The chicken embryo as a model for campylobacter invasion: comparative virulence of human isolates of Campylobacter jejuni and Campylobacter coli

Abstract

Eleven-day-old chicken embryos were used to compare the relative virulence of minimally passaged human isolates of Campylobacter jejuni and Campylobacter coli. Graded doses of bacteria were inoculated onto the chorioallantoic membrane, and 50% lethal doses were calculated at 72 h postinfection. Strains varied markedly in their ability to invade the chorioallantoic membrane and kill the embryos. The 50% lethal doses varied by about 6 logs for 25 strains of C. jejuni, and by 2 logs for 5 strains of C. coli. Although both outbred and inbred embryos were employed in the study, the latter were found to be more susceptible to infection with most strains. All isolates were screened for plasmid DNA, but there was no apparent relationship between plasmid content and virulence of strains for the embryos. Neither could virulence be associated with the production of siderophores by the strains. The ability of selected strains of C. jejuni to invade the liver of embryos was also studied. The number of campylobacters culturable from the liver was found to be inversely related to the 50% lethal dose of the strain. By inoculating 11-day-old embryos intravenously, it was possible to demonstrate that a strain of C. jejuni which was poorly virulent after chorioallantoic inoculation was relatively noninvasive. Invasiveness alone, however, could not fully account for the lethality of two highly virulent strains of C. jejuni administered by the intravenous route. Finally, there was no correlation between motility and virulence in this model system.

Human immune response to Campylobacter jejuni proteins expressed in vivo

“…These proteins have been shown to be extremely important in resistance to serum bactericidal activity and resistance to phagocytosis. The virulence of C.jejuni has been reported to be increased by passing it through chicken embryos (15).…”

“…There have been reports regarding change in the expression of * Corresponding author. proteins and also in the virulence of several organisms, including C. jejuni, Vibrio cholerae, and Mycoplasma dispar, by modification of growth conditions in vivo and in vitro (3,15,20,21). In this paper, we describe the reaction of the human volunteer immune sera to proteins from C. jejuni grown under standard microaerophilic conditions and also to novel proteins from C. jejuni that were expressed in vivo in rabbit ileal loops.…”

A two‐year study of the distribution of ‘thermophilic’ campylobacters in human, environmental and food samples from the Reading area with particular reference to toxin production and heat‐stable serotype

“…In addition to epidemiological studies, there has been a considerable number of reports describing potential pathogenic traits in C. jejuni and C. coli using in-vivo or in-vitro techniques Such reports include the use of animal models. Several potential models have been described including newly hatched chicks (Sanyal et al 1984;Welkos 1984), chicken embryos (Davison & Solomon 1980;Field et al 1986), hamsters (Humphrey et at. 1985), various strains of mice (Blaser et al 1983;Kazmi et al 1984;Stewart-Tull et al 1984;Newell 1986;Yrios & Balish 1986), and rabbits (Caldwell & Walker 1986).…”

Adhesion to and invasion of HEp-2 cells by Campylobacter spp

“…Blood and leukocytes have frequently been observed in the feces of patients diagnosed or infected with C. jejuni (3,11). Direct tissue invasion is further supported by in vivo models (13,17,35). Intracellular organisms have been observed by immunofluorescence and electron microscopy in infected chickens (35,36).…”