A survey of methods and protocols currently being used to determine antimicrobial susceptibility of bacteria associated with fish disease

A questionnaire was used to survey methods and protocols currently employed by laboratories involved in determining the antimicrobial susceptibility of bacteria associated with fish disease. Thirty-one laboratories in 18 countries reported the methods they employed for non-fastidious (Group 1) organisms. Of these 29 reported the use of disc diffusion methods and only 8 reported the use of MIC methods. Of these 8, only 4 reported using MIC methods in routine testing of clinical isolates. There was significant, but not complete, harmony in the protocols used for disc diffusion studies. Seventy-six percent of the laboratories reported the use of either the M42-R (CLSI, 2003) or other closely related protocols. The changes that will be required to increase the harmony in test protocols are discussed. The most significant will be the inclusion of control strains and the QA procedures associated with M42-R (CLSI, 2003) and in the harmonisation of the content of the discs.