Vancomycin and maltodextrin affect structure and activity of Staphylococcus aureus biofilms

• Published in: Biotechnology and bioengineering Vol. 112; no. 12; pp. 2562 - 2570
• Main Authors: Kiamco, Mia Mae, Atci, Erhan, Khan, Qaiser Farid, Mohamed, Abdelrhman, Renslow, Ryan S., Abu-Lail, Nehal, Fransson, Boel A., Call, Douglas R., Beyenal, Haluk
• Format: Journal Article
• Language: English
• Published: United States Blackwell Publishing Ltd 01.12.2015; Wiley Subscription Services, Inc
• Subjects: Anti-Bacterial Agents - metabolism; Antibiotics; Bacteria; biofilm; Biofilms; Biofilms - drug effects; Biofilms - growth & development; Bioreactors - microbiology; Cell growth; Diffusion; Drug Interactions; Maltodextrin; Microscopy; Osmotic Pressure; oxygen; Oxygen - metabolism; Polysaccharides - metabolism; Respiration; Staphylococcus aureus; Staphylococcus aureus - drug effects; Staphylococcus aureus - physiology; structure; Vancomycin; Vancomycin - metabolism; Yeast; vancomycin; maltodextrin; oxygen; Staphylococcus aureus; structure; biofilm
• ISSN: 0006-3592; 1097-0290
• DOI: 10.1002/bit.25681

ABSTRACT Hyperosmotic agents such as maltodextrin negatively impact bacterial growth through osmotic stress without contributing to drug resistance. We hypothesized that a combination of maltodextrin (osmotic agent) and vancomycin (antibiotic) would be more effective against Staphylococcus aureus biofilms than either alone. To test our hypothesis, S. aureus was grown in a flat plate flow cell reactor. Confocal laser scanning microscopy images were analyzed to quantify changes in biofilm structure. We used dissolved oxygen microelectrodes to quantify how vancomycin and maltodextrin affected the respiration rate and oxygen penetration into the biofilm. We found that treatment with vancomycin or maltodextrin altered biofilm structure. The effect on the structure was significant when they were used simultaneously to treat S. aureus biofilms. In addition, vancomycin treatment increased the oxygen respiration rate, while maltodextrin treatment caused an increase and then a decrease. An increased maltodextrin concentration decreased the diffusivity of the antibiotic. Overall, we conclude that (1) an increased maltodextrin concentration decreases vancomycin diffusion but increases the osmotic effect, leading to the optimum treatment condition, and (2) the combination of vancomycin and maltodextrin is more effective against S. aureus biofilms than either alone. Vancomycin and maltodextrin act together to increase the effectiveness of treatment against S. aureus biofilm growth. Biotechnol. Bioeng. 2015;112: 2562–2570. © 2015 Wiley Periodicals, Inc. Vancomycin and maltodextrin increase the efficiency of biofilm treatment. The authors' findings demonstrate that combined effect is dose‐dependent but follows a “u‐shaped” function. There is a threshold after which further increases in the concentration of the hyperosmotic compound slow the diffusion of the antibiotic and the treatment effectiveness is reduced.