Alonso R, Aucken H M, Perez-Diaz J C, Cookson B D, Baquero F, Pitt T L
Servicio de Microbiología, Hospital Ramon y Cajal, Madrid, Spain.
Epidemiol Infect. 1993 Aug;111(1):99-107. doi: 10.1017/s0950268800056727.
Variations in rDNA gene loci in DNA digests of 209 clinical isolates of Serratia marcescens were determined with an Escherichia coli rRNA probe. Forty-one restriction fragment length polymorphism patterns (ribotypes) were identified, based on the size of 4-14 (mean 7.5) hybridization bands. The patterns differed by more than a single band in 98% of pair-wise comparisons. On a subset of 76 isolates, ribotyping proved to be marginally more discriminating than biotyping (discrimination index 0.92 v. 0.89) followed by serotyping (0.87) and bacteriocin typing (0.74). About one-third of isolates belonged to unique ribotypes and only two ribotypes exceeded 5% in frequency (23.0 and 6.4% respectively). A combination of serotype or biotype with ribotyping defined a similar number of strains, although none of the methods alone was sufficiently discriminatory to identify strains. We conclude that due to the accessibility of biotyping and the lack of commercially available antisera for S. marcescens, the biotype and ribotype together provide reliable markers of strain identity.
用大肠杆菌rRNA探针测定了209株粘质沙雷氏菌临床分离株DNA消化物中rDNA基因位点的变异情况。基于4至14条（平均7.5条）杂交带的大小，鉴定出41种限制性片段长度多态性模式（核糖型）。在98%的两两比较中，这些模式的差异超过一条带。在76株分离株的一个子集中，核糖分型的鉴别能力略高于生物分型（鉴别指数分别为0.92和0.89），其次是血清分型（0.87）和细菌素分型（0.74）。约三分之一的分离株属于独特的核糖型，只有两种核糖型的频率超过5%（分别为23.0%和6.4%）。血清型或生物型与核糖分型相结合确定的菌株数量相似，尽管单独使用任何一种方法都不足以鉴别菌株。我们得出结论，由于生物分型易于操作，且缺乏市售的粘质沙雷氏菌抗血清，生物型和核糖型共同提供了可靠的菌株鉴定标记。
