Exam 3 Micro review

Body locations with normal Microbiota

Skin - Commensal, human unaffected microbes get nutrients

Small Intestine - Mutual, microbiota help digestion while they get stable enviroment

Throat - Commensal, humans unaffected microbes dont harm or hurt

Body location which are sterile

Brain

Heart

Blood

Why are some body parts sterile

They contain barriers that prevent microbes, Microbes would impair function, strong immune surveillance and no benefit for microbes to be there

Why do some body parts contain microbiota

Relationships exist where either the host or microbe are benefiting, some areas are constantly exposed to the outside world, helps train the immune system, the eviroment supports growth

What is an opportunistic infection?

caused by microbes that normally don’t cause disease in a healthy person but take advantage of certain conditions to become harmful. often part of your normal microbiota (commensal) or are common in the environment. They only cause problems when given the right “opportunity.”

What are some “opportunities” that allow opportunistic infections to cause disease?

Can occur from weakened immune system, breach of a physical barrier, antibiotics flushing good bacteria, entering the wrong body system

The difference between ENDO- and EXO-toxins?

Endotoxins originate as a part of the bacterial cell wall, whereas exotoxins are produced and secreted by the bacteria

Collagenase

Breaks down collagen, allowing pathogen to spread through tissues.

Hyaluronidase

Breaks down hyaluronic acid, allowing pathogen to spread through tissues.

Coagulase

Catalyzes the production of fibrin clots.

Kinase

Allows bacteria to escape from fibrin clots.

Order of Infection process

Portal of entry, Adhesion, Invasion, Multiplication, Infection of target, disease, and portal of exit.

Can you identify a virulence factor for each step of the infection process?

Portal of entry - Enzymes or penetration mechanisms hyaluronidase or collagenase

Adhesion - Fimbriae, Pili, Surface proteins

Invasion - Invasive enzymes, streptokinase - dissolves clots so bact. can spread

Multiplication - Biofilm formation protects microbes while they multiply

Infection of target - Evasion of immune system through capsules, immune inhibitors

Disease - Endotoxins (direct cell damage), Exotoxins (trigger inflammation)

Portal of exit - Toxins inducing excretion help pathogen spread

Infection ≠ Disease: why not?

Infection infections multiplication, disease indicates damage or symptoms

Contact transmission - Direct, indirect, droplets

Requires you to be in close proximity to someone (or to objects they have been in contact with); involves short distances. (touching, fomites, sneezing, coughing) <1M

Vehicle transmission - Airborne, Waterborne, Foodborne

Carried by a nonliving intermediary

Aerosols, Contaminated water or food

Vector - Mechanical, Biological

Carried by a living intermediary

Biological - Mosquito, Tick, Mite, Flea, Biting fly

Mechanical - Housefly, Roach

Zoonotic transmission

From animal to human, can be direct, indirect, waterborne, foodborne, or biological or mechanical vector

What route of transmission would be a rabies bite on a human

Zoonotic, Direct

Cow excretes in water, person drinks water, gets E. Coli. What kind of transmission

Zoonotic, Fecal oral, Waterborne

Mosquito bites bird, gets west nile, then bites human

Biological Vector, Zoonotic, and not communicable

Mosquito bites girl infected w/ malaria then bites another person

Biological Vector, not zoonotic, not communicable, not contagious

Isolation vs Quarantine

Isolation separates sick people with contagious disease from people who are not sick

Quarantine seperates those exposed to see if they will become sick

Lists cases of notifiable conditions by region and state

Smallpox, Botulism, Measles, Tuberculosis

Anthrax, Covid-19, West nile, HIV/AIDS

Types of HAI’s

Exogenous - external source, MRSA

Endogenous - patients normal microbiota are the source, E. Coli

Iatrogenic - infection directly caused by a medical procedure, Catheter AUTI

List at least 4 of the universal precautions for EVERY hospital interaction

Wear gloves, Wash hands, Wear masks, Avoid injury from needles, Vaccinate

Distinguish between signs and symptoms of disease (give examples)

Signs are Objective, measurable, and observable evidence of disease that a healthcare provider (or others) can detect. Fever, Rash, Hypertension, Elevated WBC count

Symptoms are subjective experiences felt and reported by the patient.

Pain, Nausea, Fatigue, Dizziness, Headache

What is a hospital acquired infection

a nosocomial infection—is an infection that a patient develops while receiving care in a healthcare facility that was not present or incubating at the time of admission

What are the 3 contributing factors to HAIs (why are they common in the hospital

setting

Immunocompromised patients, increase presence of infectious agents, many opportunities for spread

Where do innate immune responses take place

Outside and Inside the body

Barrier surface like skin and mucus membranes

In the blood WBC’s circulate

The lymphatic system helps detect and transport pathogens to immune cells

Where do adaptive immune responses take place

Inside the body

Lymph nodes and spleen

As well as blood

1st line of defense physical and chemical (innate)

Skin - preventing entry

Mucus - lines respiratory, digestive, and urogenital tracts

Sebum - acidic inhibiting bacteria

Lysozyme - break down bacterial cell walls

2nd line of defense 4 components (innate)

