Week 10- infection basics Flashcards
What are Koch’s postulates
- The microorganism must be found in every organism with the disease
- The pathogen can be isolated from the infected organizm and grown in a pure culture
- The cultured organism should cause the disease when introduced into a healthy organism
- The pathogen must be isolated from the new host and must be identical to the microorganism grown in culture
What is the only one of Koch’s postulates that was not disproven
The pathogen must be isolated from the host and must be identical to the microorganism grown in culture
What idea around one specific microbe is important for Kuch
One specific microbe causes one specific case of an illness (i.e. usually strep pnumonia can cause pnumonia)
Resident vs transient microorganisms
Resident- live in or on us consistantly
Transient- live on us temporarily
What are opportunisitic pathogens
Cause diseases when the host allows them to do so (i.e. when immune system is weak)
What are primary pathogens
Something like the flu- can infect healthy hosts and cause infections
What are communicable vs noncommunicable diseases
Communicable- spread from one person to another by direct contact (i.e. herpes)
Noncommunicable- can not be spread from one person to another (i.e. teatnus)
Local vs systemic infections
Local- found in one area, often near site of entry
Systemic- Affects entire body
What is an example of a virus that goes from being Local to being Systemic
Varicella zoster infects through lungs and then becomes systemic chickenpox
What are the stages of pathogenesis in the body
- Transmission/Entry
- Adhesion
- Invasion
- Infection
- Evasion of host immune system
Active vs passive carrier
Active: Carry disease, can transmit to someone else
Passive: Has disease in body fluid or on skin, is asymptomatic, but is not “infected”
Are passive carriers symptomatic or asymptomatic
asymptomatic
What are sterile sites on the body
Brain, spinal cord, heart, blood vessils, ovaries, liver, fat, blood vessils
What are steril fluids in the body
CSF, fluid in eye, blood, fluid in heart cavity
What is an infectious disease
a disease caused by a pathogen (can be communicable or noncommunicable)
What is a zoonotic infection
an infectious diasese that can be spread from animal to humans
What are the 3 main types of infectious disease transmission
Contact, vehicle, or vector
What are types of Contact transmission
Direct, indirect, droplet (larger droplets), congenital
What are vehicle transmission types
Airborne, waterborn, foodborne
What are vector transmission types
Mechanical (body or feet of arthropod (insect) to person), biological ( bite, vomit, or poop of insect
Virulance is classified by what
the ability of a microorganism to cause an infection and damage to its host
A mild cold vs extreme infection (Virulance has degrees- very dangerous vs not)
Where does mucosa line our body
Mouth, respiratory, GI, urinary tract
Was COVID or H1N1 more virulant
H1N1, which was killing younger people earlier.
What are the 5 portals of entry into the body by a pathogen
- skin
-nose
-mouth
-colon
-vagina
What are the approxamate number of pathogens that cause disease?
Viruses and prions: 14-15%
Bacteria: 38-41%
Fungi: 22-23%
Protozoa: 4-5%
Helminths: 20%
What is adhesion
A protein or glycoprotein on the surface of a pathogen that helps it adhere to receptors on the host cell.
What is pathogenicity
The ability of a pathogen to cause an infectious disease
Ability is either present or not present
What is one example of a host defense and how pathogens overcome this defense
Host defense: microbe ingested and killed by phagocytes > Outer wall or capsule will impede phagocytosis.
Host defense: The host produces an antibody > destroys the antibody by having the bacterium produce IgA protease
What are the mechanisms of antibiotic resistance
- They multiply more quickly than humans, 2. they can perform horizontal gene transfer to mutate genes for antibiotic resistance
What is horizontal gene transfer
Plasmid exchange, and plasmids often carry genes for antibiotic resistance
Where do you find c difficile
soil and gut of humans and animals
What are the common diseases that c diff are associated with
Gangrene
Tetanus
Botulism
Food poisoning
Pseudomembranous colitis
What is an important cause of pathology in most c diff diseases
Potent protein exotoxins
Diseases caused by Clostridium tetani
Teatnus toxin- block release of glycine and GABA, cause paralysis and lockjaw
In soil in spores, when break skin they germinate.
Cannot be spread from person to person
What is the pathology of Clostridium Botulinum
Acts on neurons to stimulate contractions, blocks release of AcH
Clostridium difficile pathology and diseases
Severe abdominal pain, dharrhea, fever, can cause septic shock and death. Can get it from touching contaminated surfaces, breathing air, or taking antibiotics
Clostridium Perfringens pathology
Gas gangrene
found in soil and feces, can enter through a wound
cause necrosis, produces alpha toxin which leads to cell lysis and death
Mycobacterium genus characteristics
Tuberculosis, leprocy.
How to prevent Mycobacterium genus
Vaccination in endemic areas, pasteurization of milk
How is teberculosis initiated
mycobacterium tb can survive in macrophages, and tb is thought to be initatated that way
What is a fomate
an contaminated object (indirect contact)
What does H pylori use in invasion
Exoenzyme- urease- to turn urea into ammonia to cause ulcers. At High pH, mucin liquefies, and can invade gastric tract.
How do pathogens adhere
fimbriae, pili, spike proteins( viruses) , etc Hooks (protozoa)
What does staph aureus produce
TSST
What is most common cause of death due to infection worldwide
TB
How many bacterial cells cause TB
10
