CHAPTER 22MICROBIOLOGY

DEFINITIONS

• Pathogen

• Opportunist

• Spores

CLASSIFICATION OF MICROORGANISMS

• Bacteria

• Viruses

• Protozoa

• Fungi

• Worms

• Arthropods

BACTERIA

• Simple • Single-celled• Most are not harmful to

humans• Some cause human

bacterial diseases: – Examples:

VIRUSES• Smaller, simpler

structure

• All parasites

• All cause disease

• Common human viral diseases:– Examples:

PROTOZOA

• Single-celled• Natural habitats

– Fresh water– Salt water

• Human protozoan parasites– Malaria– Amebic desentery– Pneumocystis

pneumonia

FUNGI

• Unicellular/multicellular• Decomposes organic matter in the soil

and fresh water and help recycle nutrients

• Fungal disease– Ringworm (skin)– Yeast infection– Meningitis

WORMS

• Multicellular • Non-pathogenic• Infestation

– Trichinosis– Hookworm– Tapeworm

ANTHROPODS

• Multicelluar

• Vectors of disease

• Infestations– Mites– Ticks– Scabies

NOMENCLATURE

• 2 names– Genus

• 1st

• Capitalized• Often abbreviated with

1st letter

– Species

• Example: Staphylococcus aureus (S. aureus).

NORMAL FLORA

• Resident flora– Transient flora– May become pathogenic if:

• Functions:– 1.– 2.

INFECTIOUS DISEASE

• Caused by:– Microorganisms; OR – Toxins of microorganisms

• Reproduction of microorganism happens in the host

• Factors– Virulence of _______– Resistance of _______

DEFINITIONS

• Clinical infections• Symptoms• Subclinical• Reservoirs• Incubation period• Prodromal period• Invasion period• Acme• Self limiting

TYPES OF INFECTION

• Localized• Systemic• Bacteremia• Septicemia• Acute• Chronic• Secondary infection• Nosocomial infections• Endogenous infections

EPIDEMIOLOGY

• Definition:

• Epidemic

• Endemic

• Pandemic

PORTALS OF ENTRY & EXIT

Portal of entry:

Portal of exit:

Spread of disease:

RESERVOIRS OF INFECTIONS

• Carrier:

• Zoonoses:

– Examples:– Rocky Mtn spotted fever,

lyme disease, rabies, plague

SPREAD OF INFECTION

• NON –COMMUNICABLE – Resident species causes disease under

certain condition; OR– Non- resident species causes disease

when it enters the body– Cannot spread directly or indirectly from

host to host– Example: cystitis, tetanus, botulism

SPREAD OF INFECTION

• COMMUNICABLE– Some may be called “Contagious” – Easily spread by casual contact– Direct spread of pathogens

• Cutaneous contact• Respiratory droplets• Contaminated blood

– Indirect spread of pathogens• Contaminated food & water: Vectors• Fomites: inanimate objects

METHODS OF CONTROL OF MICROBES

• Disinfection

• Antiseptics

• Disinfectant– Bactericides– Bacteriostatic

• Sterilization

• Ionizing radiation

PUBLIC HEALTH MEASURES

FOOD• Pasteurization

• Inspections

WATER• Diverting human

sewage away from water supply

• Chlorinating water

EMERGING DISEASES & BIOLOGICAL WEAPONS

• Increasing awareness– Lyme disease, Ebola, West Nile, SARS– http://www.youtube.com/watch?

v=p19Wsi47JFQ

• Biological weapons– Anthrax– Smallpox: – http://www.youtube.com/watch?

v=1iXfZ1eYdtA

THE PATHOGENS

BACTERIA

• SHAPES– COCCUS (round)

– BACILLUS (rod)

– SPIRILLUM (coils)

• ARRANGEMENT– STAPHYLO

(clusters)

– STREPTO (chains)

– DIPLO (pairs)

DEFINITIONS

• Binary fission• http://www.youtube.com/watch?v=hOyUcjqcGpQ

• Aerobic vs. Anaerobic– Facultatively anaerobic

• Gram stain: + or –– How cell wall responds to stains

• Culture & sensitivity

• Resistance

SPECIAL CHARACTERISTICS

• CAPSULE

• SPORES

• TOXINS

– Neurotoxins

– Endotoxins

ANTIBIOTICS

• Broad spectrum

• Narrow spectrum

• Action of antibiotics

• Possible side effects

VIRUSES

–Not cells• DNA or RNA

surrounded by protein shell

–Host specific

–Obligatory intracellular parasites

Viruses

• http://www.youtube.com/watch?v=Rpj0emEGShQ

• http://www.youtube.com/watch?v=lFl3FRNpU4E&feature=related

• http://www.youtube.com/watch?v=rbYwNOcKqqc

• http://www.youtube.com/watch?v=r1mJYaPQDtM&feature=related

ANTIVIRAL MEDICATIONS

• AZT• Acyclovir• Ribavirin• Medication must be able to enter

infected cells to be effective• Viruses uses the cell’s DNA to

replicate.

FUNGI

– Fungi may be unicellular, like yeasts, or multicellular, like the molds.

– In small numbers, yeasts are part of the resident flora of the skin and mucous membranes.

– Molds reproduce by forming spores.

DEFINITIONS

• SAPROPHYTES

• MYCOSES- may be superficial (skin & mucous membranes) or systemic (gained access to the interior of the body)

• CANDIDA ALBICANS

ANTIFUNGAL MEDS

• Amphotericin b

• Ketoconazole

• Fluconazole

• Griseofulvin

PROTOZOA

– Entamoeba and Giardia are spread by the fecal-oral route in contaminated food or water.

– Trypanosoma causes African sleeping sickness.

– Plasmodium causes malaria.

– Toxoplasma may cause abnormalities in a developing fetus.

– Pneumocystis causes pneumonia in AIDS patients.

Protozoa

• http://www.youtube.com/watch?v=oLI2WeUGWlc

• http://www.youtube.com/watch?v=BqjMYEfViKA&feature=related

MEDICATIONS

• Metronidazole

• Pentamidine

WORMS

– Flukes or tapeworms are usually acquired by eating poorly cooked fish or meat that contains cysts.

– Hookworms live in the small intestine, feed on blood, and may cause a severe anemia.

– Pinworm infestation of the colon is probably the most common worm infestation in North America.

– Trichinella is acquired by eating poorly cooked pork or wild game that contains cysts.

Worms

• http://www.youtube.com/watch?v=Zrn7jTqKBFs

ARTHROPODS

– Lice are vectors of epidemic typhus.– Fleas are vectors of plague.– Mosquitoes are vectors of malaria, yellow

fever & encephalitis.– The scabies mite causes intense itching

when it burrows into the skin.– Wood ticks are vectors of Rocky

Mountain spotted fever.– Deer ticks are vectors of Lyme disease.

• http://www.youtube.com/watch?v=z7OZUSfTh6M&feature=related

THE END OF A&P! Just for fun….

• Nerve impulses can travel up to 426 feet per second

• 450,000 people die in the US r/t smoking related diseases: like a jumbo jet crashing each day with no survivors

• One kidney filters 180 quarts of fluid each day• Your heart beats over 36 million times per year• You have 110,000-150,000 hairs on your head

• You have over 16,000 miles of capillaries• Each strand of hair can support 100 g of

weight, so, you could support the weight of 2 elephants on your head

• You have about a quarter of a million sweat glands on your feet

• Your eyes can see approximately 7 million shades of color

• Due to its sterile nature, urine could be used to clean a wound when no antiseptic is available