Abstract
Vibrio cholerae is a cause of serious endemic diarrhoea associated with cholera in many regions in the world. A total of 256 stool and rectal
swabs were collected from patients suspected to have cholera admitted to three hospitals in Hillah, Babylon Governorate, Iraq, for the period
1 September to 29 December 2017. After the routine culture of samples for isolation and identification of V. cholerae isolates, PCR was
performed for molecular detection of V. cholerae isolates based on 16S ribosomal RNA gene. Toxigenicity was detected by RTX toxin
genes. PCR technique emphasized molecular detection of V. cholerae for eight isolates. Only two isolates (25%) possessed both the rtxA
and rtxC genes, while only three isolates (37.5%) possessed the rtxB gene. DNA sequencing was performed for the eight isolates via
analysis and phylogenetic tree. The observed bacterial variants were compared to their neighbour homologous reference sequences using
the National Center for Biotechnology Information (NCBI) BLAST server (Basic Local Alignment Search Tool; https://blast.ncbi.nlm.nih.
gov/Blast.cgi). The findings indicated that the eight investigated isolates of V. cholerae were positioned in three different phylogenetic
positions. Partial sequence dissimilarities were reported between GenBank isolate accession number MK212155.1 and these six clustered
GenBank accession numbers of the same species. For the first time in Babylon Governorate, Iraq, the molecular assay, sequencing and
phylogenetic tree are reported for V. cholerae and their toxins isolated during the 2017 cholera outbreak.
© 2020 The Authors. Published by Elsevier Ltd