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Contact me : christine.delorme@inra.fr

♦ Research Activities:

The goal of my projects is to understand interaction between commensal and food bacteria, and host using bacteria species of the salivarius group.

Streptococci from the salivarius group are present in all the sections of the human gastrointestinal tract (GIT) (Streptococcus salivarius) and in transit by consumption of fermented dairy products (Streptococcus thermophilus). S. salivarius species is one of the early colonizers of neonatal oral mucosal surfaces few hours after birth and it remains prevalent in the oral cavity and sub-dominant in the gut. These two closely species living in or transiting through GIT.

Phylogeny and nucleotide diversity of the two streptococci species were characterized by multilocus sequence typing scheme (MLST). In order to understand population structure and diversity of both populations comparative genomic analysis were performed. S. thermophilus species displays a low level of nucleotide variability, due to its recent emergence with the development of agriculture. By contrast, nucleotide variability is high in the S. salivarius, reflecting their long-standing association with humans. Analyses of genomic content have indicated a considerable variability of gene content and differences in potential adaptive features. Evidence of widespread genetic exchanges was observed in both streptococci species.

Since few years, I have studied bacterial functions of these streptococci involved in the interactions with host :

                → Anti-inflammatory properties of S. salivarius and S. thermophilus strains have been identified using cellular model and TNBS-induced colitis mouse model. Metabolic compound has been identified in S. salivarius supernatant to promote immunoregulatory responses. Identification of new microbial metabolites being to offer new therapeutic treatments for Inflammatory bowel diseases (IBD).

                → Certain S. salivarius strains are associated with infections occurring after invasive surgery activities. I identified bacterial genetic determinant involved in virulence using genomic comparative analysis of oral and blood isolates, and characterization of virulence of 50 strains in Galleria mellonella insect model.

♦ Curriculum Vitae

Research Experience:

Since 2010      Research scientist at INRA, Micalis Institut, Jouy-en-Josas, France.

• Anti-inflammatory properties of S. salivarius and S.thermophilus
• Identification of molecular determinants as pathogenic factors in opportunistic S. salivarius

2001-2009      Research scientist at INRA, S.D. Ehrlich's unit, Jouy-en-Josas, France.

• Genetic variability in salivarius group and genome sequencing
• Gene transfer and comparative genomics in food streptococci

1993-2000      Research scientist at INRA, S.D. Ehrlich's unit, Jouy-en-Josas, France.

• Regulation of gene expression in Lactococcus lactis

1989-1992      PhD at INRA, Research, S.D. Ehrlich's unit, Jouy-en-Josas, France.

• Regulation of gene expression in Lactococcus lactis

 Education:

• 2011   HDR (Accreditation to supervise PhD students), University of Paris-Saclay, France.
• 1992   PhD degree, UPMC University of Paris, France.

 Research Expertise :

Microbiology - Molecular Biology -  Comparative genomic - Gene expression - Functional genetics - Food and Commensal Streptococci - Lactic Acid Bacteria -  Bacteria/Host Interaction

Other activities and responsabilities  :

• Supervision of 2 PhD students, 7 Master 2 and 3 Master 1
• Member of 7 thesis jury and 1 thesis committee

 Scientific Production  :

• 43 peer-reviewed international publications,
• 2 reviews, 1 book chapter,
• h-index: 24

♦ Peer-reviewed publications of the last five years :

• Dahmane, N., Robert, E., Deschamps, J., Meylheuc, T., Delorme, C., Briandet, R., Leblond-Bourget, N., Guedon, E., Payot-Lacroix, S. (2018). Impact of cell surface molecules on conjugative transfer of the integrative and conjugative element ICESt3 of Streptococcus thermophilus. Applied and Environmental Microbiology, 84 (5), 109-2117.DOI : 10.1128/AEM.02109-17

