Antibiotics

  • Bacitracin
  • Chloramphenicol
  • Erythromycin
  • Kanamycin
  • Nalidixic Acid
  • Nitrofurantoin
  • Novobiocin
  • Optochin
  • Penicillin
  • Streptomycin
  • Sulfamethoxazole
  • Tetracycline

Biochemical tests

  • Acid from glucose
  • Adonitol fermentation test
  • Antibiotic susceptibility tests
  • Arabinose fermentation test
  • Arabitol fermentation test
  • Arginine dihydrolase test
  • Bacitracin susceptibility test
  • Catalase test
  • Cellobiose fermentation test
  • Citrate utilization test
  • Coagulase test
  • Deoxyribonuclease (DNase) test
  • Dulcitol fermentation test
  • Esculin hydrolysis test
  • Fructose fermentation test
  • Galactose fermentation test
  • Gas from glucose
  • Gelatin hydrolysis test
  • Glucose fermentation
  • Glycerol fermentation test
  • Growth in KCN (potassium cyanide)
  • Growth on 6.5% NaCl
  • Growth on 7.5% NaCl
  • Growth on bile salts test
  • Hand Hygiene and Infection Control
  • Hemolysis on blood agar
  • Hydrogen sulfide (H2S) production test
  • Indole production test
  • Inositol fermentation
  • Kirby-Bauer Antibiotic Susceptibility Test
  • Lactose fermentation test
  • Lipase test (using corn oil)
  • Lysine decarboxylase test
  • Malonate utilization test
  • Maltose fermentation test
  • Mannitol fermentation test
  • Mannose fermentation test
  • Melezitose fermentation test
  • Melibiose fermentation test
  • Methyl red test
  • Motility test
  • myo-Inositol fermentation test
  • Nitrate reductase test
  • Novobiocin susceptibility test
  • OF glucose test
  • Optochin susceptibility test
  • Ornithine decarboxylase test
  • Oxidase test
  • Phenylalanine deaminase test
  • Raffinose fermentation test
  • Rhamnose fermentation test
  • Ribose fermentation test
  • Salicin fermentation test
  • Sorbitol fermentation test
  • Starch hydrolysis test
  • Sucrose fermentation test
  • Trehalose fermentation test
  • Urea hydrolysis test (Christiansen’s)
  • Voges-Proskauer test
  • Xylitol fermentation test
  • Xylose fermentation test

Gram negative bacilli

  • Buttiauxella agrestis
  • Cedecea davisae
  • Cedecea lapagei
  • Cedecea neteri
  • Citrobacter amalonaticus
  • Citrobacter amalonaticus biogroup 1
  • Citrobacter freundii
  • Citrobacter koseri
  • Cronobacter sakazakii
  • Edwardsiella hoshinae
  • Edwardsiella ictaluri
  • Edwardsiella tarda (wild type)
  • Edwardsiella tarda biogroup 1
  • Enterobacter aerogenes
  • Enterobacter amnigenus biogroup 1
  • Enterobacter amnigenus biogroup 2
  • Enterobacter cancerogenus
  • Enterobacter cloacae
  • Enterobacter gergoviae
  • Escherichia coli
  • Escherichia fergusonii
  • Escherichia hermannii
  • Escherichia vulneris
  • Ewingella americana
  • Hafnia alvei
  • Klebsiella oxytoca
  • Klebsiella pneumoniae subspecies ozaenae
  • Klebsiella pneumoniae subspecies pneumoniae
  • Klebsiella pneumoniae subspecies rhinoscleromatis
  • Kluyvera ascorbata
  • Kluyvera intermedia
  • Leclercia adecarboxylata
  • Mollerella wisconsinsis
  • Morganella morganii subspecies morganii
  • Morganella morganii subspecies sibonii
  • Proteus mirabilis
  • Proteus myxofaciens
  • Proteus penneri
  • Proteus vulgaris
  • Providencia alcalifaciens
  • Providencia rettgeri
  • Providencia rustigianii
  • Providencia stuartii
  • Rahnella aquatilis
  • Raoultella ornithinolytica
  • Raoultella terrigena
  • Salmonella bongori
  • Salmonella enterica
  • Salmonella enterica subspecies arizonae
  • Salmonella enterica subspecies enterica
  • Salmonella enterica subspecies houtenae
  • Salmonella enterica subspecies paratyphi
  • Salmonella enterica subspecies salamae
  • Salmonella typhi
  • Serratia ficaria
  • Serratia fonticola
  • Serratia marcescens
  • Serratia odorifera biogroup 1
  • Serratia plymuthica
  • Serratia proteamaculans subspecies proteamaculans
  • Serratia rubidaea
  • Shigella dysenteriae
  • Shigella flexneri
  • Shigella sonnei
  • Shimwellia blattae
  • Tatumella ptyseos
  • Yersinia enterocolitica
  • Yersinia frederiksenii
  • Yersinia kristensenii
  • Yersinia pestis
  • Yersinia pseudotuberculosis

