Mycoplasma hyorhinis is one of the causative agents of polyserositis and arthritis in post-weaning pigs. Here we describe the development of a multi-locus sequence typing (MLST) protocol for the characterization of M. hyorhinis field isolates. A total of 104 field isolates from different geographical locations, swine production systems, and clinical backgrounds, were analyzed. Twenty-seven genes, including housekeeping and those encoding surface proteins, were evaluated to index diversity. Genes encoding surface proteins were included to increase the discriminatory power of the MLST. Four target gene fragments were selected to be included in the final MLST-s (surface) protocol: pdhB, p95, mtlD and ung. Within each locus the nucleotide variation ranged from 1.4% to 20%. The 104 field isolates were classified into 39 distinct sequence types (STs). Multiple STs were found within the same production system and within the same pig. The majority of STs grouped strains from the same production system; however, cases existed where multiple systems shared a ST, indicating potential relationships between pig flows. The majority of the nucleotide changes observed in these genes generated synonymous changes, while non-synonymous changes were exclusively in the mtlD gene fragment, suggesting that this protein is undergoing selection. Molecular typing of M. hyorhinis will primarily aid swine practitioners with pig flow management and identifying sources of infection during outbreaks.
Bibliographical noteFunding Information:
This study was funded by The National Pork Board (grant #12-044) to AR and MC and by intramural funding from the College of Veterinary Medicine University of Minnesota–EZD program 2012 to MC. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
© 2019 Clavijo et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.