Microbiology 265 Final - Yan Boucher, Via Shak Part 1 Antimicrobials

Front 1

What is disinfection?

Back 1

Killing inhibition or removal of micro organism from inantimate objects. Endospores still there.

Front 2

What are some examples of disinfection?

Back 2

Phenolic - inanimate
Boiling water
UV irradiation
Hydrogen Peroxide

Front 3

What is sterilization?

Back 3

Destruction removal of all viable organisms, including endospores

Front 4

What are some examples of sterilization?

Back 4

Autoclave- steam, 15 min at 2 atm
high energy ionizing radiation

Front 5

What is sanitization?

Back 5

Reduction of microbial population to a safe level determined by public health standards
Anionic detergents and soaps

Front 6

What is antisepsis?

Back 6

Prevention of infection of living tissue by microorganisms
Iodine, merthiolate, ethanol

Front 7

What is chemotherapy?

Back 7

microbes living within a living thing, inject or ingest chemicals inside of them to kill or inhibit the growth inside tissues

Front 8

What factors affect antimicrobial activities?

Back 8

1. Population size - larger populations take longer to kill
2. Population composition - sensitivity
3. Concentration or intensity of antimicrobial agent - the more concentration, the better it'll work.
4. Duration of exposure - the longer the antimicrobial is exposed, more it'll kill
5. Temperature - higher temp is better
6. Local environment- Environmental factor , live spongy is harder for antimicrobials, pH viscosity, concentration of organic matter

Front 9

What is thermal killing?

Back 9

Moist heat more effective than dry heat - autoclave is better than incineration (because H2O disrupts H bonding)
Dry heat is slow
Boiling water - effective against eukaryotic spores not prokaryotic
Autoclaving- Steam under pressure. Kills everything (almost all bacterial endospores)
Dry heat - requirees several hours to do the same as 15 minutes in autoclave

Front 10

What is decimal reduction time?

Back 10

time it takes for reduction of population ten fold

Front 11

What is pasteurization?

Back 11

method by which you reduce the total microbial population to increase shelf life for heat sensitivite materials (usually liquids like beer milk wine)
- effective against gram (-) pathogens.

Front 12

What is the difference between the modern method versus the older method?

Back 12

Modern - 15 sec at 71 C
Older - 15 minutes at 15 C

Front 13

What is tyndalization?

Back 13

Back in the old days
Sequential boiling to sterilize
- first boiling -> kill vegetative cells but not spores
let it incubate in nutrient rich broth, lets spores germinate back to vegetative form
Next day Second boiling - kills everything

Front 14

What is filtration?

Back 14

-removes organisms that are heat sensitive.
- membrane filter - cant take out viruses
-high efficiency particulate air (HEPA) use
Get a sheet , use gamma rays to poke holes
We can use a vaccum

Front 15

What is an ultramicrobacteria?

Back 15

cant remove using a filter, they are able to move through (rod shaped)

Front 16

Ultraviolet and ionizing radiation - physical radiation
is it ionizing?

Back 16

UV Disinfection (non ionizing)
-Thiamine dimer formation causes major injury to DNA
-Surface sterilization only does not penetrate glass, dirt films, water, and other substances
-Works best near 260 nm to destroy pyrimidine bases

Front 17

What is ionizing radiation? (x rays gamma )

Back 17

steralization
Food irradiation
forms oxygen radicals, they damage DNA

Front 18

What does the suffix -static mean?

Back 18

that the agent will prevent growth of the type of organism in question (e.g., bacteriostatic, fungistatic)
-prevents the population from growing

Front 19

What does the suffix -cide mean?

Back 19

that the agent will kill the kind of organism in question - the cell is still there tho. the corpse

Front 20

Name the Chemical Antimicrobial Agents

Back 20

Phenolics
Alcohols
Halogens
Heavy metals
Aldehydes and lactones
Sterilizing gases
Vapor-phase hydrogen peroxide
Quaternary ammonium

Front 21

What are phenolics?

