Normal Flora or Pathogen?/Antimicrobials

Question 1

What three interactions can define the relationships of humans and their bacteria?

Answer 1

Commensalism, Mutualism, Parasitism

Question 2

What is commensalism?

Answer 2

One benefits, other gets neither benefit nor harm

Question 3

How might we benefit from commensal bacteria?

Answer 3

They compete with harmful bacteria

Question 4

Important examples of mutualism in gut bacteria

Answer 4

Regulation of pro-antiinflammatory T-cell switch
Loss of certain bac associated with Crohn’s
Interactions with hormones

Question 5

Alteration in microbiota of URT associated with…

Answer 5

Asthma

Question 6

Significance of resident flora?

Answer 6

Very unique for each individual body part

Question 7

Name for organisms that are not normally pathogenic, but can cause disease under special circumstances?

Answer 7

Opporutnistic/Pathobiont

Question 8

Three special circumstances that pathobionts may play into?

Answer 8

Immunocompromised individuals
Accidental entry
Inflammation

Question 9

Why is skin hard to colonize?

Answer 9

low pH
high NaCl
Lysozyme

Question 10

Three primary bacterial organisms associated with the skin.

Answer 10

Staph Epidermis
Aerobic Corynebacterium
Propionibacterium acnes (in oily spots)

Question 11

What part of the skin colonizes G-

Answer 11

Oily parts

Question 12

What part of the epidermis has a substantially different microbial community from the others? Why?

Answer 12

Labia minora

Acidic conditions let lactobacilis take over

Question 13

Three primary bacterium of the nasopharynx?

Answer 13

Proprionibacterium
Staph epidermis (and sometimes aureus)
Diptheroids (chinese characters)

Question 14

Four opportunistic bacteria associated with nasopharynx?

Answer 14

Viridans streptococci
Streptococcus pneumoniae
Nisseria meningitidis
Hemophilus influenzae

Question 15

Bacteria at the base of dental plaques

Answer 15

streptococcus

Question 16

Four most important resident bacteria of the mouth and oropharynx?

Answer 16

alpha-hemolytic Strep (including mutans)
Staph epidermis (and aureus)
Pasteurellaceae
Actinomyces israelii

Question 17

Most important bacteria of the stomach?

Answer 17

helicobacter pylori

Question 18

Most important bacteria of the duodenum?

Answer 18

Lactobacillis

Question 19

Most important bacteria of jejuno-ileum?

Answer 19

Enterobacteriaceae

G- Anerobes (Bacteroides)

Question 20

Most important bacteria of the colon?

Answer 20

Bacteroides

Question 21

Three gut enterotypes important for establishment of digestive health?

Answer 21

Bacteroides
Prevotella
Ruminococcus

Question 22

What bacteria is more prevalent in high fat diets? high fiber diets?

Answer 22

fat – Bacteroides

Fiber – Prevotella

Question 23

Relationship of bacteria to gut flora

Answer 23

They don’t directly contact eachother, or inflammation will occur.

Question 24

Most common bacteria of the vagina

Answer 24

Lactobacillis
Bacteriodes
Prevotella

Question 25

Changes in vaginal pH over the life cycle?

Answer 25

Acidic at birth | neutral till puberty, then acidic again

Question 26

Most common bacteria of conjunctiva?

Answer 26

Staph/Strep Hemophilus diptheroids

Question 27

List Six Sterile Areas

Answer 27

``` Lungs beyond trachea Internal organs (minus digestive tract) Fluids (Blood, Lymph, Semen) CNS Ear beyond Eardrum Fetus ```

Question 28

Difference between viral and bacterial latency

Answer 28

In bacterial latency, organism is still present, but in lower numbers

Question 29

Three types of adhesion factors involved in virulence factors.

Answer 29

Pili/Fimbriae Adhesins Capsules

Question 30

Intracellular invasion/colonization factors

Answer 30

Streptokinase - dissolves blood clots Hyaluronidase - Hydrolyzes connective tissues Neurominidase - Degrades sialic acid glue Collagenase - Destroys tissue

Question 31

Two types of intraceullular invasion/colonization factors

Answer 31

Uptake by non-professional phagocytes | Uptake by professional phagocytes

Question 32

How do non-professional phagocytes work?

Answer 32

Secreted effectors (T3-6) - cause membrane ruffles Internalin polymerizes actin to allow comet tails Ipas and Opas -- promote engulfment

Question 33

Five prevalent ways bacteria deal with phagocytes

Answer 33

``` Avoid Them Kill Them Prevent Lysosomal fusion with phagosome Break out of phagolysozome Resistance to lysozomal enzymes ```

Question 34

What are endotoxin and exotoxin made of?

