Pathogenic Potential of Environmental Vibrio Cholerae Strains Carrying Genetic Variants of the Toxin-Coregulated Pilus Pathogenicity Island

TitlePathogenic Potential of Environmental Vibrio Cholerae Strains Carrying Genetic Variants of the Toxin-Coregulated Pilus Pathogenicity Island
Publication TypeJournal Articles
Year of Publication2003
AuthorsFaruque SM, Kamruzzaman M, Meraj IM, Chowdhury N, Nair BG, Sack BR, Colwell RR, Sack DA
JournalInfection and ImmunityInfect. Immun.
Volume71
Issue2
Pagination1020 - 1025
Date Published2003/02/01/
ISBN Number0019-9567, 1098-5522
Abstract

The major virulence factors of toxigenic Vibrio cholerae are cholera toxin (CT), which is encoded by a lysogenic bacteriophage (CTXΦ), and toxin-coregulated pilus (TCP), an essential colonization factor which is also the receptor for CTXΦ. The genes for the biosynthesis of TCP are part of a larger genetic element known as the TCP pathogenicity island. To assess their pathogenic potential, we analyzed environmental strains of V. cholerae carrying genetic variants of the TCP pathogenicity island for colonization of infant mice, susceptibility to CTXΦ, and diarrheagenicity in adult rabbits. Analysis of 14 environmental strains, including 3 strains carrying a new allele of the tcpA gene, 9 strains carrying a new allele of the toxT gene, and 2 strains carrying conventional tcpA and toxT genes, showed that all strains colonized infant mice with various efficiencies in competition with a control El Tor biotype strain of V. cholerae O1. Five of the 14 strains were susceptible to CTXΦ, and these transductants produced CT and caused diarrhea in adult rabbits. These results suggested that the new alleles of the tcpA and toxT genes found in environmental strains of V. cholerae encode biologically active gene products. Detection of functional homologs of the TCP island genes in environmental strains may have implications for understanding the origin and evolution of virulence genes of V. cholerae.

URLhttp://iai.asm.org/content/71/2/1020
DOI10.1128/IAI.71.2.1020-1025.2003