Microbiology in Human Affairs: Exam 3- Wainwright Spring 2023

The study of the body's defenses against specific pathogens

immunology

innate agents of resistance

Methods and agents of defense against pathogens that we naturally have.

Why is having healthy skin important to our immune system?

Most pathogens cannot penetrate through the skin, which gives us a defense against disease.

Keratin fibers (dead skin)

What is the outer layer of skin (stratum corneum) made up of?

Why is a burn patient so difficult to take care of in a healthcare setting?

The constant dehydration and lack of resistance to outside microbes weakens the immune system exponentially.

mucous membranes

Moveable and sticky membranes that trap "bugs", preventing them from attaching to living cells. If it can't attach, it can't infect.

Why are colds so much more common in the winter time?

Due to the cold and dry nature of the air in the winter time, mucous membranes dry out. When they are dry, they lose their sticky and moveable characteristics which prohibit them from trapping microbes. This makes it easier for microbes to attach and infect healthy, living cells.

stomach acid

What is hydrochloric acid?

stomach ulcers?

Stomach acid coming in contact with stomach lining, presence of helicobacter pylori, and being urease positive is the cause of what?

Eating undercooked pork.

What is one of the largest causes of intestinal worms?

1/7

What percent of the population has intestinal worms?

Rhodovirus and norovirus

What two viruses are notorious for passing through the stomach and infecting the intestines?

Why is lacrimation (tears) so beneficial to the immune system?

they contain lysozyme, which is a major protein that offers many antimicrobial benefits

Where do most respiratory infections begin?

The eyes. The eyes are directly exposed to the world at all times, and are connected to the nasal passages.

Gram positive

Are most of the microbes that trouble us Gram positive or Gram negative?

White blood cells. They fight against infections in the body.

What are leukocytes?

The bone marrow

Where are White blood cells created?

four signs of inflammation?

Rubor- redness

Tumor- swelling

Calor- warming

Dolor- pain

Why are anti-inflammatory drugs actually more harmful than helpful?

Inflammation is what's actually fighting the infection. If we suppress it, the healing process will take longer. It's best to let the infection and inflammation run its course.

Why does inflammation cause redness?

In the event of an infection, we need more blood (RBCs) to go to that area. More blood pooling= redness to the skin

Why does inflammation cause swelling?

In order to get more blood to the site of infection, our blood vessels dilate, causing the area to swell.

Why does inflammation cause the area to get warmer?

Blood is warmer that the rest of the body. More blood to the area means that area will feel warmer.

Why is inflammation painful?

When blood vessels dilate, they can press on nerve endings causing pain to the area.

The hypothalamus

What part of the brain controls the body's thermostat?

Interleukin 1

What is found in the blood that causes the hypothalamus to up the body's temperature?

105 degrees Farenheit

What temperature in adults can cause convulsions?

107 degrees Farenheit

What temperature in adults is typically fatal?

Our body's normal flora is responsible for resistance to outside pathogens.

Why do we need our body's normal flora?

Clostridium difficile?

A bacteria that causes infectious diarrhea / colitis. It can occur when antibiotics "wipe-out" a person's normal gut flora.

Fecal transplant

What is the common treatment for C. diff?

complement

a group of proteins, that leads to the lysis of invading cells

T-cytoxic lymphocytes?

type of white blood cell that can remember what pathogens they've already been in contact with. They often destroy the infected cell.

clonal selection

lymphocytes remember what pathogens they've already been in contact with. When they come in contact with a pathogen, they will clone themselves so the new cell will also know that pathogen. These are memory cells.

B-lymphocyte

A cell that encounters something foreign and transforms itself into a plasma cell.

The plasma cell can make 150,000 antibodies per second.

Forever

How long do antibodies stay in your body?

Why can we not gain immunity to the common cold?

There are too many of them that change constantly. If they are changing constantly, our lymphocytes technically having "seen" them before.

T-helper cell

These cells will circulate the blood "checking out" foreign things. These cells alone can't actually do anything about a pathogen, but they relay this info through interleukins to the B-lymphocytes.

Antigen-antibody complex

What activates complement?

four outcomes of complement activation

1. Stimulate phagocytosis: digest and destroy pathogen

2. Stimulate inflammation: gets more agents of immunity at site of infection

3. AAC will stick to the surface of RBCs: RBCs pass through the spleen, where the pathogen will be destroyed

4. Membrane attack complex: Lysis destroys the infection

By being exposed to the pathogen or disease

How do we get antibodies?

getting the antibodies by having the disease

What is naturally acquired active immunity?

getting the antibodies by way of vaccine

What is artificially acquired active immunity?

baby getting antibodies from mother in womb. only lasts about 6 months of life

What is naturally acquired passive immunity?

intentionally exposing baby to pathogens.

15 x 15 vaccine program

What is artificially acquired passive immunity?

Vaccines are not 100% effective unless every person in the world gets the vaccine.

