what is the purpose of Eosin Methylene Blue (EMB)
To test for coliforms in environmental samples. coliforms produce acid and gas from lactose fermentation . It inhibits the growth of gram positive organisms
what is the purpose of Hektoen Enteric Agar(HE)
to isolate and differentiate salmonella and shegella
what is the purpose of the MacConkey agar
to isolate and differentiate enterobacteria based on the ability to ferment lactose and inhibit gram positive bacteria
what are the nurtients or food for bacteria for Macconkey?
beef extract, peptone and lactose, bile salts, neural red and crystal violet
what are the other components of MacConkey?
pancreatic digest of gelatin and distilled or deionized water
what is the purpose of mannitol salt agar
for isolation and differentiation of Staphylococcus aureus. differentiates pathogenic for nonpathogenic staph
what are the nutrients or food for bacteria for Mannitol salt agar?
beef extract, peptone, agar and distilled or deionized water
what is the purpose of blood agar
allows differentiation of fastidious bacteria based on their ability to hemolyze RBCs
what is the purpose of the triple sugar iron agar (TSI)
differentiate bacteria on the basis of glucose fermentation, lactose fermentation, sucrose fermentation and sulfur reduction
What are the other components of the TSI agar?
animal proteins, ferrous sulfate and sodium thiosulfate
what is the purpose of the catalase test?
differentiates bacteria based on their ability to respire. respiration is converting glucose to ATP. It also tests directly or indirectly for prescence of electron transport chain which generates the ATP of a cell. It differentiates staph(catalase +) from strep(catalase -.) The catalase breaks hydrogen peroxide into water and oxygen. The O2 indicates bubbles on the slide.
what are the reactions or growth results of the catalase test?
If bubbles occur that catalase is present and the symbol is positive. If no bubbles are present than catalase is absent and the symbol is negative.
what is the purpose of the coagulase test?
to differentiate staphylococcus aureus from other gram-positive cocci.( staph aureus uses plasma components in host via coagulase to convert fibrinogen into fibrin protective barriers.)
what is bound coagulase?
the clumping factor. it's attached to the bacterial cell wall and reacts directly with fibrinogen in plasma
what is free coagulase?
an extracellular enzyme that reacts with a plasma component called coagulase-reacting factor (CRF)
a microorganism capable of both fermentation and respiration that grows in the presence and absence of oxygen
anaerobe that grows in the presence of oxygen but doesn't use it metabollically
an organism that requires oxygen but can't tolerate it at atmospheric levels of it