Obiukwu, C.E. and Nwanekwu, K.E.
Department of Microbiology, Imo state University, Owerri, Owerri, Nigeria
The in-vitro antimicrobial activities of five local Nigerian spices- Monodora myristica, Tetrapleura tetraptera, Zingiber officinale, Piper guineense and Xylopia aethiopica against enteric pathogens- Escherichia coli, Salmonella typhi, Shigella flexneri and Staphylococcus aureus were investigated. The ethanol extract showed varied degree of activity with zones of inhibition ranging from 10mm to as much as 26mm for various organisms. The minimum inhibitory concentration (MIC) and minimum bacteriocidal concentrations (MBC) were also determined using the broth dilution method. The MICs ranged from 62.5μg/ml to >1000μg/ml and MBCs values in the range of 500μg/ml to 1000μg/ml for the plant extracts. The crude extract of T. tetraptera was the least active, having inhibitory effects only against two organisms E. coli and S. aureus. P. guineense recorded the strongest antimicrobial activity as shown by the largest diameter of the zones of inhibition exhibited and lowest MIC values.
Keywords: In-vitro, antimicrobial, species, enteric, pathogens, concentration.