Unravelling the eco-specificity and pathophysiological properties of Cutibacterium species in the light of recent taxonomic changes

Acne microbiome: From phyla to phylotypes

Acne vulgaris is a chronic inflammatory skin disease with a complex pathogenesis. Traditionally, the primary pathophysiologic factors in acne have been thought to be: (1) altered sebum production, (2) inflammation, (3) excess keratinization and (4) colonization with the commensal Cutibacterium acnes. However, the role of C. acnes has been unclear, since virtually all adults have C. acnes on their skin yet not all develop acne. In recent years, understanding of the role of C. acnes has expanded. It is still acknowledged to have an important place in acne pathogenesis, but evidence suggests that an imbalance of individual C. acnes phylotypes and an alteration of the skin microbiome trigger acne. In addition, it is now believed that Staphylococcus epidermidis is also an actor in acne development. Together, C. acnes and S. epidermidis maintain and regulate homeostasis of the skin microbiota. Antibiotics, which have long been a staple of acne therapy, induce cutaneous dysbiosis. This finding, together with the long-standing public health edict to spare antibiotic use when possible, highlights the need for a change in acne management strategies. One fertile direction of study for new approaches involves dermocosmetic products that can support epidermal barrier function and have a positive effect on the skin microbiome.

Species- and strain-level diversity of Corynebacteria isolated from human facial skin

BACKGROUND

Sequencing of the human skin microbiome revealed that Corynebacterium is an ubiquitous and abundant bacterial genus on human skin. Shotgun sequencing further highlighted the microbial "dark matter" of the skin microbiome, consisting of microorganisms, including corynebacterial species that were not cultivated and genome-sequenced so far. In this pilot project, facial human skin swabs of 13 persons were cultivated to selectively obtain corynebacteria. 54 isolates were collected and 15 of these were genome-sequenced and the pan-genome was determined. The strains were biochemically characterized and antibiotic susceptibility testing (AST) was performed.

RESULTS

Among the 15 sequenced strains, nine different corynebacterial species were found, including two so far undescribed species, tentatively named "Corynebacterium vikingii" and "Corynebacterium borealis", for which closed genome sequences were obtained. Strain variability beyond the species level was determined in biochemical tests, such as the variable presence of urease activity and the capacity to ferment different sugars. The ability to grow under anaerobic conditions on solid agar was found to be species-specific. AST revealed resistances to clindamycin in seven strains. A Corynebacterium pseudokroppenstedtii strain showed additional resistance towards beta-lactam and fluoroquinolone antibiotics; a chromosomally located 17 kb gene cluster with five antibiotic resistance genes was found in the closed genome of this strain.

CONCLUSIONS

Taken together, this pilot study identified an astonishing diversity of cutaneous corynebacterial species in a relatively small cohort and determined species- and strain-specific individualities regarding biochemical and resistance profiles. This further emphasizes the need for cultivation-based studies to be able to study these microorganisms in more detail, in particular regarding their host-interacting and, potentially, -beneficial and/or -detrimental properties.

First case of Cutibacterium avidum-infected pelvic lymphocele post-lymphadenectomy for endometrial cancer: A case report

Background

Pelvic lymphocele (lymphocyst) infection after lymphadenectomy is a rare complication that can cause the spread of inflammation to neighboring organs whose microbiology is not well known. Cutibacterium avidum causes various infections. However, no case reports of C. avidum pelvic lymphocele infection are available; therefore, its clinical characteristics in pelvic lymphocele infections remain unknown.

Case presentation

A 38-year-old woman with obesity (body mass index: 38.1 kg/m2) and a history of pelvic lymphadenectomy and chemotherapy for endometrial cancer presented with worsening left lower quadrant (LLQ) pain with fever. Physical examination revealed decreased abdominal bowel sounds and tenderness on LLQ palpation with no signs of peritonitis. Computed tomography (CT) revealed an infected left pelvic lymphocele with inflammation spreading to the adjacent sigmoid colon. Following blood culture, ampicillin/sulbactam (2 g/1 g every 6 h) was administered intravenously. Anaerobic culture bottles revealed gram-positive rods on day 4 of incubation at 37 °C. No other disseminated foci were observed in enhanced whole-body CT and upon transthoracic echocardiography. The isolates grew aerobically and anaerobically on blood agar plates with strong hemolysis. The bacterium was identified as C. avidum using a combination of characteristic peak analysis with matrix-assisted laser desorption ionization (MALDI) and 16S rRNA gene sequencing. The patient was diagnosed with C. avidum pelvic lymphocele infection. Based on penicillin susceptibility, the patient was successfully treated with intravenous ampicillin/sulbactam and de-escalated with intravenous ampicillin (2 g every 6 h) for 10 days, followed by oral amoxicillin (2000 mg/day) for an additional 11 days without drainage.

