Antibacterials!By, Becky Luoma

Definition:

•Antibacterials are chemicals, which prevent the growth and multiplication of bacteria

Infectious Organisms• The types of micro-organisms that can cause different types of diseases are:

▫ Bacteria▫ Viruses▫ Fungi▫ Yeasts▫ Protozoa

• The most typical bacterium are made of:▫ A single cell▫ Protective wall

Proteins Sugars Lipids

▫ Cytoplasm▫ Granules of glycogen▫ Lipids▫ Other food reserves▫ Each cell has a single chromosome that consists of a deoxyribonucleic acid (DNA) strand▫ Some may have flagellum

• There are some aerobic bacterium that require oxygen to thrive▫ They will most likely be found infecting surface areas

Skin Respiratory tract

• Anaerobic bacterium are much more dangerous because they need either either very little oxygen or no oxygen at all▫ They will most likely be found inside of the body

Bowel Stomach

• There are a lot of bacteria that are actually beneficial to the body and do not cause disease▫ Some exist in or on the body but don’t do anything at all▫ Some cannot even live in or one the body

• The average size of a bacterium is 0.001mm wide

Narrow and Broad Spectrum Antibiotics:• Narrow antibiotics can only fight against certain types of

bacteria▫ All penecillins are narrow antiobiotics

• Broad spectrum antibiotics are effective when used against many different types of bacteria▫ Tetracyclines

Aureomycin Terramycin

• To determine what antibiotics must be given to the patient, blood, sputum (mucus), urine, pus, or stool samples must be taken▫ Because this takes time to do, broad spectrum antibiotics are

generally prescribed at first Once the bacteria that is infecting the body is known, it may be

switched to a narrow spectrum antibiotic to target a specific bacterium

Mechanism of Action of Antibiotics:

• Two main mechanisms to destroy bacteria that antibiotics use▫Penicillins and the cephalosporins don’t allow

from bacteria to make normal cell walls It does this by inactivating an enzyme necessary

for the cross linking of bacterial cell walls. The enzyme is known as transpeptidase. It accepts the penicillin as a substrate into the active site and then makes the enzyme completely inactive and deteriorates the cell wall

▫Other antibiotics go inside of the bacteria and interfere with the chemical activities that must be taken out to sustain their life Can prohibit the bacteria from turning glucose

into energy

Discovery of Penicillin:

• The first antibacterial that worked was called dye trypan red and was created by Paul Ehrlich as a cure for sleeping sickness▫ Sleeping sickness is caused by the bite of a tsetse fly in

Africa where it inserts trypanosomes The cure contained an arsenic compound (salvarsan)

which is effective against syphilis• The first ‘sulfa duh’ prontosil was created which is

effective against streptococcal bacteria (strep)•  Alexander Fleming left a Petri dish containing one of

the culture in the laboratory when he went on a holiday▫ Mold had developed on the cultures, and he realized

that the growth of the bacterium had been stopped The mold inhibited the growth of bacteria

Called Penicillin

Discovery of Penicillin (continued):•Even though Fleming found this, he did

not pursue this amazing discovery▫Howard Florey and Ernest Chain isolated

and purified penicillin after Fleming found it Tried to use on a police man who had

septicaemia Not enough penicillin because it was only

grown in Petri dishes▫Police man died, but then penicillin started to be

made in bulk

Penicillin

•Now, penicillin is produced in bulk because it took a very long time to make a supple amount of it from Petri dishes▫Grown in large tanks containing corn-steep

liquor▫Different types of penicillin and antibiotics

can be made in laboratories because the structure was determined

Penecillin’s structure: (polar)

Overuse and Resistance to Penicillins• Penicillinase allows for certain bacteria to be

resistant to the penicillin so that they can multiply▫Can deactivate penicillin G (the original penicillin)▫So chemists have made it so that other penicillins

can keep the active part of these bacteria the same, but completely morph their side chain so that they can’t carry out their actions and so that they are more resistant to the penicillinase Bacteria multiply and mutate too fast, so antibiotics

and medicines that are completely effective are hard to come by and are even more resistant breeds Called ‘super bugs’

Overuse and Resistance to Penicillins (continued):

Differences between Penicillins (and Cephalosporins) and Sulfa Drugs• Sulfa drugs:

▫ Stop bacteria from growing However, they do not kill

the bacteria▫ The first antibiotics created▫ Completely manmade and

natural▫ Have many different effects

on the people using them More common to have

problems than in Penicillins

Taken with another drug (erythromycin or trimethropin)

More allergic reactions Some even life-

threatening

Patient Compliance:

•Because so many different drugs are being used to treat many infections, the patient must comply▫The number of allergies and responses to

antibiotics is so high that death could possibly occur

•Resistance problems (caused by the feedstocks as previously talked about)

Citations:•http://www.chm.bris.ac.uk/

webprojects2002/thornton/how_does_penicillin_work.htm

•http://health.howstuffworks.com/health-illness/treatment/medicine/medications/question88.htm

•http://www.drreddy.com/antibx.html#sulfa•http://www.detectingdesign.com/images/

Antibiotics_Viruses/lactam1.jpg•http://www.uen.org/utahlink/activities/

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