Diversity and Antimicrobial Activity of Vietnamese Sponge-Associated Bacteria.

Ton That Huu Dat,Pham Viet Cuong,Nguyen Thi Kim Cuc,Hauke Smidt,Detmer Sipkema

doi:10.3390/md19070353

Ton That Huu Dat, Pham Viet Cuong + Show 3 more

Open Access

https://doi.org/10.3390/md19070353

Copy DOI

Abstract

This study aimed to assess the diversity and antimicrobial activity of cultivable bacteria associated with Vietnamese sponges. In total, 460 bacterial isolates were obtained from 18 marine sponges. Of these, 58.3% belonged to Proteobacteria, 16.5% to Actinobacteria, 18.0% to Firmicutes, and 7.2% to Bacteroidetes. At the genus level, isolated strains belonged to 55 genera, of which several genera, such as Bacillus, Pseudovibrio, Ruegeria, Vibrio, and Streptomyces, were the most predominant. Culture media influenced the cultivable bacterial composition, whereas, from different sponge species, similar cultivable bacteria were recovered. Interestingly, there was little overlap of bacterial composition associated with sponges when the taxa isolated were compared to cultivation-independent data. Subsequent antimicrobial assays showed that 90 isolated strains exhibited antimicrobial activity against at least one of seven indicator microorganisms. From the culture broth of the isolated strain with the strongest activity (Bacillus sp. M1_CRV_171), four secondary metabolites were isolated and identified, including cyclo(L-Pro-L-Tyr) (1), macrolactin A (2), macrolactin H (3), and 15,17-epoxy-16-hydroxy macrolactin A (4). Of these, compounds 2-4 exhibited antimicrobial activity against a broad spectrum of reference microorganisms.

Highlights

IntroductionPublisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations
The 16S rRNA gene sequence analysis showed that cultivable bacteria from the Vietnamese sponges belonged to four phyla, which is much lower compared to the 15 phyla that were detected by direct Illumina MiSeq amplicon sequencing analysis of the same sponge samples [28]
The failure of obtaining the diverse bacteria associated with sponges by cultivation can be partially explained by the failure to mimic the natural growth conditions of sponge-associated bacteria in the laboratory

Summary

Introduction

Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. Antimicrobial resistance decreases the possibilities for prevention and treatment of infectious diseases caused by viruses, bacteria, parasites, and fungi. Factors listed as causes for the rising prevalence of antibiotic resistance include over-prescription of antibiotics both in hospitals and agriculture, poor infection control in hospitals and clinics, lack of hygiene, and poor sanitation [1,2,3,4,5]. Antibiotic resistance has considerable social and economic impact by the increase of morbidity and mortality of infectious diseases. It is estimated that approximately 700,000 people die every year from drug-resistant infections

Objectives

Methods

Results

Discussion

Conclusion