Infection Introduction Flashcards
In high income countries what infections are low/
Acute, community onset infections are low but healthcare associated infections occur and there is a high rate of antibiotic resistance to gram negative bacteria
What does altered micro biome cause
Obesity, IBD, liver disease (not important)
What is Kochs postulates
Micro organisms always associated with the disease which can be isolated
What are the types of microorganisms
Viruses, prokaryotes like bacteria archaea, eukaryotes like fungi and protists
What do you microbes have
A Boundry (cell wall), A cytoplasm with proteins lipids and organelles etc and transport requirements (take nutrients in and out)
How do you name microbes
By taxonomy, in italics, genus is stated first then species
What is different about prokaryotes
They have no membrane-bound organelles and can divide quickly
What is protozoa
Spread between humans and animals e.g. Malaria
What is helminths
Major tropical and zoonotic diseases
What Is the name for a a round bacteria
Coccus
Gram-positive have
A dense cell wall consisting of peptidoglycan and stain a purple/blue colour
What do you gram negative bacteria have
A thin peptidoglycan layer and an outer membrane and it stains a pink colour
Steps of staining
Dry on glass plate
Stain with crystal violet and set with iodine
Decolourise with alcohol
Counterstain with safarin (pink colour)
Use sterile technique e.g. Bunsen burner and alcohol
Bacteria grow in
Clusters or chains
What bacteria grow in clusters
Gram-positive cocci 
What are acrobes
Use oxygen as final electron accepter
What are Anaerobes
Fermentation, final electron exceptor is organic molecule
What is a facultative anaerobe
Switches between aerobic and anaerobic
Bacteria need what to survive
The right temperature, PH and salt content and nutritional requirements e.g. bringing in purines, pyrimidines, amino acids and excreting enzymes/ waste preoducts
Types of bacteria that lack a cell wall
Mycoplasma, chlamydia
Bacteria that have cell walls that just don’t stain well
Mycobacteria
Bacteria envelope structure influences
Susceptibility to antibiotics and determines pathogenicity
Differences about mycobacteria
They have a very thick lipid membrane anchored to peptidoglycan
The capsule of the bacteria is
A polysaccharide coat that helps hide immunogenic cell wall, immunity requires antibodies to the capsule
Ribosomes do
Protein synthesis
Ribosomes 50 S and 30 S subunits contain
RNA and proteins
What can be a target of antibiotics
Bacterial RNA
Mobile genetic element code for
Toxins and antibiotic resistant genes
Bacteria can have… So they are resistant to heat and disinfectant
Spores
Stages of bacterial growth
Lag phase
Exponential phase/ log phase
Stationary phase
Death phase
Gene regulation alter
Growthrate to adjust to environment
