prokaryotic lab: lecture 17

fill in the blank for these litmus test results

control/alkaline/acid/acid curd reduction/ alkaline peptonization reduction

Chronic Granulomatous disease(CGD)

-genetic disorder

-WBCs(phagocytes) are unable to kill certain types of bacteria and fungi. People with CGD often get life threatening bacterial/fungal infections

enrichment-culture technique

makes use of conditions designated to enable a particular type of microorganism to grow faster than all others in a sample

Van Delden’s

anaerobic conditions and sulfare, enrichment for sulfate-reducing bacteria(grrowth produces black precipiate)

Bristol’s broth

no carbon source, enrichment for algae and cyanobacteria

Chu’s broth

no nitrogen source, enrichment for cyanobacteria

antimicrobial agent

Any chemical or physical agent that inhibits the growth of a microorganism or kills it

Chemotherapeutic Drugs

Chemical compounds taken internally to ease the symptoms of a disease or speed a patient’s recovery

Antibiotic

-A chemotherapeutic drug

• A chemical substance produced by a microorganism stops the growth or kills other microorganism, is effective in small doses

known antibiotics and their sources

fungi→penicillum

bacillus→bacitracin and polymyxin

streptomyces→many antibiotics like streptomycin, erythromycin and tetracyline

ANTIBIOTICS (ARE/ARE NOT) TYPICALLY EFFECTIVE

AGAINST VIRUSES

ARE NOT

Kirby Bauer Method

• Broth culture has to have a standard turbidity, known as the 0.5 MacFarland Standard

• Antibiotic disks are of a standard concentration

• Only Mueller-Hinton agar is used

• Temperature affects diffusion of antibiotics. Plates are incubated at a specific temperature and stopped at 24 hours before inhibition zones are

measured

Mueller-Hinton agar is used in Kirby-Bauer test b/c

It has all purpose-media ingredients

• It is a looser agar, which allows the antibiotic to diffuse more easily across the media

• It has starch, which can bind to toxins produced by the bacteria as these toxins may interfere with

the antibiotic

chemical antimicrobial agents

referred to antiseptics, disinfectants & Antibiotic

Antiseptics

• Chemicals that are meant to be applied to

living tissue

• Alcohol

• Iodine

• Heavy metals

• Detergents

• Honey

Disinfectants

• Chemicals that are intended to be applied to the surfaces of nonliving

• Ammonia

• Bleach

• Strong oxidizing agents

TWO IMPORTANT RULES FOR DISINFECTANTS/ANTISEPTICS

1.)use most concentrated form that will cause the least damage when applied to surface

2)for long term use, either apply a combination of agents or change agent used often

Zone-of-inhibition method

It does not discriminate between bacteriostatic (inhibits bacterial growth) and bactericidal (kills the bacteria) chemicals