The Human Body in Health and Illness 4
The Human Body in Health and Illness, 4 th edition Barbara Herlihy Chapter 5: Microbiology Basics 1
Lesson 5 -1 Objectives • Define disease and infection. • Describe the types of bacteria by shape and staining characteristics. • List the characteristics of the different types of pathogens. Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved. 2
Lesson 5 -1 Objectives (cont’d. ) • Define portals of exit and portals of entry. • List common ways in which infections are spread. • Identify the microbiological principles described in six germ-laden stories. Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved. 3
What is Disease? • Disease: Failure of the body to function normally • Pathogens: Disease-producing microorganisms • Infection: Invasion of the body by a pathogen – Localized: Restricted to a small area – Systemic: More widespread; usually spread through blood Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved. 4
Microorganisms and Multicellular Pathogens • • • Bacteria Viruses Fungi Protozoa Worms Arthropods Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved. 5
Looking at Bacteria • Single cell • Have cell wall • Often grouped by shapes, clusters Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved. 6
Shapes of Bacteria 1. Coccus (round) – Diplococci – arranged in pairs – Streptococci – arranged in chains – Staphylococci – bunches of grapes 2. Bacilli (long and slender) 3. Curved rods a. vibrio – slight curve and resemble a comma b. spirillum – long cell that coils like a corkscrew c. spirochete – tightly coiled spirilla capable of waving and twisting motions Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved. 7
Images of Bacteria • cocci Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved. 8
Bacteria • bacilli Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved. 9
Vibrio, Spirillum, Spirochete • Vibrio • Spirillum • Spirochete Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved. 10
Viruses, Fungi, Protozoa: Single Cell Organisms • Virus consists of DNA or RNA with a protein shell. • Viruses reproduce only within a host. • Fungi cause mycotic infections. • Protozoa are animal-like microbes. Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved. 11
Protozoans • Four main types – Amebas – Ciliates – Flagellates – Sporozoa Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved. 12
Arthropods and Worms: Multicellular Organisms • Worms – Round or flat – Transmission by fecal-oral route • Arthropods – Animals with jointed legs – Ectoparasites (mites and lice) and vectors (mosquitoes, biting flies, fleas, and ticks) Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved. 13
Identifying Bacteria in the Lab • Staining – Gram stain • Gram-positive (purple or blue) • Gram-negative (pink or red) – Acid-fast stain (retains red stain) • Culture: Pathogen sample collected and grown in a medium Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved. 14
The Spread of Infection • Portals of entry – Respiratory tract – Gastrointestinal tract – Genitourinary tract – Eyes – Skin – Parenteral routeinjuries that penetrate the skin or mucous membrane Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved. 15
The Spread of Infection (cont’d. ) • Portals of exit – Respiratory tract – Gastrointestinal tract – Genitourinary tract – Eyes(tears) – Skin – Breasts(milk) Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved. 16
The Spread of Infection (cont’d. ) • Modes of transmission – Person-to-person • Vector – living or nonliving object that transfers a pathogen from one organism to another • Fomite – a nonliving vector – Environment-to-person • Contact with contaminated water, air, food, or soil – Tiny animals-to-person • Biological vector – responsible for part of the life cycle of the pathogen • Mechanical vector – just carries the pathogen Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved. 17
Dr. Semmelweis screams, “Wash those Mitts!” • Read the story of Dr. Semmelweis. • What does the story tell us about nosocomial infection? • Identify current parallels. – H 1 N 1 flu – MRSA Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved. 18
Rick, Nick, and the Sick Tick • Read the story of the sick tick. • What does the story tell us about animal vector, reservoir of infection and zoonosis? • How does the story illustrate the difference between a communicable disease and a contagious disease? Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved. 19
Flora and Her Vaginal Itch • Read Flora’s story. • What does this story tell us about normal flora, antibiotics, and superinfection? Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved. 20
Why Typhoid Mary Needed to Lose her Gallbladder • Read Mary’s story. • How does this famous historical event illustrate the concepts of carriers and reservoirs of infection? Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved. 21
A Pox News Alert • Read the account of the various uses of the term pox. • Describe the range of conditions described as poxes, and identify the most important contemporary and historical examples. Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved. 22
The Chief of Staph Reports. . . • Read the account of Staphylococcus-induced conditions. • Name important resistant strains and explain what the story suggests about resistance. Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights reserved. 23
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