Review

Review

  1. Mutualism both organisms benefit.

  2. Commensalism: one organism benefit, does not affect the other.

  3. Nosocomial infection is an infection acquired in the hospital.

  4. Sporadic disease is a disease that occurs occasionally.

  5. Communicable disease is a disease that can be transmitted from host to host via contact such as typhoid fever, m. tuberculosis, etc.

  6. Prodromal period is the short period after incubation period and before period of illness in which mild signs and symptoms occur.

  7. Disease can occur in all stages of the disease (incubation period, prodromal period, period of illness, period of decline and period of convalescenence)

  8. An example of indirect contact (fomite) transmission is an infection obtained from a contaminated needle.

  9. An example of vector is a flea that spreads a disease.

  10. Disinfectants are used to destruct vegetative (such as table) microbes not living tissue.

  11. Antisepsis is a treatment directed at living tissue.

  12. Factors that influence the effectiveness of antimicrobial treatments includes ph, presence of organic matter, microbial characteristics, number of microbes, etc.

  13. The temperature of autoclave for sterilization s 121 degrees Celcius for 15 minutes.

  14. The limitation of autoclave is that it cannot sterilize heat sensitive materials such as prions and endospores.

  15. Pasteurization is the best way to sterilize milk.

  16. Pasteurization includes HTST (high – temperature short-time) and UHT (ultra-high-temperature).

  17. Halogens are iodine and chlorine agents.

  18. Cholrox or chlorine added with water is a form of disinfectant.

  19. Bacterial/pathogens attach themselves to the host by means of ligand, fimbraie and spike.

  20. Pseudomonas aeruginosa is an example of an organism that does not produce exotoxin.

  21. Exotoxins are usually produce by gram positive organisms.

  22. Endotoxin are usually produce by gram negative organisms.

  23. Exotoxin can be turned or inactivated into toxoid.

  24. Endotoxin cannot be turned into toxoid.

  25. Escherichia coli is an example of endotoxin because it is gram negative.

  26. Complements systems are made up of over 30 proteins circulating in the body and is part of 2nd line defense.

  27. The cells of the mucous membrane are covered with cilia in the lower respiratory tract.

  28. Emigration or diapedesis is the term that describe when phagocyte squeeae between the blood vessel lining to reach damaged area.

  29. An indication that the body is rising is when the skin remains cold but there is a sensation of chill.

  30. Complement proteins are proteins that circulate normally in blood serum of healthy person.

  31. Interferons are host specific but not virus specific.

  32. The complement system kills by Enhancing phagocytosis.

  33. Plasma cells are formed from B –cells.

  34. T cells originate from the bone morrow then matures in the thymus.

  35. Epitopes are found on the antigen.

  36. Antigen binding site are found on an anti-body.

  37. Penicillin is an example of a hapten.

  38. Antibodies are globulins proteins made in response to a specific antigen.

  39. IgG is a class of immunoglobulin with the most amount in the serum.

  40. Helper T-cells, Th, plays an important and central role in the immune response.

  41. Interleukins are cytokines that serve as communications between WBC (white blood cells).

  42. Natural acquired active is a type of immunity one gets after recovering from the mumps.

  43. Natural acquired passive is a type of immunity one gets from the colostrums of mothers milk.

  44. IgA colostrums

  45. Artificial acquired active is a type of immunity one gets from vaccination.

  46. Artificial acquired passive is a type of immunity one gets from serum injection.

  47. Immunity is immediate and temporary (lasts a few weeks or months) for passive natural and artificial immunities.

  48. Hay fever is an example of Anaphylactic reaction.

  49. Capsules, enzymes, cell walls help penetrate host.

  50. When protozoa invade host, ruptures and waste products result.

  51. Natural killer cells can attack parasites.

  52. IgE can indicate an allergic reacition. (E for allergy).

  53. IgA (colostrums) is given to a child through breast feeding for milk. (vitamin A – milk).

  54. Tetanus cannot be transmitted through the air.

  55. Cholera Vibrio is an entero toxins that causes diarrhea, loss of fluid and dehydration.

  56. Transient microbiota is present for several days, weeks, months then disappears.

  57. Boil and abscess is an example of localized infection.

  58. Phagocytosis, fever, inflammation, antimicrobiotic substance (complement, interferon) are the 2nd line defense mechanisms.