Conclusions

C. avidum should be considered a causative microorganism of pelvic lymphocele infection. Peak analysis using MALDI and distinctive growth on blood agar plates are suitable for identifying C. avidum. Mild pelvic lymphocele caused by C. avidum can be treated with a short course of appropriate antimicrobial treatment without surgical intervention.

Stalactites Core Prospect as Environmental "Microbial Ark": The Actinomycetota Diversity Paradigm, First Reported from a Greek Cave

Speleothems found in caves worldwide are considered the natural libraries of paleontology. Bacteria found in these ecosystems are generally limited to Proteobacteria and Actinomycetota, but rare microbiome and "Dark Matter" is generally under-investigated and often neglected. This research article discusses, for the first time to our knowledge, the diachronic diversity of Actinomycetota entrapped inside a cave stalactite. The planet's environmental microbial community profile of different eras can be stored in these refugia (speleothems). These speleothems could be an environmental "Microbial Ark" storing rare microbiome and "Dark Matter" bacterial communities evermore.

Multidrug Resistance Plasmid pTZC1 Could Be Pooled among Cutibacterium Strains on the Skin Surface

Acne vulgaris is a chronic inflammatory skin disease that is exacerbated by Cutibacterium acnes. Although antimicrobials such as macrolides, clindamycin, and tetracyclines are used to treat acne caused by C. acnes, the increasing prevalence of antimicrobial-resistant C. acnes strains has become a global concern. In this study, we investigated the mechanism by which interspecies transfer of multidrug-resistant genes can lead to antimicrobial resistance. Specifically, the transfer of pTZC1 between C. acnes and C. granulosum isolated from specimens of patients with acne was investigated. Among the C. acnes and C. granulosum isolated from 10 patients with acne vulgaris, 60.0% and 70.0% of the isolates showed resistance to macrolides and clindamycin, respectively. The multidrug resistance plasmid pTZC1, which codes for macrolide-clindamycin resistance gene erm(50) and tetracycline resistance gene tet(W), was identified in both C. acnes and C. granulosum isolated from the same patient. In addition, whole-genome sequencing revealed that the pTZC1 sequences of C. acnes and C. granulosum showed 100% identity using comparative whole-genome sequencing analysis. Therefore, we hypothesize that the horizontal transfer of pTZC1 between C. acnes and C. granulosum strains may occur on the skin surface. The plasmid transfer test revealed a bidirectional transfer of pTZC1 between C. acnes and C. granulosum, and transconjugants that obtained pTZC1 exhibited multidrug resistance. In conclusion, our results revealed that the multidrug resistance plasmid pTZC1 could be transferred between C. acnes and C. granulosum. Furthermore, since pTZC1 transfer among different species may aid in the prevalence of multidrug resistant strains, antimicrobial resistance genes may have been pooled on the skin surface. IMPORTANCE The emergence of antimicrobial resistance not only in Cutibacterium acnes strain but also other skin bacteria such as Staphylococcus epidermidis is a big concern due to antimicrobial use for the treatment of acne vulgaris. Increased prevalence of macrolides-clindamycin resistant C. acnes relates to the acquisition of exogenous antimicrobial resistance genes. erm(50) is harbored by the multidrug resistance plasmid pTZC1, which has been found in C. acnes and C. granulosum strains isolated from patients with acne vulgaris. In this study, C. acnes and C. granulosum with pTZC1 were found in the same patient, and plasmid transfer between C. acnes and C. granulosum was proved by transconjugation assay. This study showed plasmid transfer between other species and the possibility of further prevalence antimicrobial resistance between Cutibacterium species.