Why are some diseases such as mumps and measles still present even though we have vaccines for them?

Mumps vaccine

What vaccine are some people suspicious of causing autism?

How can bugs gain advantage on the immune system?

1. High numbers of microbes

2. Mycobacteria

3. Capsules

4. Weakened immune system

5. Streptococci

They release hemolysins, which destroys RBCs

Why is streptococci especially harmful to the immune system?

Our immune system begins to destroy our own tissues

What happens when the immune system fails to differentiate between self and non-self?

Hashimoto's disease

An autoimmune disease in which the I.S. attacks thyroid gland

Diabetes mellitus

Autoimmune disease in which I.S. attacks pancreas and insulin production

Lupus

Autoimmune disease in which I.S. attacks connective tissues

Chron's Disease

Autoimmune disease in which I.S. attacks the bowel

Syphilis

What disease did Paul Erlich use chemicals to treat for the first time?

Medications that inhibit peptidoglycan (cell wall) synthesis:

Beta Lactam Antibacterials: Penicillins, Cephalosporins, Vancomycin, Carbapenems

Medications that inhibit protein synthesis:

Aminoglycosides, Macrolides, Tetracyclines, Chloramphenicol

Medications that inhibit DNA replication

Fluoroquinolones: Ciprofloxacin, Levofloxacin, Ofloxacin (take with probiotics)

Rifamycin: Rifampin (TB treatment)

Medications that inhibit folic acid synthesis

"Sulfa drugs": Sulfamethoxalone, Sulfadiazine

Medications that inhibit mycolic acid synthesis

Isoniazid, Ethambutol, Pyrazinamide, Streptomycin, Rifamycin.... all used simultaneously to treat tuberculosis

Medications that inhibit ergosterol synthesis

Nystatin, Amphotericin B, Ketoconazole, Itraconazole, Terbinafine, Naflidine, Flucytosine, Griseofulvin

Anti- Malarial and Anti Toxoplasma Medications

Hydroxychloroquine, Mefloquine, Diiddohydroxychloroquine, Pyrimethamine, Atovaquone

Female mosquito

What is the vector of malaria?

1%

What is the mortality rate of malaria?

Anti Intestinal Protozoa Medications

Metronidazole (Flagyl) and Iodoquinole

Anti Trypanosome Medications

Eflornithine, Nifurtimox

Not very effective

How effective are anti trypanosome medications?

Anti Viral Medications: nucleoside analogues

Acyclovir, Ganciclovir, Penciclovir, Valacyclovir--- reduces number of exacerbations

Anti Viral Medications: Attachment prevention

Enfuviritide (Valtrex), and Maraviroc

Influenza Medications

Amantadine, Rimantadine, Oseltamivir (tamiflu), and Redesvivir (used for Covid-19)

Process of infection

Reservoir--> Route-->Portal of entry-->Attachment-->Penetrate-->Acquisition of nutrients-->Avoid immune system-->Colonization (reproduction)-->Invasion-->Infection

Pathogen

any agent that can cause disease

Pathogenicity

power of an organism to cause disease

ID 50

measure of pathogenicity; how many microbes required to cause infection in 50% of animals tested

Virulence

measure of severity

LD 50

measure of virulence; how many microbes required to cause death in 50% of animals tested

Invasion

ability of a microbe to attach and penetrate to a single cell

Invasiveness

ability of a microbe to spread to other cells

Routes of Transmission

How is the microbe picked up?

direct contact transmission

contact with infected person; touching, contact w/ bodily fluids, etc.

indirect contact transmission

don't actually touch the person; aerosol transmission

contact by fomite

non-living surface; touching something an infected person previously touched

Parenteral transmission

subcutaneous, directly through skin

Fecal-oral transmission

Drinking fecal-contaminated water

Portal of entry:

how does the microbe enter the body?

nose, mouth, eyes, urethra, ears, open skin

Infection

How invasive is it?

Signs

can be observed by outside party

blood pressure, rash, body temp, etc.

Symptoms

something the patient experiences and reports; cannot be observed or verified by outside party

headache, body aches, psychological complaints, etc.

Reservoirs

where is the microbe normally found without harming the reservoir?

Transmissibility

How contagious is it? How does it spread?

non-contagious disease

cannot spread person to person

usually microbial infections that release toxins

Communicable disease

can be spread person to person, but UNLIKELY

Highly contagious disease

easily spread person to person

Endemic disease

stays in one area, does not spread anywhere else

Epidemic disease

spreads from "home" community to other surrounding areas

Pandemic disease

Spreads worldwide (like Covid-19)

Emerging diseases

New disease found that we've never encountered

1. Organism changed OR

2. first ever encounter

BSL 1

Gloves and goggles for precaution; these microbes typically don't cause disease

BSL 2

Direct contact transmission only

BSL 3

Aerosol transmission

BSL 4

Extremely virulent and contagious disease

"Space suit" with positive pressure ventilation required, stand-alone building with air-tight rooms, only 11 in the world