Dissecting the taxonomic heterogeneity within Propionibacterium acnes: proposal for Propionibacterium acnes subsp. acnes subsp. nov. and Propionibacterium acnes subsp. elongatum subsp. nov.

Abstract

Propionibacterium acnes subsp. acnes subsp. nov. and Propionibacterium acnes subsp. elongatum subsp. nov. are described. These emanate from the three known phylotypes of P. acnes, designated types I, II and III. Electron microscopy confirmed the filamentous cell shape of type III, showing a striking difference from types I/II, which were short rods. Biochemical tests indicated that, in types I/II, either the pyruvate, l-pyrrolidonyl arylamidase or d-ribose 2 test was positive, whereas all of these were negative among type III strains. Matrix-assisted laser-desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) spectra, which profile mainly their ribosomal proteins, were different between these two groups. Surface-enhanced laser-desorption/ionization time-of-flight mass spectrometry (SELDI-TOF MS) spectra of all phylotypes revealed a specific protein biomarker that was overexpressed in type III strains compared with types I/II only when grown aerobically. Reference strains had high whole-genome similarity between types I (>91 %) and II (>75 %), but a considerably lower level of 72 % similarity with type III. recA and gyrB sequence dendrograms confirmed the distant relatedness of type III, indicating the presence of two distinct centres of variation within the species P. acnes. On the other hand, cellular fatty acid profiles and 16S rRNA gene sequence relatedness (>99.3 %) circumscribed the species. Thus, we propose two subspecies, Propionibacterium acnes subsp. acnes subsp. nov. for types I/II and Propionibacterium acnes subsp. elongatum subsp. nov. for type III. The type strain of Propionibacterium acnes subsp. acnes is NCTC 737T ( = ATCC 6919T = JCM 6425T = DSM 1897T = CCUG 1794T), while the type strain of Propionibacterium acnes subsp. elongatum is K124T ( = NCTC 13655T = JCM 18919T).

Strains of the Propionibacterium acnes type III lineage are associated with the skin condition progressive macular hypomelanosis

“…Combined with functional differences, this could potentially explain their association with PMH on the truck, but not facial acne. Our genomic comparisons also revealed that the Japanese facial isolate JCM1890928 lacked a number of genomic regions found in the other three type III genomes, but shared similarities with P. acnes isolates belonging to the type I and type II lineages which are abundant on facial skin12. This could indicate that isolates belonging to this lineage are equipped with unique metabolic properties to aid adaptation to the niche from where they were isolated, but this suggestion is currently tentative due to the assembly of JCM18909 which has a much lower N50 than the other genomes.…”

Propionibacterium acnes phylogenetic type III is associated with progressive macular hypomelanosis

“…Subtype III differs also in biochemical tests, matrix-assisted laser desorption–ionization time-of-flight mass spectrometry (MALDI-TOF MS) spectra, and genetic markers; thus, it was recently proposed as a new subspecies with the name P. acnes subsp. elongatum [31]. This subtype has rarely been cultured from healthy controls, opportunistic infections, or acne patients [14, 16, 18, 32].…”

Propionibacterium namnetense sp. nov., isolated from a human bone infection

“…Using these systems, strain NTS 31307302 T can clearly be differentiated from its closest relatives (Table 1); however, as demonstrated by Dekio et al (2015), there are fewer tests that are reliable for the differentiation of the subspecies of P. acnes (Table S1, available in the online Supplementary Material). Further, metabolic characterization of the type subspecies of P. acnes was performed by the BIOLOG system following the manufacturer's instructions.…”

“…Studies by McDowell and colleagues employing molecular methods not only confirmed these two types but revealed a third type (McDowell et al, 2005(McDowell et al, , 2008. Recently, Dekio et al (2015) formally proposed that types I/II represent P. acnes subsp. acnes and type III represents a second subspecies, P. acnes subsp.…”

“…acnes and type III represents a second subspecies, P. acnes subsp. elongatum (Dekio et al, 2015). The present investigation focused on clinical material recovered from a human bone biopsy and the characterization of a P. acnes-like organism isolated.…”