Gram positive cocci

  • Dermacoccus nishinomiyaensis
  • Enterococcus avium
  • Enterococcus faecalis
  • Enterococcus faecium
  • Enterococcus gallinarum
  • Kocuria kristinae
  • Kocuria rosea
  • Kocuria varians
  • Kytococcus sedentarius
  • Lactococcus lactis
  • Lactococcus raffinolactis
  • Macrococcus caseolyticus
  • Micrococcus luteus
  • Micrococcus lylae
  • Nesterenkonia halobia
  • Rothia mucilaginosa
  • Staphylococcus aureus
  • Staphylococcus auricularis
  • Staphylococcus capitis
  • Staphylococcus caprae
  • Staphylococcus carnosus
  • Staphylococcus chromogenes
  • Staphylococcus cohnii ssp. cohnii
  • Staphylococcus cohnii ssp. urealyticum
  • Staphylococcus epidermidis
  • Staphylococcus gallinarum
  • Staphylococcus haemolyticus
  • Staphylococcus hominis
  • Staphylococcus hyicus
  • Staphylococcus intermedius
  • Staphylococcus lentus
  • Staphylococcus saccharolyticus
  • Staphylococcus saprophyticus
  • Staphylococcus sciuri
  • Staphylococcus simulans
  • Staphylococcus warneri
  • Staphylococcus xylosus
  • Streptococcus acidominimus
  • Streptococcus agalactiae
  • Streptococcus bovis
  • Streptococcus criceti
  • Streptococcus equi
  • Streptococcus equinus
  • Streptococcus ferus
  • Streptococcus iniae
  • Streptococcus mutans
  • Streptococcus pneumoniae
  • Streptococcus pyogenes
  • Streptococcus ratti
  • Streptococcus salivarius
  • Streptococcus sanguinis
  • Streptococcus sobrinus
  • Streptococcus uberis

Media

  • 6.5% NaCl broth
  • Arginine dihydrolase broth
  • Bile esculin agar slant
  • Blood agar
  • Christiansen’s urea broth
  • DNase agar with methyl green plate
  • Lysine decarboxylase broth
  • Malonate broth
  • Mannitol salt agar
  • MRVP broth
  • Mueller Hinton Agar
  • Nitrate broth with Durham tube
  • Nutrient agar plate
  • Nutrient broth
  • Nutrient gelatin
  • OF glucose broth
  • Ornithine decarboxylase broth
  • Phenol red adonitol broth
  • Phenol red arabinose broth
  • Phenol red arabitol broth
  • Phenol red cellobiose broth
  • Phenol red dulcitol broth
  • Phenol red fructose (levulose) broth
  • Phenol red galactose broth
  • Phenol red glucose (dextrose) broth with Durham tube
  • Phenol red glycerol broth
  • Phenol red inositol broth
  • Phenol red lactose broth
  • Phenol red maltose broth
  • Phenol red mannitol broth
  • Phenol red mannose broth
  • Phenol red melezitose broth
  • Phenol red melibiose broth
  • Phenol red raffinose broth
  • Phenol red rhamnose broth
  • Phenol red ribose broth
  • Phenol red salicin broth
  • Phenol red sorbitol broth
  • Phenol red sucrose (saccharose) broth
  • Phenol red trehalose broth
  • Phenol red xylitol broth
  • Phenol red xylose broth
  • Phenylalanine agar slant
  • Potassium cyanide (KCN) broth
  • Rabbit plasma
  • Simmons’ citrate agar slant
  • Spirit blue agar plate
  • Starch agar
  • Triple sugar iron agar slant
  • Tryptone broth

