infection

Bacteria are bigger than viruses

major difference between viruses and bacteria according to karen

From the damaged tissue and inflammation

where do signs and symptoms for viruses and bacteriacome from?

Colonization

Microorganism grows and multiplies without tissue changes

Infection

Damage/change to tissues from colonization

Bacteremia

infection by bacteria in the blood

Gram +

normal skin and respiratory flora is gram positive or negative?

-, anaerobes

normal GI flora is gram positive or negative?

+, yeast

normal genital flora is gram positive or negative?

Norml (resident) flora

Multiple species of bacteria live on body surfaces but no physical reaction to them, enmeshed

Transient flora

Flora sits on surface temporarily, easily shed

exogenous

source of viral infection microbes

exogenous (others)

endogenous (self)

source of viral infection microbes [2]

Direct contact

Skin to skin, mucous membrane to mucous membrane transmission

Indirect contact

Contact via an intermediate surface

Vehicle born

indirect contact on an inanimate object

Vector born

indirect contect with a live intermediate

Droplet

transmission where cough or sneeze shoots microbes 1-2 meters. enters through mucous membranes.

Airborne

Tiny droplet nuclei, carried by dust, can travel metres, stay in the air, enter URT and go into the LRT

All airborne transmitted by droplet but not vice versa!

How are droplet and airborne related?

1. S+S of altered tissue function, inflammation

2. diagnostic imaging

3. lab work

How is infection diagnosed? [3]

WBC and differential

Lab work for both bacterial and viral

Culture and sensitivity and gram stain

Lab work for bacterial infections

serolog, Ag, detection, virus isolation

Lab work for viral infections [3]

bacterial

high neutrophils in lab work means:

viral

high lymphocytes in lab work means what?

protozoa, worms

high basophils in lab work means what?

number of microorganisms is greater than the defenses

infection occurs when…

microbial load

number of microorganisms

Virulence

Harshness of microorganisms

1. portal of entry

2. host

3. agent

4. transmission

5. reservoir

6. portal of exit

elements in the chain of infection: [6]

1. species grown

2. how much (colony count)

3. what antibiotic sensitive to

4. if WBCs are present

5. if any squamous/epithelial cells are present

culture and sensitivity identifies what? [5]

infection

if c&s reports 3+-4+ bacteria/WBCs, what does this mean?

means there is contamination. NOt a good specimen, can’t interpret results

if C&s reports 3+-4+ squamous epithelia cells, what does this mean?

see if bacteria are present and what type

Gram stain tests for what?

depending on the amount of peptidoglycan in cell wall wich determines if gram + or -

cell wall of bacteria will colour depending on what in gram stain?

serology

an antibody titre detects IgM or change in IgG

1. influenza

2. herpes

rapid antigen detection can be used for selected viruses only [2]

decrease microbial load so immune response and inflammation can eliminate them (cleaning, controlling damage)

goal of infection treatment

droplet and contact (can live short time on surfaces)

how is rhinovirus transmitted?

1. eyes

2. nose

3. mouth

where is rhinovirus absorbed? [3]

Infects mucosal cells of upper respiratory tract.

Rhinovirus likes cooler temps so remains in upper

what cells does rhinovirus infect?

1. it replicates in host cell and produces new virions

2. instead of releasing new virus into the bloodstream to infect other cells, it causes cells to temporarily fuse and spread cell to cell

How does rhinovirus spread and infect?

1. damage to cells causes prostaglandin synthesis

2. there is minimal mast cell disruption after initial entry

Rhinovirus inflammation is caused by what?

1. mucous

2. edema

3. nasopharynx

4. pain

Rhinovirus S+S related to inflammation: [4]

1. hard to breathe through nose

2. hard to swallow

S+S of rhinovirus related to altered function: [2]

infected host cell and damage by fusion

target for immune response in rhinovirus

1. cell mediated immunity and cytotoxic t-cells destroy

2. interferon prevents neighboring cells from producing new virions

3. antibody production from exposure to rhinovirus antigen is important for subsequent infections

immune response in rhinovirus: [3]

anitbody binds to the virus and neutralizes it, preventing new infection

compliment is activated to WBC attracted to digest antigen-antibody comples

what happens when exposed to the same strain of rhinovirus a second time?

1. age

2. wearing a mask

Number of colds decreases with what? [2]

1. not smoking or vaping

2. increase humidity

3. good nutrition

you can improve respiratory defenses by: [3]

A,B,C

three types of influenza

A and B

types of influenza that cause annual outbreak

C

influenza type that causes much less severe issues

1. haemagglutinins (H)

2. neuraminidases (N)

spike proteins on surface of influenza A

droplet and contact

How does influeza spread?

there is short-term colonization of the throat. The virus can shed before the onset of symptoms

how can influenza spread if not showing symptoms?

usually 1-3 days after initial exposure (range is 1-7)

how long does influenza take to onset?

infects all cells lining the respiratory tract, leading to serious inflammation and desquamation

what cells does influenza infect?

