Methods of polyvalent bacteriophage preparation for the treatment of bacterial infections

A method of obtaining multivalent bacteriophage strain charactarised in that:

• a) a sufficient number (n) of pathogenic bacterial strains of a specific species appearing randomly in a given region is accumulated, by which the isolated bacterial stains are possibly drug-resistant strains,
• b) a sufficient number of bacteriophage strains specific to at least one of the bacterial stains of the given species is accumulated,
• c) the lytic activity of the accumulated bacteriophage strains on each accumulated bacterial strain is determined, the value p, which is the proportion of the number of strains lysed by a given phage to the number of all the accumulated bacterial strains, is estimated,
• d) from the resultant value of p, it is tested whether n fulfills the condition:
• n
• ≥
• pq
• d
• 2
• ⁢
• z
• 1
• -
• α
• 2
• where:
• q=1−p
• d is a constant no larger than 0.1, optimally no larger that 10% p
• z1−α is a random variable of the normal distribution dependent on the confidence factor 1−α, which is not less that 0.95
• e) the bacteriophage strains is selected which fulfils the criterion in d) and has a value of p not less than 2/n, optimally not less than 0.5.