Clinical and Biological Features of Cutibacterium (Formerly Propionibacterium) avidum , an Underrecognized Microorganism

Abstract

The recent description of the genus has altered the taxonomy of species. These organisms still belong to the genera of the skin coryneform group, and the most-studied species remains . is also a known skin commensal. This underrecognized microorganism can, however, act as a pathogen after bacterial seeding and can be considered opportunistic, causing either superficial or deep/invasive infections. It can cause numerous infections, including but not limited to breast infections, skin abscesses, infective endocarditis, and device-related infections. The ecological niche of is clearly different from that of other members of the genus: it is found in the axillary region or at wet sites rather than in dry, exposed areas, and the number of microorganisms increases during puberty. Historically, it has been used for its ability to modulate the immune response and for its antitumor properties. Conventional microbial culture methods and identification processes allow for its accurate identification and characterization. Thanks to the modern omics tools used for phylogenomic approaches, understanding pathogenesis (including host-bacterium interactions and virulence factor characterization) is becoming easier, allowing for more thorough molecular characterization. These analyses have revealed that causes diverse diseases mediated by multiple virulence factors. The recent genome approach has revealed specific genomic regions within this species that are involved in adherence and biofilm formation as well as fitness, survival, and defense functions. Numerous regions show the presence of phages and horizontal gene transfer. remains highly sensitive to a broad spectrum of antibiotics, such as β-lactams, fluoroquinolones, macrolides, and rifampin, although erythromycin and clindamycin resistance has been described. A long-term treatment regimen with a combination of antibiotics is required to successfully eliminate the remaining adherent bacteria, particularly in the case of deep infections after debridement surgery.

Cutibacterium avidum: A rare but expected agent of breast implant infection

“…C. avidum is highly susceptible to multiple antimicrobials, including beta-lactam agents and fluoroquinolones. Clindamycin resistance has been described [4], and in our case, maybe could explain the failure of antibiotic perioperative prophylaxis and further empirical treatment, but unfortunately, we could not perform susceptibility testing. The treatment includes early surgical debridement and appropriate antibiotic therapy, and in some patients, implant removal is required to resolve the infection.…”

“…Infections caused by this microorganism are usually associated to predisposing factors such as surgery, foreign bodies and malignancy. As a skin commensal, previously considered of low pathogenicity, it is now recognized as a causative organism of serious spontaneous and surgical site infections (SSI) [4]. Indeed groin colonization is a recognized risk factor for hip periprosthetic joint infection [5].…”

A Pan-Genome Guided Metabolic Network Reconstruction of Five Propionibacterium Species Reveals Extensive Metabolic Diversity

“…Interestingly, commensal organisms were found to have reduced diversity in their biosynthetic pathways and a wider range of degradative capabilities, particularly in comparison to P. freudenreichii . These findings likely reflect the greater reliance of proteolytic activity as a source of carbon and energy among commensal propionibacteria given their nutrient-scarce microenvironment [ 10 ]. Although representative species for all four genera that compose the former Propionibacterium genus were considered in this analysis, the analysis needs to be expanded further to encompass newly available sequenced species [ 91 , 92 , 93 ] before it can be generalized more broadly.…”

“…The cutaneous propionibacteria group represents a distinct phylogenetic clade in the Propionibacterium genus and have been reclassified as Cutibacterium [ 3 ]. These species are opportunistic pathogens [ 10 , 11 ] and play an important role in skin health, inhabiting different regions of the skin reflective of their metabolic specialisation. For example, P. avidum inhabits moist, nutrient-scarce regions rich in sweat glands such as the axilla where they are likely dependent on proteolytic activity to supply amino acids as a major carbon and energy source, whereas P. acnes inhabits hair follicles and appears to predominantly rely on sebum degradation via lipases [ 10 ].…”

“…These species are opportunistic pathogens [ 10 , 11 ] and play an important role in skin health, inhabiting different regions of the skin reflective of their metabolic specialisation. For example, P. avidum inhabits moist, nutrient-scarce regions rich in sweat glands such as the axilla where they are likely dependent on proteolytic activity to supply amino acids as a major carbon and energy source, whereas P. acnes inhabits hair follicles and appears to predominantly rely on sebum degradation via lipases [ 10 ]. The final member of the newly proposed genera to update the traditional Propionibacterium genus consists of Pseudopropionibacterium and includes P. propionicum , which causes actinomycosis [ 12 ].…”