[Effect of physical and chemical factors on Pasteurella multocida bacteriophages]

Studied was the effect of some physical factors (temperature, pH of various values) and some chemical ones (urea, sodium citrate, sarcolysin, methylene blue, acridine orange, pyronin, crystal violet, potassium permanganate, fuchsin, tetracycline and tetraolean) on phages specifically lysing Pasteurella multocida strains, having the following signature: 3, 4, 6, 22, 32, 115, 967, 1075, and C-2. All investigated phages showed signs of inactivation at 48 degrees C with a further linear dependence, and at 65 degrees C up to 99.99 per cent of them were inactivated. With phages of group III inactivation discontinued between 50 and 60 degrees C, at 65 degrees C it being equal to that observed with I and II group phages. It was found that a broth medium of pH 7.5 was the optimum one for P. multocida phages. With altered pH values lowest percentage of survived phage particles showed I group phages, while those of II and III group proved more stable. So far as the chemical factors were concerned it was established that with the exception of pyronin and potassium permanganate which inactivated the P. multocida phages from 90 to 100 per cent, all other agents produced full inactivation (100 per cent). However urea did not inactivate I group phages, both it and sodium citrate inactivated partially II and III group phages. The variations established with the phages in terms of their physical and chemical behaviour may serve as subsidiary signs bearing upon their classification.