The influence of incubation time, sample preparation and exposure to oxygen on the quality of the MALDI-TOF MS spectrum of anaerobic bacteria

AbstractWith matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), bacteria can be identified quickly and reliably. This accounts especially for anaerobic bacteria. Because growth rate and oxygen sensitivity differ among anaerobic bacteria, we aimed to study the influence of incubation time, exposure to oxygen and sample preparation on the quality of the spectrum using the Bruker system. Also, reproducibility and inter-examiner variability were determined. Twenty-six anaerobic species, representing 17 genera, were selected based on gram-stain characteristics, growth rate and colony morphology. Inter-examiner variation showed that experience in the preparation of the targets can be a significant variable. The influence of incubation time was determined between 24 and 96 h of incubation. Reliable species identification was obtained after 48 h of incubation for gram-negative anaerobes and after 72 h for gram-positive anaerobes. Exposure of the cultures to oxygen did not influence the results of the MALDI-TOF MS identifications of all tested gram-positive species. Fusobacterium necrophorum and Prevotella intermedia could not be identified after >24 h and 48 h of exposure to oxygen, respectively. Other tested gram-negative bacteria could be identified after 48 h of exposure to oxygen. Most of the tested species could be identified using the direct spotting method. Bifidobacterium longum and Finegoldia magna needed on-target extraction with 70% formic acid in order to obtain reliable species identification and Peptoniphilus ivorii a full extraction. Spectrum quality was influenced by the amount of bacteria spotted on the target, the homogeneity of the smear and the experience of the examiner

Non-surgical peri-implantitis treatment using a pocket irrigator device; clinical, microbiological, radiographical and patient-centred outcomes-A pilot study

Aim: The aim of this prospective cohort study was to assess the effect of a pocket irrigator/evacuator device (IED) in the non-surgical treatment of peri-implantitis. Material and Methods: In total 24 patients having 38 implants diagnosed with peri-implantitis were included in this study. Peri-implant pockets were irrigated six times in three consecutive weeks. The primary outcome was bleeding on probing (BoP). Secondary outcome parameters included plaque index (Pl), suppuration on probing (SoP), probing pocket depth (PPD), marginal bone loss (MBL), presence and numbers of periodontal pathogens. Parameters were assessed at baseline and 3 months after the last treatment. Treatment pain perception was scored using the visual analog scale (VAS) after the first and last treatment. Results: At 3 months, IED treatment revealed significant reduction of peri-implant BoP (71% [±20] vs 57% [±28] [P =.014]) and peri-implant plaque scores (10 [±14] to 5 [±9] [P =.039] [T0 vs T3 respectively]). Significant reduction in mean peri-implant PPD from 4.92 mm (SD ± 1.28) to 4.66 mm (SD ± 1.35) (P =.041) was observed. In addition, a reduction in VAS pain score between the first and the last (6th) treatment was found (P =.039). No reduction in SoP (P =.088) was found. No changes in mean periodontal full mouth plaque, BOP, SOP and PPD levels, MBL and microbiological outcomes were found. Conclusion: Beneficial clinical effects in terms of BoP, PPD and PI were found at 3 months after IED treatment. However, the IED does not seem to effectively treat peri-implantitis in terms of disease resolution

The optimization and validation of the Biotyper MALDI-TOF MS database for the identification of Gram-positive anaerobic cocci

