Intro to microbiology Flashcards
1820-1910: ??? founded the science of medical statistics – demonstrating the impact of infectious disease on overcrowded populations
Florence Nightingale
??? demonstrated that microorganisms do not spontaneously generate. He suggested such germs could cause human illness and developed “Germ Theory”
Louis Pasteur
TRUE or FALS: swan neck flask with broth media inside boiled to sterilisation. Left for period of time, proved nothing spontaneously grew.
TRUE
Koch developed use of pure culture technique into a ??? which became critical for isolating and culturing bacteria. initially used gelatin
solid media
Koch isolated Vibrio cholerae and ??? using solid media
Tuberculosis bacillus
Koch postulate 1: The bacteria must be present in ???
every case of the disease.
Koch postulate 2: The bacteria must be isolated from the host with the disease and grown in ???
pure culture
Koch postulate 3: The specific disease must be reproduced when a pure culture of the bacteria is inoculated into a ???
healthy susceptible host
Koch postulate 4: The bacteria must be ??? from the experimentally infected host.
recoverable
what couldn’t be determined by Koch’s postulates?
viruses
why can’t Koch postulates be applied to viruses?
son’t behave the same as bacteria, are much smaller
koch postulations limitations: can’t capture all relationships of bacteria with human hosts. For example, no ??? of infection for that particular microorganism e.g. leprosy. OR can’t be grown in pure culture in the lab
animal model
TRUE or FALSE: koch postulations limitations: doesn’t account for a harmless pathogen that becomes harmful in certain circumstances
TRUE
Harmless microorganisms may cause disease if:
- It has acquired extra virulence factors making it pathogenic.
- It gains access to deep tissues via trauma, surgery, an IV line, etc.
- It infects an ???
- Not all people infected by a bacteria may develop disease-subclinical infection is usually more common than clinically obvious infection.
immuno-compromised patient
Koch’s postulates have been modified over the years to
encompass:
Viruses
Obligate parasites
Slow viruses (viruses that cause symptoms in an infected host long
after the original infection and which progress slowly)
The microbial causation of cancer.
Molecular postulates relate to what is happening more at the ??? level. Criteria for determining whether a specific bacterial virulence factor
has a role in pathogenesis.
genetic level
molecular postulates 1: Identify gene (or gene product) responsible for virulence determinant
- Show gene present in strains of bacteria that cause the disease
- PRESENT or NOT PRESENT (?) in avirulent strains
Not present
molecular postulates 2:
- Disrupting the gene reduces OR increases (?) virulence
reduces
Molecular postulates 3:
Complementation with the gene restores ???
- Introduction of the cloned gene into avirulent strain restores ???
virulence
Molecular postulates 4 and 5: The gene is expressed in vivo. Specific immune response to gene product is ???
protective
Experimental demonstration of
Koch’s Molecular Postulates: using Prp, a multifunctional plasminogen binding M protein, is used. ??? replaces 2 amino acids which abolishes plasminogen binding activity. Complementation of the prp mutant is achieved by reverse complementation which results in stable complemented strains
for in vivo studies or where gene copy number is an issue. Plasminogen binding ability results reveals virulence determinant
Alanine
TRUE or FALSE: Microbiology today is more focused on the relationships among microorganisms and with their environment rather than specific microbes
TRUE
biofilms: One or more types microorganisms physically linked together and to the underlying surface by ???
substances they secrete
bacteria are usually found individually or in communities?
communities
