ABSTRACT
A multiple laboratory study was conducted in accordance with the standards established by the Clinical and Laboratory Standards Institute (CLSI), formerly the National Committee for Clinical Laboratory Standards (NCCLS), for the development of quality control (QC) ranges using dilution antimicrobial susceptibility testing methods for bacterial isolates from aquatic animal species. QC ranges were established for Escherichia coli ATCC 25922 and Aeromonas salmonicida subsp. salmonicida ATCC 33658 when testing at 22, 28 and 35 degrees C (E. coli only) for 10 different antimicrobial agents (ampicillin, enrofloxacin, erythromycin, florfenicol, flumequine, gentamicin, ormetoprim/sulfadimethoxine, oxolinic acid, oxytetracycline and trimethoprim/sulfamethoxazole). Minimum inhibitory concentration (MIC) QC ranges were determined using dry- and frozen-form 96-well plates and cation-adjusted Mueller-Hinton broth. These QC ranges were accepted by the CLSI/NCCLS Subcommittee on Veterinary Antimicrobial Susceptibility Testing in January 2004. This broth microdilution testing method represents the first standardized method for determining MICs of bacterial isolates whose preferred growth temperatures are below 35 degrees C. Methods and QC ranges defined in this study will enable aquatic animal disease researchers to reliably compare quantitative susceptibility testing data between laboratories, and will be used to ensure both precision and inter-laboratory harmonization.
Subject(s)
Aeromonas salmonicida/drug effects , Anti-Bacterial Agents/toxicity , Escherichia coli/drug effects , Microbial Sensitivity Tests/methods , Microbial Sensitivity Tests/standards , Culture Media/chemistry , Quality Control , Reproducibility of Results , TemperatureABSTRACT
Quality control (QC) ranges for disk diffusion susceptibility testing of aquatic bacterial isolates were proposed as a result of a multilaboratory study conducted according to procedures established by the National Committee for Clinical Laboratory Standards (NCCLS). Ranges were proposed for Escherichia coli ATCC 25922 and Aeromonas salmonicida subsp. salmonicida ATCC 33658 at 22 and 28 degrees C for nine different antimicrobial agents (ampicillin, enrofloxacin, erythromycin, florfenicol, gentamicin, oxolinic acid, oxytetracycline, ormetoprim-sulfadimethoxine, and trimethoprim-sulfamethoxazole). All tests were conducted on standard Mueller-Hinton agar. With >/=95% of all data points fitting within the proposed QC ranges, the results from this study comply with NCCLS guidelines and have been accepted by the NCCLS Subcommittee for Veterinary Antimicrobial Susceptibility Testing. These QC guidelines will permit greater accuracy in interpreting results and, for the first time, the ability to reliably compare susceptibility test data between aquatic animal disease diagnostic laboratories.
Subject(s)
Aeromonas/drug effects , Escherichia coli/drug effects , Microbial Sensitivity Tests/standards , Water Microbiology , Animals , Diffusion , Quality Control , TemperatureABSTRACT
Results obtained with a Technicon Flame Photometer Model IV Auto-Analyzer, which utilizes curve regeneration in conjunction with a mini-computer for the continuous-flow determination of serum electrolytes, is presented. The system, featuring optimal flow conditions, subjects sample peaks to a mathematical treatment to effectively remove exponential deformation. The evaluation, undertaken after 2 months of operation in the routine clinical laboratory, utilizes the Flame Photometer Model III as the "referee" procedure. The comparison includes a statistical analysis of quality control reference material, simultaneously determined patient data and an evaluation of repeated patient data. The system gave comparable results to those obtained for the Flame Photometer Model III and provides the additional benefits of increased sample throughput, decreased reagent comsumption and sample interaction and gives reductions in the clerical tasks associated with the retrieval of data from Auto-Analyzer systems.
