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.