ABSTRACT
OBJECTIVES: To determine the antimicrobial potential of marine actinomycetes against drug-resistant pathogens represented by strains of methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus faecalis (VRE). MATERIALS AND METHODS: Strains of actinomycetes (29) isolated from marine sediment were evaluated by their characteristics in two culture media and by testing their inhibitory capacity by in vitro antagonism against multi-drug resistant (MDR) pathogenic bacteria for MRSA and VRE. Organic extracts of 3 selected actinomicetes were processed to determine the minimum inhibitory concentration (MIC) of the active compound. RESULTS: Most isolated actinomycetes belong to a homogeneous group of write-gray actinomycetes with a good growth in Marine Agar. The inhibitory rates of the isolates were above 85% for both pathogens with inhibition zones greater than 69 and 78 mm in diameter for MRSA and VRE respectively. Dichloromethane extracts of 3 isolates (I-400A, B1-T61, M10-77) showed strong inhibitory activity of both pathogens, M10-77 being the highest actinomycete strain with antibiotic activity against methicillin-resistant S. aureus ATCC 43300 and vancomycin-resistant E. faecalis ATCC 51299 with a minimum inhibitory concentrations (MIC) of 7.9 and 31.7 µg/ml respectively. Phylogenetic analysis of M10-77 strain showed 99% similarity with the marine species Streptomyces erythrogriseus. CONCLUSIONS: Marine sediments of the central coast of Peru, are a source of actinomycetes strains showing high capacity to produce bioactive compounds able to inhibit pathogens classified as multi-drug-resistant such as methicillin-resistant S. aureus and vancomycin-resistant E. faecalis.
Subject(s)
Actinobacteria/physiology , Antibiosis , Enterococcus faecalis , Methicillin-Resistant Staphylococcus aureus , Actinobacteria/isolation & purification , Enterococcus faecalis/drug effects , Geologic Sediments/microbiology , Peru , Seawater/microbiology , Vancomycin/pharmacology , Water MicrobiologyABSTRACT
Objetivos. Determinar el potencial antimicrobiano de actinomicetos marinos frente a cepas S. aureus meticilino-resistentes (MRSA) y E. faecalis vancomicina-resistentes (VRE). Materiales y métodos. En dos medios de cultivo se sembraron 29 cepas de actinomicetos aislados de sedimento marino. Se evaluó la capacidad inhibitoria mediante pruebas de antagonismo in vitro para MRSA y VRE. Se procesó los extractos orgánicos de tres actinomicetos seleccionados para determinar la Concentración Mínima Inhibitoria (CMI) del compuesto activo. Resultados. La mayoría de los actinomicetos aislados correspondieron a un grupo homogéneo de blanco-grisáceos (62 por ciento) con buen nivel de crecimiento en agar marino. Los porcentajes inhibitorios fueron superiores a 85 por ciento para ambos patógenos con halos de inhibición mayores a 69 y 78 mm de diámetro para MRSA y VRE respectivamente. Los extractos diclorometánicos de tres de los actinomicetos aislados (I-400A, B1-T61, M10-77) mostraron gran potencial inhibitorio de ambos patógenos, siendo M10-77 la cepa de actinomiceto de mayor actividad antibiótica frente a S. aureus ATCC 43300 resistente a meticilina y E. faecalis ATCC 51299 resistente a vancomicina con una Concentración Mínima Inhibitoria (CMI) de 7,9 y 31,7 μg/ mL respectivamente. El análisis filogenético de la cepa M10- 77 presenta un 99 por ciento de similaridad con la especie marina Streptomyces erythrogriseus. Conclusiones. El sedimento marino de la costa central del Perú es fuente promisorio de cepas de actinomicetos con gran capacidad de producir compuestos bioactivos capaces de inhibir patógenos tipificados como multidrogo-resistentes tales como S. aureus meticilino resistentes y E. faecalis vancomicina resistentes.
Objectives. To determine the antimicrobial potential of marine actinomycetes against drug-resistant pathogens represented by strains of methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus faecalis (VRE). Materials and methods. Strains of actinomycetes (29) isolated from marine sediment were evaluated by their characteristics in two culture media and by testing their inhibitory capacity by in vitro antagonism against multi-drug resistant (MDR) pathogenic bacteria for MRSA and VRE. Organic extracts of 3 selected actinomicetes were processed to determine the minimum inhibitory concentration (MIC) of the active compound. Results. Most isolated actinomycetes belong to a homogeneous group of write-gray actinomycetes with a good growth in Marine Agar. The inhibitory rates of the isolates were above 85 percent for both pathogens with inhibition zones greater than 69 and 78 mm in diameter for MRSA and VRE respectively. Dichloromethane extracts of 3 isolates (I-400A, B1-T61, M10-77) showed strong inhibitory activity of both pathogens, M10-77 being the highest actinomycete strain with antibiotic activity against methicillin-resistant S. aureus ATCC 43300 and vancomycin-resistant E. faecalis ATCC 51299 with a minimum inhibitory concentrations (MIC) of 7.9 and 31.7 μg/ml respectively. Phylogenetic analysis of M10-77 strain showed 99 percent similarity with the marine species Streptomyces erythrogriseus. Conclusions. Marine sediments of the central coast of Peru, are a source of actinomycetes strains showing high capacity to produce bioactive compounds able to inhibit pathogens classified as multi-drugresistant such as methicillin-resistant S. aureus and vancomycin-resistant E. faecalis.
