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Pathogenic organisms
Pathogenic organisms
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  1. 1. MICROBIOLOGY Nursing Path www.drjayeshpatidar.blogspot.com
  2. 2. DEFINITIONS • Pathogen • Opportunist • Spores 5/18/2018 2www.drjayeshpatidar.blogspot.com
  3. 3. CLASSIFICATION OF MICROORGANISMS • Bacteria • Viruses • Protozoa • Fungi • Worms • Arthropods 5/18/2018 3www.drjayeshpatidar.blogspot.com
  4. 4. BACTERIA • Simple • Single-celled • Most are not harmful to humans • Some cause human bacterial diseases: – Examples: 5/18/2018 4www.drjayeshpatidar.blogspot.com
  5. 5. VIRUSES • Smaller, simpler structure • All parasites • All cause disease • Common human viral diseases: – Examples: 5/18/2018 5www.drjayeshpatidar.blogspot.com
  6. 6. PROTOZOA • Single-celled • Natural habitats – Fresh water – Salt water • Human protozoan parasites – Malaria – Amebic desentery – Pneumocystis pneumonia 5/18/2018 6www.drjayeshpatidar.blogspot.com
  7. 7. FUNGI • Unicellular/multicellular • Decomposes organic matter in the soil and fresh water and help recycle nutrients • Fungal disease – Ringworm (skin) – Yeast infection – Meningitis 5/18/2018 7www.drjayeshpatidar.blogspot.com
  8. 8. WORMS • Multicellular • Non-pathogenic • Infestation – Trichinosis – Hookworm – Tapeworm 5/18/2018 8www.drjayeshpatidar.blogspot.com
  9. 9. ANTHROPODS • Multicelluar • Vectors of disease • Infestations – Mites – Ticks – Scabies 5/18/2018 9www.drjayeshpatidar.blogspot.com
  10. 10. NOMENCLATURE • 2 names – Genus • 1st • Capitalized • Often abbreviated with 1st letter – Species • Example: Staphylococcus aureus (S. aureus). 5/18/2018 10www.drjayeshpatidar.blogspot.com
  11. 11. NORMAL FLORA • Resident flora – Transient flora – May become pathogenic if: • Functions: – 1. – 2. 5/18/2018 11www.drjayeshpatidar.blogspot.com
  12. 12. INFECTIOUS DISEASE • Caused by: – Microorganisms; OR – Toxins of microorganisms • Reproduction of microorganism happens in the host • Factors – Virulence of _______ – Resistance of _______ 5/18/2018 12www.drjayeshpatidar.blogspot.com
  13. 13. 5/18/2018 13www.drjayeshpatidar.blogspot.com
  14. 14. DEFINITIONS • Clinical infections • Symptoms • Subclinical • Reservoirs • Incubation period • Prodromal period • Invasion period • Acme • Self limiting 5/18/2018 14www.drjayeshpatidar.blogspot.com
  15. 15. TYPES OF INFECTION • Localized • Systemic • Bacteremia • Septicemia • Acute • Chronic • Secondary infection • Nosocomial infections • Endogenous infections 5/18/2018 15www.drjayeshpatidar.blogspot.com
  16. 16. EPIDEMIOLOGY • Definition: • Epidemic • Endemic • Pandemic 5/18/2018 16www.drjayeshpatidar.blogspot.com
  17. 17. PORTALS OF ENTRY & EXIT  Portal of entry:  Portal of exit:  Spread of disease: 5/18/2018 17www.drjayeshpatidar.blogspot.com
  18. 18. RESERVOIRS OF INFECTIONS • Carrier: • Zoonoses: – Examples: – Rocky Mtn spotted fever, lyme disease, rabies, plague 5/18/2018 18www.drjayeshpatidar.blogspot.com
  19. 19. 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 5/18/2018 19www.drjayeshpatidar.blogspot.com
  20. 20. 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 5/18/2018 20www.drjayeshpatidar.blogspot.com
  21. 21. METHODS OF CONTROL OF MICROBES • Disinfection • Antiseptics • Disinfectant – Bactericides – Bacteriostatic • Sterilization • Ionizing radiation 5/18/2018 21www.drjayeshpatidar.blogspot.com