Prevalence of antimicrobial-resistant Cutibacterium isolates and development of multiplex PCR method for Cutibacterium species identification

INTRODUCTION

Cutibacterium species such as C. acnes, C. avidum, and C. granulosum are known anaerobic skin inhabitants and often cause surgical site infections. These species are genetically similar and are difficult to identify rapidly. In addition, their pathogenicity and antimicrobial resistance remain unknown. In this study, antimicrobial resistance in Cutibacterium isolates was studied and a multiplex PCR method for their identification was developed.

METHODS

A total of 497 C. acnes, 71 C. avidum, and 25 C. granulosum strains which were isolated from the acne pustule and infectious regions, were used.

RESULTS

The antimicrobial resistance rates of C. acnes, C. avidum, and C. granulosum strains isolated from patients with acne vulgaris were higher than those of strains isolated from patients with infectious diseases. In particular, macrolide-clindamycin-resistant strains were isolated most frequently from all species. Among the resistant strains, strains with 23S rRNA mutations were the most common in C. acnes (24.3%, 71/292), whereas C. avidum and C. granulosum strains were most frequently found with erm(X). For the first time, a C. granulosum strain carrying pTZC1, which codes erm(50) and tet(W), was isolated from patients with acne vulgaris. Regarding the rapid identification of causative pathogens from infectious regions, three Cutibacterium species were identified with 100% sensitivity and specificity using multiplex PCR method.

CONCLUSIONS

Our data showed that antimicrobial resistance differed among Cutibacterium species. The multiplex PCR method may contribute to the rapid detection of Cutibacterium species and selection of appropriate antimicrobial agents.

Preoperative topical benzoyl peroxide treatment is effective in reducing Cutibacterium acnes in shoulder surgery: a systematic review

BACKGROUND

Cutibacterium acnes (C acnes) colonization can have a significant impact on patients undergoing both arthroscopic and open shoulder surgery with regard to postoperative infection. Its resistance to standard preoperative skin preparations and prophylactic antibiotics has led to a need for a more targeted therapy. Topical benzoyl peroxide (BPO) has been used by dermatologists in the treatment for acnes due to its bactericidal and penetrative effects through the dermal layer. The aim of this systematic review is to review the effectiveness of topical BPO preoperatively in shoulder surgery in reducing C acnes colonization and postoperative infection.

METHODS

A review of the online databases Medline and Embase was conducted on December 15, 2021, according to Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. The review was registered prospectively in the PROSPERO database. Clinical studies reporting superficial and deep sample microbiology and postoperative complications were included. The studies were appraised using the revised Cochrane Risk of Bias 2 (ROB 2) tool for randomized studies and the Methodological Index for Non-Randomized Studies (MINORS) tool.

RESULTS

The search strategy identified 10 studies for inclusion (6 randomized control trials, 2 prospective cohort studies, and 2 case series), including a total of 482 patients. Seven studies were comparable, testing BPO against alternative standard skin preparations. Of the 10 studies, 7 showed a decrease in the load of C acnes on the skin and/or deep tissues, of which 6 demonstrated statistical significance. Men were shown to have a statistically significant increase in the colonization rate of C acnes. Scheer et al (2021) demonstrated 4500 colony-forming units/mL in males and 900 colony-forming units/mL in females. In studies where the number of BPO applications was higher, BPO appeared more effective. Dizay et al demonstrated C acnes elimination in 78.9% with more than 1 application compared with 66.7% if only applied once. Three studies looked at the effectiveness of BPO during the operative timeline with 1 demonstrating its statistically significant effectiveness at reducing colonization 2 hours into the operation (P = .048).

CONCLUSION

BPO is effective as a topical treatment at reducing C acnes colonization before shoulder surgery. However, the relationship between duration of treatment, frequency of application, and gender requires further research.

