-staining

Question 4

Is myobacteria acid fast or non-staining?

Answer 4

it is acid fast

Question 5

What is the shape of pneumococcus? Is it gram negative or positive?

Answer 5

• cocci in pairs

- gram positive

Question 6

What are the three forms of cocci bacteria?

Answer 6

pairs, chains, clusters

Question 7

What color does gram positive show up vs gram negative?

Answer 7

gram positive = blue/purple

gram negative = red/pink

Question 8

What are two other names for pneumococcus?

Answer 8

Streptococcus pneumoniae

S. pneumoniae

Question 9

What is the shape of group A strep? gram positive or negative?

Answer 9

gram positive cocci in chains

Question 10

What is the scientific name for group A strep?

Answer 10

streptococcus pyogenes

Question 11

What is the shape of staphylococcus spp? Gram positive or negative?

Answer 11

Gram positive cocci in clusters

Question 12

What is the shape of neisseria spp? gram negative or positive?

Answer 12

gram negative cocci

Question 13

What is the shape of campylobacter spp? gram negative or positive?

Answer 13

gram negative rods/bacilli

Question 14

What is an example of a bacteria that cannot be visualized by gram stain?

Answer 14

spirochetes

Question 15

What are 3 bacterial structures that are targets of antibiotic action?

Answer 15

• cell wall
• protein synthesis
• DNA synthesis

Question 16

What is the structure of bacteria?

Answer 16

• prokaryotes with no organelles

Question 17

What are characteristics of gram negative bacteria?

Answer 17

• two lipid bilayers surrounding thin layer of peptidoglycan

- outer lipid membrane contains porins and LPS

Question 18

What are characteristics of gram positive bacteria?

Answer 18

• outer thick layer of peptidoglycan
• single inner lipid bilayer
• peptidoglycan layer contains surface proteins/carbs that can act as virulence factors [teichoic acid, lipoteichoic acid

Question 19

What is the structure of the peptidoglycan layer?

Answer 19

• parallel strands of murein = alternating NAM [n-acetyl muramic acid] and NAG [n-acetyl-glucosamine]
• parallel strands are cross-linked by peptide chains

Question 20

What is murein?

Answer 20

strand of alternating NAM and NAG that makes up the peptidoglycan layer

Question 21

What are porin channels? Why are they important?

Answer 21

structure on outer lipid membrane of gram negative bacteria

• allow entry of nutrients and antibiotics
• modification of porin channel is a mech of antibiotic resistance

Question 22

What are LPS [lipopolysaccharides]? Why are they important?

Answer 22

• LPS = lipopolysaccharide = endotoxins
• on outer lipid bilayer of gram negative bacteria
• important because as bacteria die, LPS are released and can trigger cytokine cascade that causes severe symptoms of infection distant to site of infection

Question 23

What is normal flora vs transient flora?

Answer 23

normal = we have it all the time, low virulence, rarely causes disease
transient = usually not normal flora but can easily colonize for period of time, slightly higher virulence, usually doesn't cause disease

Question 24

What is one normal skin flora?

Answer 24

staphylococcus epidermis

Question 25

What is one transient skin flora?

Answer 25

staphylococcus auereus

Question 26

What are two normal upper respiratory tract flora?

Answer 26

- anaerobic cocci | - viridans streptococci

Question 27

What are 3 normal bacteria in GI tract

Answer 27

- bacteroides [anaerobic rods] - e coli [enterobacteriaceae] - enterococci

Question 28

What is one normal bacteria in GU tract?

Answer 28

lactobacillus

Question 29

What are 3 transient upper respiratory tract bacteria?

Answer 29

- neisseria spp - streptococcus pneumoniae - haemophilus influenzae

Question 30

What are the steps by which a bacteria becomes disease?

Answer 30

1. bacteria enters 2. bacteria adheres and colonizes and multiplies 3. bacteria invades 4. disease caused by either direct effect of organism on tissue or by the inflammatory immune response

Question 31

What are the three factors that come together to cause disease

Answer 31

- bacterial factors = virulence factors - host factors - environmental factors

Question 32

What are three environmental factors that lead to disease?

Answer 32

- overcrowding [easier to spread] - climate [ex. in certain season] - antibiotic use

Question 33

What are 3 host factors that lead to disease?

Answer 33

- immunocompromised state - extremes of age - breach in barriers

Question 34

What are some types of immunocompromised states that contribute to disease?

Answer 34

- primary congential immunodeficiencies - AIDS - transplantation - cancer - sickle cell disease - alcohol use - diabetes - malnutrition

Question 35

What are some examples of breaches in barriers that contribute to disease?

Answer 35

- skin and mucus membranes [break in skin] - gastric pH [high gastric pH] - flushing [urine, saliva] --> urinating/saliva you are forcing out organisms - ciliary function - mucus and secretory IgA - normal flora

Question 36

What are examples of virulence factors that contribute to disease?

Answer 36

- ability to block part of immune system response [phagocytosis, antibodies, complement] - slime and biofilms - toxins [endotoxin vs exotoxin] - adhesion - flagella - ability to survive phagocytosis - ability to survive in hostile environment