The Role of Bacteria in Infection

M. Stafford

What is a Prokaryote?

• Unicellular

• Lacks a nucleus

• Small 1-5 micrometers

Bacteria are Examples of Prokaryotic Cells

• Two Kingdoms

• Eubacteria – found everywhere

• Archaebacteria – found in harsh environments

Shapes of Bacteria

Growth and Reproduction

• Binary Fission

• Conjugation• Spore Formation -

endospore

Importance of Bacteria

• Producers• Decomposers• Many human uses

Soil bacteria

Bacteria and Disease

• Some use cells for food

• Example Mycobacterium causes tuberculosis

• Some release toxins

• Example – Streptococcus

• Releases a toxin that can cause a rash and scarlet fever

• Diphtheria – Corynebacterium diphtheria infects the throat and releases toxins into the bloodstream.

• Destroys tissues can cause heart failure, paralysis and death

Preventing Bacterial Disease

• Your first line of defense against bacterial infection is your skin

• Wash your hands

Preventing Bacterial Disease

• Vaccine – a weakened or killed pathogen that is used to stimulate the body’s immune system

• Antibiotic – blocks the growth and reproduction of bacteria

Fleming - penicillin

Control of Bacteria

• Sterilization by heat• Disinfectants• Food storage and

processing

Video – Killer microbe

• 8 minutes