Bosshard P P, Abels S, Zbinden R, Böttger E C, Altwegg M
Institute of Medical Microbiology, University of Zürich, 8028 Zürich, Switzerland.
J Clin Microbiol. 2003 Sep;41(9):4134-40. doi: 10.1128/JCM.41.9.4134-4140.2003.
We have evaluated over a period of 18 months the use of 16S ribosomal DNA (rDNA) sequence analysis as a means of identifying aerobic gram-positive rods in the clinical laboratory. Two collections of strains were studied: (i) 37 clinical strains of gram-positive rods well identified by phenotypic tests, and (ii) 136 clinical isolates difficult to identify by standard microbiological investigations, i.e., identification at the species level was impossible. Results of molecular analyses were compared with those of conventional phenotypic identification procedures. Good overall agreement between phenotypic and molecular identification procedures was found for the collection of 37 clinical strains well identified by conventional means. For the 136 clinical strains which were difficult to identify by standard microbiological investigations, phenotypic characterization identified 71 of 136 (52.2%) isolates at the genus level; 65 of 136 (47.8%) isolates could not be discriminated at any taxonomic level. In comparison, 16S rDNA sequencing identified 89 of 136 (65.4%) isolates at the species level, 43 of 136 (31.6%) isolates at the genus level, and 4 of 136 (2.9%) isolates at the family level. We conclude that (i) rDNA sequencing is an effective means for the identification of aerobic gram-positive rods which are difficult to identify by conventional techniques, and (ii) molecular identification procedures are not required for isolates well identified by phenotypic investigations.
我们在18个月的时间里评估了使用16S核糖体DNA（rDNA）序列分析作为临床实验室中鉴定需氧革兰氏阳性杆菌的一种方法。研究了两组菌株：（i）37株通过表型试验能很好鉴定的革兰氏阳性杆菌临床菌株，以及（ii）136株通过标准微生物学调查难以鉴定的临床分离株，即在种水平上无法鉴定。将分子分析结果与传统表型鉴定程序的结果进行了比较。对于通过传统方法能很好鉴定的37株临床菌株，表型鉴定和分子鉴定程序之间总体一致性良好。对于136株通过标准微生物学调查难以鉴定的临床菌株，表型特征在属水平上鉴定出136株中的71株（52.2%）；136株中的65株（47.8%）在任何分类水平上都无法区分。相比之下，16S rDNA测序在种水平上鉴定出136株中的89株（65.4%），在属水平上鉴定出136株中的43株（31.6%），在科水平上鉴定出136株中的4株（2.9%）。我们得出结论：（i）rDNA测序是鉴定用传统技术难以鉴定的需氧革兰氏阳性杆菌的有效方法，（ii）对于通过表型调查能很好鉴定的分离株，不需要分子鉴定程序。
