Does Shiga Toxin-Producing Escherichia coli and Listeria monocytogenes Contribute Significantly to the Burden of Antimicrobial Resistance in Uruguay?

Abstract

Shiga toxin-producing Escherichia coli (STEC) and Listeria monocytogenes are worldwide recognized zoonotic pathogens. Recent reports have emerged about the circulation of antimicrobial-resistant STEC and L. monocytogenes isolates. To assess the frequency of antimicrobial resistance and related genes in these pathogens, we studied 45 STEC and 50 L. monocytogenes isolates locally recovered from different sources. Antimicrobial susceptibility testing was performed by disk-diffusion method, and the genomic sequences of three selected STEC and from all 50 L. monocytogenes isolates were analyzed for antibiotic resistance genes. Four STEC and three L. monocytogenes isolates were phenotypically resistant to at least one of the antibiotics tested. Resistance genes aph(3 ′′)-Ib, aph(3 ′)-Ia, aph(6)-Id, bla T EM−1B , sul2, mef(A), and tet(A) were found in a human STEC ampicillin-resistant isolate. All L. monocytogenes isolates harbored fosX, lin, mdrL, lde fepA, and norB. Overall resistance in L. monocytogenes and STEC was low or middle. However, the high load of resistance genes found, even in susceptible isolates, suggests that these pathogens could contribute to the burden of antimicrobial resistance.

Phenotypic and genotypic characterization of Shiga toxin-producing Escherichia coli strains recovered from bovine carcasses in Uruguay

“…from animal and human origins ( Gomi et al, 2017 ; Li et al, 2021 ), being an important concern in human health. Also, the presence of this gene in STEC from bovine feces and in a STEC O145:H25 isolated from an HUS case have been reported in our country ( Mota et al, 2020 ; Umpiérrez et al, 2022 ).…”

Genomic Epidemiology of Shiga Toxin-Producing Escherichia coli Isolated from the Livestock-Food-Human Interface in South America

“…The stx subtype most frequently detected was stx2a (54.6%, n = 71), followed by stx1a (26.9%, n = 35), stx2c (22.3%, n = 29), stx2d (16.2%, n = 21), stx2b and stx2g (1.5%, n = 2), and stx1c (0.8%, n = 1). Among the other virulence genes assessed, the most frequently detected was ehaA (96.2%, n = 125), followed by iha Studies focusing on the AMR of STEC strains isolated from the livestock-beef-human interface in South America are scarce [38,41,[61][62][63]. In this study, genomic analysis revealed a low prevalence of resistance genes.…”

Virulence and Antibiotic Resistance Genes in Listeria monocytogenes Strains Isolated From Ready-to-Eat Foods in Chile

“… Mafuna et al (2021) encountered resistance genes in strains such as fosX , lin , mprF , and norB , and they reported an increasing global trend of resistance genes present in the food chain. L. monocytogenes is currently considered to be intrinsically resistant to fosfomycin because of the lack of expression in the membrane transport systems and a natural resistance to lincomycin due to the ribosomal protection of an ATP-binding cassette F (ABC-F) protein ( Mota et al, 2020 ).…”