Poster communication in One Health EJP Annual Scientific Meeting

June 9^th, 2021

Aldea-Ramos I., Moreno MA., Gibello A. and Hernandez M.

Aim: To study the dynamics of antimicrobial resistance determinants in a commercial laying hen farm where antimicrobials where scarcely used (Moreno et al., 2019) using the extended spectrum betalactamase (ESBL) resistance gene blaSHV-12.
Methods: Faecal samples of animals (from day-old chicks to laying hens) of fours batches were analysed. McConkey agar plates with cefotaxime (1 mg/L) were used for recovery of presumptive ESBL Escherichia coli. Isolates with different antimicrobial
resistance profiles were characterized by whole genome sequencing and those in which the blaSHV-12 gene was detected are shown.
Results: Bla SHV-12 gene was identified in E. coli isolates belonging to multilocus sequence type 155 in the second batch when pullets were sampled at week 15. The gene was found in an IncI1-26 plasmid harboring also tet(A) gene and a class 1 integron carrying aadA1, aadA2, sul3, and cmlA1 genes. Moreover, the isolates had an IncX1 plasmid, harboring qnrS1 and blaTEM1B genes. The same isolate was detected at week 24 in the same batch moved to a laying house (a colistin treatment was
administered at week 23) and again four months later in another batch of laying hens (at 23 weeks) housed in a different laying house of the same farm.
Conclusions: These results suggest the environmental persistence of the blaSHV-12 gene in this farm for at least six months carried by the same plasmid located in identical E. coli isolates

	Servicio de Zoonosis de Transmisión Alimentaria y Resistencia a Antimicrobianos (ZTA). Centro de Vigilancia Sanitaria Veterinaria (VISAVET). Universidad Complutense (UCM).
	Departamento de Sanidad Animal. Facultad de Veterinaria. Universidad Complutense (UCM).
	Unidad de Microbiología. Departamento de Biotecnología y Ciencia de los Alimentos. Universidad de Burgos (UBU).