Statistical analysis Statistical significance was determined using a two-tailed paired Student’s t-test. The results were considered statistically significant with P ≤ 0.05 (*) and P ≤ 0.001 (**). Acknowledgements We would like to thank Dr. Steen for providing the Lactococcus lactis subsp. cremoris strain MG1363. This work was supported in part by National Protein Tyrosine Kinase inhibitor Institutes and Health Grant AI50666 and by a research grant (RFDG) from the West Virginia University Research and Graduate Education (to S. L.). H. Oliver-Kozup was supported by a grant from the West Virginia Graduate

Student Fellowship in Science, Technology, Engineering and Mathematics (STEM). Confocal microscopy experiments were performed in the West Virginia University Microscope Imaging Facility, which is supported in part by the Mary Babb Randolph Cancer Center and NIH grant P20 RR016440. We would like to acknowledge the assistance of the West Virginia Selleckchem CHIR99021 University Flow Cytometry core facility which was supported in part by a grant P30 RR032138 from the National Institutes of Health. The findings and conclusions in this report are those of the authors and do not necessarily represent the views of the National Institute of Occupational Safety and Health. Electronic supplementary material Additional file 1: Figure S1. Biofilm formation by the isogenic wild-type and scl1 -inactivated GAS strains. The figure

shows gallery views and X-Y orthogonal Z-stack views of GFP-expressing GAS biofilms at 24 h rendered by confocal laser scanning microscopy (CLSM). Figure S2. Biofilm formation by the wild-type and Scl1-expressing L. lactis strains. The figure shows gallery views and X-Y orthogonal Z-stack views of GFP-expressing L. lactis biofilms at 24 h rendered by CLSM. (PDF 2 MB) References 1. Conley J, Olson ME, Cook LS, Ceri H, Phan V, Davies HD: Biofilm formation by group a streptococci: is there a relationship with treatment failure? J Clin

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