INVOLVEMENT OF RESPIRATORY CHAIN IN BIOFILM FORMATION IN PORPHYROMONAS GINGIVALIS

Oral Communication presented at the ";Forum des Jeunes Chercheurs";, Brest (France) 2011

Prevalence of oropharyngeal beta-lactamase-producing Capnocytophaga spp. in pediatric oncology patients over a ten-year period

BACKGROUND: The aim of this study was to evaluate the prevalence of beta-lactamase-producing Capnocytophaga isolates in young children hospitalized in the Pediatric Oncology Department of Hôpital Sud (Rennes, France) over a ten-year period (1993–2002). METHODS: In neutropenic children, a periodic survey of the oral cavity allows a predictive evaluation of the risk of systemic infections by Capnocytophaga spp. In 449 children with cancer, 3,053 samples were collected by oral swabbing and plated on TBBP agar. The susceptibility of Capnocytophaga isolates to five beta-lactams was determined. RESULTS: A total of 440 strains of Capnocytophaga spp. were isolated, 309 (70%) of which were beta-lactamase producers. The beta-lactamase-producing strains were all resistant to cefazolin, 86% to amoxicillin, and 63% to ceftazidime. The proportion of strains resistant to third-generation cephalosporins remained high throughout the ten-year study, while susceptibility to imipenem and amoxicillin combined with clavulanic acid was always conserved. CONCLUSION: These results highlight the risk of antibiotic failure in Capnocytophaga infections and the importance of monitoring immunosuppressed patients and testing for antibiotic susceptibility and beta-lactamase production

Porphyromonas gingivalis Participates in Pathogenesis of Human Abdominal Aortic Aneurysm by Neutrophil Activation. Proof of Concept in Rats

International audienceBACKGROUND: Abdominal Aortic Aneurysms (AAAs) represent a particular form of atherothrombosis where neutrophil proteolytic activity plays a major role. We postulated that neutrophil recruitment and activation participating in AAA growth may originate in part from repeated episodes of periodontal bacteremia. METHODS AND FINDINGS: Our results show that neutrophil activation in human AAA was associated with Neutrophil Extracellular Trap (NET) formation in the IntraLuminal Thrombus, leading to the release of cell-free DNA. Human AAA samples were shown to contain bacterial DNA with high frequency (11/16), and in particular that of Porphyromonas gingivalis (Pg), the most prevalent pathogen involved in chronic periodontitis, a common form of periodontal disease. Both DNA reflecting the presence of NETs and antibodies to Pg were found to be increased in plasma of patients with AAA. Using a rat model of AAA, we demonstrated that repeated injection of Pg fostered aneurysm development, associated with pathological characteristics similar to those observed in humans, such as the persistence of a neutrophil-rich luminal thrombus, not observed in saline-injected rats in which a healing process was observed. CONCLUSIONS: Thus, the control of periodontal disease may represent a therapeutic target to limit human AAA progression

Treponema, Iron and Neurodegeneration

International audienceSpirochetes are suspected to be linked to the genesis of neurological diseases, including neurosyphillis or neurodegeneration (ND). Impaired iron homeostasis has been implicated in loss of function in several enzymes requiring iron as a cofactor, formation of toxic oxidative species, inflammation and elevated production of beta-amyloid proteins. This review proposes to discuss the link that may exist between the involvement of Treponema spp. in the genesis or worsening of ND, and iron dyshomeostasis. Proteins secreted by Treponema can act directly on iron metabolism, with hemin binding ability (HbpA and HbpB) and iron reductase able to reduce the central ferric iron of hemin, iron-containing proteins (rubredoxin, neelaredoxin, desulfoferrodoxin metalloproteins, bacterioferritins etc). Treponema can also interact with cellular compounds, especially plasma proteins involved in iron metabolism, contributing to the virulence of the syphilis spirochetes (e.g. treponemal motility and survival). Fibronectin, transferrin and lactoferrin were also shown to be receptors for treponemal adherence to host cells and extracellular matrix. Association between Treponema and iron binding proteins results in iron accumulation and sequestration by Treponema from host macromolecules during systemic and mucosal infections

