Public: Microbial Interactions with Humans in health and disease Flashcards Preview

Pharmacy Year 2 Semester 1 > Public: Microbial Interactions with Humans in health and disease > Flashcards

Flashcards in Public: Microbial Interactions with Humans in health and disease Deck (18):

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
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.


Give some examples of non-pathogenic organisms

Lactobacillus acidophilus, Bifidobacterium longum, Erwinia caratavora, Saccharomyces carlsbergensis.


Give examples of opportunistic pathogens

Pseudomonas aeruginosa, Burkholdaria cepacia, Trichophyton mentagrophytes


Give examples of obligate pathogens

Smallpox virus, measles virus, rabies virus, Neisseria gonorrhoeae (a bacterium)