Serum resistance in Haemophilus ducreyi requires outer membrane protein DsrA.

ABSTRACT: Haemophilus ducreyi is resistant to killing by normal serum antibody and complement. We discovered an H. ducreyi outer membrane protein required for expression of serum resistance and termed it DsrA (for "ducreyi serum resistance A"). The dsrA locus was cloned, sequenced, and mutagenized. An isogenic mutant (FX517) of parent strain 35000 was constructed and characterized, and it was found to no longer express dsrA. FX517 was at least 10-fold more serum susceptible than 35000. DsrA was expressed by all strains of H. ducreyi tested, except three naturally occurring, avirulent, serum-sensitive strains. FX517 and the three naturally occurring dsrA-nonexpressing strains were complemented in trans with a plasmid expressing dsrA. All four strains were converted to a serum-resistant phenotype, inc

SUBMITTER: Elkins C 

PROVIDER: S-EPMC97321 | biostudies-literature | 2000 Mar

REPOSITORIES: biostudies-literature