Antimicrobial activity of garlic (Allium sativum ) on selected uropathogens from cases of urinary tract infection

Introduction: The etiologic agents of urinary tract infection (UTI) occur among both the Gram-positive and Gram-negative bacteria including those that exhibit resistance to commonly used standard antibiotics. Both the male and female individuals can be prone to developing UTI. Garlic (Allium sativum) has been associated with antibacterial activity, though with scanty reports on uropathogens. This study was, therefore, carried out to determine the antibacterial efficacy of aqueous and methanol extracts of garlic (A. sativum)in vitro against six uropathogens (Escherichia coli , Staphylococcus saprophyticus, Pseudomonas aeruginosa, Proteus spp., Klebsiella spp., and Serratia marcescens ) and a reference strain, E. coli ATCC-25922 . Materials and Methods: The bacterial isolates were collected from the Routine Microbiology Laboratory, University College Hospital, Ibadan, and were authenticated by Gram staining and some conventional biochemical tests. The isolates were then subjected to antimicrobial susceptibility testing against both the aqueous and methanol extracts of garlic. Phytochemical screening was also carried out on the plant. Results: Both aqueous and methanol extracts had maximum zones of growth inhibitions of 22 mm at 200 mg/mL and 25 mm at 200 mg/mL against E. coli, followed by P. aeruginosa with zones of growth inhibitions of 21 mm and 25 mm at the same concentration. Proteus spp., exhibited the lowest zones of growth inhibition of 16mm at 200mg/mL.and 10mm at 25mg/mL to methanol and aqueous extracts respectively. The minimum inhibitory concentrations MICs and MBCs of the aqueous and ethanol extracts of garlic varied for each organism. Escherichia coli had the MICs' of 100mg/mL and MBC of 220mg/mL while the MIC and MBC of the aqueous extract on the Proteus spp. are 100mg/mL and 320mg/mL respectively. The MBCs recorded were relatively higher in comparison to the MIC values. Conclusion: These findings showed that garlic could be of therapeutic use in the management of bacterial mediated UTI.