intro to GI microbio Flashcards
what is the importance of gut flora
- healthy flora can protect against establishment of pathogens
what are the methods of investigating the microbiology of GI disease
- qualitative (general assessment of level)
- quantitative (enumeration normally vs. volume or weight)
- visual examination (microscope total count or general assess)
- culture
- molecular detection
- slides/smears
what factors affecct floral composition
- age of animal (maternal immunity, acquired immunity, old age)
- stress levels
- use of drugs
- genetics (some genetic lines more resistant to certain strains of bacteria than others)
- diet
- illness
what is meant by the term competitive exclusion between bacteria
existing bacterial flora present a competitive barrier to incoming bacteria so can exclude and prevent colonisation and or infection
- competition for nutrition
- competition for space
what factors can relating to sample handling can impact the results of microbio tests
- fresh vs long time dead
- chilled
- oxygen availibility
- time
- moisture
what genetic factors are essential for colonisation or disease by bacteria
- surface structures for adhesion and stop wash out
- LPS and membrane integrity for tolerance of harmful factors
- motility to get to target niches
- general gene regulation for stres responses to turn on genes required to adapt to the GI environment
- specific transporters to take up GI specific nutrients
- invasion to sustain colonization
how do antimicrobials disrupt competitive exclusion
can remove sensitive organisms from a particular niche and therefore leave a space to be repopulated by intrinsically resistant bacteria allowing overgrowth of undesirable bacteria
