Study of the genus Porphyromonas in the lung micro-environment of people with cystic fibrosis

Des études récentes sur le microbiote pulmonaire des patients atteints de mucoviscidose ont mis en lumière une part importante de bactéries anaérobies dont le rôle exact n’est pas connu à ce jour. Parmi ces bactéries, le genre Porphyromonas est associé à un microbiote sain et identifié comme un genre d’intérêt, car potentiellement prédictif de la colonisation à Pseudomonas aeruginosa au niveau pulmonaire chez les patients atteints de mucoviscidose. Toutefois, très peu d’informations sont disponibles sur les espèces non pigmentées de Porphyromonas comme P. catoniae à l’inverse de P. gingivalis. L’objectif de cette thèse était de mieux comprendre le rôle du genre Porphyromonas au sein du microbiote pulmonaire des patients atteints de mucoviscidose.Cette thèse a permis de mettre en évidence que les espèces non pigmentées de Porphyromonas (P. catoniae et P. pasteri) dominaient dans l’environnement pulmonaire et non P. gingivalis. Contrairement à l’espèce P. gingivalis, ces espèces arborent un comportement commensal vis-à-vis de l’hôte voir un comportement potentiellement protecteur lors de l’infection pulmonaire à P. aeruginosa dans un modèle murin de pneumonie aiguë. Bien que d’autres études soient nécessaires pour conclure définitivement, cette thèse met en avant l’importance de distinguer les espèces pigmentées et non pigmentées de Porphyromonas au niveau pulmonaire dont les impacts semblent opposés.Recent studies on lung microbiota highlight an important part of anaerobic bacteria those role is not yet deciphered. Among those bacteria, the genus Porphyromonas is associated with a healthy microbiota and was identified as a potential predictive biomarker of lung infection to Pseudomonas aeruginosa in people with cystic fibrosis. However, not much informations are available on non-pigmented species of Porphyromonas like P. catoniae, conversely to P. gingivalis. The goal of this thesis was to better understand the role of Porphyromonas within the lung microbiota of people with cystic fibrosis.This thesis highlights that non pigmented species of Porphyromonas (P. catoniae and P. pasteri) dominate in the lung environment and not P. gingivalis. Conversely to the species P. gingivalis, those species seems to act as commensals for the host and are potentially protective in the context of a lung acute infection by P. aeruginosa in a murin model. Despite the need of further studies to conclude, this thesis highlight the importance to distinguish pigmented and non pigmented Porphyromonas species in the lung environment as they seem to act differently

Les bactéries anaérobies, ces inconnues du microbiote pulmonaire

La médecine a longtemps considéré le poumon comme un organe stérile. Il est désormais évident qu’il est colonisé par des microorganismes, y compris chez les sujets sains. Parmi les bactéries présentes dans le microbiote pulmonaire, une part importante est anaérobie (strictes ou facultatives). Si l’intérêt et l’impact du microbiote, en général, et pulmonaire en particulier, vont grandissant, peu d’études s’intéressent à ces inconnues que représentent ces bactéries anaérobies résidentes des poumons. Cette synthèse bibliographique décrit la biodiversité des anaérobies en situation physiologique et dans différentes maladies respiratoires chroniques (mucoviscidose, BPCO, asthme), abordant tour à tour leurs rôles dans l’effet de flore barrière, dans l’inflammation, ou encore comme potentiel biomarqueur de certaines maladies pulmonaires

Porphyromonas: A neglected potential key genus in human microbiomes

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The Human Microbiome, an Emerging Key-Player in the Sex Gap in Respiratory Diseases