Back 21

denature proteins by disrupting H-bonding. Used in laboratory and hospitals as disinfectants.
TOXICish

Front 22

What is the function of alcohol in terms of antimicrobial agents?

Back 22

-denature proteins by disrupting H-bonding and
dissolve membrane lipids. Used as disinfectants and antiseptics.
-Do not kill endospores

Front 23

What are halogens in terms of antimicrobial agents?

Back 23

(e.g. chloride and iodine) oxidize cell constituents. Used as disinfectants and antiseptics. Oxygen radical
Cl2 + H2O-> HCl + HCl -> 2HCl + O

Front 24

What are heavy metals?

Back 24

(e.g. mercury, silver) inactivate proteins by covalent binding. Used as antiseptics.
TOXIC

Front 25

What are aldehydes and lactones?

Back 25

inactivate proteins by covalent binding. Used as antiseptics

Front 26

What are sterilizing agents?

Back 26

(e.g., ethylene oxide) covalently bind to and inactivate proteins

Front 27

What is quaternary ammonium?

Back 27

(e.g. cationic detergents) disrupt biological membranes and denature proteins

Front 28

Phenol Coefficient
What do hydrophobic molecules do better than phenol? Examples?

Back 28

potency of disinfectants compared to that of phenol
they disrupt membranes better.
Example. Hexachlorophene, Isopropyl alcohol vs. ethanol

Front 29

Joseph Lister did what? How ?

Back 29

First to use antiseptic before surgery.Invented how doctors wash hands. Made procedure to do surgery.

Front 30

Which are the two most used chemotherapeutic agents?

Back 30

Chemicals taken internally to kill or inhibit the growth of microbes within host cells - Antibiotics, Antifungals, Antivirals . There is no drug that does all three
Selective toxicity
MOST ARE ANTIBIOTICS. - chemicals synthesized by microbes that are effective controlling bacteria growth
Two biggest are pecillin and streptomycin

Front 31

What is selective toxicity?

Back 31

allows chemicals to target microbe without harming the host

Front 32

Who discovered Salvarsan? And what is it ?

Back 32

Paul Ehrlich
called compound 666
treats syphilis; replaced mercury which was equally toxic to bacterium and the host

Front 33

Who was Gerhard Domagk?

Back 33

Screened more than 1000 synthetic dyes against Streptococcus
Prontosil was the first of the sulfa drugs

Front 34

Who was Alexander Flemin?

Back 34

discovered penicillin

Front 35

Who was Selman Waksman?

Back 35

Discovered streptomycin

Front 36

What makes streptomycin and whats so special about this bacteria DAWG?

Back 36

Streptomyces griseus. These are filamentous bacteria that have linear chromosomes.

Front 37

What are the desired characteristics of antimicrobial drugs?

Back 37

Selective toxicity with minimal side effects

Therapeutic dose the drug level required for clinical treatment of a particular infection - the better the drug is the lower the dose needed for best results

Broad spectrum activity (against a wide variety of pathogens) sometimes more desirable than narrow spectrum activity

Chemotherapeutic agents can occur naturally, be synthetic or semi-synthetic (chemical modifications of naturally occurring antibiotics to make them better.)

Front 38

What is MIC?

Back 38

mininmum inhibitory concentration . lowest dose of antibiotic that prevents growth
does not mean it will kill already living ones

Front 39

What is MLC?

Back 39

minimum lethal concentration - lowest dose that kills the pathogen

Front 40

What is the Disk diffusion test? (Kirby Bauer method)

Back 40

dicks impregnated with specific drugs. inoculated with test microbe . Drug diffuses from disk into agar, establishing concentration gradient . clear zones noticed . measure size of MIC MLC

Front 41

What drugs target different pathogens?

Back 41

no drugs that affect viruses or fungi can effect bacteria as well

Front 42

What is tetracyclin?

Back 42

broad spectrum, penetrates gram negative and positive

Front 43

What is sulfanilamide?

