Genetic diversity of Neisseria lactamica strains from epidemiologically defined carriers

Abstract

We assessed the genetic diversity of 26 Neisseria lactamica strains from epidemiologically related sources, i.e., groups of kindergartens and primary schools in three Bavarian towns, by the partial sequencing of the argF, rho, recA, and 16S ribosomal genes. We found a total of 17 genotypes, of which 12 were found only in one strain. The genotypes comprised 5 alleles of the argF gene, 9 of rho, 8 of recA, and 10 of the 16S ribosomal DNA. Sequence analysis by determination of homoplasy ratios and split decomposition analysis revealed abundant recombination within N. lactamica.

FIG. 1

Polymorphic sites (boldface letters) within the argF, recA, rho, and 16S ribosomal genes of N. lactamica. The positions of the polymorphic sites are shown above the nucleotide sequences in vertical format. The numbers were defined according to the sequenced fragments of the genes and do not reflect the position relative to the start codon. Amino acid changes resulting from nonsynonymous mutations are indicated below the nucleotide sequences by single-letter code.

FIG. 2

Linkage distances of 26 N. lactamica strains analyzed in this study as determined by UPGMA analysis. The strain numbers are on the right, and the allele numbers (parentheses) are given in the following order: 16S ribosomal DNA, argF, recA, rho.

FIG. 3

Split graphs for the N. lactamica sequences obtained in this study. Split decomposition was analyzed with SPLITSTREE, version 3.1 (16). The fit values were 100, 100, 88, and 83% for argF, 16S ribosomal DNA, recA, and rho, respectively.