Normal Flora or Pathogen?/Antimicrobials Flashcards Preview

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Flashcards in Normal Flora or Pathogen?/Antimicrobials Deck (65)
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1

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

Commensalism, Mutualism, Parasitism

2

What is commensalism?

One benefits, other gets neither benefit nor harm

3

How might we benefit from commensal bacteria?

They compete with harmful bacteria

4

Important examples of mutualism in gut bacteria

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

5

Alteration in microbiota of URT associated with...

Asthma

6

Significance of resident flora?

Very unique for each individual body part

7

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

Opporutnistic/Pathobiont

8

Three special circumstances that pathobionts may play into?

Immunocompromised individuals
Accidental entry
Inflammation

9

Why is skin hard to colonize?

low pH
high NaCl
Lysozyme

10

Three primary bacterial organisms associated with the skin.

Staph Epidermis
Aerobic Corynebacterium
Propionibacterium acnes (in oily spots)

11

What part of the skin colonizes G-

Oily parts

12

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

Labia minora
Acidic conditions let lactobacilis take over

13

Three primary bacterium of the nasopharynx?

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

14

Four opportunistic bacteria associated with nasopharynx?

Viridans streptococci
Streptococcus pneumoniae
Nisseria meningitidis
Hemophilus influenzae

15

Bacteria at the base of dental plaques

streptococcus

16

Four most important resident bacteria of the mouth and oropharynx?

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

17

Most important bacteria of the stomach?

helicobacter pylori

18

Most important bacteria of the duodenum?

Lactobacillis

19

Most important bacteria of jejuno-ileum?

Enterobacteriaceae
G- Anerobes (Bacteroides)

20

Most important bacteria of the colon?

Bacteroides

21

Three gut enterotypes important for establishment of digestive health?

Bacteroides
Prevotella
Ruminococcus

22

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

fat -- Bacteroides
Fiber -- Prevotella

23

Relationship of bacteria to gut flora

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

24

Most common bacteria of the vagina

Lactobacillis
Bacteriodes
Prevotella

25

Changes in vaginal pH over the life cycle?

Acidic at birth
neutral till puberty, then acidic again

26

Most common bacteria of conjunctiva?

Staph/Strep
Hemophilus
diptheroids

27

List Six Sterile Areas

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

28

Difference between viral and bacterial latency

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

29

Three types of adhesion factors involved in virulence factors.

Pili/Fimbriae
Adhesins
Capsules

30

Intracellular invasion/colonization factors

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

31

Two types of intraceullular invasion/colonization factors

Uptake by non-professional phagocytes
Uptake by professional phagocytes

32

How do non-professional phagocytes work?

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

33

Five prevalent ways bacteria deal with phagocytes

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

34

What are endotoxin and exotoxin made of?

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

35

How do superantigens work?

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

36

What are PAI?

Collections of genes for virulence factors in one chromosomal location

37

How do we identify different bacteria locations?

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

38

Difference between a prevalence and incidence graph?

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

39

Difference between epidemic and endemic?

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

40

Why should you take caution diagnosing with diagnostic sequencing?

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

41

What does bacteriostatic mean?

Inhibits the growth of bacteria

42

What does a MIC test evaluate?

The minimum effective dose of an antibiotic in broth

43

What happens in a kirby bauer test?

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

44

Better version of a Kirby Bauer test?

E test in which you can read MIC from a strip

45

Which heat is more effective, wet or dry?

Wet

46

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

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

47

Most common sterilization method?

Autoclave + Ethylene Oxide

48

Why must one worry about filtration?

Flexible forms/L-forms of bacteria and small, slow growing cells may get through

Doesn't filter out viruses

49

What do high-level chemical disinfectants do?

Kills everything, even spores

50

What do Intermediate chemical disinfectants do?

Allow spores and some naked viruses to survive

51

What do low-level disinfectants do?

Allow spores, mycobacterium, some pseudomonas, and naked viruses

52

Two prevalent forms of disinfection?

Alcohol
Aldehyde

53

How do alcohols work against?

Dissolve lipids, denature proteins, dry out cells

54

How do aldehydes work against bacteria?

Crosslink or alkylate proteins

55

What do phenolics do?

Denature proteins, dissolve membranes.

56

Pros and cons of phenolics

Useful at high concentration
Irritants

57

Common phenolics? Particularly useful against?

Lysol, hexachlorophene
Staph and Strep

58

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

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

59

Two commonly used halogens?

Iodine and Chlorine

60

How does iodine work?

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

61

How does chlorine work?

Oxidizing agent (NaClO)

62

How do cationic detergents work?

Solubilize cell membranes

63

Cationic detergents must not be mixed with...

Anionic detergents

64

How do heavy metals work?

Derivatize -SH groups
Block Disulfide bonds

65

Example of the use of heavy metals in antibiotic treatment?

AgNO3 as prophylactic in newborn eyes
Ag-impregnated catheter tubing