Assessment of the antimicrobial effect of three plants used for therapy of community-acquired urinary tract infection in Rio Grande do Sul (Brazil).

ETHNOPHARMACOLOGICAL RELEVANCE: The urinary tract infections (UTI) are among the infectious diseases of bacterial origin most commonly diagnosed, and may result in a significant mortality. The microorganisms most frequently involved in community-acquired infections are Escherichia coli and Klebsiella pneumoniae, both Gram-negative bacillus of the Enterobacteriaceae family. In southern Brazil, it is common the treatment of UTI using herbs and teas, a tradition inherited from the ancient indigenous people. Nevertheless, there is still poor scientific information about the action of these plants. MATERIALS AND METHODS: Tests included the determination of minimum inhibitory concentration (MIC) by microdilution method at concentrations of 5000-156.25 µg/µL, and evaluation of antimicrobial activity by agar disc diffusion method at concentrations 500-12.5 µg/µL, against the microorganisms Escherichia coli and Klebsiella pneumoniae. RESULTS: In the tests for MIC and antimicrobial activity by disc diffusion method in agar, the growth of Escherichia coli and Klebsiella pneumoniae isolates were not inhibited by extracts from Piptochaetium montevidense, Bulbostylis capillaris and Juncus capillaceus employed in the study. CONCLUSIONS: Despite the popular use of the plants used in this study, there is no relation between the use and the expected antimicrobial activity. Prolonged use of these plants may worsen the disease and lead to kidney involvement, and in severe cases, lead to death.