Lecture 1- Basic Concepts Of Microbial Pathogenicity And Virulence Flashcards
1) Emerging and reemerging infectious diseases. 2)Classification - emerging and re-emerging infectious diseases. 3) Terminology 4) Pathogen 5) Koch's postulate
What are opportunistic infection?
Intentions caused by organisms that wouldn’t usually cause disease in a healthy person.
Which 3 groups of people are susceptible to opportunistic infections?
Young babies
Immunocompromised patients
Older people
What are zoonotic infections?
Infections from animals.
What is a horizontal gene transfer?
When an organism acquires genome from other organisms
Which two factors cause rapid change in the genetic make up of microbes?
Horizontal gene transfer
Hyper-mutation
What are new new diseases?
Diseases caused by PREVIOUSLY UNIDENTIFIED microbes.
Which classification of diseases recently entered human population?
New new diseases
Name on characteristic of new new diseases with relation to human lifestyle.
New-new diseases take advantage of changes in human lifestyle.
Name two examples of new-new diseases?
Lyme disease
Legionnaires disease
What are new-old diseases?
Diseases that have been known for a long time but now their microbiological cause has been determined.
Name 2 examples of new-old diseases.
Campylobacter - food Bourne disease.
Helicobacter Pylori - causes stomach ulcers.
What are old-new diseases?
Diseases with known causes that were once thought to be under control but are re-emerging.
What characteristic is allowing old-new diseases to re-emerge?
The long known pathogens of old-new diseases acquire new traits.
Give 4 examples of old-new diseases.
MRSA
Tuberculosis
E.Coli
Influenza A
What are old-old diseases?
These are diseases with known causes but recently recognised again because of their importance.
Give one example of old-old diseases.
Chlamydia trachomatis
What is colonization?
The ability of a microbe to remain in one place and multiply there.
This is usually a precursor to an infection
How does colonization play a role in infection?
It is usually the precursor to an infection.
What is an infection?
The successful colonisation and multiplication of a microbe capable of causing disease.
What is disease?
The dynamic process involving a sufficient change in the normal function of an organism’s cells or tissues to cause symptoms.
What is pathogenicity?
A microbe’s ability to cause disease (relative term)
What is virulence?
The degree of pathology caused by a microbe (quantitative term)
What is pathogenesis?
The mechanisms a microbe uses to cause a disease.
What are virulence factors?
These are features that contribute to a microbe’s ability to colonise and cause disease
Which two categories describe microbes able to cause disease?
True or opportunistic.
What are TRUE microbes?
These are microbes that READILY produce disease in healthy hosts.
What are OPPORTUNISTIC microbes?
These are microbes that cause disease in a COMPROMISED HOST or when a PARTICULAR MICROBE enters an UNUSUAL SITE in a host.
Give examples of 3 TRUE MICROBES.
Vibrio CHOLERA, Yersinia PESTIS, SALMONELLA sp.
Give 2 examples of OPPORTUNISTIC MICROBES.
Staphylococcus AUREUS, Streptococcus PNEUMONIAE.
What are Koch’s postulates?
The commandments of infectious disease.
Recite the 4 Koch’s postulates
1) Microbe must BE ASSOCIATED with SYMPTOMS or the disease and BE PRESENT at the site of infection.
2) Microbe must be ISOLATED from disease lesions and GROWN AS PURE CULTURE.
3) CULTURED MICROBE must REPRODUCE the disease when INNOCULATED into a susceptible healthy host.
4) The microbe must be RE-ISOLATED in pure culture from the SUSCEPTIBLE HEALTHY HOST in 3.
What is the proposed 5th Koch’s postulate?
Knowledge or microbe should enable effective therapeutic and preventative measures.
