Establishment of a Mycoplasma hyorhinis challenge model in 5-week-old piglets

Dorottya Földi; Zsófia Eszter Nagy; Nikolett Belecz; Levente Szeredi; József Földi; Anna Kollár; Miklós Tenk; Zsuzsa Kreizinger; Miklós Gyuranecz

doi:10.3389/fmicb.2023.1209119

Establishment of a Mycoplasma hyorhinis challenge model in 5-week-old piglets

Front Microbiol. 2023 Aug 4:14:1209119. doi: 10.3389/fmicb.2023.1209119. eCollection 2023.

Authors

Dorottya Földi^{1

2}, Zsófia Eszter Nagy^{1

2}, Nikolett Belecz^{1

2}, Levente Szeredi^{2

3}, József Földi⁴, Anna Kollár^{2

3}, Miklós Tenk^{2

3}, Zsuzsa Kreizinger^{1

2

5}, Miklós Gyuranecz^{1

2

3

5}

Affiliations

¹ Veterinary Medical Research Institute, Budapest, Hungary.
² National Laboratory of Infectious Animal Diseases, Antimicrobial Resistance, Veterinary Public Health and Food Chain Safety, Budapest, Hungary.
³ Department of Microbiology and Infectious Diseases, University of Veterinary Medicine, Budapest, Hungary.
⁴ Euvet Bt., Gödöllo, Hungary.
⁵ MolliScience Kft., Biatorbágy, Hungary.

Abstract

Introduction: Mycoplasma hyorhinis is an emerging swine pathogen with high prevalence worldwide. The main lesions caused are arthritis and polyserositis, and the clinical manifestation of the disease may result in significant economic losses due to decreased weight gain and enhanced medical costs. We aimed to compare two challenge routes to induce M. hyorhinis infection using the same clinical isolate.

Methods: Five-week-old, Choice hybrid pigs were inoculated on 2 consecutive days by intravenous route (Group IV-IV) or by intravenous and intraperitoneal routes (Group IV-IP). Mock-infected animals were used as control (control group). After the challenge, the clinical signs were recorded for 28 days, after which the animals were euthanized. Gross pathological and histopathological examinations, PCR detection, isolation, and genotyping of the re-isolated Mycoplasma sp. and culture of bacteria other than Mycoplasma sp. were carried out. The ELISA test was used to detect anti-M. hyorhinis immunoglobulins in the sera of all animals.

Results: Pericarditis and polyarthritis were observed in both challenge groups; however, the serositis was more severe in Group IV-IV. Statistically significant differences were detected between the challenged groups and the control group regarding the average daily weight gain, pathological scores, and ELISA titers. Additionally, histopathological scores in Group IV-IV differed significantly from the scores in the control group. All re-isolated strains were the same or a close genetic variant of the original challenge strain.

Discussion: Our results indicate that both challenge routes are suitable for modeling the disease. However, due to the evoked more severe pathological lesions and the application being similar to the hypothesized natural route of infection in Group IV-IV, the two-dose intravenous challenge is recommended by the authors to induce serositis and arthritis associated with M. hyorhinis infection.

Keywords: ELISA; Mycoplasma hyorhinis; PCR; challenge; infection; pig.

Grants and funding

This study was supported by the Momentum (Lendület) Programme (LP2022-6/2022) of the Hungarian Academy of Sciences and Project no. RRF-2.3.1-21-2022-00001, which has been implemented with the support provided by the Recovery and Resilience Facility (RRF), financed under the National Recovery Fund budget estimate, RRF-2.3.1-21 funding scheme. DF was supported by the New National Excellence Program (ÚNKP-21-3) and the Doctoral Student Scholarship Program of the Co-operative Doctoral Program (KDP-2020) of the Ministry of Innovation and Technology. The funders had no role in study design, data collection and interpretation, or the decision to submit the manuscript for publication.