Relationship among Streptococcus gallolyticus Subsp. gallolyticus, Enterococcus faecalis and Colorectal Neoplasms in Recurrent Endocarditis: A Historical Case Series

The role of time to positive blood cultures in enhancing the predictive capability of DENOVA score for diagnosing infective endocarditis in patients with Enterococcus faecalis bacteremia

DENOVA-score is useful to stratify the risk of infective endocarditis (IE) in Enterococcus faecalis bacteremia. Recently, time to positive (TTP) of blood cultures has also been related with a higher risk of IE. The objective was to evaluate DENOVA- score with TTP to improve its specificity. We performed a retrospective, case-control study in adult patients with E. faecalis bacteremia. Thirty-nine patients with definite E. faecalis IE and 82 with E. faecalis bacteremia were included. The addition of a TTP ≤ 8 h to DENOVA-score did not improve the diagnostic accuracy of this score.

Guideline for designing microbiome studies in neoplastic diseases

Oncobiosis has emerged as a key contributor to the development, and modulator of the treatment efficacy of cancer. Hereby, we review the modalities through which the oncobiome can support the progression of tumors, and the emerging therapeutic opportunities they present. The review highlights the inherent challenges and limitations faced in sampling and accurately characterizing oncobiome. Additionally, the review underscores the critical need for the standardization of microbial analysis techniques and the consistent reporting of microbiome data. We provide a suggested metadata set that should accompany microbiome datasets from oncological settings so that studies remain comparable and decipherable.

Proteomics-based vaccine targets annotation and design of multi-epitope vaccine against antibiotic-resistant Streptococcus gallolyticus

Streptococcus gallolyticus is a non-motile, gram-positive bacterium that causes infective endocarditis. S. gallolyticus has developed resistance to existing antibiotics, and no vaccine is currently available. Therefore, it is essential to develop an effective S. gallolyticus vaccine. Core proteomics was used in this study together with subtractive proteomics and reverse vaccinology approach to find antigenic proteins that could be utilized for the design of the S. gallolyticus multi-epitope vaccine. The pipeline identified two antigenic proteins as potential vaccine targets: penicillin-binding protein and the ATP synthase subunit. T and B cell epitopes from the specific proteins were forecasted employing several immunoinformatics and bioinformatics resources. A vaccine (360 amino acids) was created using a combination of seven cytotoxic T cell lymphocyte (CTL), three helper T cell lymphocyte (HTL), and five linear B cell lymphocyte (LBL) epitopes. To increase immune responses, the vaccine was paired with a cholera enterotoxin subunit B (CTB) adjuvant. The developed vaccine was highly antigenic, non-allergenic, and stable for human use. The vaccine's binding affinity and molecular interactions with the human immunological receptor TLR4 were studied using molecular mechanics/generalized Born surface area (MMGBSA), molecular docking, and molecular dynamic (MD) simulation analyses. Escherichia coli (strain K12) plasmid vector pET-28a ( +) was used to examine the ability of the vaccine to be expressed. According to the outcomes of these computer experiments, the vaccine is quite promising in terms of developing a protective immunity against diseases. However, in vitro and animal research are required to validate our findings.

Enterococcus spp. and Streptococcus spp. bloodstream infections: epidemiology and therapeutic approach

Streptococcus spp. and Enterococcus spp. are frequent etiologies of bloodstream infection and endocarditis. In recent years, the incidence of Enterococcus spp. has been increasing, especially with nosocomial involvement, and with a high mortality rate. In this entity, the risk of endocarditis and its relationship with colorectal neoplastic pathology remains to be clarified, in order to establish indications for echocardiography and colonoscopy. In the case of Streptococcus spp., the risk of endocarditis depends on the species and the mortality rates are usually lower. Finally, in recent years, the treatment of endocarditis has been directed towards oral consolidation regimens and new long-term antibiotic treatments.

Spinal Infection Due to Enterococcus faecalis as the First Manifestation of Colorectal Cancer

Spinal epidural abscess is a relatively infrequent surgical indication, but it may be neurologically compromising. The most frequent pathogen is Staphylococcus aureus, present in two-thirds of the cases. Enterococcus faecalis is part of the intestinal flora and is uncommon in this condition. Colorectal cancer is reported to be a cause of hematogenic translocation and distant infection. We present a case of an 82-year-old patient admitted for acute low back pain with increased inflammatory markers and negative blood cultures. An MRI revealed an epidural lumbar abscess with adjacent spondylitis. After surgical treatment, E. faecalis was identified, and antibiotics were adjusted accordingly. A colonoscopy revealed colon cancer. This is the first case in the literature of a spinal epidural abscess by E. faecalis as the first manifestation of a newly diagnosed colorectal cancer. When facing a spinal infection caused by atypical intestinal bacteria and no other clear sources, a colonoscopy should be considered.

The Regulations of Essential WalRK Two-Component System on Enterococcus faecalis

Enterococcus faecalis (E. faecalis) is a Gram-positive, facultative anaerobic bacterium that is highly adaptable to its environment. In humans, it can cause serious infections with biofilm formation. With increasing attention on its health threat, prevention and control of biofilm formation in E. faecalis have been observed. Many factors including polysaccharides as well as autolysis, proteases, and eDNA regulate biofilm formation. Those contributors are regulated by several important regulatory systems involving the two-component signal transduction system (TCS) for its adaptation to the environment. Highly conserved WalRK as one of 17 TCSs is the only essential TCS in E. faecalis. In addition to biofilm formation, various metabolisms, including cell wall construction, drug resistance, as well as interactions among regulatory systems and resistance to the host immune system, can be modulated by the WalRK system. Therefore, WalRK has been identified as a key target for E. faecalis infection control. In the present review, the regulation of WalRK on E. faecalis pathogenesis and associated therapeutic strategies are demonstrated.