We are Not Alone

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We are Not Alone
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They are in the air we breathe . . .
In our food . . .
On our skin . . .
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-on everything we touch.
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They are . . .
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microorganisms
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What are microorganisms?
(also called microbes)
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Microbes are small living plants or animals most
of which are not visible to the naked eye. Some
microbes cause disease or infection. Many
microbes are good organisms that help keep
balance in the environment and the body.
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What microbes lack in size, they make up in
number.
On the average human, there are about 100
trillion microbes.
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Good vs. Bad Microorganisms  Microorganisms
that cause disease (germs) are referred to as
pathogens.  
Yeah, Im bad.
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Microorganisms that are harmless or beneficial
are called nonpathogens.
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Most microbes are considered beneficial or
harmless.
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beneficial organisms
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Pathogens 3
opportunists
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The role of good microorganisms
Marine freshwater microbes form the basis of
the food chain in oceans, lakes, and rivers.
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Soil microbes help break down wastes.
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Humans and other animals depend on bacteria in
their intestines for digestion and synthesis of
vitamins including vitamin B (for
metabolism) vitamin K (for blood clotting)
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Microorganisms have many commercial
applications They are used in synthesis of
chemical products such as
acetone
alcohol
enzymes
organic acids
many drugs
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They are used in the food industry for producing
pickles
cheese
vinegar
alcoholic beverages
green olives
bread
yogurt
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Main Classes of Pathogenic Organisms

• Bacteria
• simple one-celled organisms
• At home within climate of human body
• compose largest group of pathogens

• Fungi yeasts molds
• Plant-like organisms that live on dead organic
  matter
• Grow best in dark, damp places

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• 3) Viruses - smallest microbes
• acellular particles (not a complete cell)

• 4) Protozoa
• one-celled animals often found in decayed
  materials contaminated water

• 5) Helminths
• parasitic worms
• caused by larval egg infestations

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Bacterial Infections
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Impetigo
highly contagious bacterial infection
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Extensive case of impetigo on underarm of baby.
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Fetal Tetanus (note severe muscle contractions)
Due to toxin production as a result of bacterial
infection.
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Diphtheria
Note swelling in neck
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Diphtheria membrane
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Cellulitis An acute bacterial inflammation of
connective tissue.
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Lymes Disease
hallmark bulls-eye lesion
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Tiny deer tick vector that transmits lymes
disease.
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Fungal Infections
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Candidiasis Oral Thrush
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Oral Thrush tongue
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Candidiasis of Skin Typical red, slightly most
lesions.
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Nail Fungus
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Black Hairy Tongue
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Cutaneous Fungal Infection Tinea Versicolor
Note hypopigmented fungal lesions
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Cutaneous Fungal Infection Ringworm
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Cutaneous Blastomycosis Hand Wrist
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Subcutaneous Blastomycosis Manifested by
subcutaneous abscesses in upper chest
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Chromomycosis Deep fungal infection with
granulomatous lesions.
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Viral Infections
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Viral Infection Verruca Vulgaris (Wart)
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Herpes Type I Oral Herpes
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More Oral Herpes
healing stage
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Neonatal Herpes
Premature infant born with classic cigarette
burn pattern of HSV infection.
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Poliomyelitis (also called infantile
paralysis) Note deformed right leg
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Iron Lung used by polio victims
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Varicella (Chickenpox with oral involvement)
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Measles (rubeola) Rash usually begins on face
and spreads to trunk and extremities.
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Mumps Note edema to cheeks and neck
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Viral Hepatitis Severely distended abdomen
(ascites). Secondary complication from hepatitis.
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Parasitic Protozoan Infections
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Leishmaniasis (protozoan systemic
disease) Severe nodular, disfiguring
lesions transmitted by sand fly
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Dracunculiasis (Fiery Dragon Worm) Found just
under skin of human host.
Causes blisters at site of infestation.
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Ulceration from worm.
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A fiery dragon worm emerges from leg.
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Elphantiasis (filariasis)
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Elphantiasis affecting left leg and genitals
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Intestinal helminthes cause infestations in
intestinal tract and abdominal organs such as the
liver and spleen.
Always in pairs.
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Helminthes which have infested the
liver. hepatomegaly and ascites
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Intestinal Roundworms
Mass of 800 worms removed from childs ileum
during autopsy
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Loa Loa eye worm infestation in conjunctiva
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Loa loa being extracted from under conjunctivia.
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Hydatid cyst formed by tiny tapeworm that
migrated to brain.
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• Summary
• Microbes are microscopic organisms
• About 100 trillion microbes live on the average
  human
• Bad microbes are pathogens
• About 3 of microorganisms are pathogenic
• Main classes of pathogenic microbes include
  bacteria, fungi, viruses, protoza, helminths

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Thats all folks.