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

International audienceThe recent description of the genus Cutibacterium has altered the taxonomy of Propionibacterium species. These organisms still belong to the genera of the skin coryneform group, and the most-studied species remains Cutibacterium acnes. Cutibacterium avidum 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 sperficial or deep/invasive infections. It can cause numerous infections, including but not limited to breast infections, skin abscesses, infective endocarditis, and device-relate infections. The ecological niche of C. avidum 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 C. avidum pathogenesis (including host-bacterium interactions and virulence factor characterization) is becoming easier, allowing for more thorough molecular characterization. These analyses have revealed that C. avidum 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. C. avidum 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

GENOTYPAGE CAPSULAIRE ET ANALYSE DU COMPORTEMENT A L'EGARD DES BETA-LACTAMINES DE SOUCHES DE HAEMOPHILUS INFLUENZAE ISOLEES LORS D'OTITES MOYENNES AIGUES DE L'ENFANT

NANTES-BU Médecine pharmacie (441092101) / SudocSudocFranceF

LETTERS TO THE EDITOR Can 16S rRNA PCR be the solution for a rapid detection of Propionibacterium acnes in surgical shoulder or spine samples? Comments on " A rapid method for detecting Propionibacterium acnes in surgical biopsy specimens from the shoulder "

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LETTERS TO THE EDITOR Can 16S rRNA PCR be the solution for a rapid detection of Propionibacterium acnes in surgical shoulder or spine samples? Comments on " A rapid method for detecting Propionibacterium acnes in surgical biopsy specimens from the shoulder "

International audienceno abstrac

Cutibacterium acnes molecular typing: time to standardize the method

International audienceBACKGROUND:The Gram-positive, anaerobic/aerotolerant bacterium Cutibacterium acnes is a commensal of healthy human skin; it is subdivided into six main phylogenetic groups or phylotypes: IA1, IA2, IB, IC, II and III. To decipher how far specific subgroups of C. acnes are involved in disease physiopathology, different molecular typing methods have been developed to identify these subgroups: i.e. phylotypes, clonal complexes, and types defined by single-locus sequence typing (SLST). However, as several molecular typing methods have been developed over the last decade, it has become a difficult task to compare the results from one article to another.AIMS:Based on the scientific literature, the aim of this narrative review is to propose a standardized method to perform molecular typing of C. acnes, according to the degree of resolution needed (phylotypes, clonal complexes, or SLST types).CONTENT:We discuss the existing different typing methods from a critical point of view, emphasizing their advantages and drawbacks, and we identify the most frequently used methods. We propose a consensus algorithm according to the needed phylogeny resolution level. We first propose to use multiplex PCR for phylotype identification, MLST9 for clonal complex determination, and SLST for phylogeny investigation including numerous isolates.IMPLICATIONS:There is an obvious need to create a consensus about molecular typing methods for C. acnes. This standardization will facilitate the comparison of results between one article and another, and also the interpretation of clinical data

In vitro emergence of fluoroquinolone resistance in Cutibacterium (formerly Propionibacterium ) acnes and molecular characterization of mutations in the gyrA gene

International audienceIn vitro occurrence of levofloxacin (LVX) resistance in C. acnes and characterization of its molecular background were investigated. The mutation frequency was determined by inoculation of 108 cfu of C. acnes ATCC 11827 (LVX MIC = 0.25 mg/L) on LVX-containing agar plates. The progressive emergence of resistance was studied by a second exposure to increasing LVX concentrations. For mutants, the QRDR regions including the gyrA and parC genes were sequenced and compared to both C. acnes ATCC 11827 and C. acnes KPA171202 reference sequences (NC006085). The importance of the efflux pump system in resistance was investigated by using inhibitors on selected resistant mutants with no mutation in the QRDR. C. acnes growth was observed on LVX-containing plates with mutation frequencies of 3. 8 cfu × 10-8 (8 × MIC) and 1.6 cfu × 10-7 (4 × MIC). LVX resistance emerged progressively after one-step or two-step assays. In LVX-resistant isolates, the MIC ranged from 0.75 to >32 mg/L. Mutations were detected exclusively in the gyrA gene. Ten genotypes were identified: G99 C, G99 D, D100N, D100 H, D100 G, S101L, S101W, A102 P, D105 H and A105 G. Mutants S101L and S101W were always associated with a high level of resistance. Mutants with no mutation in the QRDR were more susceptible when incubated with an efflux pump inhibitor (phenyl-arginine β-naphthylamide) only, suggesting, for the first time, the expression of such a system in C. acnes LVX-resistant mutants

Draft Genome Sequence of an Erythromycin-Resistant Propionibacterium acnes Isolate Recovered from Folliculitis of the Scalp

International audiencePropionibacterium acnes is now well-known and recognized for its implication in the pathogenesis of acne vulgaris. Here, we report the draft genome sequence of an erythromycin-resistant P. acnes strain isolated from a case of folliculitis of the scalp belonging to phylotype IA1 and sequence type 18 (ST18)

Immune discrepancies during in vitro granuloma formation in response to Cutibacterium (formerly Propionibacterium ) acnes infection

International audienceCutibacterium (formerly Propionibacterium) acnes is involved in chronic/low-grade pathologies such as sarcoidosis or prosthetic joint infection (PJI). In these diseases, granulomatous structures are frequently observed. In this study, we induced a physiological granulomatous reaction in response to different well-characterized clinical C. acnes isolates in order to investigate the cellular process during granuloma formation. Three C. acnes isolates selected according to their origin (PJI, sarcoidosis and acne) were typed by MLST. All C. acnes isolates generated granulomatous structures in our experimental conditions. The bacterial burden was better controlled by granulomas induced by the sarcoidosis C. acnes isolate. The PJI C. acnes isolate, belonging to CC36, promoted the recruitment of CD8 þ lymphocytes inside the granu-loma. In contrast, the acne and sarcoidosis C. acnes isolates, belonging to phylotypes IA 1 /CC18 and IA 2 / CC28, respectively, generated a higher number of granulomas and promoted the recruitment of CD4 þ lymphocytes inside the granuloma. Our results provide new evidence supporting the role of C. acnes in the development of sarcoidosis and new explanations concerning the mechanisms underlying PJI due to C. acnes