Microbiology concepts

Microbiology Concepts

IHS Unit 3

Goals

• Identify and discuss organisms that cause disease in humans.

Pathogens

• An organism that causes disease in humans is called a pathogen. – A pathogen that causes a specific disease is the agent.

Types of Pathogens

• Most communicable (infectious) diseases in humans are caused by either viruses or bacteria.

• Some diseases are caused by protozoa or fungi.

• The specific traits of a given organism determine what type of disease is caused and how it passes from person to person.

Bacteria

• Single celled microorganisms that are the most numerous type of organism on the planet. – Only a small percentage of bacteria

cause disease in humans. Most are harmless or even helpful.

– Variations in size, cell wall, chemicals produced, etc. effect the types of disease caused.

– Antibiotics are effective in treating infections that are not self limiting.

Viruses• Viruses are strange organisms that are not

even truly living. – They do not look like other life on our planet,

leading to some biologists calling them “aliens.”

– In order to “live” and replicate themselves, they hijack other cells and use there organelles to make viral DNA.

– Then, they kill that cell and release the new viruses.

– Viruses are usually self limiting, and can be treated by dealing with symptoms or antiviral medication.

– Antibiotics are NOT effective.

Protozoa

• Literally means “primitive animal”– Single celled organisms

that behave sort of like animals.

– Cause disease such as amoebic disentery and malaria.

– Technically a parasite. – Special antiprotozoal

medicine is used to treat.

Fungi

• These are organisms such as molds and yeast. – Reproduces via spores

(spores are often an agent of disease.

– Some fungi even help us by producing antibiotics.

– Fungi are treated with antifungal medicines.

Resistance

• If an organism is resistant, it means that it does not respond to the normal treatments used for it. – This is dangerous, because it often means that

patients have to take stronger medications with more side effects or that there is no way to treat the disease.

– Resistance is caused by both overuse of antibiotics in healthcare and the use in agriculture.

Importance in Healthcare

• Health care providers and Laboratory specialists have the task of figuring out what type of organism causes disease. – This is the only way we can have specific and

effective treatment. – Choosing the wrong treatment can allow the

disease to get worse, and also contributes to the growing problem of antibiotic resistant organisms.