In-vitro Antimicrobial Activity of the Combined Effect of Kalanchoe crenata and Vernonia amygdalina on Salmonella Species

Introduction: The breakthrough in the treatment of pathogenic diseases was the unearthing of naturally occurring antipathogenic agents or antibiotics. There have been upsurges in antibiotic-resistant strains of clinically important pathogens, which made way to the emergence of new-fangled bacterial strains that are multi-resistant. The major aim of scientists is to develop new antibiotics or other therapeutic strategies at a pace greater than that at which bacteria are developing resistance. The development of resistance to first-line antimicrobial therapies made way to recommendations for combination therapies for the treatment of some infections and some of this form of chemotherapy seems to be very successful.

Objectives: This research was carried out to determine the effect of Kalanchoe crenata extracts on Salmonella typhi load. Also, to assess the potency of the extract of Vernonia amygdalina on Salmonella typhi and finally to ascertain the effect of the combined extract of Kalanchoe crenata and Vernonia amygdalina on Salmonella typhi.

Methods: In this research, Salmonella typhi was exposed to a crude extract of Kalanchoe crenata and Vernonia amygdalina and also the combination of the two extracts. Agar wells diffusion method was employed.

Results: The combined effect was not sensitive to the Salmonella strain. The Salmonella strain was resistant to V. amygdalina than to K. crenata. K. cranata had the strongest activity against S. typhi with its highest zone of growth inhibition of 20 mm and lowest zone of inhibition of 7 mm while V. amygdalina produced a consistent zone of growth inhibition of 5-6 mm; The combined effect produced a zone inhibition diameter only at the 100 mg/ml with a zone of inhibition value of 14 mm. The subsequent lower concentrations did not show any activity against the microbes. At P-value = 0.05 two-way ANOVA statistics exhibited significant differences amongst the effects produced by the different extracts, though there were no substantial differences in the effects produced by the various concentrations.

Conclusion: The Salmonella strain was resistant to V. amygdalina than to K. crenata. At P-value = 0.05 there was a substantial difference in the sensitivity of the bacteria to the different extracts.