Subject(s)
Actinobacteria/physiology , Antibiosis , Enterococcus faecalis , Methicillin-Resistant Staphylococcus aureus , Actinobacteria/isolation & purification , Enterococcus faecalis/drug effects , Geologic Sediments/microbiology , Peru , Seawater/microbiology , Vancomycin/pharmacology , Water MicrobiologyABSTRACT
En el presente trabajo evaluamos la actividad antibacteriana y antifúngica de actinomycetes marinos sobre patógenos de origen clínico. Asimismo, fueron evaluadas la capacidad de producir enzimas extracelulares como carbohidrasas, lipasas y proteasas. Los Actinomycetes fueron aislados de sedimentos colectados entre setiembre a diciembre del 2005 de las Bahías de Ancón (Lima) e Independencia (Ica) de 34 y 100 m de profundidad. El aislamiento se realizó en Agar Caseína - Almidón (ACA) y Agar Marino (AM) con adición de Cicloheximide (10 ng/mL). Las evaluaciones antimicrobianas fueron realizadas frente a bacterias patógenas antibiótico-multirresistentes y hongos de origen clínico; en tanto, para evaluar su actividad multienzimática se utilizaron sustratos poliméricos diversos. Se aislaron un total de 62 actinomycetes, de los cuales 31 (50 por ciento) mostraron actividad antibacteriana frente a Staphylococcus aureus, 36 (59 por ciento) frente a Pseudomonas aeruginosa y 23 (37 por ciento) a ambos patógenos. Las cepas de actinomycetes I-400A y M10-77 identificadas en cada caso como Streptomyces y Thermoactinomyces fueron las que exhibieron mayor actividad inhibitoria frente a P. aeruginosa y S. aureus respectivamente. Asimismo, 13 actinomycetes (20,97 por ciento) mostraron actividad antifúngica frente a cultivos de Candida albicans cepa 1511 y 17 (27,42 por ciento) frente a Candida albicans cepa 1511MIC; sin embargo, ningún actinomycete presentó actividad inhibitoria frente a Aspergillus niger, Aspergillus fumigatus y Trichophyton mentagrophytes. La mayoría de los actinomycetes mostraron tener actividad multienzimática capaz de hidrolizar compuestos poliméricos como el tween-80 (96 por ciento), la gelatina (95 por ciento), almidón (93 por ciento), lecitina (88 por ciento) y la caseína (74 por ciento).
In the present research we evaluated the antibacterial and antifungical activity of marine actinomycetes over pathogen of clinical origin. Likewise, it was evaluated the capacity to produce extracellular enzymes like carbohidrases, lipases and proteases. The Actinomycetes were isolated from sediments collected between September to December 2005 of Ancón (Lima) and Independencia (Ica) Bays at depths of 34 and 100 m. The isolation was performed in Casein - Starch Agar (CSA) and Marine Agar (AM) with addition of Cicloheximide (10 ng/mL). The antimicrobial evaluations were done comparing them with pathogenic antibiotic-multiresistant bacteria and fungi from clinical origin; in as much, to evaluate their multienzimatic activity several polimeric substrates were used. A total of 62 actinomycetes were isolated, 31 of there (50 per cent) showed antibacterial activity in opposite to Staphylococcus aureus, 36 (59 per cent) in opposite to Pseudomonas aeruginosa and 23 (37 per cent) to both pathogens. Strains of actinomycetes I-400A and M10-77 identified in each case like Streptomyces and Thermoactinomyces exhibited higher inhibitory activity against S. aureus and P. aeruginosa respectively. Also, 13 actinomycetes (20,97 per cent) showed to antifungical activity against cultures of Candida albicans strain 1511 and 17 (27,42 per cent) with Candida albicans strain 1511MIC; nevertheless, no actinomycete displayed inhibitory activity to the growth of Aspergillus niger, Aspergillus fumigatus and Trichophyton mentagrophytes. Most Actinomycetes showed to have multienzymic activity able to hydrolysis polymerics compounds like the tween-80 (96 per cent), gelatin (95 per cent), starch (93 per cent), lecitine (88 per cent) and casein (74 per cent).
