Genomic Analysis of Argentinean Streptococcus agalactiae Isolates

KOVACEC, VERÓNICA; DI GREGORIO S; PAJON M; POKLEPOVICH T; CAMPOS J; MOLLERACH MARTA; BONOFIGLIO LAURA

Online

Congreso; World Microbe Forum; 2021

American Society for Microbiology and Federation of European Microbiological Societies

Streptococcus agalactiae (GBS) is an emerging pathogen that causes severe infections in humans and animals. To our knowledge, there is no genomic data of GBS strains circulating in Argentina. The aim of this work was to characterize the whole genome sequences of 10 representative human GBS strains selected within an Argentinean Multicentric Study and to contextualize them with publicly available global GBS genomes.Whole genome sequencing was performed using Illumina MiSeq v2 platform. De novo assemblies were obtained with SPAdes. In addition, 148 GBS assemblies from 18 countries on 5 continents, from human and animal hosts, were accessed from public databases. All assemblies were annotated with Prokka and a core gene alignment was generated with Roary. Single nucleotide polymorphisms were extracted with SNP-sites and a phylogenetic tree was constructed using RAxML. MLSTs were determined with Pathogenwatch and assigned to clonal complexes (CC). Plasmid rep, virulence factors (VF) and antimicrobial resistance (AMR) genes were searched with ABRicate.The core-SNPs tree showed our strains interspaced in the phylogeny related to human and animal GBS from 5 continents, grouped within 7 CC, the most prevalent being CC23 (3/10) and CC19 (2/10). Globally, the genomes analyzed belonged to 44 STs and 15 CC, the most frequent being CC260 (27%), CC1 (13%), CC23 and CC19 (both 11%). Clade distribution was related to CC but we found no relation between VF/AMR genes presence and CC. VF associated with evasion of host defenses and tissue damage were found in the 158 genomes, while VF associated with adherence to host tissues were present in all of our strains but in 69% of the strains globally. AMR genes to one or more antibiotic families were found in 52% of the genomes, our 10 strains included. AMR genes to tetracyclines (tet) were the most prevalent both locally (L) and globally (G) (L: 9/10, G: 51.3%), followed by macrolides/lincosamides (L: 4/10, G: 24.7%), aminoglycosides (L: 2/10, G: 5.7%), chloramphenicol (L: 1/10, G: 1.9%) and vancomycin (L:0/10, G: 1.3%). Replicons were detected in 4/10 of our strains and 34% globally, repUS43 being the most frequent (L: 4/10, G: 33.5%) and present in 75% of the strains with tet genes.Argentinean GBS strains are related to strains circulating globally. There seems to be no evidence of CC spread associated with particular VF or AMR genes in the genomes analyzed. The presence of macrolides/lincosamides resistance genes found locally and worldwide is alarming, as these are the main treatment against GBS when penicillin is not an option.