Characterization of Actinobacillus pleuropneumoniae isolated from pigs in Japan using whole genome sequencing

• Published in: Comparative immunology, microbiology and infectious diseases Vol. 102; p. 102062
• Main Authors: Ozawa, Manao, Kawano, Motoshi, Abo, Hitoshi, Issiki, Yukari, Kumakawa, Mio, Kawanishi, Michiko, Kojima, Akemi, Iwamoto, Shoko
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.11.2023
• Subjects: Actinobacillus; Antimicrobial resistance; Vaccine; Whole genome sequencing; Vaccine; Antimicrobial resistance; Whole genome sequencing; Actinobacillus
• ISSN: 0147-9571; 1878-1667
• DOI: 10.1016/j.cimid.2023.102062

We conducted whole-genome sequencing to investigate the serotypes, the presence of virulence and antimicrobial resistance genes, and the genetic relationships among isolates of Actinobacillus. pleuropneumoniae derived from diseased pigs. Serotype 2 (71.2%) was the most common, but the prevalence of serotypes 6 (13.6%) and 15 (6.8%) increased. Existing vaccines are considered ineffective on the isolates belonging to serotypes 6 and 15. The phylogenetic tree based on core genome single nucleotide polymorphisms showed that the isolates were clustered by serotype. Of the isolates, 62.5% did not have an antimicrobial resistance gene, including a florfenicol resistance gene, but 32.2% had a tetracycline resistance gene. The antimicrobial resistant phenotype and genotype were almost identical. The plasmid-derived contigs harbored resistance genes of aminoglycosides, tetracyclines, β-lactams, phenicols, or sulfonamides. It has been suggested that isolates with different genetic properties from vaccine strains are circulating; however, antimicrobial resistance may not be widespread. •First report of A. pleuropneumoniae from pigs in Japan using whole genome sequencing.•Isolates were clustered by serotype, and two clusters were formed in the serotype 2 isolates.•Potential spread of isolates different from the existing vaccine strains.•None of the isolates have a florfenicol resistance gene.