Ch. 14 15 & 16 Test- Microbiology

iron-binding proteins

sequester iron to prevent access to microbes causing nutritional immunity; examples of proteins are transferrin, lactoferrin, and ferritin

Swallowed living microbes are often destroyed by

gastric juices which have a pH of 2 and contain digestive enzymes (pepsin).

diseases are classified in terms of

how they behave in the host.

contact

Direct: Requires close association between infected and susceptible host Indirect: Spread by fomites. Fomites are inanimate objects like a door knob, a Kleenex tissue, a cutting board Droplet: Transmission via airborne droplets

chronic

Disease that develops slowly over time Appearance of symptoms: Slow/gradual Duration: Months or years Examples: Kidney disease, osteoporosis

subclinical

Disease with no noticeable signs or symptoms Appearance of symptoms: N/A Duration: Varies Examples: Diabetes (type II), thyroid disorders, chlamydia

latent

Disease with periods of no symptoms followed by periods with symptoms Appearance of symptoms: On and off Duration: Life-long Examples: HSV-1, HSV-2

acute

Disease with rapid onset and resolution Appearance of symptoms: Rapid Duration: Days or weeks Examples: Strep throat, flu

Zoonoses

Diseases transmitted from animals to humans Ex. rabies and Lyme disease

transient microbiota

Does NOT permanently colonize host Present for days, weeks, or months Picked up from environment or others Typically associated with disease

Extent of Host Involvement

Does this disease affect a limited area? Does this disease spread throughout the entire body? Does the host have some sort of resistance against this disease established? Has the host been infected with this microbe before?

The "A" portion of an A-B exotoxin is responsible for shutting down host cell protein synthesis? True or False

True

Sweat contains

Salt, Antimicrobial peptides Lysozyme (Enzyme that destroys cell walls)

communicable disease

a disease that is spread from one host to another

Microbes can evade detection by the host through the secretion of enzymes? True or False

True

are the portals of entry for the pathogen also the way in which they exist the body to be transmitted? True or False

True

pandemic disease

Worldwide epidemic

prodromal period

short period after incubation; early, mild symptoms Here, you may start to feel nauseated an you may start to run a low-grade fever

reservoirs of infection

sites where pathogens are maintained as a source of infection

antimicrobial peptides

small chains of amino acids which are present on the skin, mucus membranes, and are secreted by neutrophils (immune cells); they inhibit microbial growth by a variety of mechanisms and recruit immune cells to sites of infection Responses include: Inhibiting cell wall synthesis Creating pores Destroying DNA or RNA Recruiting granulocytes

Interferons

special cytokines which trigger antiviral signaling with cells; main types are IFNα, IFNβ, and IFNγ

When the normal microbiota and other body defenses are overcome_____ results

disease

The Stages of a Disease

Incubation Prodromal Period of illness Period of decline Convalescence

systemic infection

an infection throughout the body

susceptibility

lack of immunity

focal infection

systemic infection that began as a local infection

ways Microbial survive phagocytosis

-Leukocidins -Membrane attack complexes -Prevent lysosome fusion and grow in phagosome: - Inactivate digestive enzymes in lysosome: HIV - Resist digestion

Microbia inhibit adherence or engulfment of phagocytosis

-M protien -Capsules -Biofilms

inflammation steps

1) Vasodilation 2) Swelling 3) Clot formation 4) Phagocytosis 5) Capillaries return to normal size, blood flow and fluid leakage into the affected area abate.

Endotoxins and the pyrogenic response

1. A microphage in just a gram-negative bacterium 2. The bacterium was degraded into a vacuole, releasing endotoxins that induce the macrophage to produce cytokines IL-1 and TNF-a. 3. Cytokines are released into the bloodstream by macrophages, through which they traveled to the hypothalamus of the brain. 4. The cytokines induce the hypothalamus to produce prostaglandins, which reset the bodies thermostat to a higher temperature, producing fever.

Functions of fever

1. Accelerates the defense mechanisms and repair of tissues 2. Enhances activity of antiviral and antibacterial enzymes 3. decrease microbial growth due to sensitivity to elevated temperatures

purpose of inflammation

1. Destroy the agent of injury and remove byproducts of injury 2. Limit spread of injury to other tissues 3. Repair or replace damaged tissue

mechanisms of evasion of phagocytosis

1. Inhibit adherence or engulfment 2. Survive phagocytosis

steps of phagocytosis

1.chemotaxis: cell comes in close proximity to given objects/particles. 2. adherence: surface receptors on the phagocyte bind/adhere to the surface of the particle. 3. ingestion: phagocyte starts expanding as it surrounds the molecule 4. digestion: enzymes in the vesicle (e.g. lysosome) break down the molecule into simpler components

blood

55% plasma (non-cellular components) and 45% formed elements (cells)