• Couvigny, B., Kulakauskas, S., Pons, N., Quinquis, B., Abraham, A.-L., Meylheuc, T., Delorme, C., Renault, P., Briandet, R., Lapaque, N., Guedon, E. (2018). Identification of new factors modulating adhesion abilities of the pioneer commensal bacterium Streptococcus salivarius. Frontiers in Microbiology, 9. DOI : 10.3389/fmicb.2018.00273

• Delorme, C., Legravet, N., Jamet, E., Hoarau, C., Bolotine, A., El-Sharoud, W. M., Darwish, M. S., Renault, P. (2017). Study of Streptococcus thermophilus population on a world-wide and historical collection by a new MLST scheme. International Journal of Food Microbiology, 242, 70-81. DOI : 10.1016/j.ijfoodmicro.2016.11.016

• Couvigny, B., de Wouters, T., Kaci, G., Jacouton, E., Delorme, C., Dore, J., Renault, P., Blottière, H., Guédon, E., Lapaque, N. (2015). Commensal Streptococcus salivarius modulates PPARγ transcriptional activity in human intestinal epithelial cells. Plos One, 10 (5). DOI : 10.1371/journal.pone.0125371

• Delorme, C., Abraham, A.-L., Renault, P., Guedon, E. (2015). Genomics of Streptococcus salivarius, a major human commensal. Infection, Genetics and Evolution.DOI : 10.1016/j.meegid.2014.10.001

• Kaci, G., Goudercourt, D., Dennin, V., Pot, B., Dore, J., Dusko Ehrlich, S., Renault, P., Blottiere, H., Daniel, C., Delorme, C. (2014). Anti-inflammatory properties of Streptococcus salivarius, a commensal bacterium of the oral cavity and digestive tract. Applied and Environmental Microbiology, 80 (3), 928-934.DOI : 10.1128/AEM.03133-13

 ♦ Peer-reviewed publications in the MetaHit project :

