Category: P

Medium (for the cultivation of mycobacteria, especially) prepared by the sterilization of fresh potato, in water which is discarded before the potato is sterilized a second time. In Alkaline potato medium the water is replaced with solution of sodium bicarbonate, and in Glycerol potato medium with 5 per cent glycerol in water.  

Swelling of bacterial protoplasm, due to excessive intake of water from a suspending fluid of low osmotic pressure.  

Microbicidal substances released by blood platelets.  

Micro-organisms gaining their energy requirement by photosynthesis from sunlight—a property shared by algae. Such bacteria are not pathogenic to man.  

Bacterium the colonies of which acquire colour on exposure to light, particularly certain of the mycobacteria in which the feature is an aid to identification. Certain microorganisms in which a pigment develops when it is grown in the presence of light, such as Mycobacterium kansasii.  

General diluent in microbiology, 0.8 per cent aqueous sodium chloride containing 0.034 per cent potassium dihydrogen phosphate and 0.121 per cent dipotassium hydrogen phosphate.  

The detection of Staphylococcus pyogenes colonies by their growth on agar containing phenolphthalein phosphate. Coagulase-positive staphylococci produce phosphatase which liberates phenolphthalein from the medium. Colonies of staphylococci which have released the indicator are then apparent when exposed to ammonia vapour.  

Characterization test of the ability of an enterobacterium to deaminate phenylalanine to phenylpyruvic acid a property peculiar to the Proteus md Providencia species. Performed by adding ferric chloride to a culture in buffered DL-phenylalanine, green colour indicating positivity. The phenylalanine may be included in a yeast extract agar or alternatively in malonate – phenylalanine fluid…

Acid-resistant penicillins and hence suitable for oral administration. Listed as phenethicillin, propicillin and phenbenicillin.  

The demonstration of in vivo bacteriolysis by the injection of cholera vibrios into a guinea-pig, together with anti-cholera serum devoid of complement. Withdrawn peritoneal fluid shows progressive lysis of the vibrios, due to the action of the antiserum plus the animal’s own complement.