Pyocine Typing of Mucoid Strains of Pseudomonas Aeruginosa Isolated from Children with Cystic Fibrosis

SUMMARY The relationship between mucoid and non-mucoid strains of Pseudomonas aeruginosa isolated from the sputum of children with cystic fibrosis was investigated by typing the strains by pyocine production. The mucoid strains were usually untypable by the standard technique, but extraction and assay of the pyocines produced in liquid cultures showed that the strains belonged to recognised pyocine types. When mucoid and non-mucoid strains occurred simultaneously, they were of the same pyocine type; it is suggested that they are variants of the same strain.