A highly drug-resistant strain of cholera appears to be spreading in East Africa, researchers reported yesterday in the New England Journal of Medicine.
In a letter to the editor, a team led by researchers from France's Institut Pasteur say the AFR13 7PET strain of Vibrio cholerae O1 is resistant to 10 antibiotics, including azithromycin and ciprofloxacin and third-generation cephalosporins. Azithromycin and ciprofloxacin are two of the three recommended antibiotics, in addition to doxycycline, for treating cholera.
Cholera causes severe diarrhea and dehydration that can quickly become life-threatening if not treated. While mild cases are primarily treated using oral rehydration solution, more severe cases may need antibiotics.
The AFR 7PET strain belongs to a lineage of V cholerae that was introduced into East Africa from South Asia in 2013-2014, the researchers say. But it was first identified in a massive cholera outbreak in Yemen that began in 2018 and sickened more than 2 million people. It was also confirmed in cholera cases in southern and eastern Lebanon in 2022.
Cases imported into Europe
Using data from cholera surveillance systems of several European countries, the researchers found that the AFR 7PET strain has now spread to East Africa.
They identified isolates belonging to the strain in European travelers returning from Kenya in 2023, and in 2024 in cholera patients on the French Island of Mayotte, which is located off the coast of southeastern Africa. The cases in Mayotte were initially in patients who had come from Tanzania and Comoros.
The researchers suspect that the strain has contributed to major cholera outbreaks in Kenya in 2022 and in Tanzania and Comoros in 2024 but say the extent of its involvement needs to be confirmed.
Global rise in cholera cases
The report comes amid a rise in global cholera cases that began in 2021. According to the most recent World Health Organization (WHO) update, 486,760 cholera and acute watery diarrhea cases and 4,018 deaths were reported from 33 countries across five WHO regions from January to October 27, 2024.
If the new strain that is currently circulating acquires additional resistance to tetracycline, this would compromise all possible oral antibiotic treatment.
Although the WHO report shows cases are down this year, the number of cholera deaths in October were 54% higher than in October 2023. The WHO says the spike in deaths may be attributed in part to where cholera outbreaks have occurred this year, such as conflict-affected areas where access to healthcare is compromised, regions where massive flooding has damaged critical infrastructure, and areas with inadequate medical facilities.
The authors of the letter say the findings call for real-time, transborder surveillance of the AFR13 7PET strain.
"This study demonstrates the need to strengthen global surveillance of the cholera agent, and especially to determine how it reacts to antibiotics in real time," senior author Francois-Xavier Weill, MD, PhD, said in an Institut Pasteur news release. "If the new strain that is currently circulating acquires additional resistance to tetracycline, this would compromise all possible oral antibiotic treatment."
