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culture & sensitivity (C&S)
Placement of tissue in a growth medium to propagate growth of bacteria or other micro-organism to the point where they can be identified & tested for sensitivity to various antibiotics.
- Reading & reporting culture results: Culture plates are examined after 16-24 hours of incubation. At this time, culture growth is examined & a preliminary report is made based upon these observations.
- Preliminary reports of gram negative rods are based on the organism's ability to ferment lactose in the MacConkey agar used for specimen inoculation. Lactose-fermenting colonies appear pink on the agar surface.
- Lactose fermenters include: E. coli, Klebsiella, Enterobacter, Serratia, Citrobacter. Some organisms are 'stronger' lactose fermenters than others.
- Bacteria without the ability to ferment lactose on MacConkey agar appear clear on the agar surface. - Non-lactose fermenters include: Pseudomonas, Acinetobacter, Proteus, Providencia, Salmonella, Shigella
- Each of the different organisms has a characteristic appearance on agar & this observation is also made to help make a preliminary determination of the organism(s) present.
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culture