International audienceThe sex gap is well-documented in respiratory diseases such as cystic fibrosis and chronic obstructive pulmonary disease. While the differences between males and females in prevalence, severity and prognosis are well-established, the pathophysiology of the sex difference has been poorly characterized to date. Over the past 10 years, metagenomics-based studies have revealed the presence of a resident microbiome in the respiratory tract and its central role in respiratory disease. The lung microbiome is associated with host immune response and health outcomes in both animal models and patient cohorts. The study of the lung microbiome is therefore an interesting new avenue to explore in order to understand the sex gap observed in respiratory diseases. Another important parameter to consider is the gut-lung axis, since the gut microbiome plays a crucial role in distant immune modulation in respiratory diseases, and an intestinal “microgenderome” has been reported: i.e., sexual dimorphism in the gut microbiome. The microgenderome provides new pathophysiological clues, as it defines the interactions between microbiome, sex hormones, immunity and disease susceptibility. As research on the microbiome is increasing in volume and scope, the objective of this review was to describe the state-of-the-art on the sex gap in respiratory medicine (acute pulmonary infection and chronic lung disease) in the light of the microbiome, including evidence of local (lung) or distant (gut) contributions to the pathophysiology of these diseases.Le dépistage néonatal (DNN) de la mucoviscidose a permis une prise en charge multidisciplinaire très précoce des nourrissons et a amélioré le pronostic de cette maladie. Il a connu, en une vingtaine d’années, un développement international spectaculaire. Les performances du DNN national français, réalisé depuis 2002, répondent aux exigences des standards européens en termes de valeur prédictive positive et de sensibilité. Nous pouvons noter, en particulier, un nombre très faible de cas en attente de conclusion, un pourcentage très élevé de tests de la sueur réalisés et d’identification des mutations du gène c ystic fibrosis transmembrane conductance regulator (CFTR) , un ratio important de cas de mucoviscidose par rapport aux cas de diagnostics non conclus, ainsi qu’une stratégie efficace pour repérer les faux-négatifs. Une nouvelle organisation du DNN français a été mise en place. Il est donc capital de maintenir l’efficacité du processus ainsi mis en place, du nouveau-né en maternité jusqu’au diagnostic dans des centres de ressources et de compétences de la mucoviscidose, avec le recueil exhaustif des données et leur validation

Anaerobes in cystic fibrosis patients' airways

International audienceAnaerobes are known to constitute an important part of the airway microbiota in both healthy subjects and cystic fibrosis (CF) patients. Studies on the potential role of anaerobic bacteria in CF and thus their involvement in CF pathophysiology have reported contradictory results, and the question is still not elucidated. The aim of this study was to summarize anaerobe diversity in the airway microbiota and its potential role in CF, to provide an overview of the state of knowledge on anaerobe antibiotic resistances (resistome), and to investigate the detectable metabolites produced by anaerobes in CF airways (metabolome). This review emphasizes key metabolites produced by strict anaerobic bacteria (sphingolipids, fermentation-induced metabolites and metabolites involved in quorum-sensing), which may be essential for the better understanding of lung disease pathophysiology in CF

Prevotella melaninogenica, a Sentinel Species of Antibiotic Resistance in Cystic Fibrosis Respiratory Niche?

International audienceThe importance and abundance of strict anaerobic bacteria in the respiratory microbiota of people with cystic fibrosis (PWCF) is now established through studies based on high-throughput sequencing or extended-culture methods. In CF respiratory niche, one of the most prevalent anaerobic genera is Prevotella, and particularly the species Prevotella melaninogenica. The objective of this study was to evaluate the antibiotic susceptibility of this anaerobic species. Fifty isolates of P. melaninogenica cultured from sputum of 50 PWCF have been included. Antibiotic susceptibility testing was performed using the agar diffusion method. All isolates were susceptible to the following antibiotics: amoxicillin/clavulanic acid, piperacillin/tazobactam, imipenem and metronidazole. A total of 96% of the isolates (48/50) were resistant to amoxicillin (indicating beta-lactamase production), 34% to clindamycin (17/50) and 24% to moxifloxacin (12/50). Moreover, 10% (5/50) were multidrug-resistant. A significant and positive correlation was found between clindamycin resistance and chronic azithromycin administration. This preliminary study on a predominant species of the lung “anaerobiome” shows high percentages of resistance, potentially exacerbated by the initiation of long-term antibiotic therapy in PWCF. The anaerobic resistome characterization, focusing on species rather than genera, is needed in the future to better prevent the emergence of resistance within lung microbiota

Methods for predicting the risk of developing pulmonary colonization/infection by pseudomonas aeruginosa