Back 43

its a competitive inhibitor for PABA, a precursor of Folic acid (nucleic acid precursor ) . therefore nucleic acids arent made
SABA

Front 44

What are antimicrobial analogues?

Back 44

Look like the growth factors but inhibit growth
very toxic

Front 45

What are quinolones?

Back 45

Synthetic antibacterial compounds
Inhibits bacterial DNA gyrase, the enzyme that supercoils DNA for packing into the cell
Effective against many G- urinary tract infections and respiratory infections
Effective against Bacillus anthracis

Front 46

RNA synthesis inhibitors
Is It toxic

Back 46

toxic. because can not be really selective
Prokaryotes and eukaryotes do not differ greatly in how they synthesize nucleic acids

Front 47

How do rifamycin and rifampin function?

Back 47

bind RNA polymerase and block transcription

Front 48

Cell wall biosynthesis inhibitors . Whats the group's name . How do they work and what can break them

Back 48

B-lactams- cyclic peptides
-Penicillin : member thiazolidine ring
-Cephalosporin : 6 member dihydrathiazine

Bind to transpeptidases: enzymes that cross-link peptidoglycan monomers, cause weakening of the cell wall

B- lactamase breaks down B-lactam rings

Front 49

Which gram are susceptible to B lactam drugs. Where are the B-lactamases found

Back 49

Gram posotive cells:
outer membrane is impermeable to penicillin in gram -
β-lactamases in periplasmic space for gram negative
B-lactam only affect the gly interbridges therefore gram negative is not susceptible

Front 50

Penicillin function by. ALL STEPS
Tell me about new penicillin combat against gram negative bacteria

Back 50

pencillin binds to transpeptidase (also know as Pencilling binding protein PBP); activity is blocked

Penicillin-PBP complex stimulates release of autolysin

Occurs during active cell wall biosynthesis (growth)

New penicillin structures not readily hydrolyzed by ß -lactamases

Front 51

How is ampicillin protected from lactamases?

Back 51

it is co treated with clavulanic acid
ß-lactam structure like ampicillin
clavulanic acid acts as a inhibitor by binding to B-lactamase, preventing ampicillin from being attacked.

Front 52

What is cycloserine?

Back 52

blocks D-Ala peptidization, cant be put into peptidoglycan

Front 53

What is bacitracin?

Back 53

blocks the dephosphorylation of bactoprenol.

Front 54

What is vancomycin?

Back 54

binds to the terminal D-Ala in peptidogylcan precursor

Front 55

What are protein synthesis inhibitors?

Back 55

Aminoglycosides
Macrolides
Tetracyclines

Front 56

What are aminoglycosides?

Back 56

Streptomycin , kanamycin
Inhibit protein synthesis by binding to the small subunit of the ribosome
Effective mostly against Gram-negative bacteria

Front 57

What are macrolides?

Back 57

Erythromycin
11% of total world production and use of antibiotics
Inhibit protein synthesis by binding to the large subunit of the ribosome

Front 58

What is tetracyclines?

Back 58

First broad spectrum
Inhibits protein synthesis by blocking tRNA attachment to ribosome
Effective against almost all Gram-positive and Gram-negative bacteria

Front 59

What is daptomycin?

Back 59

Cyclic lipopeptide

Inserts into cytoplasmic membrane, makes pore

Primarily targets Gram positive—it lacks an outer membrane. In gram - it has a membrane and it takes away activity that would affect inner membrane.

if the cell changes, it will be resistant to daptomycin or daptomyscin is resitant to changes

Front 60

Anti-fungal drugs. Why is it difficult to treat for them? And what does it target

Back 60

Fungal infections difficult to treat due to biological similarity between host and pathogen
Acts on sterols and chitin ( a cell wall polymer)

Front 61

What is nystatin?

Back 61

first discovered antifungal by hazel brown

Front 62

What are superficial mycoses?

