Unraveling the 2023 cholera outbreak in Rourkela municipal corporation of Odisha, India: Antibiotic resistance, virulence factors, and water contamination insights

Abstract

Background: In December 2023, a cholera outbreak was detected from Rourkela district, Odisha, prompted an investigation using field epidemiology methods and further research of the isolates from cases. The outbreak, likely was triggered by piped water contamination following unseasonal rainfall.

Materials and methods: A laboratory-based descriptive study, focused on the microbiological and molecular detection and characterization of 34 cases of acute diarrheal disease. Samples collected for bacteriological and molecular tests were investigated at ICMR-Regional Medical Research Centre, Bhubaneswar.

Results: Vibrio cholerae in 35 % and diarrhoeagenic E. coli in 23.5 % of samples, highlighting these as the primary pathogens. The causative agent was identified as V. cholerae El Tor strain (7PET) detected for the first time in the area. Antibiotic resistance was seen for ampicillin, tetracycline, azithromycin, and chloramphenicol with notable complete resistance to ciprofloxacin. This resistance was attributed to the presence of mobile genetic elements such as SXT ICE, conferring resistance through genes like dfrA1, sulII, tetA, tetG and flor. Essential virulence genes including ctxAB, toxR, tcpA, ace, and hlyA were found in 100 % of the V. cholerae strains, with zot present in 66.6 % of isolates.

Conclusion: This study highlights the evolving antibiotic resistance patterns and genetic factors contributing to V. cholerae virulence, providing pivotal breakthroughs in public health strategies aimed at controlling future outbreaks.

Keywords: Antibiotic resistance; India; MIC; Outbreak; Vibrio cholerae.