Evaluation of antimicrobial activity of the endophytic actinomycete R18(6) against multiresistant Gram-negative bacteria

Carvalho, Tiele da Silva; Sand, Sueli Terezinha Van der

doi:10.1590/0001-3765201620140655

Cited by 4 publications

(1 citation statement)

References 27 publications

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“…However, that extract did not stand treatment at 100°C, as its activity started to drop after 3 minutes and was completely lost after 30 minutes. The author suggested the presence of peptide bonds in the molecule of that substance [ 32 ]. Since the substance produced by our strain Streptomyces sp.…”

Section: Resultsmentioning

confidence: 99%

Biological Characteristics and Antimicrobial Activity of EndophyticStreptomycessp. TQR12-4 Isolated from EliteCitrus nobilisCultivar Ham Yen of Vietnam

Hong-Thao

Mai-Linh

Hong-Lien

et al. 2016

International Journal of Microbiology

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Ham Yen orange (Citrus nobilis Lour) is the highly valuable commercial fruit of Vietnam. With the blooming of fruit production and farming area, this specialty crop is facing threats from several serious diseases; therefore the search for new effective biocontrollers is required to prevent the existing excessive use of fertilizers and plant protection chemicals. Endophytic actinomycetes are of great scientific interest due to their high potential of application in agriculture and pharmaceutical research. In this work, endophytic actinomycetes were isolated from a native orange species of Northeast mountainous province Tuyen Quang. Among 49 isolates obtained, the isolate TQR12-4 strongly inhibited test pathogens Colletotrichum truncatum, Geotrichum candidum, Fusarium oxysporum, and F. udum. This isolate gave comparatively high biomass yields on different substrates, for example, carboxy methyl cellulose, starch, protein, and chitin, within a wide range of temperature from 15 to 45°C and pH from 4 to 10. Sequence analysis of 16S rDNA gene showed that TQR12-4 shared 99% similarity to Streptomyces prasinopilosus; however, it slightly differed from the latter in spore morphology and hence was named as Streptomyces sp. TQR12-4. A thermostable antifungal substance of nonpeptide nature produced by Streptomyces sp. TQR12-4 had MIC against Fusarium udum of 100 μg/mL and 400 μg/mL respective to extract fractions X 4 and X 5.

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Section: Resultsmentioning

confidence: 99%

Biological Characteristics and Antimicrobial Activity of EndophyticStreptomycessp. TQR12-4 Isolated from EliteCitrus nobilisCultivar Ham Yen of Vietnam

Hong-Thao

Mai-Linh

Hong-Lien

et al. 2016

International Journal of Microbiology

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Actinomycin-Producing Endophytic Streptomyces parvulus Associated with Root of Aloe vera and Optimization of Conditions for Antibiotic Production

Chandrakar

Gupta

2018

Probiotics & Antimicro. Prot.

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Endophytic actinomycetes are a rich source of novel antimicrobial compounds. The aim of this study was to evaluate the production of antimicrobial compound by endophytic Streptomyces sp. Av-R5 associated with root of Aloe vera against multidrug-resistant human pathogens. The 16S rRNA sequence of the isolate Av-R5 has been identified as Streptomyces parvulus NBRC 13193 (AB184326) and the sequence was submitted to the National Center for Biotechnology Information (NCBI) GenBank database (accession number KY771080). Streptomyces parvulus Av-R5 grown under submerged fermentation condition optimized by central composite design (glucose 11.16 g/L, soybean meal 10.25 g/L, sodium chloride 11.18 g/L, calcium carbonate 1.32 g/L at pH 7.19 at 31.42 °C with 6.04% seed inoculum for 10 days of incubation) exhibited the highest activity against multidrug-resistant Staphylococcus aureus JNMC-3, Staphylococcus epidermidis JNMC-4, Klebsiella pneumoniae MTCC-3384, Klebsiella pneumoniae JNMC-6, Pseudomonas aeruginosa MTCC-741, Proteus vulgaris JNMC-7, Candida albicans MTCC-183, and Aspergillus niger MTCC-872. The structures of the active compounds were elucidated by UV-Vis spectroscopy, H andC NMR, FT-IR, and ESIMS. Actinomycin D and actinomycin X were detected in crude extracts and major components were eluted by HPLC at 10.96 and 6.81 min, respectively. In this case, a high yield of actinomycin D and actinomycin X (400 mg/L) was achieved with Streptomyces parvulus Av-R5, fermented in glucose soybean meal broth media, which can be used in industrial fermentation process to obtain high yields.

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Isolation and identification of promising antibiotic-producing bacteria

Sitotaw

Ayalew

Girma³

et al. 2022

Open Chemistry

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Multiple stresses in waste dumpsite soils can drive antibiotic production as one of the strategies for survival. Bacteria are the most prolific producers of antibiotics. This study investigated the antibiotic production potential of bacteria isolated from Bahir Dar city municipal solid waste dumpsite (MSWDS). Bacteria were isolated from soil collected from the dumpsite on starch casein or nutrient agar. The isolates were carefully screened for antimicrobial activity against six pathogenic bacterial test strains. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were also determined from cell-free metabolites of the most promising isolates. Isolates showing antimicrobial activity were identified using cultural and biochemical methods. A total of 143 distinctive colonies were obtained and tentatively identified to 13 bacterial genera. Twenty-six (18.18%) of the isolates (six Bacillus and 20 actinobacteria related) demonstrated antimicrobial activities at least against one of the tested bacterial strains. These isolates were related to two actinobacterial and 11 other bacterial genera. Seven out of 26 isolates showed a broad-spectrum of antibiotic activities. Two isolates, which showed a wide spectrum, were selected for the MIC and MBC tests against Escherichia coli and Staphylococcus aureus. The MIC and MBC of the isolates were recorded to be 250–500 µg/mL against the test strains. Bahir Dar city MSWDS contained a high incidence of antibiotic-producing bacteria. Strain level identification of the isolates and detailed characterization of the metabolites will give a good insight into the antimicrobial production potential in the waste dumpsite.

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Evaluation of antimicrobial activity of the endophytic actinomycete R18(6) against multiresistant Gram-negative bacteria

Cited by 4 publications

References 27 publications

Biological Characteristics and Antimicrobial Activity of EndophyticStreptomycessp. TQR12-4 Isolated from EliteCitrus nobilisCultivar Ham Yen of Vietnam

Biological Characteristics and Antimicrobial Activity of EndophyticStreptomycessp. TQR12-4 Isolated from EliteCitrus nobilisCultivar Ham Yen of Vietnam

Actinomycin-Producing Endophytic Streptomyces parvulus Associated with Root of Aloe vera and Optimization of Conditions for Antibiotic Production

Isolation and identification of promising antibiotic-producing bacteria

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