Neomycin resistance in clinical Escherichia coli from Danish weaner pigs is associated with recent neomycin use and presence of F4 or F18 fimbriaes.

Abstract

Neomycin is a first-choice antibiotic for treatment of porcine enteritis caused by enterotoxigenic Escherichia coli (ETEC), but little is known about factors influencing resistance to this drug. The aims of this study were to assess antimicrobial resistance and virulence in 325 E. coli isolates obtained in 2020 from various infections in pigs, and to identify factors associated with neomycin resistance development. Susceptibility to 16 antimicrobial agents was determined by broth microdilution, and occurrence of ETEC-associated virulence factors was screened by PCR and hemolysis on blood agar. Univariate and multivariate logistic regression analyses were performed to determine if age group, virulence factors, or antibiotic use (neomycin and other antibiotics) were associated with neomycin resistance. STa, STb, LT, F4, and F18 were detected in 14%, 37%, 26%, 21% and 23% of the isolates, respectively. Resistance was low for antimicrobials of high public health importance (1.5% for cefotaxime, 1% for colistin and no fluoroquinolone resistance) but high for drugs used for treatment of ETEC enteritis (e.g. 20% for neomycin). Isolates with the ETEC pathotype were significantly associated with the weaner age group and intestinal/fecal origin. Multivariate analysis showed that recent neomycin use and presence of F4 or F18 were significantly associated with neomycin resistance amongst isolates from weaners. These results prove an association between neomycin resistance and use at the farm level. Further research is warranted to determine why neomycin resistance was associated with F4 and F18, and whether neomycin use may co-select for virulent strains.

• Authors: Prabha Subramani, Mattia Pirolo, Svend Haugegaard, Alice Puk Skarbye, Beate Conrady, Ken Steen Pedersen, Luca Guardabassi, Peter Damborg
• Journal: Preventive veterinary medicine (Prev Vet Med) Vol. 212 Pg. 105852 (Mar 2023) ISSN: 1873-1716 [Electronic] Netherlands
• PMID: 36689897 (Publication Type: Journal Article)
• Copyright: Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.

Chemical References

• Neomycin
• Anti-Bacterial Agents
• Virulence Factors

Topics

• Swine
• Animals
• Escherichia coli Infections (drug therapy, veterinary, epidemiology)
• Neomycin (pharmacology, therapeutic use)
• Diarrhea (veterinary)
• Enterotoxigenic Escherichia coli
• Anti-Bacterial Agents (pharmacology, therapeutic use)
• Virulence Factors (therapeutic use)
• Denmark
• Swine Diseases (drug therapy, epidemiology)