bio 119 text IV

why do we need to control the growth of microbes outside our body?

physical or chemical method that kills or removes ALL microbes in/on inanimate object

Is it possible to sterilize living organisms

standard methods dont kill this microbe

an environment or procedure (aseptic technique) free of pathogens

Use of Physical or Chemical agents called Disinfectants to Kill or Inhibit VEGETATIVE pathogens on Inanimate objects

Use of Chemical agents called Antiseptics to Kill or Inhibit VEGETATIVE pathogens               on Body

Neither Disinfectants nor Antiseptics kill

Many Disinfectants are just Antiseptics that are more concentrated or applied for

Reduces pathogens to meet public health standards, ex: restrooms, public toilets

Type of Disinfection or Antisepsis     
using Physical Scrubbing with or without chemicals, ex: hand washing, alcohol swabbing

bacteriocides kill bacteria
Fungicides kill fungi
Virucides
kill viruses
Sporicides kill all = sterilize

Will inhibit growth temporarily

Example: refrigeration

reduction in the number of microorganisms and viruses, particularly potential pathogens, on living tissue ex: iodine, alochol

refers to an environment or procedure free of pathogenic contaminants ex: prep of surgical field, flame sterilization of lab equipment

use of heat to destroy pathogens and reduce the number of spoilage microorganisms in food and beverages, ex: milk and juice

suffixes that indicate destruction of a type of microbe

suffixes indicating inhibition, but not complete destruction, of a type of microbe

permanent loss of reproduction

can be used to measure efficacy of an antimicrobial agent

What % of culture dies per
time period?

what are the four general targets of antimicrobial agents

what is the most resistant microbe and the most susceptible

the higher the load(number of microbes) the

chemical disinfectants generally work best at

effect efficacy of heat and chemicals

organic matter( rats, feces, vomit, blood, saliva, biofilm secretion) can inhibit some what

for evaluating effectiveness of Disinfectants & Antiseptics

two main types of microbial control

heat

denatures proteins, disrupts membranes, cell walls, nucleic acids

shortest time to to sterilize liquids at a specific temp

lowest temp to sterilize a liquid in 10 min

time to kill 90% of microbe population at a particular

used to measure effectivness of heat sterilization

moist heat more effective at same temp than

dry heat kills by:

dry heat also kills by

denaturing enzymes stops

dry heat makes enzymes

100 degrees celsius, not spororcidial, drinking water, baby materials, food untensils

121 degrees C, psi 15, yes sporocidial, heat and moisture resistant materials

not sporocidial, fresh beverage, milk, juice, beer, wine

140 degrees C, most efficient, is sporocidial, can store at room temp indefinitely

171 degrees C/340 for 1 hour, is sporoicidal, glassware, metals, powders, oils

great than a 1000 degrees C, is sporoicidal, metals, glass, needles, dressings, animal carcasses

bacteriostatic only

0-7 degrees C, not sporoicidal, slows metabolism, faculative psychrophile can grow in this environment(listeria, yersinia)

below 0 degrees C, not sporocidial, no water available

dehydration by sun, oven, not sporocidial, preserve fruit, beans, grains, nuts, peas, yeast

freezing in liquid N or dry ice, dehydration by sublimation, not sporocidial, preserve food and microbes, prevents ice crystals from damaging cells

hypertonic solutions of sugar or salt, cells dehydrate, honey, jerky, jams, jellies, salted fish, pickels

not microbicidial, fluid passed through membrane filer w/pores that exclude microbes and particulates, heat sensitive liquids: serum, vaccines, enzymes, eye solutions, liquid vitamins, media, air: surgical masks, HEPA filiters, can sterilize/sporocidial

ejects orbital electrons from atom

sporocidial, protein damage, DNA mutations, chemical changes in organelles, produces toxic substances, used in: heat/chemical sensitive materials, food, water, medical supplies: vaccines, instruments, gloves, heart valves for grafting, us mail

what method of handling microbes prevents infection of tissues

Which molecule looks like a substrate and sits in the active site of an enzyme?

Which antimicrobial agent inhibits DNA gyrase?

_________ are beneficial microbes that compete with pathogens for resources.

an adaptive response where the population contains higher numbers of microbes that are not killed by the drug.

Electrons are ejected from atoms in cells when organisms are exposed to

A prescription of two drugs can show synergism in their effect against microbes

Which is effective against spores?

Which antimicrobial agent is the best hope for combating the avian flu virus?

Pathogen A is more
resistant to an tetracycline disc on a Kirby-Bauer diffusion susceptibility
plate compared to pathogen B.  Pathogen A will have a(n) ___________ zone
of inhibition compared to pathogen B.

what affects dissinfection

kills microbes by producing toxic free radicals

gaseous chemosterilant used in chemiclave

used to disinfect drains, cesspools, and animal quarters

heavy metal toxic to humans in minute amounts

UV 260 nm, excites, not ejects orbital electrons from atom

sporocidial or microbistatic, pyrimidine dimers, abnormal replication and transcription, in air: food prep, hospitals, schools, dental offices, liquid: water, juice, sewage treatment

characteristics of a good germicide

rapid action and long lasting, soluble in h20 and alochol(stable), kills variety of microbes but non-toxic to humans or animals, resists inactivation by organic matter, non-corrosive or non-staining, inexpensive and avaiable

