Introduction to Health Careers

Introduction to Health Careers

Unit 10 – Infection Control

Types of Microbes

Microbes – pathogenic microorganisms

Classified as bacteria, viruses, fungi, rickettsia and protozoa

I. Bacteria – one celled plants that can be pathogenic or nonpathogenic

a. Toxin – poisonous substance produced by many bacteria

b. Colony – a group of bacteria that grow together

c. Categorized according to shape

i. Cocci (round or ovoid shaped) -

1. Micrococci – appear singly

a. Cause skin and wound infections

2. Diplococci – appear in pairs

a. Cause gonorrhea, meningitis and some types of pneumomonia

3. Staphylococci – appear in irregular clusters

a. Are pus-producing and can cause abscesses, boils, wound infections, UTIs and other types of pneumonias

4. Streptococci – form chains

a. Cause rheumatic fever and strep throat.

ii. Bacilli (rod shaped) – the cause of diseases such as tuberculosis, tetanus, pertussis, botulism, diphtheria and typhoid fever

1. Bacilli – appear singly

2. Coccobacilli – somewhat oval

3. Diplobacilli – appear in pairs

4. Streptobacilli – attached end to end to form chains

iii. Spiral Shaped – cause diseases such as syphilis and cholera

1. Vibrios – curved rods

2. Spirilla – organism is rigid

3. Spirochetes – organism is flexible

II. Viruses – the smallest microbes. Cannot be seen under the traditional light microscope

a. Obligate intracellular parasites – viruses can only live inside another organism and depend on other cells for food, nutrients and means of reproduction

b. Cause diseases such as the common cold, influenza, pneumonia, chickenpox, croup, hepatitis, AIDS, measles, mumps, herpes, warts and polio

c. Viral infections are difficult to treat because they multiply rapidly, are easily transmitted, resistant to many disinfectants and are not killed by antibiotics.

III. Fungi – large group of simple plants. There are two groups that are potential pathogens: Yeast – one celled; Molds – multicellular

a. Cannot produce their own nutrients so they live on other organic materials.

b. Cause diseases such as athlete’s foot, ringworm, skin and scalp infections.

IV. Rickettsia – much smaller than bacteria and have rod or spherical shapes.

a. Must live inside the cell of another organism

b. Passed through the bite of fleas, lice, ticks and mites

c. Typhus is the only infection transmitted by humans

V. Protozoa – the only microorganism classified as an animal

a. Found throughout the human body on the skin, intestines and the mucous membranes of the nose and throat

b. Also found in decayed material, water contaminated with sewage waste, food washed in contaminated water or handled by unwashed hands.

c. Cause diseases such as: dysentery (gastrointestinal), trichomoniasis (STD), Toxoplasmosis, pneumocystis pneumonia (common cause of death in AIDS patients) and malaria