Symptoms

A change in body functions that are felt by the individual suffering from a disease Things that you feel when you are sick: discomfort, Pain, Fatigue, Headache, Nausea Dizziness

Signs

A change in body functions that can be observed Things that can be seen or measured by a physician: Temperature (fever), Heart rate, Blood pressure Lab tests (blood work, enzyme levels, etc) Lesions, Rash, Swelling

Symbiosis

A close relationship between two species that benefits at least one of the species.

adherence

A microbe must BIND to host cells or tissues This is accomplished by adhesins/ligands (proteins of microbe) that bind to receptors (proteins on host cells)

Commensalism

A relationship between two organisms in which one organism benefits and the other is unaffected

Parasitism

A relationship between two organisms of different species where one benefits and the other is harmed

Mutualism

A relationship between two species in which both species benefit

Normal microbiota protect the host by

Outcompeting transient microbes for nutrients Producing substances harmful to invading microbes Affecting pH and available oxygen

Primary infection

Acute infection that causes an initial illness The first time a person is exposed to a pathogen....SO they get SICK individual has no immunity to this pathogen

antigenic variation

Altering of pathogen's surface proteins (antigens) Allows for pathogen to escape or hide from host cell defenses

Pathogen

An organism that causes disease

Nosocomial (Hospital-Acquired) Infections

Are acquired as a result of a hospital stay. 5-15% of all hospital patients acquire nosocomial infections. The transmission of disease to hospitalized patients is reduced through wearing personal protective equipment (PPE). Gloves, Masks, Goggles and face shields, Gowns

Vector

Arthropods... especially fleas, ticks, and mosquitoes Transmit disease by 2 general methods: Mechanical transmission: Arthropod carries pathogen on feet Biological transmission: Pathogen reproduces in vector

Superantigens

Exotoxins that cause an intense immune response due to release of cytokines ("cytokine storm") from host cells Symptoms: fever, nausea, vomiting, diarrhea, shock, and death

animal reservoirs

Both wild and domesticated animals are able to transmit pathogens to humans (zoonoses)

How Bacterial Pathogens Invade the Host

Capsules Cell Wall Components Enzymes Antigenic variation

Pyrogens

Chemicals which induce fevers

examples of enzymes

Coagulases Kinases Hyaluronidase: Collagenase IgA proteases

Dermis

Collagen fibers help skin resist abrasions that could introduce microorganisms

What is the function of lysozyme?

Degrade cell walls of bacteria & other invaders.

skin is composed of two major layers call

Epidermis, Dermis

Formed elements of blood

Erythrocytes (red blood cells) Platelets (clotting cells/fragments) Leukocytes (immune cells)

Enzymes

Extracellular factors that are released by microbes factors include coagulase, kinase, collagenase Can do a number of things to host cells including: Digest materials between cells, Form clots and Digest clots- All help pathogen to penetrate deeper into tissues OR hide from the host cell defense

The ID50 for a pathogen is the same for any portal entry? True or False

False

The Innate immune system defenses the host against specific pathogens and has a memory?True or False

False

Incidence

Fraction of a population that contracts a disease during a specific time New cases ONLY Disease risk Indicator of disease spread amongst a population

Prevalence

Fraction of a population that have a specific disease at a given time, regardless of when it first appeared Takes into account BOTH old and new cases Disease burden Tells how seriously and how long a disease affects a population

Predisposing Factors

Gender Inherited traits Climate and weather Fatigue Age Lifestyle choices Nutritional choices Chemotherapy

Basosphils

Granulocyte Stain blue with basic dye Not phagocytic Release histamine which triggers inflammation and allergic reactions

Neutrophils

Granulocyte Stain purple (neutral) Highly mobile and are phagocytic (eat microbes) First to arrive at injury or infection Increases are indicative of bacterial infection

Eosinophils

Granulocyte Stain red with acidic dye Motile; Slightly phagocytic Produce chemicals to facilitate fights against multicellular parasite infections and allergens

What 3 substances trigger inflammation?

Histamines, Prostaglandins,Leukotrienes

port of entry

How a microbe enters a host A majority of pathogens have a preferred one If a microbe does not get into its preferred portal, then it is unlikely to cause disease

Virulence (extent of pathogenicity) of a microbe is expressed as:

ID50 = Infectious dose 50 Number of microbes needed to cause 50% of a population to become SICK

Oils (Sebum)

Keeps the skin pliable and less likely to break/tear; Lowers skin pH

Potency of a toxin is expressed as

LD50: = Lethal dose 50 This is not a number of microbes thing, but the AMOUNT (number) of toxin from a microbe that is needed to cause 50% of a population to DIE Small LD50 = not much needed to kill someone High LD50 = much more toxin needed to kill someone

While pathogenic microbes can damage tissues on the surface, they....

