Evaluation of the feasibility of Mycoplasma hyopneumoniae detection in processing fluids

This is our Friday rubric: every week a new Science Page from the Bob Morrison’s Swine Health Monitoring Project. The previous editions of the science page are available on our website.

This week, we are sharing a report by Dr. Carles Vilalta about the evaluation of processing fluids to detect Mycoplasma hyopneumoniae.

Background

The use of processing fluids (PF) to detect and monitor PRRSvand other pathogens is increasing among producers and veterinarians. Preliminary data from our research team identified Mycoplasma hyopneumoniae in PF at the litter level, using a speciesͲspecific realͲtime PCR, in a M. hyopneumoniae endemically infected farm.

Objectives

  • To investigate the detection of M. hyopneumoniae in non-respiratory tissues and fluids collected from suckling pigs at processing age.
  • To develop an in situ hybridization (ISH) assay to further identify M. hyopneumoniae in non-respiratory tissues.

Material and methods

Freshly farrowed litters were sampled at two sow farms with previous detection of M. hyopneumoniae in PF. The following samples were obtained from:

  • Dams: Whole blood, serum,colostrum, whole placenta and vaginal swab.
  • Stillborn: Individually bagged and submitted for full diagnostics M. hyopneumoniae workup at the UMN-VDL. Whole blood was also collected during sampling.
  • Viable piglets: New born piglets were processed prior to suckling. Tails and testicles were collected individually per piglet and gender was recorded. Whole blood and laryngeal swabs were collected for all piglets. (PPE and sampling supplies were changed or disinfected between collection for each piglet)

Daily aggregated PF were collected at a sow farmover a 10-week period. A novel RNA-based ISH was developed using hybridization-coupled signal amplification system in histological tissue sections. To aid visualization of transcriptionally active bacterial organism expressing ribosomal and adhesin proteins.

Results

Mycoplasma hyopneumoniae detection in non-respiratory tissues or fluids

All dams tested negative for M. hyopneumoniae by RT-PCR in blood, serum, colostrum, placenta, and vaginal swabs. Fifty percent of dams were seropositive by Oxoid™ Mycoplasma hyopneumoniae ELISA. All blood samples from stillborn and piglets resulted negative to M. hyopneumoniae by RT-PCR. Mycoplasma hyopneumoniae was detected in 2/54 individual fluid samples (tails and testicles). M. hyopneumoniae was detected (Ct<40) over the 10-week period by RT-PCR (Figure 1). PF and their associated testicles were collected individually at the litter level. All PF were tested by M. hyopneumoniae by RT-PCR. Samples were fixed in formalin to perform ISH on positive samples.

Development of an In situ hybridization assay

The ISH-RNA technique established the distribution of M. hyopneumoniae in affected tissues in association with histological lesions, characterized by lymphoplasmocytic peribronchiolitis and/or hyperplasia of the broncho-associated lymphoid tissues. In M. hyopneumoniae positive lungs, hybridization signals were observed in the apical membrane of the respiratory epithelium of bronchi and bronchioles. Positive signals were also observed in inflammatory cells and degenerative epithelial cells within the bronchial and bronchiolar lumen. The ISH-RNA technique provided molecular detection of M. hyopneumoniae cells expressing mRNA of proteins and elucidated the localization patterns by visualization in tissue.

Mycoplasma hyopneumoniae RTͲPCR results of the daily aggregated processing fluids (PF)

Conclusions and Implications

Mycoplasma hyopneumoniae was detected intermittently in aggregated PF. In this investigation, M. hyopneumoniae was not detected in piglet tissues or samples, regardless of M. hyopneumoniae detection in aggregated PF. Regardless of the fact that environmental contamination can not be ruled out, aggregated PF could be a good indicator of M. hyopneumoniae a farm level. A specific In situ hybridization assay for M. hyopneumoniae was developed, which will be applied to nonͲrespiratory piglet tissue samples.

Evaluation of the feasibility of Mycoplasma hyopneumoniae detection in processing fluids

This report is the February edition of the Swine Disease Eradication Center (SDEC) research update. Not sure what the SDEC is? Check out this quick read about our research group collaborating with industry partners to solve problems faced by the swine industry.

Dr. Vilalta collaborated with Minnesota-based producers, the Veterinary Diagnostic Laboratory and the MycoLab to investigate processing fluids as a sample type for the detection of Mycoplasma hyopneumoniae.

Continue reading “Evaluation of the feasibility of Mycoplasma hyopneumoniae detection in processing fluids”

A quick guide to Mycoplasma hyopneumoniae diagnostics

Sample types for early detection of Mycoplasma hyopneumoniae is a popular post on this blog. Dr. Pieters, head of the MycoLAb at the University of Minnesota created an online quick guide to help swine practitioners decide which sample type they should collect if they are looking for Mycoplasma hyopneumoniae.

This guide is available at http://z.umn.edu/MycoplasmaDiagnostics

Continue reading “A quick guide to Mycoplasma hyopneumoniae diagnostics”

Piglet gut microbiota: a potential determinant for M. hyopneumoniae susceptibility

This is our Friday rubric: every week a new Science Page from the Bob Morrison’s Swine Health Monitoring Project. The previous editions of the science page are available on our website.

This week, we are sharing a report by the MycoLab regarding piglet microbiota and its potential influence of M.hyopneumoniae susceptibility.

Key points

  • Early life gut microbiota could be a potential determinant in modulating susceptibility to chronic respiratory diseases such as enzootic pneumonia in pigs.
  • Increased abundance of short‐chain fatty acid producing bacteria in piglet gut was associated with decreased M. hyopneumoniae respiratory lesions.  
  • Understanding the function and composition of a ‘healthy’ pig gut microbiota would aid to successfully implement novel disease control strategies.
Continue reading “Piglet gut microbiota: a potential determinant for M. hyopneumoniae susceptibility”

Best of Leman 2018 series #2: M. Schwartz – A systems approach to M. hyopneumoniae elimination

We launched a new series on the blog last year. Once a month, we are sharing with you a presentation given at the Allen D. Leman swine conference, on topics that the swine group found interesting, innovative or that lead to great discussions.

We can find all of the presentations selected from last year’s conference on the blog here.

Our second presentation for this year is from Mark Schwartz from Schwartz Farms sharing their experience trying to eliminate Mycoplasma hyopneumoniae from their system.

Click on the image below to see his presentation at the conference: