Multiple sequence types, virulence determinants and antimicrobial resistance genes in multidrug- and colistin-resistant Escherichia coli from agricultural and non-agricultural soils

Author(s)

Furlan, Pedro Rueda ^[1] ; Stehling, Eliana Guedes ^[1]

Affiliation

^[1] Univ Sao Paulo, Fac Ciencias Farmaceut Ribeirao Preto, Dept Anal Clin Toxicol & Bromatol, Ribeirao Preto, SP - Brazil

• Document type: Journal article
• Source: Environmental Pollution; v. 288, NOV 1 2021.
• Web of Science Citations: 1

Abstract

In soils, the presence of clinically relevant bacteria carrying ARGs, including extended-spectrum beta-lactamase- and plasmid-mediated AmpC beta-lactamase-encoding genes, is an underestimated public health problem that requires more attention. For this investigation, 300 samples from agricultural and non-agricultural soils were used to obtain 41 MDR E. coli isolates, standing out the resistance to beta-lactams, fluoroquinolones and colistin. Virulence genes related to diarrheagenic E. coli and extraintestinal pathogenic E. coli were detected. Several ARGs were found, highlighting the presence of at least one beta-lactamase-encoding gene (blaTEM, blaCMY, blaSHV, blaOXA-1-like, blaCTX-M-2, and/or blaCTX-M-15) in each isolate. Among the fluoroquinolone-resistant E. coli isolates, the plasmidmediated quinolone resistance genes (qnrB and oqxA) and substitutions in the quinolone resistance-determining regions were detected. Some isolates were resistant to colistin (MICs of 4-8 mg/L) and, although no mcr-like gene was detected, substitutions in the two-component systems involving PhoP/PhoQ and PmrA/PmrB were found. Furthermore, the E. coli isolates presented plasmids and class 1 integrons, the last one detected in all isolates. The ARGs blaTEM, aadA and dfrA and the lpfA virulence-associated gene presented statistically significant differences (P < 0.05) in agricultural soils, while the blaOXA-1-like gene presented a statistically significant difference in nonagricultural soils. Thirty-eight sequence types (STs) were identified among the isolates, spotlighting the 20 different STs that carried blaCMY and blaCTX-M-type genes and those commonly reported in infections worldwide. The occurrence of virulent, multidrug- and colistin-resistant E. coli isolates in soils could lead to contamination of surrounding environments and food, increasing the risk of human and animal exposure. Therefore, this study contributes to a better understanding of E. coli in soils and reinforces the importance of the One Health approach to antimicrobial resistance surveillance. (AU)

• FAPESP's process: 18/19539-0 - Molecular characterization of Escherichia coli isolates from the environment
• Grantee: Eliana Guedes Stehling
• Support Opportunities: Regular Research Grants