Figure 1.

Antibiotic susceptibility of nontypeable Haemophilus influenzae (NTHi) in vitro biofilms. Varying concentrations of amoxicillin (0–2 mg/mL) were added to preformed NTHi 86-028NP (white bars) and NTHi 86-028NP bla (black bars) biofilms. The amounts of amoxicillin noted on the x-axis indicate the concentration per milliliter added to each well. After 24 h, biofilms were scraped, serially diluted, and plated for bacterial counts. Bars represent the mean (± standard error of the mean). The graph represents data combined from 3 experiments (8–9 replicates total). Statistical significance was assessed by Mann-Whitney nonparametric analysis. *P < .05; **P < .005; ***P < .001. CFU, colony-forming unit.