Back 62

Infections of superficial tissues (epidermis layer)
Treated by topical application of Miconazole, Nystatin, and Griseofulvin
put on our surface to minimizes toxic systemic side effects (e.g. liver damage)

Front 63

What do we target when using anti-fungals?

Back 63

Cell wall synthesis is made by chitin (exoskeleton) .ergosterol synthesis is different from human biochemistry activity, hence we target these first to make it less toxic to us

Front 64

What can antifungals attack?

Back 64

membrane functions, cell wall synthesis, ergosterol synthesis, microtubule formation, nucleic acid synthesis

Front 65

Antiviral drug
toxicity?
Function?

Back 65

toxic to us because they use our machinery to replicate themselves
not many antiviral drugs
they disrupt RNA and DNA synthesis of the viral genome.
We usually use analogues but those are toxic to us. Very problematic

Front 66

What are protease inhibitors?

Back 66

antiviral drugs against virus specific enzymes

Front 67

What is interferons?

Back 67

Stimulate the production of host anti-viral proteins
Host cells way of protections

Front 68

What is structural analogues?

Back 68

If the analogue is of a nucleic acid, it will affect either DNA or RNA synthesis or structure. If the analogue is of an amino acid it will affect protein synthesis or structure.

Front 69

Antibiotic resistance
How is it building ? how does it transfer?

Back 69

the more we use the antibiotic, the more resistant the bacteria become ( direct correlation)
Origin and transmission of antibiotic resistance uses chromosomal or plasmid genes. PLASMID GENES EASILY TRANSFERRED hence most common.

Front 70

Nocosomial infection
Do hospitals cause high resistance in microbes?

Back 70

those that build during hospitalization
yes because they are all in one place, transferring genes and shiet

Front 71

What are the mechanism of resistance?

Back 71

Exclusion- Efflux pump (when they come in they are pumped out )
Enzymatic inactivation (enzyme degrades the the antibiotic before it harms cell)
Modification of antibiotic or target (changes the antibiotic thereby inactivating)
Alternative pathway or increase target

Front 72

What are the sources of resistance genes?

Back 72

Bacterial Chromosomes
Plasmid
Mobile genetic elements

Front 73

Bacterial chromosomes are a source of resistance genes

Back 73

spontateous mutations which usually result in a change in drug target

Front 74

Plasmid as a source of resistance genes
how are they transferred ?

Back 74

R plasmids are resistant plasmids - make proteins that make the bacteria resistant against antimicrobial drug
transferred by horizontal gene transfer
Can carry multiple resistance genes

Front 75

Mobile genetic elements
Transduction

Back 75

Transposons, integrons
genes can be exchanged between elements

Front 76

Transformation in terms acquisition of resistant genes

Back 76

Gets genes from a dead cell that had the the resistant gene then transformed into its own DNA
either goes into the form of plasmid or chromosome

Front 77

Transduction in terms acquisition of resistant genes

Back 77

FROM PLASMID TO PHAGE TO ANOTHER CELL
either to the form of plasmid or chromosome

Front 78

Conjugation in terms of acquisition of resistant genes

Back 78

when a plasmid with a resistant gene goes into a bacteria via horizontal gene transfer

Front 79

A two component site specific recombination system of The Integron/ Gene Cassette system

Back 79

free circular gene cassettes can be integrated into a different gene cassette by integron integrase at an integron associated recombination site

Front 80

How do you prevent drug resistances?

Back 80

GIve drugs in high concentration so everything is killed

Give two or more drugs at same time to kill the drug resistant bacteria as well. If one don't work then the other will

Use drugs only when necessary

Possible future solutions
Continued development of new drugs (deal with market disincentive issues)
Use of bacteriophages to treat bacterial disease - very specific and very precise. Only affect problematic bacteria

Front 81

Explain how giving drugs to animals in their feed is bad.

Back 81

because we get the drugs in low concentrations and then we get bacteria that are resistant to the drug. They multiply and we get screwed over.