The present invention relates to methods for predicting the risk of developing pulmonary colonization/infection by P. aeruginosa. The inventors analyzed the respiratory tract microbiota from 65 patients sputum samples and compared microbiota data. The inventors found that patients that will remain uninfected from P. aeruginosa exhibited 3-fold higher abundance of Porphyromonas catoniae compared to the other groups. In particular, the present invention relates to a method for predicting the risk of developing pulmonary colonization/infection by P. aeruginosa in a subject suffering from cystic fibrosis (CF) comprising measuring the abundance of Porphyromonas catoniae in a biological sample obtained from said subject

Priming with intranasal lactobacilli prevents Pseudomonas aeruginosa acute pneumonia in mice

Abstract Background Increasing resistance to antibiotics of Pseudomonas aeruginosa leads to therapeutic deadlock and alternative therapies are needed. We aimed to evaluate the effects of Lactobacillus clinical isolates in vivo, through intranasal administration on a murine model of Pseudomonas aeruginosa pneumonia. Results We screened in vitro 50 pulmonary clinical isolates of Lactobacillus for their ability to decrease the synthesis of two QS dependent-virulence factors (elastase and pyocyanin) produced by Pseudomonas aeruginosa strain PAO1. Two blends of three Lactobacillus isolates were then tested in vivo: one with highly effective anti-PAO1 virulence factors properties (blend named L.rff for L. rhamnosus, two L. fermentum strains), and the second with no properties (blend named L.psb, for L. paracasei, L. salivarius and L. brevis). Each blend was administered intranasally to mice 18 h prior to PAO1 pulmonary infection. Animal survival, bacterial loads, cytological analysis, and cytokines secretion in the lungs were evaluated at 6 or 24 h post infection with PAO1. Intranasal priming with both lactobacilli blends significantly improved 7-day mice survival from 12% for the control PAO1 group to 71 and 100% for the two groups receiving L.rff and L.psb respectively. No mortality was observed for both control groups receiving either L.rff or L.psb. Additionally, the PAO1 lung clearance was significantly enhanced at 24 h. A 2-log and 4-log reduction was observed in the L.rff + PAO1 and L.psb + PAO1 groups respectively, compared to the control PAO1 group. Significant reductions in neutrophil recruitment and proinflammatory cytokine and chemokine secretion were observed after lactobacilli administration compared to saline solution, whereas IL-10 production was increased. Conclusions These results demonstrate that intranasal priming with lactobacilli acts as a prophylaxis, and avoids fatal complications caused by Pseudomonas aeruginosa pneumonia in mice. These results were independent of in vitro anti-Pseudomonas aeruginosa activity on QS-dependent virulence factors. Further experiments are required to identify the immune mechanism before initiating clinical trials

<em>Porphyromonas</em>, a potential predictive biomarker of Pseudomonas aeruginosa pulmonary infection in cystic fibrosis

Additional material is published online only. To view please visit the journal online (http://dx.doi.org/10.1136/bmjresp-2018-000374).International audienceIntroduction : Pseudomonas aeruginosa pulmonary infections are the primary cause of morbi-mortality in patients with cystic fibrosis (CF). In this cohort study, the objective was to identify candidate biomarkers of P. aeruginosa infection within the airway microbiota. Methods : A 3-year prospective multicentre study (PYOMUCO study) was conducted in Western France and included patients initially P. aeruginosa free for at least 1year. A 16S-targeted metagenomics approach was applied on iterative sputum samples of a first set of patients (n=33). The composition of airway microbiota was compared according to their P. aeruginosa status at the end of the follow-up (colonised vs non-colonised), and biomarkers associated with P. aeruginosa were screened. In a second step, the distribution of a candidate biomarker according to the two groups of patients was verified by qPCR on a second set of patients (n=52) coming from the same cohort and its load quantified throughout the follow-up. Results : Porphyromonas (mainly P. catoniae) was found to be an enriched phylotype in patients uninfected by P. aeruginosa (pDiscussion : Further studies on replication cohorts are needed to validate this potential predictive biomarker, which may be relevant for the follow-up in the early years of patients with CF. The identification of infection candidate biomarkers may offer new strategies for CF prevision medicine