Orthodontic strategies in pediatric oncology

Cancer in children is not uncommon and can occur at any age. After summarizing the pediatric cancer epidemiology, dentofacial orthopedics and orthodontics during anticancer treatments will be discussed. Orthodontic management in children with cancer differ depending on the type and time of the anticancer therapy: before, during and after chemo- or radiotherapy. The pathophysiological, psychological, administrative and technical concerns are described for every situation. Finally, we suggest some recommendations, according to the current knowledge and our own dentist experience in the pediatric oncology department of Rennes

Prise en charge orthodontique en oncologie pédiatrique

International audienceLe cancer de l'enfant n'est pas une maladie rare et survient à tout âge. Après avoir résumé l'épidémiologie des cancers pédiatriques, l'orthopédie dento-faciale et l'orthodontie lors de la prise en charge pour un traitement anticancéreux seront discutées. La gestion orthodontique des jeunes patients est différente selon la thérapeutique anticancéreuse et selon le moment : avant, pendant et à distance de la chimiothérapie ou de la radiothérapie. Les aspects physiopathologiques, sociopsychologiques, administratifs et techniques à considérer lors de l'évaluation orthodontique chez un enfant atteint de cancer sont décrits pour chacun de ces temps. Au regard de la bibliographie actuelle et de notre expérience de chirurgiens-dentistes dans le service d'onco-hématologie pédiatrique du CHU de Rennes, nous formulons des recommandations. ABSTRACT Cancer in children is not uncommon and can occur at any age. After summarizing the paediatric cancer epidemiology, dento-facial orthopaedics and orthodontics during anticancer treatments will be discussed. Orthodontic management in children with cancer differ depending on the type and time of the anticancer therapy: before, during and after chemo-or radiotherapy. The pathophysiological, psychological, administrative and technical concerns are described for every situation. Finally, we suggest some recommendations, according to the current knowledge and our own dentist experience in the paediatric oncology department of Rennes. Article disponible sur le site http://odf.edpsciences.org ou http://dx

Multidrug-resistant oral Capnocytophaga gingivalis responsible for an acute exacerbation of chronic obstructive pulmonary disease: Case report and literature review

International audienceCapnocytophaga genus was recently known to highly contribute to the beta-lactam (BL) and macrolide-lincosamide-streptogramin (MLS) resistance gene reservoir in the oral microbiota (BL: bla and bla; MLS: erm(F) and erm(C)). But fluoroquinolone (FQ) resistance remains uncommon in literature, without available data on resistance mechanisms. For the first time, a case of acute exacerbation of chronic obstructive pulmonary disease (COPD) was described in a 78-year-old immunocompetent patient due to a multidrug-resistant Capnocytophaga gingivalis isolate with significant microbiological finding. C.gingivalis acquired resistance to third generation cephalosporins (bla gene), MLS (erm(F) gene), and fluoroquinolones. Genetics of the resistance, unknown as regards fluoroquinolone, was investigated and a substitution in QRDR of GyrA was described (Gly80Asn substitution) for the first time in the Capnocytophaga genus. A comprehensive literature review of Capnocytophaga spp. extra-oral infection was conducted. Including the present report, on 43 cases, 7 isolates were BL-resistant (17%), 4 isolates were MLS-resistant (9.5%) and 4 isolates were FQ-resistant (9.5%). The studied clinical isolate of C.gingivalis was the only one to combine resistance to the three groups of antibiotics BL, MLS and FQ. Four cases of Capnocytophaga lung infection were reported, including three infections involving C. gingivalis (two FQ resistant) and one involving C. sputigena. This multidrug-resistant C. gingivalis isolate illustrated the role of oral flora as a reservoir of antibiotic resistance and its contribution to the limitation of effective antibiotics in severe respiratory infections