Fabrice Ezo’o Mengo¹, Jean Paul Assam Assam^{1, 2}, Sylvain Leroy Sado Kamdem¹, Jean Justin Essia Ngang^1,

Introduction: In Cameroon, many medicinal plants are used to treat typhoid fever. However, studies have shown that some of these plants can induce resistance to antibiotics used against Salmonella Typhi (S. Typhi). The mechanisms by which this resistance is acquired are not clear. This article aims to determine the mechanisms of antibiotic resistance acquisition in S. Typhi strains exposed to medicinal plant extracts. Methods: Two plant extracts, Enantia chlorantha and Irvingia gabonensis, were used to induce antibiotic resistance in S. Typhi. The antibiotics tested were: Ciprofloxacin, Amoxicillin, Chloramphenicol, Gentamicin, and Cotrimoxazole. Five genes were searched for by PCR in the genome of S. Typhi samples obtained after exposure to plant extracts. These were: blaTEM and blaSHV, coding for resistance to β-lactam antibiotics; sul1, coding for resistance to sulfonamides; floR, coding for resistance to phenicols; and int1, coding for resistance to multiple antibiotics. Results: The results demonstrated that, S. Typhi exposed to the plant extracts Enantia chlorantha and Irvingia gabonensis exhibited the presence of genes sul1, floR, and int1. However, the absence of these genes in the unexposed control strain indicated that plant extracts are able to induce antibiotic resistance through genetic mutation. The blaSHV gene was not detected in any of the S. Typhi samples, in contrast to the blaTEM gene, which was present in all samples, including the control. Conclusion: Mechanisms other than genetic mutations need to be assessed to better understand how medicinal plants induce antibiotic resistance.

Salmonella Typhi, medicinal plants, antibiotics, mechanisms, resistance, genes