ISOLATION OF FC3-11, A BACTERIOPHAGE SPECIFIC FOR THE KLEBSIELLA-PNEUMONIAE PORIN OMPK36, AND ITS USE FOR THE ISOLATION OF PORIN-DEFICIENT MUTANTS

FC3-11, a bacteriophage specific for the Klebsiella pneumoniae porin OmpK36, was isolated by its ability to infect Escherichia coli strains expressing the cloned OmpK36 porin. Porin OmpK36 was shown to be the receptor for phage FC3-11 by the observations that K. pneumoniae and E. coli strains that do not express OmpK36 were resistant to phage FC3-11, the purified porin inactivated the phage, and mutants selected for FC3-11 resistance had lost OmpK36. The outer membrane protein OmpK35 was isolated from a K. pneumoniae phage-resistant mutant by using porin isolation methods and was shown to contain an N-terminal sequence typical of enterobacterial porins. Bacteriophage FC3-11, alone or in combination with previously described lipopolysaccharide-specific phages, is a valuable tool to obtain OmpK36-porinless mutants.