Public: Microbial Interactions with Humans in health and disease Flashcards
Define infection
A situation in which a microorganism is established and growing in a host, normally associated with harm to the host
define disease
damage or injury to the host that impairs host function
Describe the microbiota of the skin
Skin= dry, acid (pH 5.5) acid environment that are less likely to support the growth of most MOs BUT moist areas (e.g. sweat glands) are readily colonised by gram-positive bacteria and other normal flora of the skin
What is the skin microbiota composition influenced by?
- environmental factors (e.g. weather, humidity, temperature)
- Host factors (e.g. age, personal hygiene, health)
Describe the microbiotia of the oral cavity
- oral cavity= complex, hetergeneous microbial habitat
- saliva contains antimicrobial enzymes but high concentrations of nutrients near surfaces in the mouth promote localised microbial growth
What does the tooth consist of (microbiology wise)?
A mineral matrix (enamel) surrounding living tissue (dentin and pulp)
How do bacteria colonise tooth surfaces?
first attaching to acidic glycoproteins deposited there by saliva
What is the relationship between Fusobacterium nucleatum and streptococci?
Symbiosis of 2 bacteria:
one anaerobic, one aerobic
What is dental plaque and how does it emerge?
What happens as plaque develops?
It is a thick bacterial layer and emerges due to the extensive growth of oral MOs, especially streptococci
and as plaque continues to develop, anaerobic bacterial species begin to grow
Where to bacteria love to grow?
Give 3 kinds of places
- On smooth surfaces (e.g. teeth)
- Moist environments (mouth, armpits etc)
- places with few sheer forces (unbrushed teeth)
What occurs in the oral cavity as dental plaque accumulates?
The MOs produce high concentrations of acid that results in decalcification of the tooth enamel (dental caries)
Name 2 lactic acid bacteria that are common etiological agents in dental caries
Streptococcus sorbrinus
Streptococcus mutans
Define pathogenicity
The ability of an microorganism to multiply and grow within an infected host, at the expense of the host and without conferring benefits upon that host
Define Commensalism
Organisms grow in association with a host
but do not confer any damage to that host
i.e. co-existence
Define Symbiosis
Organisms mutually co-exist, each derives
some benefit from the other co-operative partnership
i.e. normal microbiota of the skin, gut, genitourinary tract, etc.
