 - Quality control In order to check the system with respect to correct handing, quality and consistency of materials and methods, test quality control strains with the antibiotics concerned. S. pneumoniae and H. influenzae can be determined by broth microdilution under ambient incubation. The following organisms are included as control strains: S. aureus ATCC 29213, E. faecalis ATCC 29212, S. pneumoniae ATCC 49619, E. coli ATCC 25922, E. coli ATCC 35218, K. pneumoniae ATCC 700603, and P. aeruginosa ATCC 27853. For every 500 Etests performed, a control test including the above 5 control strains will be done. 