Host-parasite relationship Flashcards
Define symbiosis
relationship b/w 2 different organisms to survive
Define Mutualism & e.g.
Both organisms benefit from each other e.g. humans and normal flora (NF)
Define Commensalism & e.g.
one benefits and host is unharmed e.g. barnacles on whales, psuedomonas
Define parasitism
parasite benefits & host is harmed
Name 1 NF (genus species) that’s major cause of human infection, and state where it is usually found
Staphylococcus aureus in nasal membranes (opportunistic in clinical areas)
OR
Staphyloccocus epidermidis on skin
Why must a mid-stream urine (MSU) sample be collected from person suspected w/ UTI?
To see if there are WBC in urine = prove there is an infection in urinary tract
What is a noscomial infection?
acquired while staying in hospital from Opportunistic NF
Why is lower respiratory tract sterile? (4 reasons)
- Cleansing action from ciliated epith. & mucociliary blanket
- Sneezing, coughing, swallowing
- phagocytic action of alveolar macrophages
- Lysozyme in mucus
What’s lysozyme and its role in tears?
enzyme that breaks down bact. cell walls: break B-1,4-glycosidic bond b/w NAM & NAG
Name 1 pathogen (genus species) that is found in Upper respiratory tract
- Streptococcus pneumoniae
- Haemophilus influenzae
- Streptococcus pyogenes
- neisseria mengitidis
Name common bact. (genus species) that causes UTI
Escherichia coli (usually in sml intestine epith.)
Desribes steps of Koch’s postulates
- Specific causative agent must be found in every causing disease
- Dideas organism isolated in pure culture
- From culture, introduce a sample of disease to healthy, susceptible animal => produce same disease
- Disease organism recovered from animal. Should be the same to prove that specific microbe = specific infectious disease
define ammensalism
one organism inhibits/destroys a diff. organism
Define predation
Predator eats prey
Name 4 bacteria on the skin
Staphylococcus epidermis, Micrococcus sp., corynebacteria, Propionibacterium acnes (anaerobe)
