Molecular characterization of Serratia marcescens strains by RFLP and sequencing of PCR-amplified 16S rDNA and 16S-23S rDNA intergenic spacer.
OBJECTIVE
To establish the specific DNA patterns in 16S rDNA and 16S-23S rDNA intergenic spacer (IGS) regions from different kinds of Serratia marcescens strains using polymerase chain reaction (PCR), restriction fragment length polymorphism (RFLP) and sequences analysis.


RESULTS
Two pairs of primers based on the 16S rDNA and 16S-23S rDNA IGS were applied to amplify the rrn operons of two kinds of S. marcescens strains. About 1500 bp for 16S rDNA and four fragments of different sizes for 16S-23S rDNA IGS were obtained. PCR-amplified fragments were analysed by RFLP and sequence analysis. Two distinct restriction patterns revealing three to five bands between two kinds of strains were detected with each specific enzyme. According to the sequence analysis, two kinds of strains showed approximately 97% sequence homology of 16S rDNA. However, there was much difference in the sequences of IGS between the two kinds of strains. Intercistronic tRNA of strains H3010 and A3 demonstrated an order of tRNA of 5'-16S-tRNA(Ala)-tRNA(Ile)-23S-3', but strain B17 harboured the tRNA of 5'-16S-tRNA(Glu)-tRNA(Ile)-23S-3'.


CONCLUSIONS
The method was specific, sensitive and accurate, providing a new technique for differentiating different strains from the same species.


CONCLUSIONS
This paper provided the first molecular characterization of 16S rDNA and 16S-23S rDNA IGS from S. marcescens strains.
Zhu
H
H
State Key Laboratory of Bioreactor Engineering, New World Institute of Biotechnology, East China University of Science and Technology, Shanghai, P.R. China.
Zhou
W Y
WY
Xu
M
M
Shen
Y L
YL
Wei
D Z
DZ
D015373:Bacterial Typing Techniques; D004269:DNA, Bacterial / Q000032:analysis*; D021903:DNA, Ribosomal Spacer / Q000032:analysis; D016133:Polymerase Chain Reaction / Q000379:methods*; D012150:Polymorphism, Restriction Fragment Length; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012338:RNA, Ribosomal, 23S / Q000235:genetics; D017422:Sequence Analysis, DNA; D012706:Serratia marcescens / Q000145:classification* / Q000235:genetics
D004269:DNA, Bacterial; D021903:DNA, Ribosomal Spacer; D012336:RNA, Ribosomal, 16S; D012338:RNA, Ribosomal, 23S