Open Access1296. Genomic Analysis of Human-Associated Outbreak Caused by Salmonella enterica serovar Infantis in Cali, Colombia
Author(s) -
Fernando Rosso,
Olga L. Rojas
Publication year - 2021
Publication title -
open forum infectious diseases
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.546
H-Index - 35
ISSN - 2328-8957
DOI - 10.1093/ofid/ofab466.1488
Subject(s) - serotype , outbreak , salmonella enterica , salmonella , clade , biology , tetracycline , genomic dna , plasmid , microbiology and biotechnology , virology , phylogenetic tree , genetics , antibiotics , gene , bacteria
Background Salmonella enterica serovar Infantis is emerging as a leading cause of foodborne infections. The Colombian National Health Institute reported 263 Infantis among all received Salmonella(n=12,966) from 1997 to 2018 being the 5th most frequent serovar in human clinical samples during this period. In this study, Infantis outbreak-associated isolates were sequenced and collectively analysed with global strains from different sources to compare their genomic content and phylogeny Figure 1. Genomic Comparisons Methods Between September 15-20 of 2019, 160 patients with gastroenteric symptoms resulting from the ingestion of a common food, arrived at Fundación Valle del Lilí. Salmonella spp were cultured from stool specimens of patients and 15 isolates were sent to the Genomic Unit of Agrosavia for whole-genome sequencing. Genomic DNA was sequenced using an Illumina®MiSeqX10 platform. Genome assembly was performed with standardized bioinformatics pipelines and in-silico serotyping with SISTR. Genomic comparisons included newly-sequenced isolates of Infantis(n=6) from a Colombian poultry farms as well as datasets from Patric(n=441) and EnteroBase(n=54). Results The 15 outbreak isolates were identified by in silico serotyping as S. Infantis, these isolates showed phenotypic sensitivity to all tested antibiotics except by tetracycline. Antimicrobial resistance plasmids IncFIBKpn3, IncX4 and the host-environment persistence plasmid pSL483 were only detected in 2 outbreak-related and 1 in poultry isolates. Out of a total of 511 high-quality sequences, ST32 was the most prevalent and were phylogenetically grouped into a single non-host specific clade. Outbreak-isolates were included in a monophyletic group with some genomes from the US and Chile, suggesting that the parent strain could have originated in those countries. Conclusion The magnitude of the outbreak(288 informed-cases) evidenced a high-virulent potential of outbreak-isolates. Routine sequencing of S.enterica and availability of genomes in Colombia can improve outbreak detection and resolution in the future. The presence of plasmids, although with low frequency, suggests a risk of the appearance of resistant clones. Disclosures All Authors: No reported disclosures