Figure 4.

Resistance to specific types of β‐lactam antibiotics is a function of PBP 3.

An exponentially growing culture of each bacterial strain was diluted to a specific optical density and used as the starting point for a fourfold dilution series. Samples (10 μl) of the dilutions were spotted onto nutrient agar plates containing the antibiotics Cephalexin (A; 0.08 μg ml⁻¹), Oxacillin (B; 0.04 μg ml⁻¹), Penicillin G (C; 0.005 μg ml⁻¹) and no antibiotic (D). Plates were then incubated at 37°C for 18 h prior to being photographed.