Fig. 6From: Evolutionary diversification of Pseudomonas aeruginosa in an artificial sputum modelBeta-lactamase production in ceftazidime and tazobactam-piperacillin resistant isolates. Activity was measured using nitrocefin, in a chromogenic assay by calculating the change in A486/390 per minute. The dashed line indicates the value of the negative control (PAO1). Ceftazidime (CAZ); piperacillin/tazobactam (TZP). Bars indicate standard errorBack to article page