Isolation, selection, and characterisation of sponge-associated actinobacteria against Staphylococcus aureus in the Kien Giang sea area

Abstract

The aim of this study is to isolate, select, and characterise some strains of sponge-associated actinobacteria against Staphylococcus aureus in the Kien Giang sea area. Actinobacteria were isolated on the starch casein agar medium and were evaluated for antibacterial activity by the agar well diffusion method. A total of 198 actinobacterial strains were isolated from 63 sponge samples in the area of Kien Giang sea, Vietnam. The results of the antibacterial activity found that 22 isolates had the ability to resist S. aureus. Based on the level of the resistance, 1 isolate was found at strong level (4.5%), 12 isolates at medium level (54.5%), and 9 isolates at weak level (40.9%). Six actinobacterial strains having the highest resistance ability to S. aureus were characterised as follows Streptomyces variabilis (N10b), Streptomyces ambofaciens (N1a), Streptomyces recifensis (N5c), Streptomyces griseoaurantiacus (H6b), Gordonia bronchialis (H6a), and Microbacterium binotii (HD2.3e) by polymerase chain reaction (PCR) method and 16S rRNA gene sequencing with SC-Act-0235-aS-20 and SC-Act-0878-aA-19 primers.