Detection of Mycoplasma hyopneumoniae and Mycoplasma hyorhinis by PCR in Processing Fluids - Dr. Amanda Sponheim, from the 2018 Allen D. Leman Swine Conference, September 15-18, 2018, St. Paul, Minnesota, USA. More presentations at http://www.swinecast.com/2018-leman-swine-conference-material

1. Detection of
Mycoplasma hyopneumoniae
and Mycoplasma hyorhinis
by PCR in processing fluids
A. Sponheim1,2; D. Murray3; L. Johnson3; C. Vilalta1; R. Stika4; E. Fano2;
M. Pieters1
1University of Minnesota, St. Paul, MN; 2Boehringer Ingelheim Animal Health, Duluth, GA;
3New Fashion Pork, Jackson, MN; 4Iowa State University, Ames, IA

2. Introduction
M. hyorhinis is known to colonize the upper and lower
respiratory tract and to spread systemically (Thacker, 2012)
◦ Unaware of M. hyorhinis detection by PCR in processing
fluids
M. hyopneumoniae is known to colonize the respiratory
tract of pigs (Zielinski and Ross, 1992)
◦ Not widely accepted to spread systemically
◦ Detection outside of respiratory tract (Friis et al., 1974; Marois et al., 2006;
Le Carrou et al., 2006; Woolley et al., 2012)
◦ M. hyopneumoniae detection by PCR in processing fluids
(Pieters et al., 2018)

3. Objective
To sample and test processing fluids from sow herds of
expected M. hyorhinis and M. hyopneumoniae statuses

4. Material and methods
Farm selection
Seven sow herds were selected
◦ All seven sow herds were known to be positive for
M. hyorhinis
◦ Sow farm 1 was expected to be M. hyopneumoniae
negative
◦ Sow farms 2-7 were expected to have a low
prevalence of M. hyopneumoniae

5. Material and methods
Sampling and testing
Each sow herd was to collect processing fluids for 4
consecutive weeks (Baker et al., 2018)
Processing fluids were pooled by processing day and
frozen after tail and testicle tissue removed
All frozen samples were shipped to the University of
Minnesota VDL
◦ M. hyorhinis and M. hyopneumoniae real-time PCR
◦ 37 Ct positive cutoff, 37.01-40 Ct suspect range

6. Results
M. hyorhinis was detected in 3/7 expected positive
sow farms
M. hyopneumoniae was detected in 4/6 expected
positive sow farms
◦ Sow farm 1 samples were negative

7. Results
M. hyorhinis PCR
4/263 (1.5%) samples were positive
◦ 35.5 Ct mean for positive samples
◦ 34.25 Ct min, 36.79 Ct max
31/263 (11.8%) samples were suspect
◦ 38.9 Ct mean for suspect samples
◦ 37.19 Ct min, 39.48 Ct max
Detected in 3/7 expected positive sow farms
◦ The percent of positive samples by farm ranged from
2.4% to 5.9%

8. Results
M. hyorhinis PCR
Sow farm 1 2 3 4 5 6 7 8 Total
1 0/7 (0%), 1 S 0/7 (0%) 0/7 (0%) 0/7 (0%) 0/7 (0%), 1 S 0/7 (0%) 0/7 (0%), 1 S 0/1 (0%) 0/50 (0%), 2 S
2 0/9 (0%), 1 S 0/7 (0%) 0/7 (0%) 0/7 (0%) 0/7 (0%), 1 S 0/37 (0%), 2 S
3 0/7 (0%), 2 S 0/7 (0%) 1/7 (14.3%), 1 S 0/7 (0%) 0/7 (0%) 0/6 (0%), 1 S 1/41 (2.4%), 4 S
4 0/6 (0%), 1 S 0/9 (0%) 0/5 (0%) 0/3 (0%) 0/23 (0%), 1 S
5 0/7 (0%), 3 S 0/5 (0%), 1 S 0/5 (0%), 1 S 0/7 (0%), 2 S 0/7 (0%), 2 S 0/7 (0%), 3 S 0/7 (0%), 3 S 0/45 (0%), 15 S
6 0/8 (0%) 0/7 (0%) 0/6 (0%), 2 S 1/7 (14.3%), 1 S 0/4 (0%), 1 S 1/32 (3.1%), 4 S
7 0/8 (0%) 0/7 (0%) 1/7 (14.3%) 1/7 (14.3%), 2 S 0/5 (0%) 2/34 (5.9%), 2 S
Study collection week

9. Results
M. hyopneumoniae PCR
19/263 (7.2%) samples were positive
◦ 33.6 Ct mean for positive samples
◦ 27.39 Ct min, 36.99 Ct max
17/263 (6.5%) samples were suspect
◦ 38.7 mean Ct for suspect samples
◦ 37.27 Ct min, 39.94 Ct max
Detected in 4/6 expected positive sow farms
◦ The percent of positive samples by farm ranged from
2.7% - 39%
Sow farm 1 samples were negative

10. Results
M. hyopneumoniae PCR
Sow farm 1 2 3 4 5 6 7 8 Total
0/7 (0%) 1/7 (14.3%)
Study collection week
1 0/7 (0%) 0/7 (0%) 0/7 (0%) 0/7 (0%) 0/7 (0%) 0/7 (0%) 0/7 (0%) 0/1 (0%)
0/7 (0%)
3 2/7 (28.6%), 4 S 2/7 (28.6%), 1 S 2/7 (28.6%), 1 S 0/7 (0%) 0/7 (0%), 1 S 0/6 (0%), 1 S
2 0/9 (0%) 0/7 (0%), 1S
0/3 (0%), 2 S
5 0/7 (0%) 0/5 (0%) 0/5 (0%)
3/5 (60%)4 5/6 (83.3%), 1 S 1/9 (11%), 1 S
0/7 (0%) 1/7 (14.3%), 1 S 1/7 (14.3%) 1/7 (14.3%)
7 0/8 (0%) 0/7 (0%) 0/7 (0%), 1 S
0/7 (0%)6 0/8 (0%) 0/7 (0%)
0/50 (0%)
1/37 (2.7%), 1 S
6/41 (14.6%), 8 S
9/23 (39.1%), 4 S
3/45 (6.7%), 1 S
0/33 (0%), 1 S
0/34 (0%), 1 S0/7 (0%) 0/5 (0%)
0/7 (0%) 0/4 (0%), 1 S

11. Conclusion
M. hyorhinis and M. hyopneumoniae were detected
in processing fluids from > 1 endemically infected
farm
◦ M. hyopneumoniae was not detected in the expected
negative farm (Sow farm 1)
M. hyorhinis and M. hyopneumoniae were not
always detected in expected positive farms

12. Discussion
Factors influencing detection are unknown
◦ Low detection of M. hyorhinis in processing fluids
could be due to an ongoing sow vaccination program
at all sampled sow farms
◦ The cause for detection of M. hyopneumoniae in
processing fluids is unknown
◦ Hypothesized to be due to contamination of
processing fluids through piglet contact with the
shedding dam

13. Next Steps
A longitudinal diagnostic sampling of nursery and
finishing pigs representative of the results
described is underway

14. Acknowledgements
New Fashion Pork sow farm staff
Boehringer Ingelheim Animal Health