Antibacterial activity of Argemone mexicana L. against multidrug resistant Pseudomonas aeruginosa, isolated from clinical samples

Objective To monitor the antipseudomonad activity of the weed Argemone mexicana ( A. mexicana ), with multidrug strains isolated from clinical samples. Methods Antibiogram of isolated strains were done with disc diffusion method and antipseudomonad activity was monitored with the agar well diffusion method. Results Twenty seven strains of Pseudomonas aeruginosa ( P. aeruginosa ) were isolated from clinical samples from a hospital; among them, 22 were resistant to antibiotics (μ/disc): cefotaxime-30, 16 to amoxyclav-30, 15 to ofloxacin-5, 13 to gentamicin-10, 10 to piperacillin-100/tazobactam-10, 8 to amikacin-30, 7 to gatifloxacin-30, 6 to netilmicin-30, 4 to piperacillin100, 3 to imipenem-10 and 3 strains to nitrofurantoin-300. Each strain was resistant to several antibiotics at specified levels. Of these 27 clinical strains, 15 antibiotic-resistant strains and a antibiotic-sensitive standard strain were used in monitoring antimicrobial activity of leaf-extracts using 3 organic solvents (acetone, methanol and ethanol) and water of the weed, prickly poppy ( A. mexicana L.). The methanol-extract had the highest level of antipseudomonad activity both with cold and hot extracts, confirmed by separate Kruskal-Wallis H tests. With the Student's t -test it was ascertained that the hot extraction concentrate yielded promising antipseudomonad activity than the cold extraction with methanol. Values of minimum inhibitory concentration (MIC) of extracts of A. mexicana using acetone, methanol and ethanol as solvents were 10, 8 and 8 mg/mL, respectively; corresponding values of minimum bactericidal concentration (MBC) were 32, 28 and 24 mg/mL for these solvents, respectively. Conclusions This study suggests that A. mexicana leaf can be used as complementary medicine in treating diseases caused by multidrug resistant strains of P. aeruginosa .