engleski

Coculture of amoeba Acanthamoeba castellanii and bacteria Campylobacter jejuni

Campylobacter jejuni is one of the leading causes of bacterial gastroenteritis in developed countries. C. jejuni has been isolated in water and has been proven to cause hydro-infections. It is also known that protozoa can influence the growth of different pathogenic bacteria, but little is known about the influence of free-living amobae on C. jejuni. In this study we explore the relationships during a coculture of Acanthamoeba castellanii and one strain of C. jejuni. A coculture of A. castellanii (ATCC 30234) trophozoites and C. jejuni in three different media (PYG, PY without glucose and PAGE media) at 37°C was established. After 24, 48 or 72 h, the cocultures were plated on blood agar to count CFU. For controls bacteria were incubated in the same conditions without amoebae. Moreover, at various times, the samples of the suspensions were examined by light microscopy. The number of adherent bacteria during 24 hours coculture in three diferent media was also tested. In the coculture experiments, the presence of A. castellanii induced a major increase in C. jejuni growth in PYG media and PY media without glucose, compared to the control. Decreased number of C. jejuni in PAGE media was detected. The results showed that C. jejuni well adhere on the amoeba and that the number of adherent bacteria increases during infection. In conclusion, the growth of C. jejuni is favored by A. castellanii under certain conditions. And therefore, in water systems, a special attention should be paid to the presence of free living amoebae, which can constitute a reservoir of C. jejuni in the environment.

Campylobacter; Acanthamoeba; interaction; reservoir of infection

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