Frozen cultures were first thawed at room temperature for 30 min, after which the tubes were vortexed for 30 s to ensure that a homogeneous mix was achieved before starting the nucleic acid extraction. Total nucleic acid extraction was performed using the NucliSENS® easyMAG® (bioMérieux, Marcy l’Etoile, France) according to the manufacturer’s instructions (generic protocol 2.0.1).