Zoonotic Potential and Antibiotic Resistance of Escherichia coli in Neonatal Calves in Uruguay

VIGNOLI, RAFAEL; ACQUISTAPACE, SOFÍA; UMPIÉRREZ, ANA; PADOLA, NORA LÍA; OLIVER, MARTÍN; ZUNINO, PABLO; ETCHEVERRÍA, ANALÍA; BADO, INÉS

MICROBES AND ENVIRONMENTS

JAPANESE SOC MICROBIAL ECOLOGY

Año: 2017 vol. 32 p. 275 - 282

1342-6311

Escherichia coli is one of the main etiological agents of neonatal calf diarrhea (NCD). The objective of this study was toassess the presence of virulence genes, genetic diversity, and antibiotic resistance mechanisms in E. coli associated with NCDin Uruguay. PCR was used to assess the presence of intimin, Shiga-like toxin, and stable and labile enterotoxin genes.Resistance to fluoroquinolones and oxyimino-cephalosporins was estimated on Müller-Hinton agar plates. Further antibioticdisc-diffusion tests were performed to assess bacterial multi-resistance. The presence of PMQR, ESBL, MCR-1, and integrongenes was evaluated. Isolates were typed using ERIC-PCR, and 20 were selected for MLST, adhesion to Hep-2 cells, in vitrobiofilm formation, and eukaryotic cytotoxicity. The prevalence of ETEC genes was lower than 3% in each case (estA and elt).Six isolates were EPEC (eae+) and 2 were EHEC/STEC (eae+/stx1+). The results of a diversity analysis showed high geneticheterogenicity among isolates. Additionally, different sequence types, including ST10, ST21, and ST69, were assigned toselected isolates. Thirty-six percent (96/264) of the isolates were fluoroquinolone-resistant, with 61/96 (63.5%) beingmultidrug-resistant. Additionally, 6 were oxyimino-cephalosporin-resistant. The qnrB, qnrS1, and blaCTX-M-14 genes weredetected, whereas no isolates carried the mcr-1 gene. Isolates had the ability to adhere to Hep-2 cells and form biofilms. Only1 isolate expressed toxins in vitro. E. coli from NCD cases in Uruguay are very diverse, potentially virulent, and may interactwith eukaryotic cells. Zoonotic potential, together with resistance traits and the presence of horizontal transfer mechanisms,may play a significant role in infections caused by these microorganisms.