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.
Our understanding of the role of
Cutibacterium acnes
in the pathophysiology of acne has recently undergone a paradigm shift: rather than
C. acnes
hyperproliferation, it is the loss of balance between ...the different
C. acnes
phylotypes, together with a dysbiosis of the skin microbiome, which results in acne development. The loss of diversity of
C. acnes
phylotypes acts as a trigger for innate immune system activation, leading to cutaneous inflammation. A predominance of
C. acnes
phylotype IA
1
has been observed, with a more virulent profile in acne than in normal skin. Other bacteria, mainly
Staphylococcus epidermis
, are also implicated in acne.
S. epidermidis
and
C. acnes
interact and are critical for the regulation of skin homeostasis. Recent studies also showed that the gut microbiome is involved in acne, through interactions with the skin microbiome. As commonly used topical and systemic antibiotics induce cutaneous dysbiosis, our new understanding of acne pathophysiology has prompted a change in direction for acne treatment. In the future, the development of individualized acne therapies will allow targeting of the pathogenic strains, leaving the commensal strains intact. Such alternative treatments, involving modifications of the microbiome, will form the next generation of ‘ecobiological’ anti-inflammatory treatments.
The role of Propionibacterium acnes in acne and in a wide range of inflammatory diseases is well established. However, P. acnes is also responsible for infections involving implants. Prolonged ...aerobic and anaerobic agar cultures for 14 days and broth cultures increase the detection rate. In this paper, we review the pathogenic role of P. acnes in implant-associated infections such as prosthetic joints, cardiac devices, breast implants, intraocular lenses, neurosurgical devices, and spine implants. The management of severe infections caused by P. acnes involves a combination of antimicrobial and surgical treatment (often removal of the device). Intravenous penicillin G and ceftriaxone are the first choice for serious infections, with vancomycin and daptomycin as alternatives, and amoxicillin, rifampicin, clindamycin, tetracycline, and levofloxacin for oral treatment. Sonication of explanted prosthetic material improves the diagnosis of implant-associated infections. Molecular methods may further increase the sensitivity of P. acnes detection. Coating of implants with antimicrobial substances could avoid or limit colonization of the surface and thereby reduce the risk of biofilm formation during severe infections. Our understanding of the role of P. acnes in human diseases will likely continue to increase as new associations and pathogenic mechanisms are discovered.
Propionibacterium acnes is an important cause of orthopedic-implant-associated infections, for which the optimal treatment has not yet been determined. We investigated the activity of rifampin, alone ...and in combination, against planktonic and biofilm P. acnes in vitro and in a foreign-body infection model. The MIC and the minimal bactericidal concentration (MBC) were 0.007 and 4 μg/ml for rifampin, 1 and 4 μg/ml for daptomycin, 1 and 8 μg/ml for vancomycin, 1 and 2 μg/ml for levofloxacin, 0.03 and 16 μg/ml for penicillin G, 0.125 and 512 μg/ml for clindamycin, and 0.25 and 32 μg/ml for ceftriaxone. The P. acnes minimal biofilm eradication concentration (MBEC) was 16 μg/ml for rifampin; 32 μg/ml for penicillin G; 64 μg/ml for daptomycin and ceftriaxone; and ≥128 μg/ml for levofloxacin, vancomycin, and clindamycin. In the animal model, implants were infected by injection of 109 CFU P. acnes in cages. Antimicrobial activity on P. acnes was investigated in the cage fluid (planktonic form) and on explanted cages (biofilm form). The cure rates were 4% for daptomycin, 17% for vancomycin, 0% for levofloxacin, and 36% for rifampin. Rifampin cured 63% of the infected cages in combination with daptomycin, 46% with vancomycin, and 25% with levofloxacin. While all tested antimicrobials showed good activity against planktonic P. acnes, for eradication of biofilms, rifampin was needed. In combination with rifampin, daptomycin showed higher cure rates than with vancomycin in this foreign-body infection model.
