We are concerned to note the content of the above article, and having been referenced throughout without being directly approached for comment, wish to place into context the activities undertaken by the British Society for Antimicrobial Chemotherapy (BSAC), a registered Charity, in relation to antibiotic susceptibility testing.

For over a decade the BSAC has supported the development and practical implementation of a national susceptibility testing methodology (BSAC method) that includes standardised in-vitro methods of antimicrobial susceptibility testing (AST). An important aspect of this work is the promotion of quality control measures that recognize disc quality as one of many potential sources of poor performance.

The BSAC method includes laboratory testing methods, peer review publication of the results of method testing [ http://bsac.org.uk/susceptibility/guidelines-standardized-disc-susceptib... ], hosting of bi-annual training courses for biomedical and clinical scientists and clinicians and an advice service to users of the methodology. As referenced in the article, User Group events offer scientists and clinicians the opportunity to discuss their questions and concerns about all aspects of AST.

The BSAC method recognizes that disc or media issues are among many potential sources of poor performance of AST and specifies a system of quality assurance that should identify disc problems.

We wish it to be noted that since 2001 BSAC has, through underwriting of a designated fund, supported the continued development of the BSAC method. The Society does not receive external funding from commercial sources for this activity nor does the Society endorse or otherwise any specific disc manufacturer.

Competing interests: NB is President of BSAC and RH is Chair, BSAC Standing Committee on Susceptibility Testing