OBJECTIVES: Gram-positive anaerobic cocci (GPAC) account for 24-31% of the anaerobic bacteria isolated from human clinical specimens. At present GPAC are underrepresented in the Biotyper MALDI-TOF MS database. Profiles of new species have yet to be added. We present the optimization of the MALDI-TOF MS database for the identification of GPAC. METHODS: Main Spectral Profiles (MSPs) were created for 108 clinical GPAC isolates. Identity was confirmed using 16S rRNA gene sequencing. Species identification was considered to be reliable if the sequence similarity with its closest relative was ≥98.7%. The optimized database was validated using 140 clinical isolates. The 16S rRNA sequencing identity was compared with the MALDI-TOF MS result. RESULTS: MSPs were added from 17 species that were not yet represented in the MALDI-TOF MS database or were underrepresented (<5 MSPs). This resulted in an increase from 53.6% (75/140) to 82.1% (115/140) of GPAC isolates that could be identified at the species level using MALDI-TOF MS. An improved log score was obtained for 51.4% (72/140) of the strains. For strains with a sequence similarity <98.7% with their closest relative (n=5) or with an inconclusive sequence identity (n=4), no identification was obtained by MALDI-TOF MS or in the latter case an identity with one of its relatives. CONCLUSIONS: For some species the MSP of the type strain was not a part of the confined cluster of the corresponding clinical isolates. Also, not all species formed a homogeneous cluster. It emphasizes the necessity of adding sufficient MSPs of human clinical isolates

Erythritol airpolishing in the non-surgical treatment of peri-implantitis:A randomized controlled trial

OBJECTIVES: To compare erythritol air-polishing with piezoelectric ultrasonic scaling in the non-surgical treatment of peri-implantitis. MATERIAL AND METHODS: Eighty patients (n=139 implants) with peri-implantitis (probing pocket depth (PPD) ≥5mm, marginal bone loss (MBL) ≥2mm as compared to bone level at implant placement, bleeding and/or suppuration on probing (BoP/SoP)) were randomly allocated to air-polishing or ultrasonic treatment. The primary outcome was mean BoP (%) at 3 months after therapy (T3). Secondary outcomes were mean SoP (%), plaque score (Plq) (%), PPD (mm), MBL (mm), full mouth periodontal scores (FMPS) (%), levels of 8 classical periodontal pathogens and treatment pain/discomfort (Visual Analog Scale, VAS). Patients who were considered successful at T3 were additionally assessed at 6, 9 and 12 months. Differences between both groups were analysed using multilevel statistics. RESULTS: Three months after therapy, no significant difference in mean BoP (%) between the air-polishing and ultrasonic therapy was found (crude analysis β (95% CI) -0.037 (-0.147; 0.073), p = 0.380). Neither secondary outcomes SoP (%), Plq (%), PPD (mm), MBL (mm), FMPS (%) and periodontal pathogens showed significant differences. Treatment pain/discomfort was low in both groups (VAS score air-polishing group 2.1 (±1.9), ultrasonic 2.6 (±1.9); p = 0.222). All successfully treated patients at T3 (18.4%) were still considered successful at 12 months follow-up. CONCLUSIONS: Erythritol air-polishing seems as effective as piezoelectric ultrasonic scaling in the non-surgical treatment of peri-implantitis, in terms of clinical, radiographical and microbiological parameters. However, neither of the proposed therapies effectively resolved peri-implantits. Hence, the majority of patients required further surgical treatment

Rheumatoid arthritis and periodontitis; a possible link via citrullination

Rheumatoid Arthritis (RA) and chronic and aggressive periodontitis are chronic inflammatory disorders characterized by deregulation of the host inflammatory response. Increased secretion of pro-inflammatory mediators results in soft and hard tissue destruction of the synovium and periodontium respectively. Both diseases share risk factors and have pathological pathways in common, resulting in loss of function and disability as a final clinical outcome. This article discusses possible interactions, particularly related to the periodontal pathogen Porphyromonas gingivalis, which could explain the observed association between these two prevalent diseases. (C) 2011 Elsevier Ltd. All rights reserved

Erythritol air polishing in the surgical treatment of peri-implantitis:A randomized controlled trial

