Effect of Different Extraction Solvents on the Antimicrobial Activity of Psidium Guajava (Guava) Leaves against Multi-Drug Resistant Bacteria Implicated in Nosocomial Infections

Abstract

This present work was designed to investigate the effect of different extraction solvents on the antimicrobial activity of Psidium guajava leaves against some multidrug resistant bacteria in nosocomial infections. The MDR isolates such as Pseudomonas aeruginosa, Escherichia coli, Staphylococcus epidermidis, Proteus mirabilis, Staphylococcus saprophyticus and Bacillus cereus were obtained from Microbiology department culture collection of Department of Microbiology University of Ibadan Nigeria and their identities reconfirmed using biochemical methods. The antimicrobial activities of the different solvent extracts were tested using agar well diffusion method while the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) of the extracts were monitored using the double fold dilution method. The results reconfirmed the identities of the bacteria as Pseudomonas aeruginosa, Escherichia coli, Staphylococcus epidermidis, Proteus mirabilis, Staphylococcus saprophyticus and Bacillus cereus. Methanol extracts at a concentration of 160 mg/ml showed the highest inhibition zone of 10.0±0.1mm followed by ethyl acetate extract with 8.0±0.6mm inhibition zone against E.coli which were significantly different (P<0.05) while Nhexane, cold and hot water showed zero inhibition zones. Ofloxacin and DMSO. showed 20.0±0.and 0.00 mm inhibition zones respectively. This trend was observed at all the other concentrations. Methanol and ethyl acetate had MIC of 40.0 mg/ml for E. coli, S. saprophyticus, P.aeruginosa and B. cereus and they showed MBC of 80.0mg/ml for E. coli, S. saprophyticus, P.aeruginosa and B. cereus and MBC of 40.0 mg/ml for S. Epidermidis. Methanol and ethyl acetate extracts could be employed in the treatment of bacterial infections caused by MDR bacteria.Contribution/Originality: The paper's primary contribution is finding that Psidium guajava (guava) leaf extracts can be used for the treatment of some multi-drug resistant bacteria implicated in nosocomial infections.Methanol and ethyl acetate extracts of the leaves possess the greatest antimicrobial activity due to the high sensitivity of the MDR organisms.

Psidium guajava L.: From byproduct and use in traditional Mexican medicine to antimicrobial agent

“…It should be noted that a proper comparison between studies cannot be made, even if similar methodologies were used, since each author established the MIC differently, for example, Soliman et al ( 41 ) defined MIC as the lowest concentration that had granular appearing micro-colonies of growth instead of filamentous radiating colonies on solid agar; while for Hemeg et al ( 68 ) MIC was the lowest concentration of extract that resulted in no visible growth on the surface of the agar. In addition, we can also find multiple differences between the methods to measure the antimicrobial effect, for example, dos Santos et al ( 44 ) used a 0.1% resazurin solution, while Festus et al ( 67 ) analyzed bacterial growth based on turbidity.…”

“…However, the highest dose used in the studies analyzed was 160 mg/ml (160,000 ug/ml) by Festus et al ( 67 ), but the highest reported MIC was 40 mg /ml (40,000 ug/ml) for the bacteria Pseudomonas aeruginosa, Bacillus cereus, and Escherichia coli ( 67 ).…”