MUST penetrate the host tissues in order to cause disease

Exotoxins that lyse hosts cells by

Making protein channels in the plasma membrane Disrupt the phospholipid bilayer Leukocidins: kills leukocytes (WBCs)Hemolysins: destroy RBCs

Major portals of entry

Mucous Membranes: Respiratory tract, Digestive Tract, Urogential tract Skin: hair follicles, sweat glands Parenteral route: Cuts, Bites , Surgical wounds

Epidermis

Multiple layers of tightly packed cells that few pathogens can penetrate. Shedding of dead skin cells removes microorganisms Contains epidermal dendritic cells that phagocytize (eat) pathogens

normal microbiota factors

Nutrients Physical and chemical factors Host defenses Mechanical factors

Secondary infection

Opportunistic infection that occurs following a primary infection. when a SECOND microbe infects an individual who is experiencing a primary infection.

Capsules

Organized covering over cell wall Prevents phagocytosis prevents detection by host defenses, so it can sneak in and invade tissues

Monocytes

Phagocytic cells Leave the blood and mature into a variety of phagocytic cells including: Macrophages, Dendritic cells influence the process of adaptive immunity-phagocytosis

Determinants of pathogenicity

Preferred portal of entry Number of Microbes Adherence if all 3 conditions cannot be met, then the microbe CANNOT cause disease!

cell wall components

Proteins that are embedded into the cell wall of a pathogen that help it hide from host defenses or to resist host defenses Increases virulence of that pathogen

Natrual Killer Cells (NK Cells)

Special Type of Lymphocyte; granular lymphocyte that release perforin and granzymes which puncture holes in the membranes of infected or cancerous cells, not phagocytic

period of decline

Signs and symptoms are present and are DECLINING

nonliving reservoirs

Soil and water are the main non-living sources of infection that transmit pathogens to humans Examples: botulism and tetanus

The First Line of Defense is comprised of:

Structures & Chemicals/substances that work to prevent pathogens from entering the body

innate immunity

The body's defenses against any pathogen

human reservoirs

The human body itself harbors the pathogen Carriers with signs/symptoms of disease transmit microbes from one person to another Carriers may have inapparent infections or latent diseases Examples: HIV/AIDS and gonorrhea

herd immunity

The immunity in most of a population deals with whether or not a majority of those within a population have been previously exposed to a pathogen that causes a disease or if they have been vaccinated against a particular pathogen

vasodilation

The term that describes when blood vessels expand and become leaky during inflammation

Both Endotoxin and Exotoxin can kill you? True or False

True

Diapedesis

When a white blood cell squeezes through from the blood vessels and moves into the tissues

convalescence

gradual recovery after an illness NO signs or symptoms of disease present. The pathogen has been cleared from your system, BUT you do not feel 100%

complement system

a cascade of proteins in the blood which when activated aid in destruction of microbes, there are three pathways: classical (antibody-mediated), alternative (direct binding of complement), and lectin (mediated by lectin)

contagious disease

a disease that is easily spread from one host to another

mucus

a mixture of glycoproteins and water; Produced by goblet cells Inhibits pathogen colonization Keeps the epithelial cells of the membranes moist. Helps to move microbes out of body cavities through the use of the mucociliary escalator.

abcess

a trapped pocket of pus beneath the surface; many times the immune system will block off the infected region trapping pus inside

Earwax (cerumen)

a waxy substance which has many of the same properties as sebum including inhibiting growth and lowering the pH of the ear canal

Pathogenicity

ability of a microbe to cause disease

Subclinical (inapparent) infection

an infection that does not cause any signs/symptoms

occurrence

an instance How many people have this disease? How often does this disease occur in the population?

sporadic disease

disease that occurs occasionally in a population (typhoid fever)

Bacteremia

bacteria in the blood

speticemia

blood poisoning

adaptive immunity

body defenses against SPECIFIC pathogens Requires time to develop, involves specialized cells, and provides memory This response it tailored to the specific pathogen

In order to make a diagnosis of disease, a physician takes into account

both the symptoms (felt by patient) and the signs (things s/he can measure) of illness.

Collagenase enzyme

breaks down collagen Collagen forms connective tissue in muscles and organs Allows pathogens to penetrate further into tissues

Endotoxins

built into the cell wall (outer membrane) of gram-negative bacteria; only released when bacterial cell dies Lipid A Fever Not Neutralized by Antitoxin LD50 (Relatively large)

A-B Exotoxin

class of exotoxin that contains A subunits, which enter the cell and disrupt cellular activities, and B subunits, which bind to host cell receptors

Coagulases (enzyme)

coagulate fibrinogen Causes blood clots to help isolate pathogen from host cell responses

infection

colonization or invasion of body tissue by pathogenic organisms

Microbial antagonism (competitive exclusion)

competition between microbes

Transmission of Disease

contact, vehicle, vectors

Granulocytes

contain large granules that stain different colors neutrophils, eosinophils, basophils

