Pathology - Bacterial Growth Flashcards
What are the macroelements bacteria use?
C, O, H, N, P and S
What microelements are used for bacteia?
P, Ca, Mg, Fe, Cu, Zn and V
What is P important for?
ATP synthesis and NA backbone
What is Ca important for?
Signal transduction pathways as well as use a second messenger molecues
What is Mg used for?
Cofactor for DNAP activity
What is Fe used for?
ETC redox tactions and metabolic pathways like in cyotchromes
How do bacteria scavenge Iron from the environment?
Siderophores
Siderophores
These are products increasing rate of transport of envrionmental iron via the cell membrane using receptors.
What is Cu used for?
Cofactor for cytocrhome oxidases in aerobic respiraiton as well as Cu-Zn Superoxide Dismutase Enzyme
Cu-Zn Superoxide Dismutase Enzyme
This is an antioxidant that generates hydrogen peroxide and dioxygen from highly reactive superoxide
Culture Media
This is a nutrient rich solution for growth and proliferation of a microgranism
What does a culture media contain?
Organic/Inorganic compounds sutable for microbial growth with antibiotics to inhibit growth of specifc bacteria
What are the types of culture media?
Complex or Defined
Liquid or Solid
Complex Media
This is where chemical composition is not known, made of digested material.
What material makes up complex media?
Peptone, Meat/Yesat extracts and carbohydrates ources
Peptones
These are mixtures of nitrogenous compoudns like AA and proteins
Where is complex media used?
For bacteria with unknown nutritional requirements and growth support for bacteria difficult to culture
Defined Media
Is one in which the chemical composition in precisely known allowing for highly controlled experiments for studying of particular metabolic pathways
Liquid Media
This is a culture media for bacterial growth in susepnsion with required nutrients dissolved
How is Liquid Media prepared?
Mixutre with required nutrients for microorganism under study, specific pH distilled then sterilization by high temperature application, then incoulation using sterile pippete and incubated
Aseptic Technique
This is the procedure under controlled conditiosn to reduce contamintaiton from microbes
How is solid media prepared?
Required nutrients in agar or gelation then inoculated using sterile loop across surface for individual colony formation, then with incubation
What is the advantages of Solid Media?
Colonise can be isolated and studied, allowing morphological analysis for identity and behavioural analysis.
Batch Culture
This is a closed system containing limited amount of nutrients with finite growth
Binary Fission
This is the exponential growth of bacteria by doubling of mass of cells then division by septum formation
What are teh steps of Binary Fission?
Genetic Material replication
Cell elongaiton and size increase
Polar segregation of replicated chromosomes
Cell division by cleavage of centre with daughter cell formation
What are the stages of the growth curve?
Lag
Exponential
Stationary
Death
Lag Phase
Adjustment of bacteria to a new environment when incoulated in a growth media
What processes occur in the lag phase?
Ribosomal and protein synthesis with limited division in preapration for exponential phase,a djusting the specific nutriends
Exponential Phase
This is the consistent doublign and maximal growth rate, influenced by assimilation and nutrients/nutrient density
Stationary Phase
This occurs when nutrients have been assimilated and waste products accumulated
How are bacteria categorise by capacity for growth?
Viable Cells
Viable but Nonculturable Bacteria
Viable But Nonculturable
This refers to bacteria in a state of low metabolic activity that do not divide, but can become resuciated and culturable.
Legionella Pneumophilia
This causes legionnaires disease, being a severe form of pneumonia
Why cant Legionella be grown on convential media?
Infect macrophages and amoebae in aquatic nevrionments intracellularly, requiring L-Cysteine which is unavailable to standard media, and cannot be synthesised by legionella, taken from exogenous source.
What are the counting methods for bacteria?
Total Count
Viable Count
Culturable Count
What are examples of total counting methods?
Sterile Dillution Buffer
Most Probable Number Method
What is the basic total coutn method?
Spreading onto an agar medium and counting of bacterial colonies to calculate total count of bacteria in original sample.
Most Probable Number Method
This is a statiscal method estimating viable bacteria numbers in a sample by inoculation in a dilution series of liquid growth.
What does total count account for?
Viable, VNBC, Culturbale and Dead Cells
Viable Count
This utilises fluoresence activity dyes counting all cells with activity, exluding dead cells.
How is viable count perofrmed?
Collecting sample, diluting by spread on solid agar medium using pippette, number of colonies counted.
Serial Dillution
This is a laboratory procedure being stepwise dilution of a substance in solution
What does viable count take into account?
Living viable cells, however ecludes bacteria that cannot growth within the agar
How is Serial Dillution performed?
Adding poriton of sample to a volume of sterile dulent, small amount rtansferred to next dilution tube, repeated until desired dilution, spread on agar, icubated then Colony Forming Units counted
What is an example of culturable count being used?
Vibrio cholera by sample of dirnking water, where presence of V-cholerae determines safety.
How is turbidity measures?
Amount of bacteria inoculated in liquid growth medium and incubated, then by spectrophotometer
Spectrophotometer
These are instruments measuring optical transmission characteristics of a sample over a range of wavelenghts
Bacteriostatic
These are medicines whose mechanisms of action stalls bacterial cellular activity without causing death.
Bacteriocidal
This is antibiotic success in bacteiral elimination
Bacteriolytric
This means destruction of bacteria throguh lysis
What are the metabolic activity classifications of bacteria?
Obligatory anaerobes and aerobes, facultative anaerobes, aerotoleratn anaerobes and microaerophilic
What are the different types of bacteria by temperature?
Psychrophiles(Opt 15C, not above 20C can below 0C)
Mesophiles(Opt between 20-40C
Thermophiles(Opt betweeen 45-80C)
Hyperthermophils(Best above 80)
How are bacteria categorieed by pH and osmolarity?
Acidophiles, Alkaliphiles and Halophiles
