Project description:Cutibacterium spp. play an increasing role in soft tissue and implant-associated infections. We isolated a novel Cutibacterium spp. from an implant and investigated this isolate using multiple identification approaches. Correct identification was hampered by inconsistent reference data. The isolate was characterised using conventional methods such as Gram stain, MALDI-TOF MS, and antimicrobial susceptibility testing against multiple antimicrobials. Partial 16S rRNA gene sequencing and whole genome sequencing were also performed. In addition, we summarised the available published sequence data and compared prior data to our strain. Conventional phenotypic identification of our isolate resulted in Cutibacterium spp. After analysis of 16S rRNA gene and genome sequences, our isolate was identified as C. modestum, a very recently described species. The 16S rRNA gene analysis was hampered by three incorrect nucleotides within the 16S rRNA gene reference sequence of C. modestum M12T (accession no. LC466959). We also clearly demonstrate that this novel species is identical to tentatively named "Propionibacterium humerusii". Retrospective data analysis indicates that C. modestum is a clinically important Cutibacterium species often misidentified as C. acnes. The isolation and identification of Cutibacterium spp. is still a challenge. The correct description of very recently named C. modestum and the availability of a correct 16S rRNA sequence of the type strain may help to clarify the taxonomical uncertainty concerning "P. humerusii". The novel C. modestum is an additional, clinically important species within the genus Cutibacterium and may represent a new member of the human skin microbiome.
Project description:Background/aimIdentifying pathogens with culture-negative pyogenic spondylitis is difficult. Shotgun metagenomic sequencing is an unbiased and culture-free approach in the diagnosis of infectious diseases. There are, however, a variety of contaminating factors that can confound the precision of metagenomic sequencing.Case reportIn a 65-year-old man suffering from culture-negative L3-5 spondylitis, metagenomics was applied to facilitate the diagnosis. The patient underwent percutaneous endoscopic lumbar discectomy. We applied metagenomic sequencing with a robust contamination-free protocol to the bone biopsy. By comparing the abundance for each taxon between the replicates and negative controls, we reliably identified Cutibacterium modestum as having a statistically higher abundance in all replicates. The patient's antibiotic therapy was switched to penicillin and doxycycline based upon the resistome analysis; the patient fully recovered.ConclusionThis application of next-generation sequencing provides a new perspective in the clinical approach to spinal osteomyelitis and illustrates the potential of this technique in rapid etiological diagnosis.
Project description:BackgroundCutibacterium modestum is one of the five species of the genus Cutibacterium. While C. acnes has been reported as an important pathogen in bone and joint infections, the clinical characteristics of C. modestum infections remain unclear. Moreover, thus far, there has been no clinical case report regarding C. modestum infections.Case presentationAn 82-year-old man with a history of repeated trigger point injections for lumbago at the L4 level presented with fever and an exacerbation of lumbago. Physical examination indicated knocking pain at the L4-L5 levels; magnetic resonance imaging showed irregular bone destruction of the L4 vertebral body, and low T1 and high T2 intensity lesions at the L4-L5 intervertebral disc. Two sets of blood cultures (two aerobic and two anaerobic) were performed. Intravenous cefazolin was administered, considering the common pathogens of vertebral osteomyelitis, such as Staphylococcus aureus. The patient's condition did not improve; thereafter, anaerobic culture bottles revealed Gram-positive rods on day 11 of incubation. There was no evidence of infective endocarditis upon transthoracic echocardiography. Needle aspiration from the L4-L5 intervertebral disc was performed on day 13 that also showed the presence of Gram-positive rods. The patient was diagnosed with vertebral osteomyelitis caused by C. modestum using a combination of characteristic peak analysis with matrix-assisted laser desorption ionization (MALDI), microbial biochemistry examinations, and 16S rRNA gene sequencing from the blood and pus cultures. He was successfully treated with alternative intravenous ampicillin, followed by oral amoxicillin for 10 weeks, according to the tests for ampicillin susceptibility, with a minimum inhibitory concentration of 0.016 μg/mL using E-test® under aerobic conditions.ConclusionsCutibacterium modestum is a microorganism that is difficult to identify. A combination of characteristic peaks with MALDI, appropriate microbial biochemical examinations, and 16S rRNA gene sequencing may serve as an efficient guide for the identification of C. modestum.