Antimicrobial and antibiofilm potential of biosurfactants isolated from lactobacilli against multi-drug-resistant pathogens.

Karthik Sambanthamoorthy,Xiaorong Feng,Ruchi Patel,Sneha Patel,Chrysanthi Paranavitana

doi:10.1186/1471-2180-14-197

Karthik Sambanthamoorthy, Xiaorong Feng + Show 3 more

Open Access

https://doi.org/10.1186/1471-2180-14-197

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Journal: BMC microbiology	Publication Date: Aug 14, 2014
Citations: 229	License type: cc-by

Affiliation: Walter Reed Army Institute of Research

Abstract

BackgroundBiosurfactants (BS) are amphiphilic compounds produced by microbes, either on the cell surface or secreted extracellularly. BS exhibit strong antimicrobial and anti-adhesive properties, making them good candidates for applications used to combat infections. In this study, our goal was to assess the in vitro antimicrobial, anti-adhesive and anti-biofilm abilities of BS produced by Lactobacillus jensenii and Lactobacillus rhamnosus against clinical Multidrug Resistant (MDR) strains of Acinetobacter baumannii, Escherichia coli, and Staphylococcus aureus (MRSA). Cell-bound BS from both L. jensenii and L. rhamnosus were extracted and isolated. The surface activities of crude BS samples were evaluated using an oil spreading assay. The antimicrobial, anti-adhesive and anti-biofilm activities of both BS against the above mentioned MDR pathogens were determined.ResultsSurface activities for both BS ranged from 6.25 to 25 mg/ml with clear zones observed between 7 and 11 cm. BS of both L. jensenii and L. rhamnosus showed antimicrobial activities against A. baumannii, E. coli and S. aureus at 25-50 mg/ml. Anti-adhesive and anti-biofilm activities were also observed for the aforementioned pathogens between 25 and 50 mg/ml. Finally, analysis by electron microscope indicated that the BS caused membrane damage for A. baumannii and pronounced cell wall damage in S. aureus.ConclusionOur results indicate that BS isolated from two Lactobacilli strains has antibacterial properties against MDR strains of A. baumannii, E. coli and MRSA. Both BS also displayed anti-adhesive and anti-biofilm abilities against A. baumannii, E. coli and S. aureus. Together, these capabilities may open up possibilities for BS as an alternative therapeutic approach for the prevention and/or treatment of hospital-acquired infections.

Highlights

Biosurfactants (BS) are amphiphilic compounds produced by microbes, either on the cell surface or secreted extracellularly
Other BS with antimicrobial activity include iturin, produced by B. subtilis [4], mannosylerythritol lipids from Candida antarctica [5], rhamnolipids from Pseudomonas aeruginosa [6] and those isolated from probiotic bacteria Streptococcus thermophilus A and Lactococcus lactis [7,8,9]
Antimicrobial assay with BS The crude BS of both L. jensenii and L. rhamnosus were tested against two clinical isolates of Multidrug Resistant (MDR) A. baumannii, E. coli and S. aureus

Summary

Introduction

Biosurfactants (BS) are amphiphilic compounds produced by microbes, either on the cell surface or secreted extracellularly. Biosurfactants (BS) are amphiphilic compounds produced mostly by microbes on their cell surface, or secreted extracellularly and exhibit strong surface and emulsifying activities. They contain both hydrophobic and hydrophilic moieties that can reduce the surface or interfacial tension in liquids [1]. Other BS with antimicrobial activity include iturin, produced by B. subtilis [4], mannosylerythritol lipids from Candida antarctica [5], rhamnolipids from Pseudomonas aeruginosa [6] and those isolated from probiotic bacteria Streptococcus thermophilus A and Lactococcus lactis [7,8,9]. It was found that all released surface active components during their mid-exponential and stationary growth phases [6]

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