Isolation And Characterization Of Marine Actinomycetes For Anti-Infective Activity Towards Pseudomonas aeruginosa PA14
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Date
2018-05
Authors
Ahmad Kamal, Siti Nur Fatin
Journal Title
Journal ISSN
Volume Title
Publisher
Universiti Sains Malaysia
Abstract
Marine environment serve as reservoir of vast useful secondary metabolites and
at the same time, new anti-infective agents are required to combat antibiotic resistant
pathogenic bacteria.Therefore, this research was carried out to screen for anti-infective
agents from the environment that are capable of overcoming Pseudomonas aeruginosa
infection through anti-virulence or boosting of host immunity activities. Marine soil
sediments were collected from Songsong Island, Yan, Kedah, Malaysia and a total of 18
actinomycetes with different morphology were successfully isolated. Secondary
metabolites from all isolates were extracted out using solid-liquid extraction method and
were screened for anti-infective activity using Caenorhabditis elegans infection model.
Only extract from isolate A5 showed significant life-span promotion of the host. Thus, it
was used for further characterization and screening. Isolate A5 showed 99.7% molecular
sequence similarity to Streptomyces sundarbansensis MS1/7 and was designated as
Streptomyces sundarbansensis CCB-PSK207 due to morphological difference observed
under the same culture condition. It can withstand up to 10% (w/v) NaCl concentration
and it showed highest growth (referring to cell dry weight) at pH7 after ten days of
cultivation compared to pH4, pH5, pH6, pH8, pH 9 and pH10. Methanolic extract A5
was further partitioned by using liquid-liquid extraction method. n-hexane partition was
found to exhibit the best hit in survival assay. Dose response assay revealed that
400μg/mL was the best concentration with survivability rate change of 69.65±4.50% as
compared to controlled worms 96-hours post PA14 infection. Therefore, all screening
assays were progressed using that concentration.
Description
Keywords
Anti-infective agents from the environment , capable of overcoming Pseudomonas aeruginosa infection