Microbiology Basics

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Chapter 5

• Microbiology Basics

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Overview

• Disease and infection
• Types of pathogens
• Laboratory identification
• Spread of infection
• Portals of entry/exit
• Modes of transmission

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• Disease
• Abnormality of structure or function of part,
  organ, or system
• Felt or observed by others
• Known or unknown cause
• Variable severity of effects

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• Categories of Disease
• Infection
• Degenerative diseases
• Nutritional diseases
• Metabolic disorders
• Immune disorders
• Neoplasms
• Psychiatric disorders

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• Predisposing Causes of Disease
• Age
• Gender
• Heredity
• Living conditions
• Emotional disturbance
• Physical and chemical damage
• Occupational diseases
• Preexisting illness

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The Study of Disease Relationship between the
pathologic and physiologic processes of medical
disorders
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• Disease Terminology
• Etiology
• Incidence
• Classification
• Acute
• Chronic
• Subacute

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• Microbiology The Study
• of Microscopic Organisms
• Bacteria (bacteriology)
• Viruses (virology)
• Fungi (mycology)
• Protozoa (protozoology)
• Algae (algology)

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Types of pathogens
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Normal Flora Population of microorganisms that
normally grows on and within the human body
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• Bacteria
• Single-celled organisms
• Lack a true nucleus
• Found everywhere
• Anaerobic
• Aerobic
• Facultative anaerobes

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• Shape and Arrangement of Bacteria
• Cocci
• Round
• Bacilli
• Short, slender rods
• Vibrios
• Short rods with a slight curvature
• Spirilla
• Long wavelike cells resembling a corkscrew
• Spirochetes
• Long wavelike cells capable of waving and
  twisting motions

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• Other Bacteria
• Rickettsia
• Chlamydia

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• Viruses
• Extremely small microorganisms
• Composed of a core of nucleic acid surrounded by
  a coat of proteins
• Grow only within living cells

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Virus size comparison.
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• Fungi
• Large group of simple plantlike organisms, few
  are
• pathogenic
• Yeasts
• Single-celled forms of fungi
• Molds
• Fuzzy, filamentous forms of fungi

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• Protozoa
• Animal-like, single-celled microbes found all
  over
• the world
• Amebas
• Ciliates
• Flagellates
• Sporozoa

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Some parasitic protozoa.
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• Parasitic Worms
• Parasites with human hosts, also called helminths
• Helminthology
• The study of parasitic worms.

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• Roundworms
• Ascaris
• Pinworms
• Hookworms
• Trichina (trichinosis)
• Filaria worm (filariasis, elephantiasis)

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Common parasitic roundworms..
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• Flatworms
• Ribbonlike or leaf shaped
• Tapeworms
• Flukes

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• Laboratory Identification
• of Pathogens
• Obtain and label specimens from patients
• Grow out bacterial cells
• Isolate individual organisms
• Multiply to form colonies
• Stain cells so they can be seen
• Perform tests to identify organisms

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• Other Methods of Identification
• Growth characteristics in liquid and solid media
• Oxygen requirements
• Ability of bacteria to utilize various
  carbohydrates
• Reaction to various chemicals
• Serologic (immunologic) tests

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Spread of infection
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• Modes of Transmission
• From infected human, insect, or animal host to
  another susceptible host
• Through direct or indirect contact

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• Portals of Entry and Exit
• Skin
• Respiratory tract
• Digestive system
• Urinary and reproductive systems