Mycoplasma hyopneumoniae genetic variability within a swine operation

Abstract

The objective of our study was to characterize the Mycoplasma hyopneumoniae genetic diversity within a swine operation comingling weaned pigs. Bronchial swabs and tracheal aspirates were collected from 3 nursery-to-finish farms. During the finishing production stages, samples were obtained from mortalities and from live coughing pigs in rooms where mortality was not observed. A total of 105 samples were examined by a M. hyopneumoniae real-time polymerase chain reaction and subjected to genetic typing using a multilocus variable number tandem repeat analysis (MLVA) assay. The MLVA was used to identify genetic variants based on the number of repeats in 2 variable number tandem repeats loci, namely P97 and P146, thought to mediate adherence of M. hyopneumoniae to swine cilia. Four distinguishable M. hyopneumoniae variants were identified: MVLA variants 9-15, 11-21, 9-21, and 7-15. Variant 9-15 was the most prevalent, observed in 79% of rooms, and detected on all 3 farms. Variant 11-21 was present in 37% of the rooms on 2 of the 3 farms. Only one 9-21 variant was identified in 1 farm, and all samples of variant 7-15 were recovered from another farm. Based on the low prevalence and limited geographic distribution of the last 2 variants, it is hypothesized that they might be the result of in-situ recombination. All variants detected in this investigation appeared to belong to 3 clusters. Overall, a limited number of variants and clusters were identified in a system that comingles pigs from different sources, suggesting limited M. hyopneumoniae genetic variation within commercial swine production environments.

Update onMycoplasma hyopneumoniaeinfections in pigs: Knowledge gaps for improved disease control

“…Whereas it has been reported that co‐infection with more than one strain resulted in more severe lesions (Michiels et al., ; Villarreal et al., ), such potentiation was not observed in others (Charlebois et al., ). To date, the lack of a known virulence marker together with the coexistence of different strains at individual and farm levels (Nathues, Grosse Beilage, Kreienbrock, Rosengarten, & Spergser, ; Pantoja, Pettit, Dos Santos, Tubbs, & Pieters, ; Vranckx, Maes, Del Pozo Sacristán, Pasmans, & Haesebrouck, ; Vranckx et al., ), prevent knowing the impact of a particular strain on the severity of clinical signs and lung lesions.…”

“…Nathues, Grosse Beilage, Kreienbrock, Rosengarten, & Spergser, 2011;Pantoja, Pettit, Dos Santos, Tubbs, & Pieters, 2016;Vranckx, Maes, Del Pozo Sacrist an, Pasmans, & Haesebrouck, 2012a;Vranckx et al, 2011), prevent knowing the impact of a particular strain on the severity of clinical signs and lung lesions.…”

The Role of Lipoproteins in Mycoplasma-Mediated Immunomodulation

“…To achieve a large variety of Vsa recombination of lipoproteins, mycoplasmas use DNA recombination ( Dybvig et al, 1998 ; Shen et al, 2000 ). Although a single cell may only transcribe a single Vsa gene, during an infection subpopulations of cells are able to express varying Vsa lipoproteins ( Pantoja et al, 2016 ).…”

Associations between animal and herd management factors, serological response to three respiratory pathogens and pluck lesions in finisher pigs on a farrow-to-finish farm

“…Instead, the higher antibody response for SIV observed from pigs in ow 1 indicates onfarm viral re-occurrence [43]. Finally, the similar Mhyo S/P ratio values between production ows could be partly due to the aforementioned Mhyo vaccination protocol but such elevated response at slaughter is probably due to natural infection [38], or reinfection with a different strain of Mhyo throughout the unit [44].…”