  59. Swelling, redness, distension of blood capillary are signs of Histamine.

  60. Histamins are produced from mast cells.

  61. Ethylene Oxide is a gaseous chemosterilizer.

  62. Sorbic acid, sodium benzoate, sodium nitrite, sodium nitrate are used to preserve meats. The sodium nitrite is responsible for the preservation of the meat red color.

  63. Zoonosis is a disease tranfered from wild animals to humans.

  64. Opportunistic pathogens are pathogens that ordinarily do not cause a disease but do so when there is an environmetal change such as when the immune system is down.

  65. Autoimmune disease occurs when self tolerance is lost. Three disorders associated with immune system include hypersensitivity, autoimmune diseased, immunodeficiences.

  66. Four types of hypersensitivity reactions include anaphylactic reactions, cytotoxic reactions, immune complex reactions, delayed cell-mediated reactions. Think of ACID. (Thanks to Amy).

  67. Allergic reactions include erythema, edema, increased mucus secretions, smooth muscle contraction, inflammatory signs amplified by neutrophils and eosinophils.

  68. The two principal hypersensitivity reactions are systemic anapylaxis (anaphylactic shock) and localized anaphylaxis.

  69. Systemic anaphylaxis is a reaction caused by the injection of allergens.

  70. Localized anaphylaxis is a reaction cause by the indigestion of foods or the inhalation of antigens (pollen, dust, etc.)

  71. Epinephrine is a treatment for systemic anaphylaxis

  72. Localized anaphylaxis can affect both lower and higher respiratory tracts.

  73. Antihistamine drugs are used to treat upper respiratory tract effects caused by localized anaphylaxis (hay fever, itchy teary eyes, coughing, sneezing).

  74. Aerosol inhalants are used to treat lower respiratory tract effects caused by localzid anaphylaxis (asthma).

  75. Delayed cell-mediated reactions involve cell-mediated response caused by T cells.

  76. PPD skin test for diagnostic of tuberculosis is an example of delayed cell-mediated reaction.

  77. Autoimmune disease is a response to self-antigens and causes damage to one’s own organs because of the loss of self tolereance.

  78. Immunodeficiency is the absence of sufficient response.

  79. AIDS (acquired immunodeficiency sysndrome) and congenital deficiencies (ie. Lack of thymus = lack of cell-mediated immunity) are examples of immunodeficiencies.

  80. Immunization by vaccines is artificial active immunity.

  81. Immunization by immunoglobulins is artificial passive immunity.

  82. Six important types of vaccines are attenuated whole-agent vaccines, inactivated whole-agent vaccines, toxoids, subunit vaccines, conjugated vaccines and nucleic acids vaccines.

  83. Attenuated vaccines are prepared from weackened living microbes. Give lifelong immunity but can mutate to virulent form such as postpoliosyndrom.

  84. Vaccines that are against measles, mumps, rubella, tuberculosis are examples of anttenuated vaccines.

  85. Inactivated whole agent vaccines are prepared from microbes that have been killed by formalin.

  86. Vaccines that are agains rabies, pertusis (whoping cough) and typhoid fever are examples of inactivated whole agent vaccines.

  87. Toxoids are inactivated exotoxin by heat and chemical substance.

  88. Tetanus and diphtheria toxoids are examples of toxoids.

  89. Subunit vaccines are antigenic fragments of microbe produced by recombinant vaccines.

  90. Specific immunoglobulins(antiserum) are antibody produce by an organism that has been previously vaccinated.

  91. The advantage of specific immunoglobulins is its immediate immune response because it is artificial passive immunity.

