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Questions and Answers
Which organism is characterized by non-motility and appears colorless on MacConkey agar?
Which organism is characterized by non-motility and appears colorless on MacConkey agar?
What is the KIA reaction for Salmonella typhi?
What is the KIA reaction for Salmonella typhi?
Which of the following organisms produces H2S?
Which of the following organisms produces H2S?
What characteristic differentiates Serratia marcescens on nutrient agar?
What characteristic differentiates Serratia marcescens on nutrient agar?
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Which organism is motile and shows no urease activity except for one species?
Which organism is motile and shows no urease activity except for one species?
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What is the purpose of the Indole test?
What is the purpose of the Indole test?
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Which reagent is used in the Methyl Red test?
Which reagent is used in the Methyl Red test?
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What color indicates a positive result in the Citrate test?
What color indicates a positive result in the Citrate test?
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What is the main principle of the Voges-Proskauer test?
What is the main principle of the Voges-Proskauer test?
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Which type of media is used for the Indole test?
Which type of media is used for the Indole test?
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After how many hours should the MR/VP broth be incubated for the Methyl Red test?
After how many hours should the MR/VP broth be incubated for the Methyl Red test?
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What color is observed in the Methyl Red test for a negative result?
What color is observed in the Methyl Red test for a negative result?
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What is the primary goal of using Kligler Iron Agar (KIA)?
What is the primary goal of using Kligler Iron Agar (KIA)?
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What indicates a positive urease test in Urea broth media?
What indicates a positive urease test in Urea broth media?
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Which of the following bacteria is classified as a lactose fermenter?
Which of the following bacteria is classified as a lactose fermenter?
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What is the expected result when hydrogen sulfide (H2S) reacts with iron in KIA media?
What is the expected result when hydrogen sulfide (H2S) reacts with iron in KIA media?
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What is the main characteristic of Enterobacteriaceae in terms of their nitrate reduction ability?
What is the main characteristic of Enterobacteriaceae in terms of their nitrate reduction ability?
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What should be avoided when performing the oxidase test to prevent false positive results?
What should be avoided when performing the oxidase test to prevent false positive results?
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How should the KIA media be inoculated for best results?
How should the KIA media be inoculated for best results?
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What color change is indicative of a positive result in the oxidase test?
What color change is indicative of a positive result in the oxidase test?
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Which of the following statements is true about the motility of Enterobacteriaceae?
Which of the following statements is true about the motility of Enterobacteriaceae?
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What is the IMVIC reaction pattern for E.coli?
What is the IMVIC reaction pattern for E.coli?
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Which of the following characteristics is true for Klebsiella sp.?
Which of the following characteristics is true for Klebsiella sp.?
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How does Proteus sp. generally appear on MacConkey agar?
How does Proteus sp. generally appear on MacConkey agar?
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In which KIA reaction is H2S production observed for Proteus vulgaris?
In which KIA reaction is H2S production observed for Proteus vulgaris?
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What key characteristic differentiates Enterobacter aerogenes from E.coli?
What key characteristic differentiates Enterobacter aerogenes from E.coli?
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Which test result is true for Marganella morgana?
Which test result is true for Marganella morgana?
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What is a common appearance of Salmonella sp. colonies on MacConkey agar?
What is a common appearance of Salmonella sp. colonies on MacConkey agar?
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Which of the following correctly identifies the motility characteristic of Citrobacter sp.?
Which of the following correctly identifies the motility characteristic of Citrobacter sp.?
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Study Notes
Biochemical Tests Procedure
- Motility Test: Media used are SIM media and MIO media.
IMVIC Reaction
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Indole Test: Detects the ability of an organism to split indole from tryptophan. Use tryptophan broth or peptone broth, or SIM/MIO media. Reagent: Kovac's. Procedure: Inoculate tryptophan broth, incubate at 35-37°C for 24 hours, add Kovac's reagent, and read immediately. Positive result is a pink or red ring.
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Methyl Red Test: Determines an organism's ability to produce acid as final products from glucose fermentation. Use MR/VP broth. Reagent: Methyl red. Procedure: Inoculate MR/VP broth, incubate at 35-37°C for 48 hours, add methyl red reagent, and read immediately. Positive result is red; negative result is yellow.
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Voges-Proskauer Test: Determines if an organism produces acetoin. Use MR/VP broth, 1-alpha naphthol, 2-40% KOH. Inoculate MR/VP broth and incubate at 35-37°C for 48 hours. Add reagents, observe for 15-45 minutes for a positive result. Positive result is a red ring; negative result is yellow.
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Citrate Test: Determines if an organism can utilize citrate as its sole carbon source. Use Simmons' citrate agar. Indicator: bromothymol blue. Procedure: Inoculate citrate agar as a fishtail. Incubate at 35-37°C for 1-4 days. Monitor for a color change. A deep blue color indicates a positive result; no change (green) indicates a negative result.
KIA (Kligler Iron Agar) Test
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Principle: Determines carbohydrate fermentation (glucose and lactose), gas production (CO2), and hydrogen sulfide (H2S) gas production. Uses glucose and lactose.
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Procedure: Inoculate KIA tubes with an organism by stabbing the butt and streaking the slant. Incubate at 35-37°C for 24 hours. Observe the results immediately following the incubation period.
Urease Test
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Principle: Determines the presence of urease enzyme.
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Procedure: Inoculate urea broth media or urea agar/slant with the organism. Incubate at 35-37°C for 24-72 hours. Observe the results following incubation. Positive result is a red color; negative result is no change (yellow).
Oxidase Test
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Principle: Detects the presence of cytochrome oxidase enzyme.
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Procedure: Pick up one or two isolated colonies using a wooden applicator stick and rub directly on filter paper impregnated with TPD reagent. Read the result within 10 seconds. A dark purple or blue color indicates a positive result; no change indicates a negative result.
Enterobacteriaceae Family
- Characteristics: Gram-negative, rod-shaped bacteria. Many are motile. Aerobic or facultative anaerobic. Ferment glucose. Oxidase negative. Catalase positive.
Other tests
- Salmonella Shigella Agar: Selective medium for isolating Salmonella and Shigella. Inhibitor factors: Brilliant green, bile salts, sodium thiosulfate, sodium citrate. pH indicator: neutral red. Source of carbohydrate: lactose.
- Other Bacteria: Specific tests and characteristics are provided for each bacterial species including E. coli, Enterobacter aerogenes, Klebsiella, Citrobacter, Proteus, Morganella, Providencia, Seratia, Yersinia pestis, Shigella.
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Description
Test your knowledge on biochemical tests including motility and IMVIC reactions. This quiz covers key procedures, media, and reagents used in various tests. Perfect for biology students looking to reinforce their understanding of microbiological testing.