  22. 22. PUBLIC HEALTH MEASURES FOOD • Pasteurization • Inspections WATER • Diverting human sewage away from water supply • Chlorinating water 5/18/2018 22www.drjayeshpatidar.blogspot.com
  23. 23. EMERGING DISEASES & BIOLOGICAL WEAPONS • Increasing awareness – Lyme disease, Ebola, West Nile, SARS – http://www.youtube.com/watch?v=p19Wsi 47JFQ • Biological weapons – Anthrax – Smallpox: – http://www.youtube.com/watch?v=1iXfZ1e YdtA 5/18/2018 23www.drjayeshpatidar.blogspot.com
  24. 24. THE PATHOGENS 5/18/2018 24www.drjayeshpatidar.blogspot.com
  25. 25. BACTERIA • SHAPES – COCCUS (round) – BACILLUS (rod) – SPIRILLUM (coils) • ARRANGEMENT – STAPHYLO (clusters) – STREPTO (chains) – DIPLO (pairs) 5/18/2018 25www.drjayeshpatidar.blogspot.com
  26. 26. 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 5/18/2018 26www.drjayeshpatidar.blogspot.com
  27. 27. 5/18/2018 27www.drjayeshpatidar.blogspot.com
  28. 28. SPECIAL CHARACTERISTICS • CAPSULE • SPORES • TOXINS – Neurotoxins – Endotoxins 5/18/2018 28www.drjayeshpatidar.blogspot.com
  29. 29. ANTIBIOTICS • Broad spectrum • Narrow spectrum • Action of antibiotics • Possible side effects 5/18/2018 29www.drjayeshpatidar.blogspot.com
  30. 30. VIRUSES –Not cells • DNA or RNA surrounded by protein shell –Host specific –Obligatory intracellular parasites 5/18/2018 30www.drjayeshpatidar.blogspot.com
  31. 31. Viruses • http://www.youtube.com/watch?v=Rpj0 emEGShQ • http://www.youtube.com/watch?v=lFl3F RNpU4E&feature=related • http://www.youtube.com/watch?v=rbYw NOcKqqc • http://www.youtube.com/watch?v=r1mJ YaPQDtM&feature=related 5/18/2018 31www.drjayeshpatidar.blogspot.com
  32. 32. 5/18/2018 32www.drjayeshpatidar.blogspot.com
  33. 33. ANTIVIRAL MEDICATIONS • AZT • Acyclovir • Ribavirin • Medication must be able to enter infected cells to be effective • Viruses uses the cell’s DNA to replicate. 5/18/2018 33www.drjayeshpatidar.blogspot.com
  34. 34. 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. 5/18/2018 34www.drjayeshpatidar.blogspot.com
  35. 35. DEFINITIONS • SAPROPHYTES • MYCOSES- may be superficial (skin & mucous membranes) or systemic (gained access to the interior of the body) • CANDIDA ALBICANS 5/18/2018 35www.drjayeshpatidar.blogspot.com
  36. 36. ANTIFUNGAL MEDS • Amphotericin b • Ketoconazole • Fluconazole • Griseofulvin 5/18/2018 36www.drjayeshpatidar.blogspot.com
  37. 37. 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. 5/18/2018 37www.drjayeshpatidar.blogspot.com
  38. 38. Protozoa • http://www.youtube.com/watch?v=oLI2 WeUGWlc • http://www.youtube.com/watch?v=BqjM YEfViKA&feature=related 5/18/2018 38www.drjayeshpatidar.blogspot.com
  39. 39. MEDICATIONS • Metronidazole • Pentamidine 5/18/2018 39www.drjayeshpatidar.blogspot.com
  40. 40. 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. 5/18/2018 40www.drjayeshpatidar.blogspot.com
  41. 41. Worms • http://www.youtube.com/watch?v=Zrn7j TqKBFs 5/18/2018 41www.drjayeshpatidar.blogspot.com
  42. 42. 5/18/2018 42www.drjayeshpatidar.blogspot.com
  43. 43. 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. 5/18/2018 43www.drjayeshpatidar.blogspot.com
  44. 44. • http://www.youtube.com/watch?v=z7OZ USfTh6M&feature=related 5/18/2018 44www.drjayeshpatidar.blogspot.com
  45. 45. 5/18/2018 45www.drjayeshpatidar.blogspot.com
  46. 46. 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 5/18/2018 46www.drjayeshpatidar.blogspot.com
  47. 47. • 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 5/18/2018 47www.drjayeshpatidar.blogspot.com