  92. Tetanus antitoxins and immunoglobulins agains hepatitis virus A are examples of specific immunoglobulins.

  93. Diagnostic immunology are used for the diagnosis of interactions (serological reactions) of humoral antibodies with antigen. For instance, an unknown antigen can be identified using a known antibody. An unknown antibody can be identified using a known antigen.

  94. Important serological reactions include precipitation, agglutination, neutralization, complement fixation and enzyme-linked immunosorbent assay and fluorescent. (PANCE).

Corrections are always welcome. Thank You.

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Chapter 7 The Control of Microbial Growth

Chapter 7 The Control of Microbial Growth

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The Terminology of Microbial Control

  • Aseptic surgery is surgery performed under sterilized condition to prevent microbial contaminantion to the patient.

  • Sterilization is the removal of all forms of microbial organisms.

  • Commercial sterilization is a limited heat treatment, just enough to destroy microbes, and not to degrade the quality of the foods.

  • Disinfection is the destruction of vegetative pathogens on an inert surface or substance by using chemicals.

  • Antisepsis refers to the destruction of microbes in living tissue.

  • Degerming refers to the removal of not killing of microbes in a limited area.

  • Sanitization is the lowering of microbial counts on eating utensils.

  • Biocide or germicide refers to the killing of microbes.

  • Bacteriostasis refers to the inhibition of bacteria and not killing them.

  • Sepsis refers to microbial contamination.

  • Asepsis refers to the absence of significant microbial contamination.

The Rate of Microbial Death

Influential Factors of Antimicrobial Treatments

  1. The number of microbes.

  • The more microbes the longer it take to eliminate them.

  1. Environmental Influences.

  • Presence of organic matter (blood, vomit, feces) inhibits antimicrobial actions.

  • Nature of suspending medium (high fats and proteins) protects microbes.

  • Heat is more effective under acidic conditions.

  1. Time of exposure.

  • More-resistant microbes require longer antimicrobial exposure.

  1. Microbial characteristics

  • Microbial characteristics affect chemical and physical control methods.

Actions of Microbial Control Agents

Alteration of Membrane Permeability

  • Microbial Control Agents target plasma membrane damaging its lipids causing it to leak.

Damage to Proteins and Nucleic Acids

  • Antimicrobial agents denatures microbial proteins and damages DNA and RNA.

Physical Methods of Microbial Control

  1. Heat

Moist Heat (kills microorganisms by denaturation)

  • Boiling

  • Autoclave (steam under pressure; preferred method; complete sterilization; 121 deg C for 15 min)

  • Pasteurization (incomplete sterilization; classical method: 63 deg C for 30 min; high temp method: 72 deg C for 15 sec; ultra high temp: 140 deg C for 1 sec; thermoduric organism survives.

Dry Heat (Kills by oxidation)

  • Flaming (Such as the one used in lab)

  • Hot-air sterilization (Items to be sterilized are placed in the oven at 170 deg C for 2 hours.

  1. Filtration

  • Removes microbes

  • HEPA (high-efficiency particular air) removes microorganisms larger than .4 um.

  • Membrane filters have become popular in industrial and laboratory use.

  1. Low Temperatures

  • Psychrotrophs grow at refrigerator temperature.

  1. High Pressures

  • Used usually to preserved fruit juices. Endospores are resistant to high pressures.

  1. Desication

  • In the absence of water, microorganisms cannot grow or reproduce but can remain viable for years.

  1. Osmotic Pressure

  • Cause osmolysis

  • Molds and yeasts are more capable than bacteria of growing in materials with low moisture or high osmotic pressure.

  1. Radiation

  • Ionizing radiation includes gamma rays, X rays, or high energy electron beams.

  • Nonionizing radiation include UV (ultraviolet) light.

Chemical Methods of Microbial Control

Types of Disinfectants

  1. Phenol and Phenolics

  • Phenols rarely used as antiseptic or disinfectant because its skin irritation and disagreeable odor factors.

  • Phenolics is a derivative of phenols altered to have less irritation and disagreeable odor factors.

  • Cresols is one of the most frequently used phenolics.

