Propionibacterium acnes and Staphylococcus epidermidis Isolated from Refractory Endodontic Lesions Are Opportunistic Pathogens

Abstract

The predominant cultivable microbiota from 20 refractory endodontic lesions (9 with abscesses and 11 without abscesses) were determined, and Propionibacterium acnes and Staphylococcus epidermidis were among the most predominant organisms. The number of species identified from lesions with abscesses (14.1 ؎ 2.6) was significantly greater (P < 0.001) than the number from lesions without abscesses (7.4 ؎ 5.9). Comparison of perioral isolates using repetitive extragenic palindromic PCR of the same species from the same subjects demonstrated that the endodontic and skin populations were significantly different. The P. acnes isolates were typed on the basis of recA gene sequence comparison, and only three types (types I, II, and III) were identified among 125 isolates examined. However, we found that type I (type IA and IB) isolates were primarily isolated from the skin, while types II and III were significantly more likely to be isolated from the endodontic lesions (P < 10 ؊10 ). We found that the robustness of the recA phylotypes was not strong by comparing the partial gene sequences of six putative virulence determinants, PAmce, PAp60, PA-25957, PA-5541, PA-21293, and PA-4687. The resulting neighbor-joining trees were incongruent, and significant (phi test; P ‫؍‬ 2.2 ؋ 10 ؊7 ) evidence of recombination was demonstrated, with significant phylogenetic heterogeneity being apparent within the clusters. P. acnes and S. epidermidis isolated from refractory endodontic infections, with or without periapical abscesses, are likely to be nosocomial infections.Propionibacterium acnes and coagulase-negative staphylococci, including Staphylococcus epidermidis, have been identified among the microflora of endodontic infections (8,12,40,50,52,55,56,63,64), but their importance as endodontic pathogens has largely been ignored due to their nearly universal presence on the skin and the consequent likelihood of sample contamination. However, there is now considerable evidence that these organisms are increasingly isolated from human infections, and so their association with endodontic infections requires clarification. P. acnes, a non-spore-forming, Gram-positive anaerobic or aerotolerant rod, is a member of the resident microflora of the large intestine, conjunctiva, and external ear canal (10, 15) and accounts for approximately half of the total skin microbiota (59), predominating over other pilosebaceous flora (16,39). Although traditionally considered to be relatively nonpathogenic, an increasing number of studies have implicated P. acnes as an opportunistic pathogen responsible for a wide range of infections and inflammatory conditions. In addition to its well-established role in the pathogenesis of acnes vulgaris (16, 34), it has also been linked to synovitis-acnes-pustulosis-hyperostosis-osteitis syndrome (44, 54), sarcoidosis (17), and prostate cancer (14). Recent studies have revealed trauma and surgery as the predisposing factors associated with numerous P. acnes infections, which include brain abscesses (36), osteomyelitis ...

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

“…Data collated from three different studies have demonstrated that amongst 203 P. acnes isolates from the facial skin of 64 volunteers, type IA (~50 %) and IB (~40 %) organisms are the dominant lineages present (Shannon et al, 2006;Holmberg et al, 2009;Niazi et al, 2010). The absence of type IB strains amongst acne isolates despite their presence on facial skin provides evidence that type IA-specific factors are responsible for the association with acne.…”

“…Caveats associated with aspects of previously described single locus phylotyping of P. acnes were highlighted upon validation of the MLST approach. All strains of type IB contain a GAA polymorphism at position 897 in the recA open reading frame which has been widely used to conveniently differentiate this group from type IA strains Shannon et al, 2006;Holmberg et al, 2009;Sampedro et al, 2009;Niazi et al, 2010). While this polymorphism appears sensitive for type IB STs, it is not specific since strains confirmed as type IA by MLST were also found to occasionally share this particular recA allele.…”

Influence of a polymerizable eugenol derivative on the antibacterial activity and wettability of a resin composite for intracanal post cementation and core build-up restoration

“…P. acnes, an opportunistic pathogen in refractory endodontic infection, may be associated with contamination of dental materials during the root canal filling procedure and has been isolated from infected root canals [16]. This species has been found to have high sensitivity to essential oil components that may adhere to the bacterial surface at low concentration [57].…”

“…E. faecalis, in particular, is difficult to remove owing to its considerable virulence factors constituting a source of recurrent infection after conservative as well as surgical treatments [15]. P. acnes is an anaerobic Grampositive bacterium responsible for a wide range of infections and inflammatory conditions [16]. Therefore, development of antibacterial restorative filling materials to be reliable for a variety of dental applications need a potent antimicrobial agent which acts against a wide range of oral microorganisms.…”

Microbial quality and suitability of roof-harvested rainwater in rural villages for crop irrigation and domestic use

“…Of the total, opportunistic pathogens (Staphylococcus spp. (Niazi et al, 2010) (4%)) were identified.…”