Enhancement of <i>P</i>. <i>aeruginosa</i> CF2004 virulence factor by <i>S</i>. <i>oralis</i> in biofilms incubated without added CO₂.

<p>Bacterial strains—Pa, <i>P</i>. <i>aeruginosa</i> CF2004; So, <i>S</i>. <i>oralis</i> ATCC 35037^T. Biofilms were grown aerobically on nitrocellulose filters for 48 h at 37°C. A) photographs and (B) quantitative bacteriology (CFU / filter) of monoculture and co-culture biofilms; shaded bars <i>P</i>. <i>aeruginosa</i> CF2004 population, unshaded bars streptococcal population. (C) Pyocyanin and (D) elastase activity in biofilms. Standard deviation of triplicate or quadruplicate cultures shown. Results significantly different from control using the two-tailed t-test are denoted with asterisks (*<i>p</i><0.05, ** <i>p</i><0.01).