A new phylogenetic group of Propionibacterium acnes

Abstract

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. INTRODUCTIONPropionibacterium acnes belongs to the 'high GC' group of Gram-positive bacteria and is found predominately in the sebaceous gland-rich areas of the skin in adults (McGinley et al., 1978). Although traditionally considered a relatively non-pathogenic member of the resident human microbiota, an increasing number of studies have implicated P. acnes as the agent responsible for various clinical conditions and infections. In addition to its well described role in inflammatory acne (Eady & Ingham, 1994), P. acnes is emerging as an important pathogen in relation to medical implant-related infections, such as those associated with central nervous system shunts (Brook & Frazier, 1991), silicone implants (Ahn et al., 1996), and prosthetic heart valves and hip joints (Delahaye et al., 2005;Tunney et al., 1998Tunney et al., , 1999. Furthermore, P. acnes is responsible for endophthalmitis, ocular and periocular infections (Aldave et al., 1999;Clark et al., 1999;Horgan et al., 1999), as well as periodontal and dental infections (Debelian et al., 1992; LeGoff et al., 1997), and has been linked to synovitis-acnepustulosis-hyperostosis-osteitis (SAPHO) syndrome (Kotilainen et al., 1996), sarcoidosis (Eishi et al., 2002) and prostate cancer (Cohen et al., 2005). The identification of a wide range of putative virulence determinants within the recently published genome sequence of the P. acnes strain KPA17202 has further brought the pathogenic potential of this organism into focus (Bruggemann et al., 2004).Two distinct phenotypes of P. acnes (types I and II), which can be distinguished by serological agglutination tests and cell-wall sugar analysis, have been known for over 30 years (Johnson & Cummins, 1972). Additional studies have show...

A novel multilocus sequence typing scheme for the opportunistic pathogen Propionibacterium acnes and characterization of type I cell surface-associated antigens

“…mAb typing by immunofluorescence microscopy (IFM) was carried out as described previously . Isolates were examined for their reactivity with mouse mAbs QUBPa1 and QUBPa2, which target strains within the major P. acnes clades I and II, respectively (McDowell et al, , 2008.…”

“…These groups or phylotypes also display defining phenotypic differences with respect to cellular morphology, seroreactivity and the production of virulence determinants (Johnson & Cummins, 1972;McDowell et al, 2008). These differences led us to suggest that these groups may vary in their capacity to cause different infections or conditions McDowell et al, 2005;Lodes et al, 2006).…”

“…Sequence-based analyses of the recA housekeeping gene, as well as putative virulence genes, have shown that P. acnes comprises distinct evolutionary lineages, known as IA, IB, II and III, that share 99.8-99.9 % identity based on 16S rRNA gene sequences (McDowell et al, , 2008. These groups or phylotypes also display defining phenotypic differences with respect to cellular morphology, seroreactivity and the production of virulence determinants (Johnson & Cummins, 1972;McDowell et al, 2008).…”

The Role of Propionibacterium acnes Biofilm in Acne Vulgaris

“…The traditional paradigm of acne has generally consisted of four components, often presented in a sequential fashion. Androgen excess leads to increased [1] sebum production, along with [2] follicular hyperkeratinization which results in plugging of the follicle. This allows the bacterium [3] Propionibacterium acnes to grow within the follicle, eventually culminating in an [4] inflammatory cascade and clinically evident disease.…”

“…Propionibacterium acnes, a gram negative anaerobic rod, traditionally considered as a normal component of skin flora. P. acnes are categorized into phylotypes IA, IB, II, and III based on sequencing of their recA and hemolysin genes (tly) [2]. This microbe, however, plays a pivotal role in the pathogenesis of acne vulgaris via its biofilm forming ability.…”