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Genotyping of Mycoplasma pneumoniae clinical isolates reveals eight P1 subtypes within two genomic groups
J W Dorigo-Zetsma1, J Dankert, S A Zaat
1Department of Medical Microbiology, Academic Medical Center, 1105 AZ Amsterdam, The Netherlands. Wendelion.Dorigo@rivm.nl
Abstract:
Three methods for genotyping of Mycoplasma pneumoniae clinical isolates were applied to 2 reference strains and 21 clinical isolates. By a modified restriction fragment length polymorphism (RFLP) analysis of PCR products of the M. pneumoniae cytadhesin P1 gene, 5 subtypes were discriminated among 13 P1 type 1 strains and 3 subtypes were discriminated among 8 P1 type 2 strains. Sequence analysis of the 16S-23S rRNA gene spacer region and part of the 23S rRNA gene revealed one nucleotide difference in the intergenic spacer region in 3 of the 21 isolates. In the 23S rRNA gene sequence of the 8 P1 type 2 strains an extra adenosine was present, but it was absent from the 13 P1 type 1 strains. On the basis of M. pneumoniae genome sequence data, primers were designed to amplify large interrepeat fragments by long PCR, and these fragments were subsequently analyzed by RFLP analysis. Only two types, long PCR types 1 and 2, could be discriminated among the M. pneumoniae isolates. All P1 type 1 strains were assigned to long PCR type 1, and all P1 type 2 strains were assigned to long PCR type 2. These data obtained by three independent typing methods thus confirm the existence of two distinct M. pneumoniae genomic groups but expand the possibility of strain typing on the basis of variations within their P1 genes.
Insights
Genotyping of Mycoplasma pneumoniae using three methods revealed two distinct genomic groups. Variations in the cytadhesin P1 gene and rRNA gene regions help differentiate these Mycoplasma pneumoniae strains.
Area of Science:
- Microbiology
- Genetics
- Molecular Biology
Background:
- Mycoplasma pneumoniae is a significant human respiratory pathogen.
- Accurate genotyping is crucial for understanding M. pneumoniae transmission and epidemiology.
- Existing genotyping methods have limitations in fully characterizing strain diversity.
Purpose of the Study:
- To evaluate and compare three distinct genotyping methods for Mycoplasma pneumoniae clinical isolates.
- To identify genetic variations that can differentiate M. pneumoniae strains.
- To confirm the existence of distinct genomic groups within M. pneumoniae.
Main Methods:
- Restriction fragment length polymorphism (RFLP) analysis of the cytadhesin P1 gene.
- Sequence analysis of the 16S-23S rRNA gene spacer region and part of the 23S rRNA gene.
- Long PCR amplification of interrepeat fragments followed by RFLP analysis.
Main Results:
- RFLP of the P1 gene identified 5 subtypes among P1 type 1 strains and 3 subtypes among P1 type 2 strains.
- Sequence analysis revealed nucleotide differences in the rRNA gene spacer and variations in the 23S rRNA gene (presence/absence of adenosine).
- Long PCR and subsequent RFLP distinguished two main types, correlating perfectly with P1 type 1 and P1 type 2 strains.
Conclusions:
- Three independent genotyping methods confirm two distinct genomic groups of Mycoplasma pneumoniae.
- Variations within the cytadhesin P1 gene offer expanded possibilities for M. pneumoniae strain typing.
- These findings enhance our ability to characterize M. pneumoniae isolates for epidemiological studies.