1. sore throat

2. couh

3. sneeze

4. mucous

5. chest pain

6. dyspnea

S+S of influenza related to respiratory tract inflammation and desquamation [6]

1. abrupt high fever

2. abrupt headache

3. general malaise

4. muscle aches

systemic S+S of influenza related to release of cytokines and cell contents [4]

1. pneumonia

2. exacerbation of underlying chronic illness

3. encephalitis

secondary complications of influenza: [3]

1. exposure to virus

2. no antibodies

3. no mask

4. impaired host defenses

increases the risk of influenza: [4]

reduces cells that produce the virus

how do inflammation and cytotoxic t-cells help influenza recovery?

antibodies neutralize newly produced virus in bloodstream before it infects new cells

how do antibodies help influenza recovery?

interferon

produced by influenza infected cells and prevents neighboring cells from producing new virions

IgG rise 10-14 days after S+S

serology diagnosis of influenza:

Tests for irus infected cells from throat swab

Rapid influenza antigen test tests for what?

1. neuraminidase inhibitors (e.g., oseltamivir, zanamivir)

2. adamantanes ([HA] inhibitors) (e.g., amantadine)

two main types of anti-influeza drugs “antivirals”

if taken within 48 hours in the course of ilness. Can reduce symptom duration and severity, complications, and antibiotic use

when are anti-influenza drugs most effective?

1. vaccination

2. other general pblic health measures

antivirals for influenza are an adjunct to what other measures? [2]

Vaccines prevent by inducing antibody production, so antibodies neutralize the virus when exposed.

How do influenza vaccines prevent infection?

The viruses change

Why is the influenza vaccine updated every year?

Vaccination

best prevention against annual influenza

Norovirus

Virus that replicated in the GI tract, shed in stool with cells. Causes gastroenteritis- often referred to as the stomach flu

12hours -2 days, symptoms last 24-72 hours

Norovirus incubation period

diarrhea and vomiting

S+S of norovirus [2]

contact

Norovirus transmission:

airborne and contact

Varicella virus transmission:

varicella virus

virus that causes chicken pox with first infection.

1. virus enters the bloodstream and moves to skin cels

2. replicates in skin cells and causes damage

3. prostaglandin and inflammation occurs

4. papules form

5. papules become vesicles (fluid-containing lesions that contain the varicella virus)

How does varicella virus infect the host? [5 steps]

1. itchy, red papules

2. fever

S+S of varicella virus

After first infection, virus enters nerve cells and becomes dormant. can develop shingles later in life

How can varicella become shingles?

1. skin infection

2. pneumonia

3. meningitis

Secondary bacterial infection from varicella virus can result in: [3]

1. severe liver damage

2. liver failure

3. cirrhosis

4. chronic carrier

5. hepatocellular cancer

complications of hepatitis B [5]

Hepatitis B

one of five hepatitis viruses. Found in body fluids (blood, semen, saliva, breast milk). is contact transmission

contact transmission. Enters liver cells via bloodstream, only affects liver cells

How does hepatitis B infect host?

60-180 days

Hepatitis B incubation period

1. pre-icteric

2. icteric

3. recovery

3 phases of hepatitis B

Pre-icteric phase: low fever, malaise, anorexia, nausea, fatigue

First 1-2 weeks of hepatitis B

Icteric phase: Jaundice for 2-6 weeks, altered liver function, hepatomegaly, pain, dark urine, anorexia

1-2 weeks after pre-icteric phase of hepatitis B

recovery phase: symptms diminish, hepatomegaly and pain

6-8 weeks after hepatitis B exposure:

SSARS-CoV-2 virus

Virus causing COVID-19

Airborne

COVID-19 transmission

chronic diseases of the CV, respiratory, neurological, endicrine, and musculoskeletal systems

COVID-1 increases risk of developing what?

Not a cold or flu or respiratory virus only; dysrefulates and damages the immune system

COVID-19 effect on the body

40%

Vaccination decreases risk of long COVID by:

endogenous (self). Ex:

1. skin flora (gram positive): Staph aureus

2. bacteria from GI tract (gram negative): E. coli

Source of surgical site infection is often what?

reduced sterile tecnique, skin cleansing, not removing hair

exogenous sources of surgical site infection [3]

At the time of surgery (not post-op) and multiply, causing local damage (prostaglandins and inflammation)

when do bacteria enter for surgical site infections?

1. redness

2. heat

3. swelling

4. pain

5. pus

6. delayed healing

7. fever

8. altered function of tissue

S+S of surgical site infection: [8]