Answer 34

Endotoxin -- Lipid A of LPS | Exotoxin -- Protein, often A-B type

Question 35

How do superantigens work?

Answer 35

Link T cells to macrophages that may not be displaying antigen. Leads to runaway inflammatory response.

Question 36

What are PAI?

Answer 36

Collections of genes for virulence factors in one chromosomal location

Question 37

How do we identify different bacteria locations?

Answer 37

Identify disease agents/reservoirs Prevalence/Incidence Graphs - Surveillance Culture/Diagnostic Sequencing

Question 38

Difference between a prevalence and incidence graph?

Answer 38

Prevalence -- TOTAL active cases in a population | Incidence -- NEW cases in a given time period

Question 39

Difference between epidemic and endemic?

Answer 39

Epidemic -- sudden spike in incidence | Endemic -- Continued high prevalence or repeated recrudescence

Question 40

Why should you take caution diagnosing with diagnostic sequencing?

Answer 40

Watch for antibiotics | Could be normal flora for patient or hospital.

Question 41

What does bacteriostatic mean?

Answer 41

Inhibits the growth of bacteria

Question 42

What does a MIC test evaluate?

Answer 42

The minimum effective dose of an antibiotic in broth

Question 43

What happens in a kirby bauer test?

Answer 43

Paper disc is soaked in antibiotics and placed on a plate of bacteria

Question 44

Better version of a Kirby Bauer test?

Answer 44

E test in which you can read MIC from a strip

Question 45

Which heat is more effective, wet or dry?

Answer 45

Wet

Question 46

Other than heat, what are some other significant methods utilized in sterilization?

Answer 46

Radiation -- UV damages any present DNA Gas -- Ethylene oxide causes alkylation of nucleic acids Filtration -- Size exclusion through 0.2 uM pore

Question 47

Most common sterilization method?

Answer 47

Autoclave + Ethylene Oxide

Question 48

Why must one worry about filtration?

Answer 48

Flexible forms/L-forms of bacteria and small, slow growing cells may get through Doesn't filter out viruses

Question 49

What do high-level chemical disinfectants do?

Answer 49

Kills everything, even spores

Question 50

What do Intermediate chemical disinfectants do?

Answer 50

Allow spores and some naked viruses to survive

Question 51

What do low-level disinfectants do?

Answer 51

Allow spores, mycobacterium, some pseudomonas, and naked viruses

Question 52

Two prevalent forms of disinfection?

Answer 52

Alcohol | Aldehyde

Question 53

How do alcohols work against?

Answer 53

Dissolve lipids, denature proteins, dry out cells

Question 54

How do aldehydes work against bacteria?

Answer 54

Crosslink or alkylate proteins

Question 55

What do phenolics do?

Answer 55

Denature proteins, dissolve membranes.

Question 56

Pros and cons of phenolics

Answer 56

Useful at high concentration | Irritants

Question 57

Common phenolics? Particularly useful against?

Answer 57

Lysol, hexachlorophene | Staph and Strep

Question 58

How do biguanides work? Where are they most commonly used? What specific type is used in that capacity?

Answer 58

Damage to Cell Membranes | Chlorhexidine is used in surgical swabs/dressings

Question 59

Two commonly used halogens?

Answer 59

Iodine and Chlorine

Question 60

How does iodine work?

Answer 60

Interferes with protein folding Used as surgical scrub Common -- water soluble form -- betadine

Question 61

How does chlorine work?

Answer 61

Oxidizing agent (NaClO)

Question 62

How do cationic detergents work?

Answer 62

Solubilize cell membranes

Question 63

Cationic detergents must not be mixed with...

Answer 63

Anionic detergents

Question 64

How do heavy metals work?

Answer 64

Derivatize -SH groups | Block Disulfide bonds

Question 65

Example of the use of heavy metals in antibiotic treatment?

Answer 65

AgNO3 as prophylactic in newborn eyes | Ag-impregnated catheter tubing