A new phylogenetic group of Propionibacterium acnes

Andrew McDowell, Alexandra L. Perry, Peter A. Lambert, Sheila Patrick

Research output: Contribution to journalArticlepeer-review


Immunofluorescence microscopy-based identification of presumptive Propionibacterium acnes isolates, using the P. acnes-specific mAb QUBPa3, revealed five organisms with an atypical cellular morphology. Unlike the coryneform morphology seen with P. acnes types I and II, these isolates exhibited long slender filaments (which formed large tangled aggregates) not previously described in P. acnes. No reaction with mAbs that label P. acnes types IA (QUBPa1) and II (QUBPa2) was observed. Nucleotide sequencing of the 16S rRNA gene (1484 bp) revealed the isolates to have between 99.8 and 99.9 % identity to the 16S rRNA gene of the P. acnes type IA, IB and II strains NCTC 737, KPA171202 and NCTC 10390, respectively. Analysis of the recA housekeeping gene (1047 bp) did reveal, however, a greater number of conserved nucleotide polymorphisms between the sequences from these isolates and those from NCTC 737 (98.9 % identity), KPA171202 (98.9 % identity) and NCTC 10390 (99.1 % identity). Phylogenetic investigations demonstrated that the isolates belong to a novel recA cluster or lineage distinct from P. acnes types I and II. We now propose this new grouping as P. acnes type III. The prevalence and clinical importance of this novel recA lineage amongst isolates of P. acnes remains to be determined.
Original languageEnglish
Pages (from-to)218-224
Number of pages7
JournalJournal of Medical Microbiology
Issue number2
Publication statusPublished - Feb 2008


  • Immunofluorescence microscopy-based identification
  • presumptive Propionibacterium acnes isolates
  • acnes
  • mAb QUBPa3
  • cellular morphology
  • nucleotide sequencing
  • 16S rRNA gene (1484 bp)
  • conserved nucleotide polymorphisms
  • phylogenetic investigations
  • recA cluster
  • recA lineage


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