Potential of Ocimum sanctum to Inhibit the Growth of Pseudomonas aeruginosa, a Disease-causing microorganism

Aim and Objectives: Plants are a good source of secondary metabolites, which have huge potential to kill micro-organisms. The present study aimed to evaluate the antimicrobial activity of Ocimum sanctum ethanol extract against drug-resistant and drug-sensitive strains of Pseudomonas aeruginosa (P. aeruginosa). Materials and Methods: A total of 119 strains of P. aeruginosa, 92 multidrug-resistant (MDR) and 27 pan sensitive strains were included in the study, which were isolated from different human clinical samples. Ocimum sanctum crude leaves extract was prepared with the standard “cold extraction method”. The susceptibility agar dilution plates were made by mixing molten Mueller- Hinton Agar (MHA) media with plant extract in different quantities to get the final extract concentration of 0.2%, 0.1% and 0.05%. These plates were used for determining the sensitive/ resistance nature of all strains of P. aeruginosa against plant extract. Results: Among 92 MDR strains in MHA plates with 0.05% of plant extract, 59 strains were sensitive and 33 were resistant. The same MDR strains in MHA plate with 0.1% of the extract showed somewhat similar trends, 61 sensitive and 31 resistant. Whereas with 0.2% of the extract, 67 strains were sensitive, 11 showed resistance while 14 showed discrete colonies. Among 27 pan sensitive strains at 0.05% concentration, there was complete growth inhibition in 23, while discrete colonies were observed in 4, though, at 0.1% and 0.2%, all strains were found as sensitive. Conclusion: Analysis of the present study showed that Ocimum sanctum extract possess compounds with antimicrobial properties against commonly used isolates of Pseudomonas aeruginosa strains.