Kills variety microbes but non-toxic to humans or animals

removal of prions on medical instruments, can sterilize

disinfectants and treatment of infectious diseases

sterilization of heat and water sensitive objects, can sterilize

soaps, degerming, detergents, antiseptic

chemically altered phenol

denatures proteins and disrupts cell membranes, original surgical antiseptic

denature proteins and disrupts cell membranes, disinfectants, antiseptics, and as a solvent in tinctures

presumably denatures proteins, disinfectants, antiseptics, water purification

•Denatures proteins (requires H20, so 70 - 90% alcohol better than 100%), Biodegradable, doesn’t increase bacterial resistance, Not good for bacterial endospores, fungal spores, non-enveloped viruses, Skin antiseptic Disinfectant for electrodes, face masks, thermometers

halogens

Antiseptic
on skin before surgery, treat burns

Disinfectant for plastics, rubber,
cutting blades, thermometers

•Disinfection drinking water,
pools, sewage, food equipment

halgoens

Disinfection
of Hot tubs, pools, cooling towers

•Disrupts
metabolism in dental biofilms

surfacants

lower surface tension of water to make it a better solvent

•Surrounds grease & oils so can be
washed away

•Antimicrobial
because disrupts membranes

•Disinfect &
sanitize floors, restrooms, eating utensils, clothing, food-processing
equipment

•Colorless, tasteless & mostly
harmless to humans

•Inhibited by organics, soaps

heavy metals

•Surgical dressings, burn creams

•Incorporated into plastics or steel
for toilet seats, catheters, stethoscopes, refrigerator doors

•Interferes w/chlorophyll in algae

•Pools, fish tanks, water storage,
reservoirs

oxidizing agents

•Effective against anaerobes

•Surfaces,
invasive instruments, food packaging

•Catalase
released from damaged human cells breaks it down into water & O2
gas

•Surfaces, food & medical
equipment

•Not
affected by organics, no toxic residue

aldehydes

Denatures proteins, inactivates nucleic acids

•Medical & dental instruments

•More effective, expensive & less
irritating than formaldehyde

sterilant for instruments, dialysis machinesIn embalming fluidIrritates mucous membranes; carcinogenic

gaseous ethylene oxide

Penetrate paper/plastic, diffuse into cracks

•Denature Proteins & DNA

Hospital & Dental instruments, NASA spacecraft, heart valves, plastics, pillows, mattresses Sugar, dried foods, drugs

•Use in Chemiclave because can be explosive,
poisonous – need to flush with air

gaseous halogen

Denature proteins by disrupting S-S bridges & H bonds

gas used to sterilize after 2001 anthrax spores mailed to U.S. Senate offices

enzymes

Tears, saliva: digests peptidoglycan cell wallCheese & wine making, sterilizing medical equipment

Removes prions on medical instruments

Generic term for drugs that act against disease

Drugs that treat infectious disease (caused by microbial pathogens)

Antimicrobials naturally produced by a microbe to destroy another microbe

Chemically altered antibiotics

Completely synthesized in a lab

penicillium, cephalosporium

bacillus, strepomyces

As first proposed by Ehrlich’s “Magic Bullet”,successful drugs must have

must be more toxic to pathogen than to host

are tough to treat because they are animals

Hardest to get Selective Toxicity for viruses because they use our

inhibition of cell wall synthesis

inhibition of pathogen's attachment to, or recognition of host

inhibition of DNA/RNA synthesis

inhibition of metabolic pathway

disruption of cytoplasmic membrane

inhibition of protein synthesis

Are Antibiotics and Semisynthetics that inhibit synthesis of new bacterial cell walls

Some bacteria have Beta-lactamases =

Are enzymes that destroy Beta-lactam ring so drug loses

Bind to & inhibit enzymes that cross-link NAMs with peptide bridges in new peptidoglycan

Only effective on growing or reproducing bacteria

Cells die due to effects of osmotic pressure when walls weakened; more effective on Gram (+)

are Antibiotics & Semisynthetics

drawbacks to Penicillins

Discovered as antibiotic
Most are now semisynthetic

Majority (~1/3) of all antibiotics administered
Injected into muscle or vein because
absorbed poorly when taken orally
Resistant to many penicillinases
Can cross blood-brain barrier

Directly interfere w/peptide cross bridges between NAMs in Gram(+)
For penicillin allergic patients
For  MRSA = methicillin resistant S.aureus
Can be toxic to kidneys

Blocks transport of NAG & NAMs from cytoplasm
Major ingredient (with polymyxin
& neomycin) in Neosporin,         
Triple antibiotic ointments

Change shape of 30S subunit or block tRNA docking site
Streptomycin, Gentamicin, Neomycin

Block tRNA docking site

Prokaryotes
& Mitochondria have

Eukaryotes have 80S, so can get some

Antibacterial
good against G(-)
Used topically
Toxic to kidneys

Antifungal
Binds to ergosterol

Antifungal
Inhibit
synthesis of ergosterol

inhibit enzymes in the Folic Acid Synthesis pathway

(Sulfa drugs) are synthetic &                           the 1st modern antimicrobial – 1935

Sulfonamide & Trimethoprim are

the more drug in the body, the fewer normal substrates are processed by the enzyme

Bacteria is then inhibited because it lacks

Inhibit DNA Gyrase, used for coiling/uncoiling replicating DNA

Plasmodium causes

Plasmodium eats

 makes toxic hemes as waste; needs to detoxify heme to survive

Inhibits heme detoxification & Ca2+ transport

Inhibits heme detoxification raises pH in food vacuoles, interfere w/ETC, increase Oxygen free radicals

uses Reverse Transcriptase enzyme (humans don’t have it) to make dsDNA from ssRNA

Reverse Transcriptase Inhibitors stop this enzyme from functioning

used against HIV Reverse transcriptase

used against Herpes

Nucleotide/nucleoside analogs are nonfunctional

When incorporated into viral DNA / RNA will block