The Effects of Selected Medicinal Plants on Non-Typhoidal Salmonella Isolated from Livestock and Humans in Abia State, Nigeria

Non-typhoidal Salmonellae (NTS) are among the bacteria currently ranking highest in multi-drug resistance globally.Antimicrobial resistance profile of some NTS isolates were studied in four farm animals namely: cow, poultry, goat and pig as well as their human handlers.According to Salmonella typing using polyvalent and monovalent antisera, 74 (4.6%) isolates out of the 1612 samples from these sources confirmed using PCR, were positive for non-typhoidal Salmonella species, 70 isolates were S. entrica Var Typhimurium, 3 Salmonella enteria Var Enteritidis, and 1 Salmonella Dublin.Three (3) medicinal plants -Vernonia amygdalina, Nanclea latifolia, and Pterocarpus santalinodes were identified and analyzed for their phytochemical constituents and antimicrobial activity against isolates.Alkaloids, flavonoids, saponnins, tannin, phenols and steroids were found in each of the plants.GC-MS analysis revealed 60 chemical constituents from each plant extract and 13 to 16 major constituents.Ethanolic extracts of the plants at different concentrations were tested against the isolates and compared with similar concentrations of ciprofloxacin.The zones of the inhibitions of the isolates at 50mg/ml of the extracts and commercial ciprofloxacin were 14.670.33,13.001.75,14.001.00,and 30.332.91 for Vernonia amygdalina (VA), Nanclea latifolia (NL), Pterocarpus santalinodes (PS), and Ciprofloxacin respectively for the cow isolates; 16.330.33,10.670.88,11.330.33,and 31.002.00for VA, NL, PS, Ciprofloxacin respectively against the goat isolates; 17.671.76,13.001.73,17.001.53and 30.332.91 respectively for V. amygdalina, N, latifolia, P. santalinoides and Ciprofloxacin respectively (human isolates); 17.001.73,15.672.96,15.001.73,and 27.004.04respectively for V. amygdalina, N. latifolia, P. santalinoides and Ciprofloxacin (pig isolates); 16.000.00,12.331.33,13.330.33,and 26.003.46respectively for V. amygdalina, N. latifolia, P. santalinoides, and Ciprofloxacin respectively against the poultry isolates.Ciprofloxacin demonstrated higher microbial inhibition than all concentrations of the plant extracts.