Module 6 - Microbiology Flashcards
Microbe
Microbes are tiny living organisms that are found all around us and are too small to be seen by the naked eye (microscopic). They include bacteria, archaea, single-cell eukaryotes, and viruses
Commensalism
one benefits one not harmed
Mutualism
both benefit and depend on each other
Parasitism
one benefits, one adversely affected
Opportunism
a change in living relationship resulting in parasitism
Outbreak
relatively high number of infections are observed where no cases or only sporadic cases occurred in the past
epidemic
sudden rapid rise in the incidence of a disease in a particular population
Pandemic
global epidemic
endemic
disease that is always present in a given population. there is a permanent reservoir (human or other animals).
Identify Koch’s 4 postulates
- suspected pathogen must be present in all cases of disease and absent from health animals
- suspected pathogen must be grown in pure culture
- cells from pure culture of suspected pathogen must cause disease in health animal
- suspected pathogen must be reisolated and shown to be the same as the original
Infection
when microorganisms invade host tissue and multiply
subclinical infection
no symptoms apparent but immune response is induced
localised infection
confined to one area of the body
systemic infection
infection spreads to other organ systems
disease
harmful alteration to the host
pathogen
microorganism capable of causing disease
pathogenesis
process of disease arising
pathogenicity
measure of ability of a pathogen to cause disease
pathogenic determinant/virulence factor
feature of a pathogen that influences how well it can cause disease
Gram positive bacteria
thick peptidoglycan layer and has a plasma membrane
purple colour
Gram negative bacteria
thin peptidoglycan layer
has outer membrane and inner membrane
red in colour
why it is important to know about the bacterial characteristics particularly in the health care setting
- Accurate ID of bacteria needed for choosing treatment
- In general, the Gram status, morphology and functional characteristics would be sufficient information for the appropriate treatment
More information to narrow down to species level - Ultimate knowledge: DNA sequencing; expensive; slow (but improving)
Macroscopy
- Colony morphology & phenotype (seen with the naked eye)
- Bacterial colony morphology: size, shape, pigmentation, elevation, margin, opacity, surface texture
- Requires culture on solid media & isolating single colonies (16 streak technique)