bacteria

archaea

fungi

protozoans

helminths

viruses

prions

algae

Characteristics of Microorganism

tremendous diversity

all small

mostly microscopic

all require aseptic techniques for isolation culture, identification, control

commensual

parasitic

pathogenic

mutualistic

Harmless to humans

Present on, in or around body all the time

harmful to humans

cause disease or other problems

Pathogenic - disease causing bacteria

parasitic - viruses, fungi, protozoans

beneficial to humans

1.  base of food chain - convert carbon dioxide & water to glucose and oxygen
2. decomposes waste
3. recycle chemicals C,H,O,N
4. digestion - synthesize some vitamins
5. bioremediation - break down toxins
6. food production - cheese
7. biotechnology - genetic engineering

1. normal flora
2. transient flora
3. opportunistic

present on or in body all the time

most harmless

some beneficial

temporarily present on body

remove with cleaning

disease causing

any microorganisme may become opportunistic

evade surface defenses - enter tissue below epithelium

1. antiobiotics resistance in bacteria
2. fecal contaminated water/drinking water
3. undercooked food
4. lack of or improper hand washing
5. reservoirs for disease agents - asymtomatic carriers
6. vectores for disease agents - from host to host
7. pet kisses

1. always present & probably always will be - strep throat
2. problem in passt but controlled now - measles
3. emerging diseases - new
4. bioweapons - anthrax, small pox

1. genetic mutations
2. disease agents spread to new location or host population
3. humans enter new habitats and come in contact w/ new/unusual pathogen species

1. west Nile encephalitis - virus
2. bovine spongiform encephalopathy - mad cow disease
3. Creutzfeldt-Jacob disease - similar to mad cow
4. Ebola hemorrhagic fever - congo, infects monkeys
5. severe acute respiratory syndrom; SARS, bird flu