1. Emerging resistance to florfenicol in Actinobacillus pleuropneumoniae isolates on two Italian pig farms.
- Author
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Brenciani A, Coccitto SN, Cucco L, Ustulin M, Albini E, Paniccià M, Vio D, Cinthi M, Giovanetti E, Massacci FR, and Magistrali CF
- Subjects
- Animals, Swine, Italy epidemiology, Phylogeny, Microbial Sensitivity Tests, Whole Genome Sequencing, Farms, Pleuropneumonia microbiology, Pleuropneumonia veterinary, Plasmids genetics, Bacterial Proteins genetics, Polymorphism, Single Nucleotide, Virulence genetics, Actinobacillus pleuropneumoniae drug effects, Actinobacillus pleuropneumoniae genetics, Actinobacillus pleuropneumoniae isolation & purification, Actinobacillus pleuropneumoniae classification, Thiamphenicol analogs & derivatives, Thiamphenicol pharmacology, Swine Diseases microbiology, Anti-Bacterial Agents pharmacology, Actinobacillus Infections microbiology, Actinobacillus Infections veterinary, Drug Resistance, Bacterial genetics
- Abstract
Actinobacillus pleuropneumoniae is responsible for porcine pleuropneumonia, a highly contagious lung infection. The control of this respiratory disease remains heavily reliant on antibiotics, with phenicols being one of the primary classes of antibiotics used in pig farming. In the present study, we describe three isolates (B2278, B2176 and B2177) of A. pleuropneumoniae resistant to florfenicol attributed to the presence of the floR gene, which were obtained from two pig farms in Italy. Florfenicol susceptibility tests indicated that B2176 exhibited an intermediate susceptibility profile, while B2177 and B2278 were resistant. All three isolates belonged to serovar 6 and tested positive for the presence of the floR gene. Whole genome sequencing analysis revealed that isolates B2176, B2177 and B2278 harbored genes encoding the toxins ApxII and ApxIII, characteristic of strains with moderate virulence. Moreover, phylogenetic analysis demonstrated that these isolates were closely related, with single nucleotide polymorphisms (SNPs) ranging from 8 to 19. The floR gene was located on a novel 5588 bp plasmid, designated as pAp-floR. BLASTN analysis showed that the pAp-floR plasmid had high nucleotide identity (99 %) and coverage (60 %) with the pMVSCS1 plasmid (5621 bp) from Mannheimia varigena MVSCS1 of porcine origin. Additionally, at least under laboratory conditions, pAp-floR was stably maintained even in the absence of direct selective pressure, suggesting that it does not impose a fitness cost. Our study underscores the necessity of monitoring the spread of florfenicol-resistant A. pleuropneumoniae isolates in the coming years., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)
- Published
- 2024
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