Genomic diversity and security profile of Corynebacterium pseudodiphtheriticum species

ELEAN, MARIANO; ORTIZ MOYANO, RAMIRO; RAYA TONETTI, FERNANDA; VILLENA, JULIO

Rosario

Congreso; 13vo Congreso Argentino de Bioinformática y Biología Computacional, la 13va Conferencia Iberoamericana de Bioinformática y la 3ra reunión anual de la red RiaBio; 2023

A2B2C, RiaBio, SolBIo

Background: Bacteria belonging to the genus Corynebacterium have usually been associated with infectious diseases. C. diphtheriae and C. ulcerans produce toxins that can induce upper respiratory tract illness characterized by sore throat, fever, and nasal discharge. However, not all the species of this genus are pathogenic. C. pseudodiphtheriticum is usually found as a member of the normal microbiota of the upper respiratory tract and some studies have indicated that these bacteria exert beneficial effects for the host. In this regard, we have shown that the strain C. pseudodiphtheriticum 090104 is able to beneficially modulate immune responses in the respiratory tract, improving the resistance to pathogens such as Streptococcus pneumoniae, Klebsiella pneumoniae and respiratory syncytial virus. Considering the positive effects of this species, we aimed to carry out a comparative genomic study of C. pseudodiphtheriticum strains to characterize their security profile in terms of virulence genes.Results: The genomes of 29 C. pseudodiphtheriticum strains, including the 090104 strain, were selected for the study. The virulent strains C. ulcerans 809, C. diphtheriae NCTC13129 and C. pseudotuberculosis PAT10 were also included for comparisons. The average nucleotide identity analysis revealed two large clusters. One constituted by the strains MSK305, 090104, CPD, CP10, MSK092, MSK080, DSM44287 and MSK037; and the second constituted by the remaining strains. All the C. pseudodiphtheriticum strains show more than 90% identity between them. The pangenomic analysis revealed a pangenome of 5050 genes, a core-genome of 1471 genes, a shell-genome of 1118 genes and a cloud-genome of 2461 genes. The presence of virulence genes dip0733, dtxr, and genes linked to secretion systems (sec genes and t2sf) was observed in all strains. The virulence gene hmuv was found to be present in 27 of 29 strains (absent in strains MSK037 and MSK092).Conclusions: C. pseudodiphtheriticum strains have low potential to generate infections due to the low number of virulence genes. However, although the risk for health is small, it is advisable to perform detailed in vitro and in vivo studies of the strains intended to be used in probiotic formulations, to ensure its complete safety.