BACTERIOLOGIST 1Daniel Brandes

Alexander Fleming Fleming was a Scottish pharmacologist

and biologist who lived from 1881 to 1955.

Fleming is best known for his discovery of Penicillin, the “Wonder Drug.”

Prior to his discovery of Penicillin

Having fought in WW1, Fleming witnessed many soldiers die from bacterial infections to combat wounds.

As Professor of Bacteriology at St. Mary’s Hospital in Paddington, London, Fleming devoted himself to do much research on the topic of antibacterial agents.

He discovered that the antiseptics used to clean wounds in the army lowered immunological defenses as opposed to destroying bacteria.

Discovery of Penicillin On September 3, 1928, Fleming made a

world changing discovery. His lab was often untidy, and he had

stacked some petri dishes of Staphylococci (A harmful Bacteria) with some other dishes.

He discovered that the staphylococci had been contaminated with a fungus, and that the bacteria did not grow near the fungus.

Discovery of penicillin The fungus, Penicillium, destroyed all of the

bacteria. After years of trials and purification of the

fungus, Penicillin was created– an antibiotic. By the end of WWII, Penicillin was being mass produced by the USA and England.

Penicillin affects all gram positive bacteria, such as those that cause scarlet fever and diphtheria.

However, when the antibiotic is used for too little time or in a too small dose, the bacteria that survives can gain resistance to the drug, rendering it less efficient.

Helpful Bacteria While we usually only consider the

harmful bacteria, 99% of the billions of bacteria on earth do not cause disease.

And many of them are extremely helpful. Human life would not have existed

without bacteria.

Helpful Bacteria Many bacteria, such as Lactobacillus

acidophilus aid in digestion. In fact, we depend on bacteria to digest food properly.

Lactobacillus acidophilus helps to digest lactose, and helps to prevent the growth of unwanted bacteria.

Many people buy samples of this bacterium to aid them in digestion.

Lactobacillus acidophilus

Helpful Bacteria Bacteria are excellent decayers. If bacteria didn’t exist, the world would

be piled in dead and decaying matter. Some bacteria break down oil as a source

of energy, and are used as a “cleanup crew” for oil spills.

Helpful Bacteria Rhizobia are a helpful type of bacteria that form

symbiotic relationships with legumes. They attach to the roots of the plant, and when they

enter, they begin a process called Nitrogen Fixation. The bacteria absorb nitrogen from the soil, and

convert it into ammonia that the plant uses. In return, the plant supplies the rhizobia with nutrients.

Rhizobia nodules in the roots of a soybean plant

Microbe Microbe: Group A streptococcus bacteria

Streptococcus bacteria can cause Strep Throat-- a painful, swollen throat with a fever when the bacteria is inhaled from water droplets in the air.

They can be killed using antibiotics, and are very common.

While Strep Throat is generally not dangerous, it can cause extreme discomfort.

Harmful Bacteria Only 1% of bacteria cause disease. However, those harmful bacteria do

cause serious problems.

Harmful Bacteria Vibrio cholerae is a bacterium that

causes cholera. Cholera is a disease that can kill in a day

if untreated, with symptoms including diarrhea and vomiting.

The disease is caused when the bacteria is introduced after ingesting contaminated food or water.

Cholera is easily treated by rehydrating the body.

Harmful Bacteria Tetanus is caused by the bacterium

Clostridium tetani . Tetanus is caused by the toxins released

by the bacteria which affect muscles. The disease can be fatal.

The bacteria are usually introduced by puncture wounds, and tetanus is not contagious.

A vaccine for tetanus is available.

Harmful bacteria Some bacteria can develop resistance to

antibiotics. This happens when antibiotics are

administered for too little time or too small a dose in a sick patient.

The surviving bacteria become immune to the antibiotic, and so are their offspring.

In this way, some antibiotics are becoming less affective, and new antibiotics have become necessary.

ResourcesFleming sources:

http://en.wikipedia.org/wiki/Alexander_Fleming http://www.nndb.com/people/696/000091423/

Helpful sources: http://www.articlesbase.com/health-articles/these-are-some-of-the-help

ful-bacteria-found-in-the-environment-around-us-356913.html

http://en.wikipedia.org/wiki/Lactobacillus_acidophilus http://www.buzzle.com/articles/helpful-and-harmful-types-of-bacteria.ht

ml

http://en.wikipedia.org/wiki/RhizobiaStrep sources:

http://www.mayoclinic.com/health/strep-throat/DS00260 http://kidshealth.org/parent/infections/bacterial_viral/strep_throat.html

Harmful sources: http://www.buzzle.com/articles/helpful-and-harmful-types-of-bacteria.ht

ml

http://www.emedicinehealth.com/tetanus/article_em.htm http://www.cdc.gov/nczved/dfbmd/disease_listing/cholera_gi.html