  1. Bisphenols

  • Bisphonol is a derivative of phenols containing two phenolic groups connected by a bridge

  • Hexachlorophene is one bisphenol used in hospital surgical and microbial control procedures. Also used in prescription lotion, pHisoHex.

  • Triclosan is another bisphenol use in bacterial soaps and some toothpastes.

  1. Biguanides

  • Chlorhexidine is a member of biguanides use for microbial control on skin and mucous membranes.

  • With detergent or alcohol it is used for surgical hand scrubs and preoperative skin preparation in patients.

  1. Halogens

  • Composed of iodine and chlorine

  • Iodine is available as tincture (solutions in acqueous alcohol) and iodophor (combination of iodine and organic molecule such as betadine)

  • Chlorine as gas (Cl2) is germicidal disinfectant because of its production of hypochlorous acid when it is added to water.

  • Sodium hypochlorite is used as household disinfectant such as (Clorox).

  • Calcium hypochlorite is used to disinfect dairy equipments and restaurant utensils.

  • Chlorine dioxide is used for area disinfection to kill endospores of anthrax bacterium.

  • Chloramines consist of chlorine and ammonia used as disinfectants, antiseptics and sanitizing agens.

  1. Alcohols

  • Alcohols such as ethanol and isopropanol kill bacteria and fungi but not endospores and non-enveloped virus.

  1. Heavy Metals and their Compounds

  • Heavy metals includes silver, mercury and copper.

  • Silver nitrate used to be apply to the eyes of the newborn to prevent gonococcal infection. Now, antibiotics are used.

  • Silver-sulfadiazine is available as topical cream for use on burns surfaces.

  • Mercuric chloride is used as bacteriostatic but discontinued because of its toxicity.

  • Copper sulfate destroys green algae in pools, tank and water supply. Also used in paints to prevent the formation of mildew.

  • Zinc chloride is present in mouth washes and used as anti-fungal in paints.

  1. Surface-Active Agents

  • Surface-active agents includes soaps and detergents to decrease surface tension of molecules of liquids.

  • Soaps and detergents are good degerming agents that removes microbes by emulsification.

  • Acid-anionic sanitizers are important in the cleaning of dairy utensils and equipments because of the negative portion (anion) of the molecule.

  • Quaternary ammonium compounds are widely used because of its bactericidal effects on gram-positive bacteria and it positively (cation) charged molecules.

  1. Chemical Food Preservatives

  • Sorbic acid and sodium benzoate prevent molds from growing in certain acidic foods such as cheese and soft drinks.

  • Sodium nitrate and sodium nitrite are added to many meat products such as ham, bacon, hot dogs to preserve the red color and prevent botulism endospore formation such as Clostridium botulinum.

  1. Antibiotics (Food usage)

    • Nisin is added to cheese to inhibit the growth of certain endospore forming spoilage.

    • Natamycin is antifungal antibiotics used in cheese.

  1. Aldehydes

  • Among the most effective antimicrobials

  • Formaldehyde gas is used to preserve biological specimen and floor disinfectant with irritative odor.

  • Glutaraldehyde is less irritating, more effective and used to disinfect hospital instruments including respiratory theraphy equipment.

  1. Gaseous Chemosterilizers

  • Ethylene oxide kills all microbes and endospores but requires longer exposures period 4 to 18 hours and used to sterilize medical supplies and equipments.

  1. Peroxygens (Oxidizing Agents)

  • Hydrogen peroxide is an antiseptic found in household cabinets and in hospital supply rooms. Also used in hair coloring products.

Microbial Characteristics and Microbial Control

Decreasing Order of Resistance to Chemical Biocides

  1. Prions

  1. Endospores of bacteria

  • Bacillus, Clostridium

  1. Mycobacteria

  • Mycobacterium

  1. Cysts of protozoa

  1. Vegetative protozoa

  1. Gram-negative bacteria

  1. Fungi, including most fungal spores

  1. Viruses without envelopes

  1. Gram-positive bacteria

  1. Viruses with lipid envelopes.

Chapter 16 Innate Immunity: Nonspecific Defense of the Host

Chapter 16 Innate Immunity:

Nonspecific Defenses of the Host

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Immunity or resistance is the body’s ability to ward off disease from microbes and protect our selves from environmental agents(pollens, drugs, foods and chemicals).