Notes de l'éditeur

  • Microbiology is the study of microorganisms and their role in the environment
  • Pathogen: microorganism that can cause disease
    Opportunist: usually harmless but may become a pathogen in certain circumstances
    Cell produced by a FUNGI for reproduction, may remain dormant yet viable for months. Cooking destroys spores, but pathogenic spores are usually inhaled rather than ingested
    A resistant cell (dormant, inactive state) of a BACTERIA to withstand extreme heat or cold or dehydration, may remain viable for decades. Can survive an hour of boiling! But can be destroyed under pressure.
    Any airborne particle that triggers an allergic reaction
    A stage in the life cycle of some PROTOZOA that contains infective sporozoites
  • Natural habitats
    Vital role of decomposing dead organic material and recycling nutrients

    Strep throat

  • natural habitats- human body

    Common cold
  • Soil is their natural habitat
    Consumes dead organic matter or smaller living things
  • First name listed is like family name, 2nd name more specific

    Like saying
    Smith Mary & Smith John
  • Flora: microorganisms living in or on us
    Resident flora:
    live on or in nearly everyone almost all of the time
    Skin, colon, small intestines
    When in “normal location” they do not cause harm, and may be beneficial
    But resident flora may cause harm if introduced to another site, i.e. E. Coli
    Resident flora may be diminished by the use of antibiotics
    Yeasts or other bacteria may overgrow, especially on mucous membranes
    Resident flora are important to us because they produce VITAMINS, also because they may inhibit growth of pathogens (competition). So what problems might we have if we don’t have enough normal flora? What about newborns/infants?

    Transient flora:
    Found periodically on the body
    May cause harm when the host’s resistance is lowered
  • virulence: ability of the pathogen to cause disease (how strong it is). Ie. Measles, 90% infectivity rate (90% of those exposed will develop measles) vs. common cold (may not develop illness unless fatigue, stress, malnutrition, etc)
    Resistance: total of the body/host’s defenses against pathogens (skin, cilia, lymphocytes, macrophages)

  • Clinical infection: infection with symptoms
    Symptoms: observable or measurable changes that indicate illness
    Subclinical infections: infection with no symptoms (gonorrhea)
    Reservoirs: someone with a subclinical infection can be a reservoir or source, and pass the infection to someone else, in whom it may become a clinical infection
    Incubation period: period of time before symptoms appear. See page 502 table 22-2. **can be contagious during this period!
    Prodromal period: follows the incubation period. Vague, non specific symptoms may appear, such as muscle aches, lethargy, fatigue.
    Invasion period: specific symptoms of the illness appear
    Acme: worst stage of the disease
    Self limiting: diseases that last a certain period of time and are usually followed by recovery (cold, chickenpox, mumps)
  • Terminology may refer to the location of the pathogens in the body, to the general nature of the disease, or to how or where the pathogen was acquired
    Localized: confined to one area of the body
    Systemic: pathogen is spread throughout body via blood or lymph
    Bacteremia: used interchangeablely with Septicemia. Bacteremia means bacteria are present in the blood
    Septicemia: the bacteria present in the blood are multiplying rapidly. Septicemia is always serious, because it means the immune defenses have been overwhelmed and are unable to stop the spread of infection.
    Acute: begins abruptly, is severe
    Chronic: progresses slowly, may last a long time
    Secondary infection: made possible by a primary infection that has lowered the host’s resistance (influenza in an elderly person may be followed by bacterial pneumonia), not by fatigue or malnourishment
    Nosocomial infections: infections acquired in hospitals or other institutions such as nursing homes. Prevent by handwashing, proper disposal of urine, feces, blood, sharps
    Endogenous: infection caused by the patient’s own normal flora that has been inadvertently introduced into an abnormal body site. E. coli

  • Epidemiology: study of the patterns and spread of disease within a population
    Epidemic: outbreak of a disease
    Endemic: disease that is present in a population, with an expected or usual number of cases in a given time. Expect a certain number of cases; like annual flu. But if the number of cases increases significantly, it is then called an epidemic
    Pandemic: epidemic that has spread through several countries; ie bubonic plague
  • Unbroken skin is an excellent barrier to pathogens, but even microscopic breaks are portals of entry.
    In the spread of diseases, a pathogen travels from one person’s portal of exit to another person’s portal of entry.
    Diseases for which the pathogen may be directly or indirectly transmitted from host to host are called communicable.
    Indirect transmission includes food, water, vectors, or fomites.

    Picture pg. 503
    Portal of entry is the way the pathogen enters a host, portal of exit is the way the pathogen leaves the body
    Many hospital procedures provide portal of entry
  • Carrier – person that is a reservoir for a disease

    Zoonoses- animal diseases that people acquire in certain circumstances
    Rocky Mtn spotted fever, lyme disease, rabies, plague

    Carrier may be someone who has recovered from the disease but continues to shed the pathogen
  • Diseases for which the pathogen may be directly or indirectly transmitted from host to host are called communicable.
    Indirect transmission includes food, water, vectors, or fomites.

