In our series, the majority of patients undergoing dental extractions developed bacteraemia, usually of a streptococcal nature, independently of the grade of oral health and of the number of extractions performed. Positive blood cultures persisted for at least 1 h after the dental procedure in a considerable number of patients, questioning the supposedly transient nature of bacteraemia following dental extractions.

Giant tortoises are amongst the longest-lived vertebrate animals and as such provide an excellent model to study traits like longevity and age-related diseases. However, genomic and molecular evolutionary information on giant tortoises is scarce. Here, we describe a global analysis of the genomes of Lonesome George, the iconic last member of Chelonoidis abingdonii , and the Aldabra giant tortoise ( Aldabrachelys gigantea ). The comparison of these genomes to those of related species, using both unsupervised and supervised analyses, led us to detect lineage-specific variants affecting DNA repair genes, inflammatory mediators and genes related to cancer development. Our study also hints at specific evolutionary strategies linked to increased lifespan and expands our understanding of the genomic determinants of ageing. These new genome sequences also provide important resources to help the efforts for restoration of giant tortoise populations.

The in vivo antimicrobial activity of 0.12% and 0.2% chlorhexidine (CHX) on the salivary flora up to 7 h after its application, using epifluorescence microscopy with the SYTO 9/propidium iodide dual staining, was evaluated. Fifteen volunteers performed a single mouthrinse with sterile water (SM-water), a single mouthrinse with 0.12% CHX (0.12% SM-CHX) and a single and double mouthrinse with 0.2% CHX (0.2% SM-CHX and 0.2% DM-CHX). Samples of saliva were taken at 30 s, and 1, 3, 5, and 7 h after each application. In comparison with SM-water, 0.2% CHX (SM and DM) showed a significant antibacterial effect up to 7 h after the mouthrinse, whereas this effect only persisted up to 5 h after the 0.12% SM-CHX mouthrinse. On comparing the two concentrations of CHX, significantly higher percentages of bacterial vitality were observed in all the saliva samples after the use of 0.12% CHX than after 0.2% CHX. On comparison of the 0.2% SM-CHX and 0.2% DM-CHX, significantly higher percentages of live bacteria were observed in the saliva samples taken at 1, 3, 5, and 7 h after the single mouthrinse compared with the double mouthrinse. The 0.2% CHX mouthrinse had the greatest antimicrobial activity on the salivary flora up to 7 h after its application, with a progressive recovery in bacterial vitality. The differences observed with respect to the 0.12% CHX mouthrinse demonstrate the influence of the concentration on its immediate antimicrobial activity and substantivity.

Epifluorescence microscopy permits evaluating the antimicrobial activity of CHX on the salivary flora in real-time. Fluorescence assays could be particularly useful to analyse simultaneously the effect of antimicrobials that alter the cytoplasmic membrane integrity on different oral ecosystems.

Abstract Genomic studies have recently identified RPS15 as a new driver gene in aggressive and chemorefractory cases of chronic lymphocytic leukemia (CLL). RPS15 encodes a ribosomal protein whose conserved C-terminal domain extends into the decoding center of the ribosome. We demonstrate that mutations in highly conserved residues of this domain affect protein stability, by increasing its ubiquitin-mediated degradation, and cell-proliferation rates. On the other hand, we show that mutated RPS15 can be loaded into the ribosomes, directly impacting on global protein synthesis and/or translational fidelity in a mutation-specific manner. Quantitative mass spectrometry analyses suggest that RPS15 variants may induce additional alterations in the translational machinery, as well as a metabolic shift at the proteome level in HEK293T and MEC-1 cells. These results indicate that CLL-related RPS15 mutations might act following patterns known for other ribosomal diseases, likely switching from a hypo- to a hyperproliferative phenotype driven by mutated ribosomes. In this scenario, loss of translational fidelity causing altered cell proteostasis can be proposed as a new molecular mechanism involved in CLL pathobiology.

Implant placement via a mucoperiosteal flap does not carry a significant risk of developing bacteraemias. The use of antibiotic prophylaxis for the prevention of focal infections such as bacterial endocarditis in "at-risk" patients undergoing dental implants is therefore questionable. Although its efficacy has not been confirmed statistically, we recommend a 0.2% CHX mouthrinse before treatment as proposed previously by the British Society for Antimicrobial Chemotherapy.

ObjectivesTo investigate the development of post-extraction bacteraemia (PEB) after the prophylactic use of chlorhexidine (CHX).Patients and MethodsA total of 201 patients who underwent a tooth extraction were randomly distributed into four groups: 52 received no prophylaxis (CONTROL), 50 did a mouthwash with 0.2% CHX before the tooth extraction (CHX-MW), 51 did a mouthwash with 0.2% CHX and a subgingival irrigation with 1% CHX (CHX-MW/SUB_IR) and 48 did a mouthwash with 0.2% CHX and a continuous supragingival irrigation with 1% CHX (CHX-MW/SUPRA_IR). Peripheral venous blood samples were collected at baseline, 30 seconds after performing the mouthwash and the subgingival or supragingival irrigation, and at 30 seconds and 15 minutes after completion of the tooth extraction. Blood samples were analysed applying conventional microbiological cultures under aerobic and anaerobic conditions performing bacterial identification of the isolates.ResultsThe prevalences of PEB in the CONTROL, CHX-MW, CHX-MW/SUB_IR and CHX-MWSUPRA_IR groups were 52%, 50%, 55% and 50%, respectively, at 30 seconds and 23%, 4%, 10% and 27%, respectively, at 15 minutes. The prevalence of PEB at 15 minutes was significantly higher in the CONTROL group than in the CHX-MW group (23% versus 4%; p = 0.005). At the same time, no differences were found between CONTROL group and CHX-MW/SUB_IR or CHX-MW/SUPRA_IR groups. Streptococci (mostly viridans group streptococci) were the most frequently identified bacteria (69–79%).ConclusionsPerforming a 0.2% CHX mouthwash significantly reduces the duration of PEB. Subgingival irrigation with 1% CHX didn’t increase the efficacy of the mouthwash while supragingival irrigation even decreased this efficacy, probably due to the influence of these maneuvers on the onset of bacteraemia.Clinical RelevanceThese results confirm the suitability of performing a mouthwash with 0.2% CHX before tooth extractions in order to reduce the duration of PEB. This practice should perhaps be extended to all dental manipulations.Trial RegistrationClinicaltrials.gov NCT02150031

We recommend the routine use of a 0.2% chlorhexidine mouthwash before dental extractions to reduce the risk of postextraction bacteremia.