Open AccessVibrio cholerae O1 strains are facultative intracellular bacteria, able to survive and multiply symbiotically inside the aquatic free‐living amoeba Acanthamoeba castellanii
Author(s) -
Abd Hadi,
Saeed Amir,
Weintraub Andrej,
Nair G. Balakrish,
Sandström Gunnar
Publication year - 2007
Publication title -
fems microbiology ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.377
H-Index - 155
eISSN - 1574-6941
pISSN - 0168-6496
DOI - 10.1111/j.1574-6941.2006.00254.x
Subject(s) - vibrio cholerae , biology , microbiology and biotechnology , el tor , intracellular parasite , bacteria , viable but nonculturable , vibrionaceae , amoeba (genus) , genetics
Vibrio cholerae species are extracellular, waterborne, gram‐negative bacteria that are overwhelmed by predators in aquatic environments. The unencapsulated serogroup V. cholerae O1 and encapsulated V. cholerae O139 cause epidemic and pandemic outbreaks of cholera. It has recently been shown that the aquatic and free‐living amoeba Acanthamoeba castellanii is not a predator to V. cholerae O139; rather, V. cholerae O139 has shown an intracellular compatibility with this host. The aim of this study was to examine the ability of V. cholerae O1 classical and El Tor strains to grow and survive in A. castellanii . The interaction between A. castellanii and V. cholerae O1 strains was studied by means of amoeba cell counts and viable counts of the bacteria in the absence or presence of amoebae. The viable count of intracellularly growing bacteria was estimated by utilizing gentamicin assay. Confocal microscopy and electron microscopy were used to determine the intracellular localization of V. cholerae in A. castellanii . The results showed that V. cholerae O1 classical and El Tor strains grew and survived intracellularly in the cytoplasm of trophozoites, and that the bacteria were also found in the cysts of A. castellanii . The interaction showed a facultative intracellular behaviour of V. cholerae O1 classical and El Tor strains and a possible role of A. castellanii as an environmental host of V. cholerae species.