Genome analysis of Salmonella enterica subsp. diarizonae isolates from invasive human infections reveals enrichment of virulence-related functions in lineage ST1256

GINER-LAMIA, JOAQUÍN; VINUESA, PABLO; BETANCOR, LAURA; SILVA, CLAUDIA; BISIO, JULIETA; SOLETO, LORENA; CHABALGOITY, JOSÉ A.; PUENTE, JOSÉ LUIS; THE SALMONELLA CYTED NETWORK; GARCÍA-DEL PORTILLO, FRANCISCO

BMC GENOMICS

BIOMED CENTRAL LTD

Año: 2019 vol. 20

1471-2164

The Salmonella CYTED Network: Fernando C. Soncini, Eleonora García-Vescovi (Universidad de Rosario-CONICET, Argentina); Griselda Flores, José Pedraza (Universidad Autónoma Gabriel René Moreno, Santa Cruz, Bolivia); Lucia Yim (Universidad de la República, Montevideo, Uruguay); Coralith García, Lizeth Astocondor, Theresa Ochoa, Noemí Hinostroza (Instituto de Medicina Tropical Alexander von Humboldt-Universidad Peruana Cayetano Heredia, Lima, Perú); and, M. Graciela Pucciarelli (Universidad Autónoma de Madrid, Centro de Biología Molecular Severo Ochoa ?CBMSO-, Madrid, Spain). Alfredo Hernández-Alvarez and Victor del Moral from the Centro de Ciencias Genómicas, UNAM. Background: Salmonella enterica subsp. diarizonae (IIIb) is frequently isolated from the environment, cold-blooded reptiles, sheep and humans; however only a few studies describe the isolation of this subspecies from invasive human infections. The factors contributing to this unusual behavior are currently unknown.Results: We report here the genome features of two diarizonae strains, SBO13 and SBO27, isolated from endocervical tissue collected post-abortion and from cerebrospinal fluid of a newborn child, respectively, in the city of Santa Cruz, Bolivia. Although isolated six years apart, SBO27 in 2008 and SBO13 in 2014, both strains belong to the same sequence type 1256 (ST1256) and show a high degree of genome conservation sharing more than 99% of their genes, including the conservation of a ~ 10 kb plasmid. A prominent feature of the two genomes is the presence of 24 genomic islands (GIs), in addition to 10 complete Salmonella pathogenicity islands (SPI) and fragments of SPI-7, a pathogenicity island first reported in the human-adapted serovar Typhi. Some of the GIs identified in SBO13 and SBO27 harbor genes putatively encoding auto-transporters involved in adhesion, lipopolysaccharide modifying enzymes, putative toxins, pili-related proteins, efflux pumps, and several putative membrane cation transport relatedgenes, among others. These two Bolivian isolates also share genes encoding the type-III secretion system effector proteins SseK2, SseK3 and SlrP with other diarizonae sequence types (ST) mainly-associated with infections in humans. The sseK2, sseK3 and slrP genes were either absent or showing frameshift mutations in a significant proportion of genomes from environmental diarizonae isolates.