Susceptibility is the body’s vulnerability to diseases and lack of immunity.

Overview of the Body’s Defenses

First Line of Defense (Innate/Nonspecific Immunity)

  • Skin

  • Mucus membrane

  • Microbiota

Second Line of Defense (Innate/Nonspecific Immunity)

  • Natural Killer Cells

  • White Blood Cells (Phagocytic)

  • Inflammation

  • Fever

  • Antimicrobial substances

    1. complement

    2. interferon

Third Line of Defense (Adaptive/Acquired Immunity)

  • T cells

  • B cells

  • Antibodies

The Concept of Immunity

Innate (nonspecific) immunity refers to the defenses present at birth such as skin and mucus membrane

Adaptive (specific) immunity refers to the defenses that have specific microbial recognition that acts against the microbes when the first line of defense is breached, such as T and B cells and antibodies.

First Line of Defense

Physical Factors

1. Skin (Intact)

  • Epidermis is the outer, thinner portion directly in contact with the external environment.

    • Top layer sheds periodically to remove microbes

    • Contains keratin as protective protein.

  • Dermis is the inner and thicker portion consisting of connective tissues.

  • Keratin is the protective protein of the epidermis layer.

2. Mucous Membranes and other physical factors

  • Consist of epithelial and underlying connective tissue layers such as respiratory and gastrointestinal tracts.

  • Less protection than skin but nonetheless inhibit microbial entrance

  • Mucus is a thick viscous fluid secreted by mucous membrane to lubricate tracts.

  • Treponema pallidum survives in mucus and can penetrate the membranes.

  • Lacrimal apparatus (lacrimal glands, tears, canals, ducts) wash away keep microorganisms from settling on the eyes.

  • Saliva produce by salivary glands dilutes microorganism, wash them away from teeths and mucous membranes of the mouth

  • Nose hairs filters inhaled microorganisms

  • Cillia in the lower respiratory tract help propels out toward the throat (ciliary escalator) microorganisms that have become trapped.

  • Epiglottis that covers the larynx (voice box) during swallowing prevents microorganisms from entering the lower respiratory tract.

  • Urine cleanse urethra

  • Vaginal secretions move microorganisms out.

  • Defecation and vomiting expel microbes

3. Normal Microbiota

  • Normal Microbiota are opportunistic microorganisms that inhabit the body and helps ward off and do not cause disease under normal conditions.

  • Normal microbiota in the vagina secrete acidic substance to prevent Candida albicans from causing vaginitis

  • Escherichia coli secretes bacteriocins that inhibit the growth of Salmonella and Shigella.

Chemical Factors

1. Sebum

  • Oily substance produce by sebaceous glands of the skin to form protective film on the skin surface and to prevent hair from drying and becoming brittle.

2. Low pH (3 and 5)

  • Caused by secretions of lactic acid and fatty acid prevents growth of many microorganisms.

3. Lysozyme

  • Contains in the perspiration breaks down cells walls of gram-positive bacteria and to lesser extent gram-negative bacteria.

4. Gastric Juice (pH 1.2-3.0)

  • Gastric juice which is a mixture of hydrochloric acid, enzymes and mucus produced by stomach glands destroy bacteria and their toxins.

  • Exception is Clostridium botulinum and Staphylococcus aureus.

  • Helicobacter pylori neutralizes stomach acid and grow to cause ulcers and gastritis.

Second Line of Defense

Leukocytes (White Blood Cells)

Granulocytes

  • Granulocytes have large granules in their cytoplasm that can be seen under a light microscope

1. Neutrophils

  • Stains a pale lilac with a mixture of acidic and basic dyes and consist of 2 to 5 lobes.

  • Phagocytic, motile, active in the initial stages of infection.