• Pedersen, H. K. , Gudmundsdottir, V., Nielsen, H. B., Hyotylainen, T., Nielsen, T., Jensen, B. A. H., Forslund, K., Hildebrand, F., Prifti, E., Falony, G., Le Chatelier, E., Levenez, F., Dore, J., Mattila, I., Plichta, D. R., Pöhö, P., Hellgren, L. I., Arumugam, M., Sunagawa, S., Vieira-Silva, S., Jørgensen, T., Holm, J. B., Trošt, K., Kristiansen, K., Brix, S., Raes, J., Wang, J., Hansen, T., Bork, P., Brunak, S., Oresic, M., Ehrlich, S. D., Pedersen, O., MetaHIT Consortium, Almeida, M., Batto, J.-M., Blottière, H., Cultrone, A., Delorme, C., Dervyn, R., Guedon, E., Haimet, F., Jamet, A., Juste, C., Kennedy, S., Khaci, G., Kleerebezem, M., Layec, S., Leclerc, M., Léonard, P., Maguin, E., Manichanh, C., Pons, N., Renault, P., Sanchez, N., Van De Guchte, M., Van Hylckama Vlieg, J., Vandemeulebrouck, G., Winogradsky, Y. (2016). Human gut microbes impact host serum metabolome and insulin sensitivity. Nature, 535 (7612), 376-381. DOI : 10.1038/nature18646
• Forslund K, Hildebrand F, Nielsen T, Falony G, Le Chatelier E, Sunagawa S, Prifti E, Vieira-Silva S, Gudmundsdottir V, Krogh Pedersen H, Arumugam M, Kristiansen K, Yvonne Voigt A, Vestergaard H, Hercog R, Igor Costea P, Roat Kultima J, Li J, Jørgensen T, Levenez F, Dore J, Almeida M, Antolin M, Artiguenave F, Batto JM, Bertalan M, Blottière H, Boruel N, Brechot C, Bruls T, Burgdorf K, Casellas F, Cultrone A, de Vos WM, Delorme C, Denariaz G, Derrien M, Dervyn R, Feng Q, Grarup N, Guarner F, Guedon E, Haimet F, Jamet A, Juncker A, Juste C, Kennedy S, Khaci G, Kleerebezem M, Knoll J, Layec S, Leclerc M, Leonard P, LePaslier D, M'Rini C, Maguin E, Manichanh C, Mende D, Mérieux A, Oozeer R, Parkhill J, Pelletier E, Pons N, Qin J, Rasmussen S, Renault P, Rescigno M, Sanchez N, Sicheritz-Ponten T, Tap J, Tims S, Torrejon A, Turner K, van de Guchte M, van Hylckama Vlieg JE, Vandemeulebrouck G, Varela E, Viega P, Weissenbach J, Winogradski Y, Yamada T, Zoetendal EG., Bjørn Nielsen H, Brunak S, Raes J, Hansen T, Wang J, Dusko Ehrlich S, Bork P, Pedersen O. (2015). Disentangling type 2 diabetes and metformin treatment signatures in the human gut microbiota. Nature, 528:262-266. DOI: 10.1038/nature15766
• Li, J., Jia, H., Cai, X., Zhong, H., Feng, Q., Sunagawa, S., Arumugam, M., Kultima, J. R., Prifti, E., Nielsen, T., Juncker, A. S., Manichanh, C., Chen, B., Zhang, W., Levenez, F., Wang, J., Xu, X., Xiao, L., Liang, S., Zhang, D., Zhang, Z., Chen, W., Zhao, H., Al-Aama, J. Y., Edris, S., Yang, H., Wang, J., Hansen, T., Nielsen, H. B., Brunak, S., Kristiansen, K., Guarner, F., Pedersen, O., Dore, J., Ehrlich, S., MetaHIT Consortium, Bork, P., Wang, J., Pons, N., Le Chatelier, E., Batto, J.-M., Kennedy, S., Haimet, F., Winogradsky, Y., Cultrone, A., Leclerc, M., Juste, C., Guedon, E., Delorme, C., Layec, S., Kaci, G., Van De Guchte, M., Vandemeulebrouck, G., Jamet, A., Dervyn, R., Sanchez, N., Blottiere, H., Maguin, E., Renault, P., Tap, J. (2014). An integrated catalog of reference genes in the human gut microbiome. Nature Biotechnology, 32, 834-841. DOI : 10.1038/nbt.2942
• Nielsen, H. B., Almeida, M., Juncker, A. S., Rasmussen, S., Li, J., Sunagawa, S., Plichta, D. R., Gautier, L., Pedersen, A. G., Le Chatelier, E., Pelletier, E., Bonde, I., Nielsen, T., Manichanh, C., Arumugam, M., Batto, J.-M., Quintanilha Dos Santos, M. B., Blom, N., Borruel, N., Burgdorf, K. S., Boumezbeur, F., Casellas, F., Dore, J., Dworzynski, P., Guarner, F., Hansen, T., Hildebrand, F., Kaas, R. S., Kennedy, S., Kristiansen, K., Kultima, J. R., Léonard, P., Levenez, F., Lund, O., Moumen, B., Le Paslier, D., Pons, N., Pedersen, O., Prifti, E., Qin, J., Raes, J., Sørensen, S., Tap, J., Tims, S., Ussery, D. W., Yamada, T., MetaHIT Consortium, Renault, P., Sicheritz-Ponten, T., Bork, P., Wang, J., Brunak, S., Ehrlich, S., Almeida, M., Le Chatelier, E., Batto, J.-M., Boumezbeur, F., Dore, J., Kennedy, S., Léonard, P., Levenez, F., Moumen, B., Pons, N., Prifti, E., Renault, P., Ehrlich, S., Jamet, A., Cultrone, A., Delorme, C., Maguin, E., Guedon, E., Vandemeulebrouck, G., Kaci, G., Blottiere, H., Van De Guchte, M., Sanchez, N., Dervyn, R., Layec, S., Winogradsky, Y. (2014). Identification and assembly of genomes and genetic elements in complex metagenomic samples without using reference genomes. Nature Biotechnology, 32, 822–828.  DOI : 10.1038/nbt.2939