Published online by Cambridge University Press: 14 April 2009
Intergeneric recombination of chromosomal genes between strains of Klebsiella pneumoniae and Enterobacter aerogenes has been observed. In these experiments a male strain of K. pneumoniae acted as donor and E. aerogenes acted as recipient. Closely linked genes were co-transferred with very high frequency, and transfer of a large fragment carrying several separated genes was not uncommon. Subcultures of a hybrid which had received a large fragment carrying five markers were tested for genetic stability; no spontaneous segregants were found among 34000 colonies tested. These results suggest that the transferred fragment had been integrated, and indicate the close genetic relationship between K. pneumoniae and E. aerogenes. This is in agreement with their very similar biochemical properties.