Probiotic cellulose: Antibiotic-free biomaterials with enhanced antibacterial activity

The alarming increase of antibiotic-resistant bacteria, causing conventional treatments of bacterial infec-tions to become increasingly inefficient, is one of the biggest threats to global health. Here, we have de-veloped probiotic cellulose, an antibiotic-free biomaterial for the treatment of severe skin infections and chronic wounds. This composite biomaterial was in-depth characterized by Gram stain, scanning electron microscopy (SEM) and confocal fluorescence microscopy. Results demonstrated that probiotic cellulose consists of dense films of cellulose nanofibers, free of cellulose-producing bacteria, completely invaded by live probiotics (Lactobacillus fermentum or Lactobacillus gasseri). Viability assays, including time evolution of pH and reducing capacity against electrochromic polyoxometalate, confirmed that probiotics within the cellulose matrix are not only alive but also metabolically active, a key point for the use of probiotic cel-lulose as an antibiotic-free antibacterial biomaterial. Antibacterial assays in pathogen-favorable media, a real-life infection scenario, demonstrated that probiotic cellulose strongly reduces the viability of Staphy-lococcus aureus (SA) and Pseudomonas aeruginosa (PA), the most active pathogens in severe skin infections and chronic wounds. Likewise, probiotic cellulose was also found to be effective to inhibit the prolifera-tion of methicillin-resistant SA (MRSA). The combination of the properties of bacterial cellulose as wound dressing biomaterial and the antibacterial activity of probiotics makes probiotic cellulose an alternative to antibiotics for the treatment of topical infections, including severe and hard-to-heal chronic wounds. In addition, probiotic cellulose was obtained by a one-pot synthetic approach under mild conditions, not requiring the long and expensive chemical treatments to purify the genuine bacterial cellulose. Statement of significance Antibiotic resistance is responsible for around 70 0.0 0 0 deaths per year worldwide, with the potential to cause 10 million deaths by 2050. New antibiotic-free approaches are thus urgently needed for the treatment and prevention of bacterial infections. We produced probiotic cel-lulose, which consists of dense films of cellulose nanofibers completely invaded by live and metabolically active probiotics. This antibiotic-free biomaterial exhibits excellent anti-bacterial activity against Staphylococcus aureus and Pseudomonas aeruginosa , the most active pathogens in skin infections and chronic wounds. Likewise, probiotic cellulose was also effective against a methicillin-resistant Staphylococcus aureus strain. The synthesis of probiotic cellulose involves a single-step reaction under mild chemical conditions, thus cheaper and safer than the conven-tional methods to obtain bacterial cellulose. (c) 2021 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved. Statement of significance Antibiotic resistance is responsible for around 70 0.0 0 0 deaths per year worldwide, with the potential to cause 10 million deaths by 2050. New antibiotic-free approaches are thus urgently needed for the treatment and prevention of bacterial infections. We produced probiotic cellulose, which consists of dense films of cellulose nanofibers completely invaded by live and metabolically active probiotics. This antibiotic-free biomaterial exhibits excellent anti-bacterial activity against Staphylococcus aureus and Pseudomonas aeruginosa , the most active pathogens in skin infections and chronic wounds. Likewise, probiotic cellulose was also effective against a methicillin-resistant Staphylococcus aureus strain. The synthesis of probiotic cellulose involves a single-step reaction under mild chemical conditions, thus cheaper and safer than the conventional methods to obtain bacterial cellulose. The alarming increase of antibiotic-resistant bacteria, causing conventional treatments of bacterial infections to become increasingly inefficient, is one of the biggest threats to global health. Here, we have developed probiotic cellulose, an antibiotic-free biomaterial for the treatment of severe skin infections and chronic wounds. This composite biomaterial was in-depth characterized by Gram stain, scanning electron microscopy (SEM) and confocal fluorescence microscopy. Results demonstrated that probiotic cellulose consists of dense films of cellulose nanofibers, free of cellulose-producing bacteria, completely invaded by live probiotics ( Lactobacillus fermentum or Lactobacillus gasseri ). Viability assays, including time evolution of pH and reducing capacity against electrochromic polyoxometalate, confirmed that probiotics within the cellulose matrix are not only alive but also metabolically active, a key point for the use of probiotic cellulose as an antibiotic-free antibacterial biomaterial. Antibacterial assays in pathogen-favorable media, a real-life infection scenario, demonstrated that probiotic cellulose strongly reduces the viability of Staphylococcus aureus (SA) and Pseudomonas aeruginosa (PA) , the most active pathogens in severe skin infections and chronic wounds. Likewise, probiotic cellulose was also found to be effective to inhibit the proliferation of methicillin-resistant SA (MRSA) . The combination of the properties of bacterial cellulose as wound dressing biomaterial and the antibacterial activity of probiotics makes probiotic cellulose an alternative to antibiotics for the treatment of topical infections, including severe and hard-to-heal chronic wounds. In addition, probiotic cellulose was obtained by a one-pot synthetic approach under mild conditions, not requiring the long and expensive chemical treatments to purify the genuine bacterial cellulose.