COMPARATIVE GENOMIC ANALYSIS AMONG ENTEROCOCCUS MUNDTII STRAINS ISOLATED FROM DIFFERENT SOURCES

BONACINA JULIETA; HORMIGO, RICARDO; SUAREZ NADIA; SESMA FERNANDO; SAAVEDRA LUCILA

Mar del Plata

Congreso; X Congreso Argentino de Microbiología General; 2014

SAMIGE

Enterococci are a diverse and versatile group of gram positive lactic acid bacteria. They live as commensal microorganisms in the gastrointestinal tract of humans and animals, but they are also found in soil, water, plants and are used in the production of fermented foods and probiotics. Due to their intrinsic characteristics and a remarkable metabolic adaptability, they are capable of surviving and growing under different conditions and to tolerate many forms of stress. The study of enterococci´s genomics has grown considerably in recent years showing new insights into the physiology of this genus. Using different approaches it has been concluded that many metabolic genes and pathways vary even within single species. Particularly, genome comparisons are really important for determining the genotypic differences between closely related bacteria and for understanding genome and molecular evolution while considering the phenotypic evolution and population genetics. Enterococcus mundtii CRL35 is a bacteriocinogenic non starter lactic acid bacteria strain whose genome was recently sequenced. Based on this information, the goal of the present work was to perform the metabolic reconstruction comparison of this strain against those belonging to E. mundtii CRL1656 (cow milk isolate), E. mundtii QU 25 (ovine faecal origin) and E. mundtii ATCC882 (fermented product origen), using RAST tool. The results obtained revealed that QU 25 has, at the chromosome level, 67 coding DNA sequences (CDS) assigned to subsystems that are not present in CRL35. Some of these genes are involved in gram positive competence, CRISPR-Cas system, citrate metabolism and toxin-antitoxin replicon stabilization systems. On the other hand, CRL35 has CDS related to bacterial restriction-modification system, sialic acid metabolism and biotin biosynthesis that are not present QU-25. Regarding CRL1656, 42 functional roles have genes assigned to subsystems that are not found in CRL35, some of which are related to the citrate metabolism and the com system. Also CRL35 has 46 roles with genes not localized in CRL1656. Finally, the strain ATCC 882 has 60 functional roles with genes involved in citrate metabolism, com system and phages production that are not present in CRL35. Only 13 roles with genes assigned are found in CRL35 and not in ATCC 882. In addition, an orthology analysis was carried out. E. mundtii CRL35, CRL1656 and ATCC 882 have 1772 orthologous proteins while the last two strains have 2141 suggesting therefore, a less evolutionary distance among them. These analyses help us to understand how enterococci adjust to different environments. Transcriptomic studies of CRL35, now under way, may provide insight into the physiological responses of this microorganism in fermented foods.