Voges-Proskauer

Biochemical tests are usually performed after pure cultures have been obtained. The standard indole, methyl red, Voges-Proskauer, citrate, and litmus milk tests may be used to show important physiological characteristics. To study the functional diversity of bacteria, the utilization of carbohydrates, amines, amides, carboxylic acids, amino acids, polymers, and other carbon and nitrogen sources can be tested.28 Dilution-based most-probable number (MPN) techniques with phospholipid fatty acids as biomarkers have been employed for studying different bacterial species in lakes.40 The patterns of antibiotic resistance in bacteria isolated from natural waters have been useful for identifying sources of water pollution.34... 

According to Levine, the methyl red test checks with the Voges-Proskauer reaction. The test for B. coli of fecal origin is the development of a red coloration in the medium after twelve hours incubation. 

Methyl red medium is made by adding methyl red to a phosphate broth and Voges-Proskauer medium is made by adding 10% KOH solution to the phosphate broth. 

Levine, M. The correlation of the Voges-Proskauer and methyl red reactions in the chlon-aerogenes group of bacteria. Jour. Inf. Dis., 18, 1916, 868-67. 

Levine. The significance of the Voges-Proskauer reaction. Jour, of Bacteriology, 1, 1916, 163-164. 

The Methyl Red and Voges-Proskauer tests are widely used to distinguish between E. coli and Klebsiella species with E. coli being MR positive, VP negative and Klebsiella being MR negative, VP positive. 

The combination of Indole, Methyl Red, Voges-Proskauer and Citrate tests is frequently known under the acronym IMViC. 

Samples from the presumptive positive tubes are then inoculated into further medium for confirmation tests for coliforms and also to determine whether E. coli is present. Results from the Voges Proskauer, Methyl Red, and Citrate tests (see later) are used to confirm the presence of coliforms. Positive results from growth on MacConkey broth at 44 °C are scored to give a statistical probability of the Most Probable Number (MPN) of E. coli per 100 ml of water sampled. 

Voges-Proskauer test is positive (also see feature number 24035). 

It is an imusual propionibacterium in that it can grow at such a low pH and can withstand heat treatment at 90 C for 10 min. P. freudenreichii (which has the highest DNA homology with the new strain and is the most heat resistant of the propionibacteria) can survive for 10 min at 80 C, but can not survive at 90 C. The catalase, oxidase, and Voges-Proskauer tests are... 

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