INTRODUCTION TO HOST-MICROBE RELATIONSHIP AND OVERVIEW OF NORMAL FLORA Flashcards
(27 cards)
What is disease
- Disturbance in the state of health wherein the body cannot carry out all its normal functions.
- Disturbance in the state of health that may result in the infection of human tissue by microbes.
What is Infection
the invasion of tissues by pathogens, their multiplication, and the reaction of host tissues to the infectious agent and the toxins they produce.
What is sign?
something that can observed externally
What is example of sign?
Temperature, color, moisture, heart rate
What is symptom?
something that can be feel internally
What is example of symptom?
Fatigue, dizziness, pain, nausea
3 Type of relationship
- Commensalism
- One organism benefits while the other is unaffected (many bacteria) - Mutualism
- Symbiosis, both organisms benefit - Parasitism
-one organism benefits at the expense of the other
What is pathogen?
microscopic organism, that causes disease in its host organism.
How does pathogen cause disease?
invade living cells 🡪 disrupting normal bodily functions 🡪 triggering immune responses.
What is pathogenicity?
ability an organism has to cause disease
What are 2 factor of pathogenicity?
- infectivity, or the ability to infect and colonize a host and virulence
- the ability to cause host cell damage.
What are 4 type of pathogenicity?
- Primary infection
- referred to the first time of exposure of pathogen to patient - Secondary infection
-additional infections resulting from primary infections
3.True pathogen
-Pathogen that can cause disease in healthy person with normal immune defense
-Exp: Influenza virus, plague bacillus, malarial protozoan
- Opportunist pathogen
-pathogen that cause by infection when host’s immune defense is weaken
- Exp: Pseudomonas sp. , candida albican
What is Virulence factor
Products from pathogen that enables a microorganism to establish itself on or within a host of a particular species and enhance its potential to cause disease
what are 5 traits of virulence factor
- Colonization
- Colonization of a niche in the host (this includes movement towards and attachment to host cells) - Immunoevasion
- evasion of the host’s immune response - Immunosuppression
-inhibition of the host’s immune response (this includes leukocidin-mediated cell death) - Entry into and exit out of cells if the pathogen is an intracellular
- Obtain nutrition from the host
Chain of infection
(6 elements for infections to occur)
- Infectious agent
-the microbe that can cause harmful infections - Susceptible host
-a person whom unable to fight the infection
(weak immune system, easier to catch infection) - Portal of entry
-opening where the pathogen may enter
- Exp: Eye, Nose, mouth, bites of vector, skins break, urinary or reproductive track - Reservoir
-Environment where pathogen can live and multiply
- Exp: Respiratory tract, equipment, food and water - Portal of exit
-The way out of infectious disease from infected person so it can spread
- exp: Respiratory droplets, blood droplets, faeces and urine, reproductive tract - Mode of transmission
-how microorganisms are transmitted from one person or place to another.
-Cough, exchange bodily fluid
2 Classification of disease
- Infectious disease
-Diseases caused by infectious agent - Non-infectious disease
-Are caused by any factor other than infectious organisms
Establish an infection
(successful invasion and colonization of a host by a pathogen)
- Gain entrance to host
- Pathogen usually have special structures or physiological characteristics that improve the chances of successful infection - Adhere
- attachment to the host surfaces depends on the interaction between host plasma membranes and bacterial adherence factors.
- adhesins: glycoprotein on attachment pili - Colonize or invade
-Colonization (growth of the
pathogen on the epithelial surface) –
produce biofilm
-Invasion (penetrating the host cell)
– depends on degree of invasiveness.
Eg: hyaluronidase - Damage host
- pathogen produce toxins to damage the host.
- hemolysins, leukocidins, neurotoxins enterotoxins. - Invade host defense
- Some pathogens invade the host cell and at the
same time, protect themselves from immune
defense
eg. coagulase enzyme (induce plasma clotting) but
at the same time, they have streptokinase (to
unclog the plasma) and spread to the other part of
the body.
5 Stage of infectious disease
- Incubation period
- no sign or symptom - Prodromal phase
- mild sign or symptom - Invasive phase
- most severe signs and sympthom - Decline phase
- Declining sign and sympthom - Convalescence period
-body recovers from a serious illness
5 way s of transmission of disease
- Airborne
- vector borne
- Food borne
- Sexually
- Vertical
Function of natural flora in human.
- Digestion of substrates
- Production of vitamins
- Stimulation of cell maturation
- Stimulation of the immune system
- Aid in intestinal transit and colonization resistance
Microbe in skin (scalp, feet, groin and penerium)
Staph. aureus Staph. epidermidis diphtheroids streptococci
Microbe in Nose
- Staph. aureus
- Staph. epidermidis
- diphtheroids
- streptococci
Microbe in Mouth
- Strep. mitis and other streptococci
- Trichomonas tenax
- Candida
Microbe in Teeth
- Streptococcus mutans
- Bacteroides Fusobacterium
- streptococci actinomyces
