Enhancement of biofilm-mode growth of CoNS cells by oxacillin at the highest serum achievable concentration. Solutions of gentamicin, oxacillin, vancomycin or the three agents in combination in TSB at the highest concentrations achievable in serum, were added to biofilm grown cells of two S. capitis isolates; 15 (biofilm-negative, ica-weak), and 22 (biofilm-negative, ica-positive). After overnight incubation, bacterial growth was stained with crystal violet and the OD600 was measured. Error bars represent standard errors of at least 3 individual experiments in triplicate. *: P = 0.004; ** P < 0.001.