Genomic characterization of Enterotoxigenic E. coli F4 and F18 positive strains from post-weaning diarrhea in pigs.

This study aimed to characterize in silico Enterotoxigenic E. coli F4- and F18-positive-isolates (n=90) causing swine post-weaning diarrhea, including pathogenic potential, phylogenetic relationship, antimicrobial and biocide resistance (R), prophage content and metal tolerance rates. F4-strains belonged mostly to the O149 and O6 serogroups and ST100 and ST48 MLST-types. F18-strains were mainly assigned to the O8 and O147 serogroups and ST10, ST23 and ST42. The highest rates of antimicrobial-R were found against streptomycin, sulfamethoxazole, tetracycline, trimethoprim and ampicillin. No resistance was found towards ciprofloxacin, cefotaxime, ceftiofur and colistin. Genes conferring tolerance to copper (showing highest diversity), cadmium, silver and zinc were predicted in all genomes. Enterotoxins (ltcA; 100 % F4, 62 % F18, astA; 100 % F4, 38.1 % F18, sta;18.8 % F4, 38.1 % F18, stb; 100 % F4, 76.2 % F18) and fimbriae encoding genes typed as F4ac and F18ac were detected in all the strains, in addition to up to 16 other virulence genes in individual strains. Phage analysis predicted between 7 and 20 different prophage regions in each strain. High diversity of plasmid replicons was shown; IncFII, IncFIB and IncFIC were prevalent among F4-isolates while IncI1, and IncX1 were dominant among F18-strains. Interestingly, F4-isolates from the early 90's belonged to the same clonal group detected for most of the F4-strains from 2018-2019 (ONT:H10-A-ST100-CH27-0). The low number of SN...
Source: Applied and Environmental Microbiology - Category: Microbiology Authors: Tags: Appl Environ Microbiol Source Type: research