Draw the how would the biochemical tests tubes would look like after inoculating

Question

Draw the how would the biochemical tests tubes would look like after inoculating the next bacteria. TSI inoculated with Salmonella typhimurium is known as a bacterium capable of fermenting glucose, but not sucrose or lactose. It usually produces H2S and doesn't forms gas. SIM inoculated with E.coli is known as a motile bacterium that produces indole and not produce H2S. Simmons citrate inoculated with Pseudomonas aeruginosa, known as a bacterium that uses the citrate as a carbon source. RM-VP inoculated with Klebsiella pneumoniae, known as a bacterium that doesn't ferments glucose using the mixed acid fermentation LIA inoculated with S. aureus a bacterium that decarboxylase the lysine and doesn't produce H2S Complete the tables

Explanation / Answer

1) TSI with S. typhimurrium -> Black precipitate ( They use thiosulfate anion to reduce sulfide to H2S which inturn reacts with ferrous sulfate to form a black precipitate of ferrous sulphate)

2)SIM with E. coli -> no blackening (since no H2S is produced which would finally form black ferrous ammonium sulfate); a diffused growth zone not confining to the line of inoculation (indicating motility); pink-red band at the top of the media (it produces tryptophanase which converts tryptophane in caesin peptone to indole. indole gives a pink-red band upon reaction with Kovcs reagent)

3) Simmons citrate with P. aeruginosa -> blue colour (citrate utilization is accompanied by utilization of ammonium salts in the media to liberate ammonia. This would increase the pH of the media causing bromophenol blue dye to chang its colour from green to blue.

4) RM-VP with K. pneumoniae -> no red colour ( it ferments glucose and further metabolizes the end-products therby neutralizing the pH)

5) LIA with S. aureus -> turbid, purple butt (as lysin in the medium get decarboxylated); no black precipitate (as no H2S is produced)

CULTURE MEDIA SELECTIVE AGENT CARBON SOURCE DIFFERENTIAL AGENT TSA none glucose none EMB eosin-methylene blue lactose lactose fermentation MAC crystal violate and bile salts lactose lactose fermentation MSA NaCl mannitol mannitol fermentation

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