micro bio test 3

CFU

colony forming unit

sterilization

removing and destorying all microbial life

commerical sterilization

killing c. botulinum endospores from canned goods

disinfection

destroying harmful microorganisms (kills 99.9 of bacterica and viruses)

antispsis

destroying harmful microorganisms from living tissue (mouth wash)

degerming

the mechanical removal or microbes from a limited area

sanitation

lowering microbial counts on eating utensils

sepsis

refers to bacterial contamination

asepsis

absence of significant contamination

biocide (germicide) treatments

kill microbes but not necessarily endospores

bacteriostatic and fungistatic

inhibit microbial and fungal growth

biological safety levels (BSLs)

CDC and NIH made 4 classification levels based on risks associased with specific pathogens

BSL- 1

used in lab/ minimal risk

BSL- 2

moderate risk to workers and environment

BSL- 3

cause serious or potential lethal diseases thru respiratory transmission

BSL-4

high risk and fatal without treatment or vaccines

BSL determined by

agents infectivity

ease or transmission, potential disease severity

type of work being done with agent

dry heat

kills by oxidation

moist heat

denatures enzymes and proteins

combination of heat and pressue

autoclave

high pressure

denatures protein, endospores may resist

desiccation

addition of solute creating a hypertonic environment, drawing water out of cells

radiation

causes the formation of thymine dimers in DNA, leading to lethal mutation in the exposed microes

food irradiation

exposed to gamma radiation by passage on a conveyor belt thru a radiation chamber

filtration

passage of liquids and air thru a screenlike material

used for heat sensitive materials

joseph lister

began using carbolic acid, phenol, as disinfectant for the treatment of surgical wounds

most common halogens

iodine, chlorine, fluorine

iodine

works by oxidizing cellular components, including sulfur-containing amino acids, nucleotides, amino acids

heavy metals

kill microbes by binding to proteins, thus inhibiting enzymatic activity

conditions influencing effectiveness of antimicroial agent

population size/ composition

concentration or intensity of an antimicrobial agent

duration of exposure

temperature

local environment

disk diffusion

method to evaluate the efficacy of chemical agents

surfactants

surface active agents, a group of chemical compounds that lower the surface tension of water

chemotherapy

the use of chemicals to treat a disease

selective toxicity

selectively finding and destorying pathogens without damaging the host

antibiotic

substance produced by a microbe that, in small amounts, inhibits another microbe

antimicrobial drugs

synthetic substances that interfere with the growth of microbes

salvarsan

arscenic containing compounds, Ehrlich and Hata discovered

penicillin

Fleming discovered

Prontosil

red dye, used for strep and staphylococcal infections

prontosil

Klarer, Mietzsch, and Domagk discovered

natural antibiotics

compounds isolated from organisms

natural antibiotics

mold, fungi, bacteria

semisynthetic antimicrobials

chemically modified derivative of a natural antibiotic

synthetic antimicrobial

developed from a chemical not found in nature

narrow spectrum of microbial activity

drugs that affect a narrow range of microbial types

broad spectrum antibiotics

affect a broad range of gram postive or gram negative bacteria

dosage

amount of medication given during a certain time interval

orally

pros- patients can more conveniently take drugs at home

cons- some drugs are not easily absorbed by GI tract into blood stream

parenteral ( intravenous or intramuscular injection)

pros- short time to reach high concentration in plasma

cons- typically preformed in health-care settings

half life of drug

rate at which 50% of a drug is eliminated from the plasma (doses/day X toxicity)

toxicity

side effects caused by the drug

selective toxicity

selectively kills or inhibits the growth of microbial targets while causing minimal or no harm to the host

synergism

two antibacterial drugs may be administered together to improve efficacy

atagonism

can occur between two antimicrobials or between antimicrobials and non antimicrobials being used to treat other conditions

inhibition of cell wall synthesis

B- lactam ring prevents the synthesis of peptidoglycan

gram postive

thick cell wall

gram negative

thin cell wall

natural penicillins

extracted from penicillium cultures

narrow spectrum of activity

susceptible to penicillinases (B- lactamseses)

semisynthetic penicillins

contain chemically added side chains, making them resistant to penicillinases

Which of the following might make a disinfectant less effective?

 

Using a low concentration

 

Applying the disinfectant for a short amount of time

 

Presence of biofilms

 

All of the above

All of the above

Which of the following does not kill or inhibit bacteria but can mechanically remove bacteria from a surface?

 

Halogens

 

Alcohols

 

Soaps

 

Phenols

Soaps

____________ is a physical method of microbial control.

 

Antibiotics

 

Alcohols

 

Ionizing radiation

 

None of the above

Ionizing radiation

Which of the following is FALSE regarding specialized transduction?

 

Phages pick up bacterial DNA during exsicion and can transfer it to a new host

 

It occurs when random host DNA is packaged during the lytic cycle

 

It can change the genetic properties of a bacterium

 

All are correct

It occurs when random host DNA is packaged during the lytic cycle

Reverse transcriptase is an enzyme that some viruses use to make ______ using ______ as a template.

 

DNA; DNA

 

DNA; RNA

 

RNA; RNA

 

RNA; DNA

DNA; RNA

injection

Viruses are released by lysing the bacteria