Bacterial extracellular vesicles (EVs) are bilayered lipid membrane structures, bearing integral proteins and able to carry diverse cargo outside the cell to distant sites. In microorganisms, EVs ...carry several types of molecules: proteins, glycoproteins, mRNAs and small RNA species, as mammalian EVs do, but also carbohydrates. Studying EVs opens a whole new world of possibilities to better understand the interplay between host and bacteria crosstalks, although there are still many questions to be answered in the field, especially when it comes to microbiota‐derived EVs. In this review, we propose to summarize and analyse the current literature about bacterial EVs and possible clinical applications, through answering three main questions: (a) What are bacterial EVs? (b) What are EV impacts on skin inflammatory disease physiopathology? (iii) What are the possible and expected clinical applications of EVs to treat inflammatory skin diseases?
The purpose of this study was to investigate if the
C. acnes
present at the end of a primary shoulder arthroplasty could be responsible for shoulder arthroplasty infection. Prospective study includes ...patients undergoing primary shoulder arthroplasty from January 2015 until December 2018. From all the patients included, 5 to 12 tissue samples were obtained and were specifically cultured to detect the presence of
C. acnes.
DNA was extracted from the
C acnes
isolated colonies and Whole Genome Sequencing (WGS) analysis was done. A cohort of 156 patients was finally included. In twenty-seven patients, the
C. acnes
was present at the end of the primary surgery. Two of these patients developed a
C. acnes
periprosthetic shoulder infection at 6 and 4 months after the primary surgery. WGS of
C. acnes
isolated colonies showed that all the revision-surgery isolates clustered near to the corresponding primary-surgery isolates compared to the other independent bacterial colonies. (99.89% of similarity).
C. acnes
present at the end of the primary surgery can be the cause of early or delayed periprosthetic joint infections in shoulder arthroplasty.
In this study, we developed and compared four protocols to prepare a bacterial pellet from 944 positive blood cultures for direct MALDI-TOF mass spectrometry Vitek® MS analysis. Protocol 4, tested on ...200 monomicrobial samples, allowed 83% of bacterial identification. This easy, fast, cheap and accurate method is promising in daily practice, especially to limit broad range antibiotic treatment.
•A new, fast and accurate method for bacterial identification is described.•Direct MALDI-TOF identification from blood bottle culture is efficient in routine.•A 99% of direct MALDI-TOF identification was obtained.•The method was congruent at the species level.•Enterobacteriaceae and staphylococci were better identified than streptococci.
Background
Recent guidelines advise against prophylactic antibiotics in patients with necrotizing pancreatitis, advocating instead a step-up drainage and necrosectomy strategy with antibiotics as ...dictated by microbiological findings. However, prompt antibiotic therapy is recommended in patients with sepsis or septic shock, a possible presentation of infected pancreatic necrosis (IPN). Consequently, in many critically ill patients with IPN, pancreatic samples are collected only after broad-spectrum antibiotic therapy initiation. Whether this prior antibiotic exposure alters the microbiological findings is unknown. The main objective was to determine whether prior antibiotic exposure sterilized the samples collected during procedures for suspected IPN in patients admitted to the intensive care unit (ICU) for acute pancreatitis with suspected IPN. We retrospectively studied 56 consecutive ICU patients admitted with suspected IPN. We collected details on the microbiological samples and antimicrobials used. A definite diagnosis of IPN was given when bacteria were identified in pancreatic samples.
Results
In all, 137 pancreatic samples were collected, including 91 (66.4%) after antibiotic therapy initiation. IPN was confirmed in 48 (86%) patients. The proportion of positive samples was 74 (81.3%) in antibiotic-exposed patients and 32/46 (69.5%) in unexposed patients (
p
= 0.58). Of the 74 positive samples from exposed patients, 62 (84%) had organisms susceptible to the antibiotics used. One-third of samples contained more than one organism. Among patients with IPN, 37.5% had positive blood cultures. Multidrug- or extensively drug-resistant bacteria were identified at some point in half the patients.
Enterobacter cloacae
complex was more frequent in the exposed group (
p
= 0.02), as were Gram-negative anaerobic bacteria (
p
= 0.03).
Conclusion
Antibiotic exposure before sampling did not seem to affect culture positivity of pancreatic samples to confirm IPN, but may affect microbiological findings. Our results suggest that, in patients with sepsis and suspected IPN, antibiotics should be started immediately and pancreatic samples obtained as soon as possible thereafter. In other situations, antibiotics can be withheld until the microbiological results of pancreatic samples are available, to ensure accurate targeting of the spectrum to bacterial susceptibility patterns.
ClinicalTrials.gov number
NCT03253861
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