Shotgun metagenomic sequencing reveals skin microbial variability from different facial sites

Biogeography (body site) is known to be one of the main factors influencing the composition of the skin microbial community. However, site-associated microbial variability at a fine-scale level was not well-characterized since there was a lack of high-resolution recognition of facial microbiota across kingdoms by shotgun metagenomic sequencing. To investigate the explicit microbial variance in the human face, 822 shotgun metagenomic sequencing data from Han Chinese recently published by our group, in combination with 97 North American samples from NIH Human Microbiome Project (HMP), were reassessed. Metagenomic profiling of bacteria, fungi, and bacteriophages, as well as enriched function modules from three facial sites (forehead, cheek, and the back of the nose), was analyzed. The results revealed that skin microbial features were more alike in the forehead and cheek while varied from the back of the nose in terms of taxonomy and functionality. Analysis based on biogeographic theories suggested that neutral drift with niche selection from the host could possibly give rise to the variations. Of note, the abundance of porphyrin-producing species, i.e., Cutibacterium acnes, Cutibacterium avidum, Cutibacterium granulosum, and Cutibacterium namnetense, was all the highest in the back of the nose compared with the forehead/cheek, which was consistent with the highest porphyrin level on the nose in our population. Sequentially, the site-associated microbiome variance was confirmed in American populations; however, it was not entirely consistent. Furthermore, our data revealed correlation patterns between Propionibacterium acnes bacteriophages with genus Cutibacterium at different facial sites in both populations; however, C. acnes exhibited a distinct correlation with P. acnes bacteriophages in Americans/Chinese. Taken together, in this study, we explored the fine-scale facial site-associated changes in the skin microbiome and provided insight into the ecological processes underlying facial microbial variations.

Multiple pathogens and prostate cancer

BACKGROUND

The aim of this review is to consider whether multiple pathogens have roles in prostate cancer.

METHODS

We have reviewed case control studies in which infectious pathogens in prostate cancer were compared to normal and benign prostate tissues. We also reviewed additional evidence from relevant published articles.

RESULTS

We confirmed that high risk human papilloma viruses are a probable cause of prostate cancer. We judged Escherichia coli, Cutibacterium acnes, Neisseria gonorrhoea, Herpes simplex, Epstein Barr virus and Mycoplasmas as each having possible but unproven roles in chronic prostatic inflammation and prostate cancer. We judged Cytomegalovirus, Chlamydia trachomatis, Trichomonas vaginalis and the Polyoma viruses as possible but unlikely to have a role in prostate cancer.

CONCLUSIONS AND ACTIONS

The most influential cause of prostate cancer appears to be infection induced chronic inflammation. Given the high prevalence of prostate cancer it is important for action to can be taken without waiting for additional conclusive evidence. These include: 1. Encouragement of all boys (as well as girls) to have HPV vaccines 2. The vigorous use of antibiotics to treat all bacterial pathogens identified in the urogenital tract 3. The use of antiviral medications to control herpes infections 4. Education about safe sexual practices.

Common Features and Intra-Species Variation of Cutibacterium modestum Strains, and Emended Description of the Species

Cutibacterium modestum is a new species coined in 2020 as the fifth species of genus Cutibacterium, which includes Cutibacterium acnes. The species is predicted as a minor but common member of skin microbiome and includes a group tentatively named as “Propionibacterium humerusii”. The description of the species has been provided only with a single strain. To establish the characteristics of C. modestum and search for possible disease-related subtypes, we investigated the biochemical characteristics of eight live strains and performed in silico comparison of nine genomes. The common features, which included the morphology of Gram-stain positive short rods, the negativity of phenylalanine arylamidase, and several unique MALDI-TOF MS spectral peaks, were considered useful in laboratory identification. Pairwise comparisons of the genomes by in silico DNA–DNA hybridization showed similarity values of 98.1% or larger, which were far higher than the subspecies cutoff of 79–80%. The 16S rRNA gene sequences of thirteen isolates and genomes were identical. Their recA gene sequences were identical except for two strains, HM-510 (HL037PA2) and Marseille-P5998, which showed unique one-nucleotide polymorphisms. The biochemical features using API kits were slightly different among the isolates but far closer than those of the nearest other species, C. acnes and Cutibacterium namnetense. Spectra of MALDI-TOF mass spectrometry showed slight differences in the presence of m/z 10,512 (10 kD chaperonin GroS) and three other peaks, further clustering the eight isolates into three subtypes. These results indicated that these isolates did not separate to form subspecies-level clusters, but subtyping is possible by using recA gene sequences or MALDI-TOF mass spectrometry spectra. Moreover, this work has confirmed that a group “P. humerusii” is included in C. modestum.