RT Journal Article
T1 Antimicrobial Susceptibility and Resistance Mechanisms in Mannheimia haemolytica Isolates from Sheep at Slaughter
A1 Álvarez Sánchez, Julio
A1 Calderón Bernal, Johan M.
A1 Torre Fuentes, Laura
A1 Hernández Martín, Marta María
A1 Pinto Jiménez, Chris E.
A1 Domínguez Rodríguez, Lucas José
A1 Fernández-Garayzábal Fernández, José Francisco
A1 Vela Alonso, Ana Isabel
A1 Cid Vázquez, María Dolores
AB Mannheimia haemolytica is the main pathogen contributing to pneumonic pasteurellosis in sheep. The aim of this study was to investigate the antimicrobial resistance levels in M. haemolytica isolates from the lungs of slaughtered sheep and to examine the genetic resistance mechanisms involved. A total of 256 M. haemolytica isolates, 169 from lungs with pneumonic lesions and 87 from lungs without lesions, were analyzed by the disk diffusion method for 12 antimicrobials, and the whole genome of 14 isolates was sequenced to identify antimicrobial resistance determinants. Levels of phenotypic resistance ranged from <2% for 10 antimicrobials (amoxicillin, amoxicillin-clavulanic, ceftiofur, cefquinome, lincomycin/spectinomycin, gentamicin, erythromycin, florfenicol, enrofloxacin, and doxycycline) to 4.3% for tetracycline and 89.1% for tylosin. Six isolates carried tetH genes and four isolates carried, in addition, the strA and sul2 genes in putative plasmid sequences. No mutations associated with macrolide resistance were identified in 23 rDNA sequences, suggesting that the M. haemolytica phenotypic results for tylosin should be interpreted with care in the absence of well-established epidemiological and clinical breakpoints. The identification of strains phenotypically resistant to tetracycline and of several resistance genes, some of which were present in plasmids, highlights the need for continuous monitoring of susceptibility patterns in Pasteurellaceae isolates from livestock.
PB MDPI
YR 2023
FD 2023-06-14
LK https://hdl.handle.net/20.500.14352/103964
UL https://hdl.handle.net/20.500.14352/103964
LA eng
NO Alvarez, J., Calderón Bernal, J. M., Torre-Fuentes, L., Hernández, M., Jimenez, C. E. P., Domínguez, L., Fernández-Garayzábal, J. F., Vela, A. I., & Cid, D. (2023). Antimicrobial Susceptibility and Resistance Mechanisms in Mannheimia haemolytica Isolates from Sheep at Slaughter. Animals : an open access journal from MDPI, 13(12), 1991. https://doi.org/10.3390/ani13121991
NO 2022 Descuento MDPI
NO Universidad Complutense de Madrid
NO Banco Santander
NO Ministerio de Ciencia, Innovación y Universidades (España)
DS Docta Complutense
RD 9 abr 2025