Genomic attributes of *Vibrio cholerae* O1 responsible for 2022 massive cholera outbreak in Bangladesh

In 2022, one of its worst cholera outbreaks began in Bangladesh and the icddr,b Dhaka hospital treated more than 1300 patients and about 42,000 diarrheal cases from March 1 to April 10, 2022. Here, we present genomic attributes of Vibrio cholerae O1 responsible for the 2022 Dhaka outbreak and 960 7th pandemic El Tor (7PET) strains from 88 countries. Strains isolated during the Dhaka outbreak cluster with 7PET wave-3 global strains but have distinct attributes corresponding to a 2021 emergence of the El Tor biotype with a most recent common ancestor linked to cholera outbreaks in India. BD-1 strains became prevalent in Bangladesh since 2016, but were not established over BD-2 lineage strains until 2018 and were predominantly associated with endemic cholera. In conclusion, the recent shift in lineage and genetic attributes, including serotype switching of BD-1.2 from Ogawa to Inaba, may explain the increasing number of cholera cases in Bangladesh.

Md Mamun Monir, Mohammad Tarequl Islam, Razib Mazumder, Dinesh Mondal, Kazi Sumaita Nahar, Marzia Sultana, Masamoto Morita, Makoto Ohnishi, Anwar Huq, Haruo Watanabe, Firdausi Qadri, Mustafizur Rahman, Nicholas Thomson, Kimberley Seed, Rita R. Colwell, Tahmeed Ahmed, Munirul Alam