Evaluation of an automatic gaschromatographic system for the identification of bacterial infective agents

[摘要] The potential clinical application of gas chromatography tomicrobial identifcation was evaluated. A completely automatedsystem, the MIS (Microbial Identification System; Hewlett-Packard) can analyse and identify pure strains by comparison oftheir cellular fatty acids patterns (C9-C20) with the referenceparameters stored in a library. Three hundred and sixty-sevenstrains were tested, comparing the gas chromatographic resultswith those obtained by the traditional microbiological methods inthe bacteriology laboratory of our Institute. A standardizedextractive procedure was followed to obtain the fatty acid methylesters (FAMEs), but some modifications to the recommendedprocedure were introduced in the bacterial growth procedures:colonies harvested not only from the recommended growth media butalso from selective media routinely used in the bacteriologylaboratory were successfully examined. These modifications did notinfluence the results but improved the ease for the user; goodagreement with the comparison method was observed as far asidentifications of genus and species are concerned for 238 cases.The major advantages of this computerized system are a reductionin the time required to obtain the final results, the elimination ofhuman errors by using the autosampler and a better inter-laboratorycomparability of results owing to a higher degree of objectivity. Onthe other hand, the limited throughput of MIS (only 40 samples in24 h) prevents its use in a large routine laboratory; this technologyis appropriate in emergency cases, in taxonomic studies and as aconfirmatory method.

[学科分类] 分析化学