Identification of cholix toxin gene in Vibrio cholerae non-O1/non-O139 isolated from diarrhea patients in Bushehr, Iran

Marziyeh  Gholizadeh Tangestani; Jafar Alinezhad; Abdolmohammad Khajeian; Somayyeh Gharibi; Mohammad Ali Haghighi

doi:10.18502/ijm.v12i4.3929

Marziyeh Gholizadeh Tangestani
Jafar Alinezhad
Abdolmohammad Khajeian
Somayyeh Gharibi
Mohammad Ali Haghighi

DOI: https://doi.org/10.18502/ijm.v12i4.3929

Keywords: Vibrio cholerae; Cholix toxin; Polymerase chain reaction

Abstract

Background and Objectives: Cholixin (cholix toxin) is a novel exotoxin in Vibrio cholerae identified as an elongation factor II specific ADP-ribosyltransferase which inhibits protein synthesis in the eukaryotic cell. Previous researches have suggested that cholixin probably is an important virulence factor in non-O1/non-O139 V. cholerae (NAG) serotypes that could be related to extra-intestinal rather than intestinal infections. This study was aimed to investigate the frequency and genetic diversity of colixin gene (chxA) in clinical V. cholerae NAG isolates.

Materials and Methods: The presence of chxA gene in 44 clinical V. cholerae NAG isolates were screened using PCR through specific primers designed for the receptor-binding domain (RBD) of chxA gene. The five PCR products of chxA gene were sequenced.

Results: This study showed that chxA gene presented in 19 V. cholerae NAG isolates. The sequences analysis of 5 out of 19 the partial chxA genes amplicon showed that 4 of them belonged to chxA I and the other one belonged to chxA II subtypes. Two distinct clusters were revealed for these isolates by phylogenic analysis, too.

Conclusion: The chxA gene contained high frequency among V. cholerae NAG isolates in Bushehr, Iran. The polymorphism study on RBD of cholixin gene is suggested as an appropriate method for phylogenic characterization of the various chxA gene subtypes.