The skin is the largest organ in the human body and is colonized by a diverse microbiota that works in harmony to protect the skin. However, when skin damage occurs, the skin microbiota is also disrupted, and pathogens can invade the wound and cause infection. Probiotics or other beneficial microbes and their metabolites are one possible alternative treatment for combating skin pathogens via their antimicrobial effectiveness. The objective of our study was to evaluate the antimicrobial effect of seven multi-strain dietary supplements and eleven single-strain microbes that contain probiotics against 15 clinical wound pathogens using the agar spot assay, co-culturing assay, and agar well diffusion assay. We also conducted genera-specific and species-specific molecular methods to detect the DNA in the dietary supplements and single-strain beneficial microbes. We found that the multi-strain dietary supplements exhibited a statistically significant higher antagonistic effect against the challenge wound pathogens than the single-strain microbes and that lactobacilli-containing dietary supplements and single-strain microbes were significantly more efficient than the selected propionibacteria and bacilli. Differences in results between methods were also observed, possibly due to different mechanisms of action. Individual pathogens were susceptible to different dietary supplements or single-strain microbes. Perhaps an individual approach such as a ‘probiogram’ could be a possibility in the future as a method to find the most efficient targeted probiotic strains, cell-free supernatants, or neutralized cell-free supernatants that have the highest antagonistic effect against individual clinical wound pathogens.

Bacteria of the genus Cutibacterium are Gram-positive commensals and opportunistic pathogens that represent a major challenge in the diagnosis and treatment of implant-associated infections (IAIs). This study provides insight into the distribution of different sequence types (STs) of C. acnes, and the presence of virulence factors (VFs) in 64 Cutibacterium spp. isolates from suspected or confirmed IAIs obtained during routine microbiological diagnostics. Fifty-three C. acnes, six C. avidum, four C. granulosum, and one C. namnetense isolate, collected from different anatomical sites, were included in our study. Using whole-genome sequencing and a single-locus sequencing typing scheme, we successfully characterized all C. acnes strains and revealed the substantial diversity of STs, with the discovery of six previously unidentified STs. Phylotype IA₁, previously associated with both healthy skin microbiome and infections, was the most prevalent, with ST A1 being the most common. Some minor differences in STs’ distribution were observed in correlation with anatomical location and association with infection. A genomic analysis of 40 investigated VFs among 64 selected strains showed no significant differences between different STs, anatomical sites, or infection-related and infection undetermined/unlikely groups of strains. Most differences in VF distribution were found between strains of different Cutibacterium spp., subspecies, and phylotypes, with CAMP factors, biofilm-related VFs, lipases, and heat shock proteins identified in all analyzed Cutibacterium spp.