SUMMARY MICROBIAL DISEASE MECHANISMS
HC 1+2 STRUCTURES INVOLVED IN VIRULENCE
Microbiologists: Micro-organism centred
Immunologists: Host centred
Latency: period between colonization
and disease.
Humans need bacteria for 10-14% of
the energy they utilize.
Host-Microbe Relationships
- Normal flora/indigenous microbiota
Bacteria that are consistently associated with an animal
These bacteria can have symbiotic interactions with their animal hosts
- Symbiosis is defined as "life together", two organisms live in association
Mutualism: Both members benefit from the association.
Bacteria: Habitat constant temperature. Supply of nutrients (glycogen)
Human:Protection from other harmful bacteria.Protection from yeast infections
Commensalism: No apparent benefit or harm. Usually one member is being helped or
harmed during the association. Relationship between two organisms are unknown or
not obvious
Parasitism: refers to an organism that grows, feeds and shelters on/in a different
organism while contributing nothing to the survival of its host.
Obligate intracellular bacteria need more virulence factors. Pathogenicity is broader than the
virulence. Pathogenicity is the ability of the whole bacterium to invade the host and the
virulence is the trait.
- Pathogen is a microorganism (or virus) that is able to produce disease or cause damage
- Pathogenicity is the ability of a microorganism to cause disease in another organism (host)
Obligate pathogens are pathogens that do not associate with their host except in the
case of disease
Opportunistic (potential) pathogens
Live in a commensal or parasitic relationship without producing disease
, Only cause disease if they have an opportunity e.g. some compromise or weakness in
the host's anatomical barriers, tissue resistance or immunity
Bacteria can be transmitted from one host to another
DNA is organized in a
nucleoid= coiled.
Methylated = self
Non-methylated=
non=self.
Gram + can be treated
with penicillin
When antibiotics are
present bacteria will
form more actively
DNA.
Not every bacterium
has a capsule:
Protection
Attachment
Escape
phagocytosis
- Virulence; relative capacity of a micobe to cause damage in the host
- Virulence factors; traits that permit a pathogen to cause disease or prevent killing/clearing
by host
HC 1+2 STRUCTURES INVOLVED IN VIRULENCE
Microbiologists: Micro-organism centred
Immunologists: Host centred
Latency: period between colonization
and disease.
Humans need bacteria for 10-14% of
the energy they utilize.
Host-Microbe Relationships
- Normal flora/indigenous microbiota
Bacteria that are consistently associated with an animal
These bacteria can have symbiotic interactions with their animal hosts
- Symbiosis is defined as "life together", two organisms live in association
Mutualism: Both members benefit from the association.
Bacteria: Habitat constant temperature. Supply of nutrients (glycogen)
Human:Protection from other harmful bacteria.Protection from yeast infections
Commensalism: No apparent benefit or harm. Usually one member is being helped or
harmed during the association. Relationship between two organisms are unknown or
not obvious
Parasitism: refers to an organism that grows, feeds and shelters on/in a different
organism while contributing nothing to the survival of its host.
Obligate intracellular bacteria need more virulence factors. Pathogenicity is broader than the
virulence. Pathogenicity is the ability of the whole bacterium to invade the host and the
virulence is the trait.
- Pathogen is a microorganism (or virus) that is able to produce disease or cause damage
- Pathogenicity is the ability of a microorganism to cause disease in another organism (host)
Obligate pathogens are pathogens that do not associate with their host except in the
case of disease
Opportunistic (potential) pathogens
Live in a commensal or parasitic relationship without producing disease
, Only cause disease if they have an opportunity e.g. some compromise or weakness in
the host's anatomical barriers, tissue resistance or immunity
Bacteria can be transmitted from one host to another
DNA is organized in a
nucleoid= coiled.
Methylated = self
Non-methylated=
non=self.
Gram + can be treated
with penicillin
When antibiotics are
present bacteria will
form more actively
DNA.
Not every bacterium
has a capsule:
Protection
Attachment
Escape
phagocytosis
- Virulence; relative capacity of a micobe to cause damage in the host
- Virulence factors; traits that permit a pathogen to cause disease or prevent killing/clearing
by host