Compliment - 30 proteins that cascade to help phago + destroy pathogens

Phagocytosis - WBC engulfing its invaders

Inflammation - Red, Swelling, Pain, Heat

Interferon - Cells produced when infected to warn nearby cells

Neutrophil

Engulf and destroy through phagocytosis

Macrophages

Bridge adaptive and innate through activating the adaptive

Phagocytose pathogens and clean up dead cells

Dendritic cells

Capture pathogens and present antigens to T cells

Basophils + Mast cells

Release histamine to trigger inflammation

B cells

Produce antibodies specific to a pathogen

Form memory B cells for a faster future response

Helper T cells (CD4+)

Coordinate immune response, activate B cells and other immune cells

Cytotoxic T cells (CD8+)

Kill infected cells directly

Memory T cells

Provide long-term immunity after infection

Eosinophils

Attack large parasite by releasing toxic granules, since too small to eat

Stages of phagocytosis

Chemotaxis - pathogens or damaged cells release chemical signals, phago attracted

Adhesion - phagocyte sticks to the pathogen, recognition occurs via immune cell

Ingestion - Engulfment, membrane wraps around it forming phagosome

Fusion - phagosome fuses with a lysosome

Killing - enzymes and toxic substances destroy the pathogen, micro fractionated

Elimination - waste expelled by exocytosis

What is interferon and what produces it

Like Paul Revere these are signaling proteins released when a cell is infected by a virus, they help nearby cells and limit the spread. They don’t kill they just interfere with viral replication

What are the 3 complement pathways and what do they do

Classic - Antibody–antigen complex forms, Links adaptive immunity → complement activation, Antibodies (IgG or IgM) bound to a pathogen, lead to patho destruction

Alternative - Starts spontaneously when complement proteins bind to microbes, Rapid, innate response, Direct contact with pathogen surfaces (no antibodies needed), Continuous “surveillance” defense against invaders

Lectin - Recognizes carbohydrate patterns on pathogens, Lectins (like mannose-binding lectin) binding to sugars on microbes, Activates complement cascade like the other pathways, require no antibodies

What is the result of complement activation

the destruction and removal of pathogens through a coordinated set of immune actions in Innate immunity. Opsonization, Inflammation, Cell lysis (MAC), Enhanced immune clearance.

4 properties of inflammation and why they occur

Heat - Vasodilation bring warm blood from the core

Redness - more blood flow since BV’s dilate

Swelling - BV’s become more permiable allowing fluid, proteins, and immune cells to leak into the tissus

Pain - prostaglandins and histamine stimulate pain receptors, pressue from swelling

3 ways the first and/or second line of defense work together to prevent infection in the

body (interactions of multiple factors)

1. Mucus traps bacteria, Lysozyme and stomach acid kill micrbobes

2. Skin and Mucus are physical barriers, if broken, inflammation is triggered bringing phagocytes to the area

3. Cilia moves microbes through mucus out of airways, macrophages destroy microbes that manage to make it through

Complement deficiency results in

Recurrent bacterial infections

Lysozyme deficiency results in

Eye infections

Goblet cell deficiency results in

Respitory infections

Gastroferritin deficiency results in

Intestinal infections

Interferon deficiency results in

Viral infection

What cell types can do phagocytosis

Neutrophils, Macrophages, and dendritic cells

Opsonization

What is complement? Where is it found?

The complement system is a group of blood plasma proteins that work together to enhance (“complement”) immune defenses. It is part of Innate immunity, but it can also be activated by antibodies. Mainly in the blood plasma (circulating in an inactive form), Also present in tissue fluids, Produced mostly by the liver

5 aspects of the adaptive response

Specificity - immune system targets one specific antigen (pathogen marker) Each B or T cell recognizes only one unique shape/structure

Inducible - response is not always active, turned on when pathogen is encountered

Clonal - deletion via apoptosis and proliferation. Effector cells fight infection, Memory cells are for future protection

Tolerance to self - the immune system does not attack itself

Memory - some lymphocytes remain as memory cells, response = stronger + faster

Apoptosis

programmed cell death to remove damaged or infected cells

Differentiation

process by which a less specialized cell becomes a more specialized cell with a specific structure and function.

Proliferation

Proliferation means the rapid increase in the number of cells by cell division.

It is an important process in both normal growth and in Adaptive immunity.

true or false Lymphocytes secrete cytokines

Lymphocytes—especially T helper cells—do secrete cytokines. Cytokines are chemical signaling proteins that help regulate and coordinate immune responses in Adaptive immunity.

Cell mediated response

Kills host cell instead of antibodies - T cells attack infected cells directly

Antibody mediated (humoral) response

Production of antibodies, uses B cells to produce antibodies that act in body fluids (“humors” like blood and lymph).

IL-2

a cytokine (signaling protein) released by helper 1 T cells that activates and clones cytotoxic T cells, enhancing NK cell activity

IL-4

produced by T helper 2, mast and basophils in order to stimulate B cell activation, antibody production, and IgE-mediated immune response

IL-12

a signaling protein produced by dendritic cells and macrophages that produces Th1 differentiation, activates NK, cells and strengthens cell-mediated immunity

What do IL-2 IL-4 IL-12 signaling proteins do

IL-2 = T cell expansion

IL-4 = B cell / antibody response (IgE, allergy)

IL-12 = Th1 / NK activation (cell-mediated immunity)

Antigen

Exogenous

Endogenous