Anti-staphylococcal and antibiotic-potentiating activities of botanicals from nine Cameroonian food plants towards multidrug-resistant phenotypes

Abstract

Background: Staphylococcus aureus is a commensal and pathogenic bacterium responsible for both community and nosocomial infections, superficial or deep, and benign or lethal. Staphylococcus aureus is a commensal and pathogenic bacterium responsible for both community and nosocomial infections, superficial or deep, and benign or lethal. Because of its infectious potential and its ability to develop resistance to many antibiotics, staphylococcal infections remain the target of reinforced clinical surveillance. To contribute to the fight against resistant staphylococcal infections, the in vitro assessment of the anti-staphylococcal activity of methanol extracts (or botanicals) of nine food plants from Cameroon, Persea americana, Psidium guajava, Syzygium jambos, Vernonia amygdalina, Citrus sinensis, passiflora edulis, Carica papaya, Aframomum letestuanum, and Garcinia kola), as well as the effects of the association of some of these botanicals with antibiotics against resistant and multidrug-resistant staphylococci. Methods: The plant secondary metabolites were extracted by maceration in methanol; the microdilution method using the rapid para-Iodonitrotetrazolium chloride (INT) colorimetric method was applied to evaluate the antibacterial activities of the botanicals as well as the effects of combining these extracts with antibiotics. Results: The botanicals had a minimum inhibitory concentration (MIC) range of 64-2048 µg/mL on the 17 staphylococcal strains and isolates tested. Extracts from Aframomum letestuanum seeds and Psidium guajava leaves and bark had the broadest activity spectra, inhibiting the growth of 95% and 85% of the studied bacteria, respectively. In the presence of an efflux pump inhibitor, reserpine, methanol extracts from Syzygium jambos leaves, Psidium guajava bark and epicarp, and Afromomum letestuanum epicarp showed a considerable increase in their activity. Botanicals from the leaves of Syzygium jambos improved the activities of tetracycline, ceftriaxone, chloramphenicol, and ampicillin against more than 80% of the tested bacteria. Conclusion: The investigated pants, mostly Psidium guajava, Syzygium jambos, and Aframomum letestuanum could be used in the treatment of staphylococcal infections with multidrug-resistant phenotypes.