Properties of the R factor R144drd3 inKlebsiella pneumoniaestrain M5a1

Abstract

SUMMARYThe R factor, R144drd3, mobilized chromosomal genes inKlebsiella pneumoniaestrain M5a1 at similar frequencies to those observed for this R factor inEscherichia coliK12. In a derivativeK. pneumoniaedonor, strain HF3, R144 persisted in the autonomous state but now gave rise to polarized transfer of the chromosome in the order Ohis…arg2…leu…trp. R144drd3 was unstable inK. pneumoniaeM5a1; after successive subculture drug resistance, colicinogeny and transmissibility were lost. In strain HF3, transmissibility was preferentially lost, but determinants for drug resistance, colicinogeny and superinfection immunity were retained; 10–11 copies per chromosome of R144 were present in log phase cultures of both strains.