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Evidence-Based Complementary and Alternative Medicine
Volume 2016, Article ID 1572697, 8 pages
http://dx.doi.org/10.1155/2016/1572697
Research Article

Antibacterial and Antibiofilm Activity of Methanolic Plant Extracts against Nosocomial Microorganisms

1Departamento de Química, Facultad de Ciencias Biológicas, Universidad Autónoma de Nuevo León, Ciudad Universitaria, 66451 San Nicolás de los Garza, NL, Mexico
2Departamento de Alimentos, Facultad de Ciencias Biológicas, Universidad Autónoma de Nuevo León, Ciudad Universitaria, 66451 San Nicolás de los Garza, NL, Mexico

Received 23 January 2016; Revised 16 May 2016; Accepted 9 June 2016

Academic Editor: Serkan Selli

Copyright © 2016 Eduardo Sánchez et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Biofilm is a complex microbial community highly resistant to antimicrobials. The formation of biofilms in biotic and abiotic surfaces is associated with high rates of morbidity and mortality in hospitalized patients. New alternatives for controlling infections have been proposed focusing on the therapeutic properties of medicinal plants and their antimicrobial effects. In the present study the antimicrobial and antibiofilm activities of 8 methanolic plant extracts were evaluated against clinical isolated microorganisms. Preliminary screening by diffusion well assay showed the antimicrobial activity of Prosopis laevigata, Opuntia ficus-indica, and Gutierrezia microcephala. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined ranging from 0.7 to >15 mg/mL. The specific biofilm formation index (SBF) was evaluated before and after the addition of plant extracts (MBC × 0.75). Opuntia ficus-indica caused the major reduction on SBF in dose-dependent manner. Cytotoxic activity of plant extracts was determined using brine shrimp lethality test (Artemia salina L.). Lethal Dose concentration (LD50 values) of the plant extracts was calculated. LD50 values for P. laevigata and G. microcephala were 141.6 and 323.3 µg/mL, respectively, while O. ficus-indica showed a slight lethality with 939.2 µg/mL. Phytochemical analyses reveal the presence of flavonoids, tannins, and coumarines.