Plasma

contains electrolytes, dissolved gases, nutrients, and proteins. Defense mechanisms include: Antibodies: proteins that bind to pathogens and neutralize by a variety of mechanisms. Iron-sequestering Molecules: harm microbes by nutritional immunity. Complement Proteins: proteins which associate with pathogens and form pores in their membranes/walls

virulence

degree of pathogenicity The strength of a microbe to cause disease

IgA proteases (enzyme)

destroy IgA antibodies Allows pathogens to escape detection in mucosal surfaces

Kinases (enzyme)

digest fibrin clots Digests clots that are formed by the body to "wall off"/isolate pathogens

Hyaluronidase enzyme

digests polysaccharides that hold cells together Allows pathogens to squeeze between cells and further penetrate tissues

epidemic disease

disease acquired by many hosts in a given area in a short time

endemic disease

disease constantly present in a population (common cold)

fever

elevated body temperature as result of A microbial substance (e.g. LPS) or Cytokines released from activated phagocytes

Macrophages

highly phagocytic cells which are present in tissues and organs and remove damaged cells and debris as well as pathogens

non-specific immunity

immediate, and provides no memory The same response occurs regardless of the pathogen

salivary glands

in the mouth produce saliva, which is a water suspension of digestive enzymes (amylase) and lysozyme. Saliva dilutes microbes and helps wash teeth and the surfaces of the mouth

First Line of Defense

intact skin, mucous membranes and their secretions, normal microbiota

severity

intensity of disease

Agranulocytes

lack visible granules intracellularly lymphocytes and monocytes

Pus

liquid formation caused by the release of inflammatory chemicals, buildup of degraded tissue, and the accumulation of dead immune cells during infection

Vaccination can confer

long-lasting or lifelong immunity against pathogens

normal microbiota

microbes normally present in and on the human body Permanently colonize the host. Do NOT cause disease under normal conditions defense through microbial antagonism; hard for pathogens to compete because of the following: Consumption of nutrients Create an environment unfavorable to other microorganisms Promote overall health by providing vitamins to host

Once established in a individual, the normal microbiota work to prevent growth of transient microbes

microbial antagonism (competitive exclusion)

period of illness

most severe signs and symptoms (at their PEAK) This period lasts anywhere from 12 - 48 hours...but for other pathogens this period of time can vary

opportunistic pathogens

normal microbiota that cause disease under certain circumstances

Local infection

pathogens are limited to a small area of the body

second line of defense

phagocytes (neutrophils, eosinophils, dendritic cells and macrophages), inflammation, fever, antimicrobial substances operates when pathogens penetrate skin and mucus membranes

dendritic cells

phagocytes located in epidermis, mucus membranes and lymphoid tissues, initiate adaptive immune response

Viremea

presence of virus in the blood

inflammation

process triggered by damage to the body Results in: Redness, Pain, Heat, Swelling And sometimes loss of function May be acute or long-lasting (chronic)

Histamines

produced by granulocytes Causes vasodilation and permeability of blood vessels

Leukotrienes

produced by granulocytes Increases vessel permeability and promotes phagocytosis

Prostaglandins

released by damaged cells Intensifies histamine action and attracts phagocytes

Exotoxin

secreted (released) from living gram-positive bacteria By-products of growing cells Protein No Fever Neutralized by antitoxin LD50 (Small)

immunity (resistance)

the ability of an organism to ward off disease caused by microbes and/or environmental agents

The rate at which a disease (or epidemic) spreads within a population and the number of individuals affected by this disease depends on

the immunity of that population

Phagocytosis

the ingestion of large cells or debris by a phagocyte, antigens from the debris may be displayed on the surface of the cell for recognition by adaptive immune cells

lacrimal apparatus

the structures that produce, store, and remove tears

incubation period

the time after exposure and before symptoms/signs appear period last from 12 - 48 hours vary between pathogens.

For a disease to persist in the population.......

there must be a continual source of that infection. This source can either be a living organism or an object that allows for that pathogen to survive, multiple, and allow for transmission.

mucus membrane

thick moist epithelium tissues that line all body cavities open to the environment Outer layers are living cells densely packed to prevent entry of microbes. often covered in Cilia (small hair like projections on respiratory mucus membranes) Release many substances which inhibit microbial growth such as mucus & tears.

sepis

toxic inflammatory condition arising from the spread of microbes, especially bacteria or their toxins from a focus infection.

vehicle

transmission by an inanimate reservoir Food: Consuming undercooked chicken that carries Salmonella, for example. Water: Drinking water from a "pristine" stream....but it contains Giardia cysts in it Air: Breathing dust that carries Hantavirus while sweeping up a cabin

Lymphocytes

white blood cells that produce antibodies that fight infection ADAPATIVE IMMUNITY B cells T cells