  • Have the ability to leave the blood, enter an infected tissue and destroy microbes and foreign particles.

2. Basophils

  • Stains blue-purple with the basic dye methylene blue

  • Phagocytic

  • Release substances such as histamine that is important in inflammation and allergic response.

3. Eosinophils

  • Stain orange or red with the basic dye eosin.

  • Phagocytic and have the ability to leave the blood.

  • Produce toxic proteins against certain parasites such as helminthes.

Agranulocytes

  • Have granules but are not visible under a light microscope.

1. Monocytes

  • Are not phagocytic until they leave the blood and mature into macrophage and become the best phagocyte in the tissue.

2. Lymphocytes

  • 3rd line of defense

  • Play a key role in the adaptive immunity.

  • Natural killer cells

  • T cells

  • B cells

Phagocytes

  • Phagocytosis is the ingestion of microorganisms and other particles by a cell.

  • Phagocytes are collective cells that perform phagocytosis.

  • Phagocytes are activated by cytokines, lipid A and lipopolysaccharides (LPS).

The Mechanisms of Phagocytosis

1. Chemotaxis and adherence of microbe to phagocyte

  • Microbe surface attaches to the plasma membrane of the phagocyte.

2. Ingestion of microbe by phagocyte

  • Pseudopods engulf the microbe

3. Formation of a phagosome

  • Phagosome surrounds the microbe.

4. Formation of phagolysosome

  • Fusion of phagososome and lysosome.

5. Digestion of ingested microbe by enzymes.

6. Formation of residual body containing indigestible material.

7. Discharge of waste materials.

Inflammation

  • Defensive response triggered by damage to the body’s tissue.

  • It is characterized by redness, pain, heat, swelling and loss of function.

  • Accute inflammation is an intense and short lasting inflammation. Example: response to boil.

  • Chronic inflammation is a less intense but long lasting inflammation. Example: response to tuberculosis.

Process of Inflammation (3 Stages)

1. Vasodilation and increased permeability of blood vessels.

  • Vasodilation is the dilation of blood vessels that increase blood flow to the damage tissue causing erythema (redness) and head associated inflammation.

  • Increased permeability allows fluid to move from blood into tissue spaces causing edema (swelling).

  • Histamine is a chemical substance released by damaged cells in response to injury and the causative agent of vasodilation and increased permeability.

  • Abscess is the focus of infection consisting of localized collection of pus, dead cells and body fluids in a cavity as a cause of the breakdown of body tissues.

2. Phagocyte Migration and Phagocytosis.

  • Margination is the sticking process of neutrophils and monocytes to the inner surface endothelium of blood vessels.

3. Tissue Repair

  • Stroma is the supporting connective tissue that causes scar for example in the case of major tissue damage.

  • Parenchyma is the functioning part of the tissue that can repair minor tissue damage with no visible signs.

Fever

  • Fever is an abnormally high body temperature. (above 37 deg Cel or 98.6 deg F)

  • Hypothalamus is the thermostat of the body (Microorganism releases LPS Phagocyte release interleukin-1hypothalamus releases prostaglandin reset hypothalamus thermotat)

  • Shivering and chill is a sign of that body temperature is increasing.

  • Crisis is the phase of the fever when the body temperature is falling.

Antimicrobial Substances

1. The Complement System

  • Complement system is a defensive system consisting of over 30 proteins produced by the liver and found circulating in the blood serum.

  • Proteins of the complement system destroy microbes by cytolysis, inflammation, phagocytosis, and prevent excessive damage to host tissues.

2. Interferons

  • Interferons (IFNs) are antiviral proteins and host-specific produced by certain cells such as lymphocytes and macrophages to prevent viral multiplication.

3. Transferrins

  • Transferrins are iron-binding proteins found in the blood, milk, saliva, and tears that inhibit the growth of bacteria by reducing the available amount of iron.

4. Antimicrobial Peptides

  • Consist of dozen amino acids produce my mucous membrane cells and phagocytes that binds to microbial plasma membranes to cause lysis.

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