Reagents, Chemicals, Stains

  • Ammonium Sulfate (saturated)
  • Barritt’s A reagent
  • Barritt’s B reagent
  • Crystal Violet
  • Ferric chloride (10%) reagent
  • Gram’s Decolorizer
  • Gram’s Iodine
  • HCl 0.1N reagent
  • Hydrogen peroxide
  • Iodine reagent
  • Kovac’s reagent
  • Methyl red reagent
  • Nitrate A reagent
  • Nitrate B reagent
  • Oxidase reagent
  • Rabbit Plasma
  • Safranine

Indole production test

About this test

What is the purpose of the test?  

This test determines whether the microbe produces indole from the amino acid tryptophan.

How is the indole production determined?  

If indole is produced, it will react with a chemical reagent added after incubation to produce a color change.

What medium is used?  

There are two media that are used for this test: Sulfide-Indole-Motility (SIM) medium and Tryptone broth medium. This program uses the Tryptone broth medium.  SIM is a nutrient medium which allows the detection of three different traits in bacteria: it contains sulfates to serve as the substrate for detecting sulfide (H2S) production; abundant tryptophan as a substrate for indole production; and its content of 0.5% agar limits bacterial swimming, thereby allowing detection of motility.  Tryptone broth serves the same purpose as SIM as far as indole production is concerned, and the means for conducting the test and interpreting results remain the same as SIM.

How is the test performed?  

An inoculum from a pure culture is transferred aseptically to a sterile tube of SIM or tryptone broth.   An inoculating wire should be used for inoculating SIM and a loop or wire for tryptone broth . SIM should be stabbed all the way to the butt carefully to disturb the medium as little as possible. The inoculated tube is incubated at 35-37 C for 24 hours.

What reagents are added?  

Five to ten drops of Kovac’s reagent are added to the tube. The reagent does not mix with water and forms a thin layer above the agar or broth. The reagent reacts with indole to produce a ring that is cherry red in color.

Performing this test in the VUMIE Online lab

Inoculation of Medium

1. Select the tryptone broth medium.  

2. Complete the process of a tube-to-tube aseptic transfer to inoculate the medium.

Incubation of the Inoculated Medium

3. Place the inoculated tube into the 35-37 C incubator.  

4. Press the New Day button to move forward 24 hours.

Addition of Reagents

5. Incubate this test for only 24 hours.  

6. Retrieve the incubated culture from the incubator.

7. This is a test that requires addition of reagents to bring about the change in appearance of a positive test. Select the dropper tool and the appropriate reagent needed from the chemical shelf. For this test, select Kovac’s.  

8. Remove the cap from the tube.  

9. Place the end of the dropper into the tube and add the reagent to the culture.  

Determination of Test Results

10. Observe test result. For this test, addition of the appropriate reagent produces a cherry-red ring floating above the culture medium if the test is positive. If negative, the ring that forms is yellow or amber.  

11. Record test result.

Uninoculated Tryptone Broth:

Positive Indole test:

Negative Indole test:


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Updated on November 1, 2022
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