Objectives: To compare erythritol air polishing with implant surface cleansing using saline during the surgical treatment of peri-implantitis. Material and Methods: During a resective surgical intervention, implant surfaces were randomly treated with either air polishing (test group n = 26 patients/53 implants) or saline-soaked cotton gauzes (control group n = 31 patients/ 40 implants). Primary outcome was change in mean bleeding on probing (BoP) from baseline to 12 months follow-up. Secondary outcomes were changes in mean suppuration on probing (SoP), plaque score (Plq), probing pocket depth (PPD), marginal bone loss (MBL), periodontal full-mouth scores (PFMS), and levels of 8 classical periodontal pathogens. Clinical and radiographical parameters were analyzed using multilevel regression analyses. Microbiological outcomes were analyzed using the Mann-Whitney U test. Results: No differences between the test and control group were found for BoP over 12 months of follow-up, nor for the secondary parameters Plq, PPD, and MBL. Between both groups, a significant difference was found for the levels of SoP (p = 0.035). No significant effect on microbiological levels was found. A total number of 6 implants were lost in the test group and 10 in the control group. At 1-year follow-up, a successful treatment outcome (PPD0.5 mm) was achieved for a total of 18 implants (19.2%). Conclusions: Erythritol air polishing as implant surface cleansing method was not more effective than saline during resective surgical treatment of peri-implantitis in terms of clinical, radiographical, and microbiological parameters. Both therapies resulted in low treatment success

Peri-implant diseases: Consensus Report of the Sixth European Workshop on Periodontology

Issues related to peri-implant disease were discussed. It was observed that the most common lesions that occur, i.e. peri-implant mucositis and peri-implantitis are caused by bacteria. While the lesion of peri-implant mucositis resides in the soft tissues, peri-implantitis also affects the supporting bone. Peri-implant mucositis occurs in about 80% of subjects (50% of sites) restored with implants, and peri-implantitis in between 28% and 56% of subjects (12-40% of sites). A number of risk indicators were identified including (i) poor oral hygiene, (ii) a history of periodontitis, (iii) diabetes and (iv) smoking. It was concluded that the treatment of peri-implant disease must include anti-infective measures. With respect to peri-implant mucositis, it appeared that non-surgical mechanical therapy caused the reduction in inflammation (bleeding on probing) but also that the adjunctive use of antimicrobial mouthrinses had a positive effect. It was agreed that the outcome of non-surgical treatment of peri-implantitis was unpredictable. The primary objective of surgical treatment in peri-implantitis is to get access to the implant surface for debridement and decontamination in order to achieve resolution of the inflammatory lesion. There was limited evidence that such treatment with the adjunctive use of systemic antibiotics could resolve a number of peri-implantitis lesions. There was no evidence that so-called regenerative procedures had additional beneficial effects on treatment outcome

There's no place like OM:Vesicular sorting and secretion of the peptidylarginine deiminase of Porphyromonas gingivalis

The oral pathogen Porphyromonas gingivalis is one of the major periodontal agents and it has been recently hailed as a potential cause of the autoimmune disease rheumatoid arthritis. In particular, the peptidylarginine deiminase enzyme of P. gingivalis (PPAD) has been implicated in the citrullination of certain host proteins and the subsequent appearance of antibodies against citrullinated proteins, which might play a role in the etiology of rheumatoid arthritis. The aim of this study was to investigate the extracellular localization of PPAD in a large panel of clinical P. gingivalis isolates. Here we show that all isolates produced PPAD. In most cases PPAD was abundantly present in secreted outer membrane vesicles (OMVs) that are massively produced by P. gingivalis, and to minor extent in a soluble secreted state. Interestingly, a small subset of clinical isolates showed drastically reduced levels of the OMV-bound PPAD and secreted most of this enzyme in the soluble state. The latter phenotype is strictly associated with a lysine residue at position 373 in PPAD, implicating the more common glutamine residue at this position in PPAD association with OMVs. Further, one isolate displayed severely restricted vesiculation. Together, our findings show for the first time that neither the major association of PPAD with vesicles, nor P. gingivalis vesiculation per se, are needed for P. gingivalis interactions with the human host

Effect of Adjunctive Systemic Azithromycin With Periodontal Surgery in the Treatment of Chronic Periodontitis in Smokers: A Pilot Study

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141533/1/jper1887.pd