Comparison of serotype, biotype and bacteriocin type with rDNA RFLP patterns for the type identification ofSerratia marcescens

Abstract

SUMMARYVariations 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.

An examination of the clonal variants of Serratia marcescens that infect the eye during contact lens wear

“…Six of the 15 isolates were of serotype of 013. In comparison, none of 209 strains was 013 in a study conducted by Alonso et al [18] and only one of 1 17 strains in the study by Rubin et al [8]. These results are very different from nosocomial studies where 014 is the major serotype isolated [8,181, whereas only one of 15 strains belonged to this serotype in the present study.…”

“…The systems used in the present study were a commercially available biochemical test kit, a commercially available serotyping kit and a rapid analysis for restriction endonuclease fragment patterns of chromosomal DNA with EcoRI. EcoRI gave an adequate number of bands to distinguish between strains, as was found also by Alonso et al [18]. To determine the type of each S. marcescens isolate only 4 days were required from first isolating the strain from the eye in the present typing scheme.…”

Serratia marcescens

“…hbotyping has also been used [91,921, and has been reported to be more discriminatory than biotyping, serotyping and bacteriocin typing, with equivalent discriminative power to total DNA analysis [93]. However, because of techiiical difficulties and.. the prolonged time needed for Southern blot analysis, its clinical use has been limited.…”

Different O and K Serotype Distributions among Clinical and Environmental Strains of Serratia Marcescens

“…In these cases it is likely that a genotypic method may prove the most satisfactory supplement. For example, ribotyping has been shown to produce results consistent with known epidemiology and biotyping [24], and to provide reliable strain discrimination when combined with biotyping or serotyping [25]. Pulsed-field gel electrophoresis of bacterial DNA digested with rare cutting enzymes also discriminates S. marcescens to strain level [26], as does DNA fingerprinting by the polymerase chain reaction [27].…”