Vibrio cholerae O139 requires neither capsule nor LPS O side chain to grow inside Acanthamoeba castellanii

Abstract

Vibrio cholerae, the causative agent of cholera, has the ability to grow and survive in the aquatic free-living amoebaAcanthamoeba castellanii. The aim of the present study was to examine the ability of the clinical isolateV. choleraeO139 MO10 to grow inA. castellaniiand to determine the effect of the bacterial capsule and LPS O side chain on intracellular growth. Results from co-cultivation, viable counts, a gentamicin assay, electron microscopy and statistical analysis showed that the association ofV. choleraeO139 MO10 withA. castellaniidid not inhibit growth of the amoeba, and enhanced growth and survival ofV. choleraeO139 MO10 occurred. The wild-typeV. choleraeO139 MO10 and a capsule mutant or capsule/LPS double mutant grew insideA. castellanii. Neither the capsule nor the LPS O side chain ofV. choleraeO139 was found to play an important role in the interaction withA. castellanii, disclosing the ability ofV. choleraeto multiply and survive insideA. castellanii, as well as the role ofA. castellaniias an environmental host forV. cholerae.