Susceptibility of Arcobacter butzleri to human blood serum.

, is a zoonotic bacterium isolated from mammals (dogs, cattle, monkeys, and swine) and domestic and wild birds (hens, turkeys, ducks, sparrows, and pelicans). It is recognized as an emerging enteric pathogen for human beings that could be also involved in extraintestinal infections such as bacteraemia and endocarditis (Kiehlbauch et al., 1991; Anderson et al., 1995; On et al., 1995; Jacob et al., 1998; Mansfield and Forsythe, 2000; Yan et al., 2000; Fernandez et al., 2007). Some of the virulence mechanisms of this bacterium have been studied, but the protective effects of normal serum and the role of complement in host defence remain to be evaluated. The protective effects of normal serum and the role of complement in host defence against invasive disease due to other enteropathogenic Gram negative bacteria, like