Phylogenetic analysis of the genus Pediococcus, including Pediococcus claussenii sp nov., a novel lactic acid bacterium isolated from beer

Pediococci are found in foods and on plants and as beer-spoilage agents. The goal of the present study was to use the DNA sequences of the first three variable regions of the 16S rRNA gene, the 16S-23S rRNA internally transcribed spacer region sequence and approximately a third of the 60 kDa heat-shock protein gene to elucidate phylogenetic groupings within the genus Pediococcus. Phylogenetic trees were created with sequence data from 31 Pediococcus and three Lactobacillus isolates. Complete 16S rRNA gene sequences from selected Pediococcus isolates were also examined. The results were interpreted in relation to the currently accepted Pediococcus species. We found that, where previously done, speciation of many Pediococcus isolates is inaccurate. Also, one grouping of seven isolates did not include any currently recognized Pediococcus species type isolate. Our phylogenetic analyses support the conclusion that these seven isolates, all of brewing spoilage origin, belong to a novel species, for which the name Pediococcus claussenii sp. nov. is proposed (type strain P06(T) = ATCC BAA-344(T) = DSM 14800(T)). Phylogenetic analysis has therefore helped to resolve problems surrounding species identification of Pediococcus isolates.