What we don’t see CAN kill us!

 Also called microbes  Cannot be seen without a microscope  May be non-pathogen or pathogen depending on where it is in body

 Aerobes are a variety of bacteria that require oxygen to grow.  Anaerobes are bacteria that grow in the absence of oxygen and are destroyed by oxygen.  Facultative anaerobes are organisms that can grow in either the presence or the absence of oxygen.

 Endogenous- originates inside the body  Exogenous-originates outside the body  Nosocomial- infection obtained in a health care facility (Ex: MRSA)  Opportunistic- occurs when host resistance is down

 Single cell  3 types: Cocci, Bacilli, Spirilla

 Round shaped  Micrococci- single cell  Diplococci-two celled

 Staphylococci-clustered  Streptococci- in chains

 “Strep throat”  Scarlet Fever  Rheumatic fever  “Flesh eating” disease  Endocarditis  Pneumonia  MRSA  Toxic Shock

 Rod Shaped  May have flagella that help the bacteria to move  Often produce spores  Occur singly, in pairs or in chains  Many produce poisons called toxins

 Some bacteria change into the most resistant form of life known called spores.  Bacteria remain alive in the spore form but are inactive.  They can survive extremes of heat and dryness and even the presence of disinfectants and radiation.

 Anthrax

 Leprosy  Tuberculosis  Tetanus  Botulism  Diphteria  Typhoid

 Spiral shaped  May be other “unusual” shapes  Example: syphilis and cholera

 The rickettsiae are short, nonmovable rods that normally live in the intestinal tract of insects such as lice, fleas, ticks, and mosquitoes.  They are very small and require host cells to reproduce.  Diseases caused by rickettsiae include typhus and Rocky Mountain spotted fever.  These diseases are transmitted to humans by way of the bite of an infected insect.

 Smallest of all bacteria  Originally thought to be a virus

 Gram staining requires crystal violet dye, iodine solution, alcohol solution, and a safranin dye be used in a certain order.  The bacteria that are stained by the dye are classified as Gram-positive. (They appear dark purple under the microscope.)  Gram negative bacteria will appear pink.  Bacteria that are positive but stain as negative are called Gram variable or there’s mixed colored staining.

 Algae range from microscopic single-cell organisms to larger multiple-cell organisms such as seaweed and kelp.  All algae contain chlorophyll, as well as pigments that cause them to appear yellow- green, brown, or red.  Algae are found in abundance in both freshwater and marine habitats.  Most algae do not produce human disease.

Red Tide

 One celled animal-like, may contain flagella  Often found in decayed materials, animal feces, and contaminated water  Cause malaria, dysentery (severe diarrhea), and African sleeping sickness  Not too common in the US

 Fungi are plants, such as mushrooms, yeasts, and molds, that lack chlorophyll.  Diseases include athlete’s foot, vaginitis, “Jock itch”, and ringworm

 Multi-cellular worms or flukes  Can be injected in food or obtained when bitten by a mosquito  Examples: pinworms, hookworms, trichinella spiralis, tapeworms

 Viruses are smallest of all microbes and only seen with electron microscope.  Viruses can live and multiply only inside an appropriate host cell.  A virus invades a host cell, copies itself, and then destroys the host cell so the viruses are released into the body.  Spread from human to human through body secretions

 HIV  Common cold  Influenza- Ex:H1N1  HPV- Human Papilloma Virus  Polio  Chickenpox  Herpes  Zoster- shingles  Simplex Type 1- cold sores  Simplex Type 2- genital herpes

 Hepatitis  HAV  HBV  HCV  HDV  HEV  HGV  Vowels: Food and Fecal Borne  Consonants: Blood Borne

 Infectious agent composed of primarily protein that is misfolded  Must reproduce inside a host cell  Gets the other proteins to misfold as well

 Prions are responsible for “mad cow” disease and possibly Alzheimer disease.  Prion-caused diseases have been found in human beings and animals.  Prions are highly resistant to heat, chemical agents, and irradiation.  There is no treatment or vaccine against prion diseases, and the only preventive measure is not eating suspect food.

Microorganisms Chlamydia AlgaeProtozoas Bacteria Viruses Cocci Micrococci Diplococci Staphylococci Streptococci FungiPrionsHelminths Bacilli Rickettsiae Spirilla