Antimicrobial resistance of Vibrio cholerae O1 strains isolated during cholera epidemics in eastern Democratic Republic of Congo between January 2011 and June 2022

Abstract Background Although the mainstay of cholera treatment remains rehydration, treatment with antibiotics is recommended in serious forms and on specific sites. However, since the late 1970s, resistance to antibiotics in strains of Vibrio cholerae (Vc) has been observed and now threatens the effective treatment and control of cholera. Objective and Methods This cross-sectional, retro-prospective, descriptive and analytical study aims to describe the long-term evolution of the antibiotic resistance profile of Vibrio choleraeO1 strains isolated at the provincial public health laboratory of North Kivu during cholera epidemics in Eastern Democratic Republic of Congo (DRC) from January 1, 2011 to June 30, 2022. Results A total of 4832 isolates of Vibrio cholerae O1 were collected, more than half of them (72.46%, n=3175) in the province of North Kivu. Of the 3 serotypes, Vc O1 Inaba was the majority (57.6%, n=2522). Among the 4382 strains of Vc O1, very high levels of resistance were found to ampicillin (74.7%), nalidixic acid (83.8%), erythromycin (73.6%), chloramphenicol (68.8%) and Sulfamethoxazole/Trimethoprim (82%). A resistance of 30% (1316/4382) was found to doxycycline, a molecule recommended by the WHO as first-line in the treatment of cholera. We found 27 different resistance profiles (MDR) with respect to the 5 main molecules recommended in anticholera therapy. In the analytical study, we observed a statistically significant evolution over time (p=0.000) of these MDR profiles, including 5% in 2011 against nearly 40% between 2021 and 2022; with a distribution statistically dependent on age (p=0.0003) including 57.4% of cases in children under 15 (27% in those under 5); with a predominance (69%) in the province of North Kivu. Conclusion The resistance of Vibrio cholerae 01 to common antibiotics is high in eastern DRC and tends to increase over time. The abusive and inappropriate use of antibiotics is one of the major causes of this emergence of antimicrobial resistance. Close monitoring and measures for the proper use of antibiotics will be necessary to stem this scourge.