    Fomites: inanimate objects that carry the pathogen. Influenza and cold viruses can survive outside their hosts for a time, so that toys, door knobs, etc. can become a vehicle of transmission

  • Communicable does not automatically mean contagious; HIV is communicable but not contagious since not spread by respiratory or cutaneous
  • Chemicals have no effect on spores

    Antiseptic: chemical that destroys bacteria or inhibits their growth on a living being
    Disinfectant: chemical used on inanimate objects

    Alcohol can be used for both.

    Bactericides: kill bacteria. Some may also kill viruses (such as bleach)
    Bacteriostatic chemicals: inhibit their reproduction & slow their growth but don’t kill.

    Sterilization: destroys all living organisms
    Autoclave: steam under pressure, kills everything including spores

    Ionizing radiation: used for materials that can’t tolerate autoclave or foods
  • pasteurized: heated to 145 F (boiling) for 30 minutes, kills pathogens (but not all bacteria)

    Chlorine: kills virtually all bacteria
  • Simple unicellular organisms
    Watery cytoplasm, single chromosome (made of DNA) surrounded by a cell membrane, and a cell wall (often rigid & strong)
    classify by shape: coccus, bacillus, spirillum
    Classify by arrangement: staphylo, strepto, diplo

    Know the shapes!

  • Binary fission: bacteria reproduce by the process of binary fission, in which the chromosome duplicates itself and the original cell divides into two identical cells.
    Aerobic: can reproduce ONLY in the presence of oxygen
    Anaerobic: can reproduce ONLY in the ABSENCE of oxygen
    Facultatively anaerobic: can reproduce with or without oxygen
    Gram stain: lab procedure; “positive” stain purple/blue, “negative” stains pink/red. Helps to identify a pathogen. STAINS THE CELL WALL!
    Culture & sensitivity: helps to choose an appropriate antibiotic
    Resistance: bacteria are able to produce an enzyme that destroys the antibiotic, rendering it useless
  • Positive: purple or blue
    Negative: red or pink
  • CAPSULE: some bacilli & cocci have capsules that enclose the entire cell and inhibit the host from phagocytosis, gives them time to reproduce

    SPORES: dormant or inactive stage, can survive in adverse conditions, such as heat (boiling), freezing.

    TOXINS: chemicals harmful to the host produced by the bacteria, similar to our digestive enzymes. Some may literally digest host tissues

    NEUROTOXINS: toxins that specifically disrupt the functioning of nerve cells

    ENDOTOXINS: chemicals that make up the walls of gram negative bacteria, cause fever and circulatory shock

    Bacterial shapes and Gram reaction are determined by their cell walls.
    Capsules inhibit phagocytosis by WBCs.
    Flagella provide motility.
    Spores are a dormant form that can survive environmental extremes.
  • Chemicals used to treat bacterial infections

    BROAD SPECTRUM: affects many different kinds of bacteria
    NARROW SPECTRUM: affects just a few kinds of bacteria

    ACTION OF ANTIBIOTICS: disrupt or inhibit the chemical reactions. Penicillin blocks the formation of cell walls. Others inhibit DNA synthesis.

    Our own cells carry out similar activities, so our own cells can be damaged by antibiotics; liver/kidney damage
  • Viruses are not cells; a virus has DNA or RNA surrounded by a protein shell of characteristic shape.
    Many viruses are host specific.
    Viruses must be within a host cell to reproduce; they use the cell’s genetic and protein synthesis machinery to make new viruses. OBLIGATORY INTRACELLULAR PARASITES!

    Page 511
    The protein shell has a shape that is characteristic for each virus.
    Some viruses may cross the placenta
    Some viruses may cause an initial infection then become dormant for years until reactivated when the host’s resistance is lowered.
    Some viruses are known to cause cells to form tumors.
  • Many challenges:
    Viruses are active only within cells, so the medication must be able to enter the cells
    Viruses are simple so not many options of what to disrupt
    Meds used to kill a virus may kill the host cell too
    Many viruses mutate frequently

    AZT: first med effective against HIV
    RIBAVIRIN: treats RSV in children
  • Pg 513
    Spores can be inhaled, AIDS patients very susceptible
  • SAPHROPHYTES: live on dead organic matter and decompose it

    MYCOSES: infections caused by fungi

    CANDIDA ALBICANS: small amount normal on skin, mouth etc. but too much can cause disease.
  • Amphotericin b: effective for systemic mycoses but can cause serious side effects

    Ketoconazole, Fluconazole, Griseofulvin = newer meds to tx fungal infections and less toxic
  • Unicellular animals, single cells adapted to life in freshwater (including soil) and saltwater. May acquire by ingesting contaminated water or food.
  • Meds used to treat intestinal protozoa
  • Worms are simple multicellular animals.