Antimicrobial, antiadhesive and antibiofilm potential of lipopeptides synthesised by Bacillus subtilis, on uropathogenic bacteria

Abstract

The aim of this study was to investigate the antimicrobial effect of lipopeptide biosurfactants from surfactin, iturin and fengycin families, synthesised by the Bacillus subtilis I'1a strain, on uropathogenic bacteria, including the effects on planktonic growth, processes of biofilm formation and dislodging. Antimicrobial activity was tested against 32 uropathogenic strains belonging to 12 different species of Gram-negative and Gram-positive bacteria. The sensitivity of 25 tested bacterial strains to the B. subtilis I'1a filtrate was confirmed by an agar diffusion assay. None of the strains seemed to be sensitive to pure surfactin at concentrations ranging from 0.1 mg × ml(-1) to 0.4 mg ml(-1). After the treatment of uropathogens with B. subtilis lipopeptides, the metabolic activity of planktonic cells was inhibited by 88.05±3.96% in the case of 21 studied uropathogens, the process of biofilm formation was reduced by 88.15±4.77% in the case of 24 uropathogens and mature biofilms of 18 strains were dislodged by about 81.20±4.72%. Ten strains of uropathogenic bacteria were selected to study the antimicrobial activity of surfactin (concentrations 0.1, 0.2 and 0.4 mg × ml(-1)). Surfactin had no influence on the metabolic activity of planktonic forms of uropathogens, however, biofilms of 5 tested strains were reduced by 64.77±9.05% in the presence of this biosurfactant at the concentration 0.1 mg × ml(-1). The negative effect of the compound on the biofilm formation process was observed at all concentrations used. The above-described results were fully confirmed by CLSM. It could suggest that synergistic application of biosurfactants could be efficient in uropathogen eradication.

Lipid composition in a strain of Bacillus subtilis, a producer of iturin A lipopeptides that are active against uropathogenic bacteria

“…The microdilution method and studies biofilm formation were carried out as described by Moryl et al (2015). …”

“…It was also found that lipopeptides extracted from cultures of these bacteria had a strong antimicrobial effect on uropathogenic bacteria, including effects on planktonic growth, and the processes of biofilm formation and dislodging (Moryl et al 2015). In this present study, we carried out a more detailed elucidation of the structure of LPs produced by the I′1a B. subtilis strain.…”

Advanced strategies for combating bacterial biofilms

“…Finally, a combination of triclosan and DspB showed synergistic anti-biofilm activity against S. aureus, S. epidermidis , and E. coli (Darouiche, Mansouri, Gawande, & Madhyastha, 2009 (Banat, Franzetti et al, 2010;Díaz De Rienzo, Stevenson, Marchant, & Banat, 2015;Makkar & Rockne, 2003, Md, 2012Padmavathi & Pandian, 2014). The high antimicrobial, antiadhesive and strong dispersal properties of BSs make them hopeful agents for eradicating biofilms (some BSs that inhibit biofilm formation are listed in Table 3) (Krasowska, 2010 (Hassan & Mohammad, 2015) Acinetobacter indicus NS NS Treatment of biofilms for seven days at 500 μg/ml resulted in up to 82.5% biofilm disruption (Karlapudi et al, 2018) B. subtilis Lipopeptide surfactin, iturin and fengycin Biofilm formation on uropathogenic bacteria reduced (Moryl, Spętana et al, 2015) Corynebacterium xerosis Lipopeptide Coryxin Disrupted preformed biofilms of E. coli (66%), S. mutans (80%), S. aureus (82.5%), and P. aeruginosa (30%). (Dalili, Amini et al, 2015) Fasciospongia cavernosa Lipopeptide NS 125 mg/ml of lipopeptide was effective in reducing the biofilm formation activity of pathogenic MDR S. aureus (Kiran, Priyadharsini et al, 2017) Bacillus licheniformis NS NS Inhibited P. aeruginosa and Vibrio harveyi biofilms on polystyrene surfaces up to around 78% and 80% respectively (Hamza, Kumar, & Zinjarde, 2016) S. lentus Glycolipid NS At a concentration of 20 μg was able to disrupt mature biofilms of V. harveyi (78.7 ± 1.93%) and P. aeruginosa (81.7 ± 0.59%; (Hamza, Satpute, Banpurkar, Kumar, & Zinjarde, 2017) Lactobacillus casei Glycolipid NS Potentially disrupted biofilm formation under dynamic conditions (Kiran, Sabarathnam, & Selvin, 2010) Lactobacillus jensenii and Lactobacillus gasseri NS NS Disrupted biofilms of E. coli, Enterobacter aerogenes and Staphylococcus saprophyticus (Morais, Cordeiro et al, 2017) Note.…”

Antimicrobial potential of haloalkaliphilic Nocardiopsis sp. AJ1 isolated from solar salterns in India

“…Surfactin is one of the most powerful lipopeptide biosurfactants produced by various strains of Bacillus subtilis , having exceptional surface activity as well as antiviral, antibacterial and antitumor properties . Surfactin is considered to be antibiotics due to their broad antimicrobial spectrum . The crude surfactin possesses antimicrobial activity against antibiotic resistant Staphylococcus aureus, E. coli strains and the pathogenic yeast Candida albicans .…”