CONSTRUCTION AND CHARACTERIZATION OF RECOMBINANT VIBRIO-CHOLERAE STRAINS CARRYING HETEROLOGOUS GENES ENCODING NON-01 ANTIGEN OR CHOLERA ENTEROTOXIN

In an attempt to study the effect of heterologous genes on the virulen ce of Vibrio cholerae 01 and non-01, rfb genes encoding biosynthesis o f non-01 antigens were introduced by homologous recombination into the chromosome of V. cholerae 01 strain 569B (serotype Inaba, biotype cla ssical). Recombinant strains were obtained which were not agglutinated with the diagnostic cholera 01 antiserum and were not sensitive to th e cholera diagnostic bacteriophage, but produced as much cholera toxin as 569B and were highly virulent in the infant rabbit intra-intestina l injection model. These data indicate that the rfb genes from the stu died V. cholerae non-01 did not alter the virulence phenotype of V. ch olerae 01. In contrast, cloned ctxAB genes from V. cholerae 01 encodin g cholera toxin introduced into a non-pathogenic strain lead to effici ent secretion of cholera toxin but to only low virulence in the infant rabbit model. (C) 1995 Academic Press Limited