Abstract

Objective: In the search for potent antimicrobial agents against bacteria and other microbial infections t his study evaluated the antibacterial properties of millipedes e xtracts against selected control strains of bacterial path ogens including Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli , and Klebsiella pneumon iae. Methods: Two species of millipedes were identified as Ophistreptus guineensis S. (Diplopoda: Spirostreptidae) and Pachybolus ligulatus V. (Diplopoda: Pachybolidae) were collected from the University of Ghana Bo tanical Gardens and placed into 3 groups - Group 1 = O. guineensis alone, Group 2 = P. ligulatus alone, and Group 3 = mixture of O. guineensis + P. ligulatus . The millipedes were killed, dried, and grounded into coarse powders. Chloroform, ethanol, aqueous extracts were prepared and screened for act ivity using agar well and paper-disc diffusion assays. Minimum inhibitory and bactericidal co ncentrations (MIC and MBC) of the most active extracts were also evaluated by the broth micro-dilution tec hnique. Results: Ethanol extracts of Group 3 ( mixture of O. guineensis + P. ligulatus ) showed the highest activity , with mean diameters of zones of inhibition of 29 ± 0.02 and 14 ± 0.00 mm against S. aureus and E. coli respectively. No activity was observed for Group 2 extracts (P. ligulatus alone), while some level of activities were o bserved for Group 1 extracts ( O. guineensis alone). MIC and MBC values of 4.9 and 25.0 mg/ml of the ethanol extract of Group 3 were found against S. aureus. Conclusions: Work is in progress to isolate the bioactive agent(s) in millipede extracts.