Molecular characterization of Rhodococcus equi isolates from horses in Poland: pVapA characteristics and plasmid new variant, 85-kb type V.
Authors: Witkowski Lucjan, Rzewuska Magdalena, Takai Shinji, Chrobak-Chmiel Dorota, Kizerwetter-Świda Magdalena, Feret Małgorzata, Gawryś Marta, Witkowski Maciej, Kita Jerzy
Journal: BMC veterinary research
Summary
# Editorial Summary: Molecular characterisation of *Rhodococcus equi* in Polish equine populations *Rhodococcus equi* remains a leading cause of pneumonia in foals worldwide, yet relatively little was known about the genetic diversity of isolates circulating in Poland before this work. Between 2001 and 2012, researchers collected samples from pneumonic foals across 13 breeding farms, using tracheobronchial aspiration and necropsy material, then characterised the isolates through plasmid profiling and pulsed-field gel electrophoresis to map their genetic relationships. The molecular analysis identified a novel 85-kb type V plasmid variant alongside characterisation of virulence plasmid (pVapA) profiles, revealing the strain diversity present in the Polish equine population. These findings are significant because understanding the plasmid types and genetic lineages circulating regionally helps inform infection control strategies on breeding farms and may ultimately guide vaccination development, particularly as different plasmid types are associated with varying pathogenic potential. For practitioners managing foals at risk of rhodococcosis, this baseline data on local strain characteristics supports more targeted approaches to prevention and biosecurity protocols tailored to regional epidemiology.
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Practical Takeaways
- •R. equi remains a significant bacterial pathogen affecting young foals in Poland; surveillance and molecular characterization help track strain prevalence and identify outbreak patterns
- •Understanding plasmid variants and virulence factors (pVapA) may inform diagnostic approaches and future treatment strategies for rhodococcosis management
- •Tracheobronchial aspiration is a viable diagnostic sampling method for confirming R. equi infection in living pneumonic foals
Key Findings
- •Molecular characterization of R. equi isolates from 13 Polish horse breeding farms identified pVapA plasmid variants and a novel 85-kb type V plasmid variant
- •Samples were collected from pneumonic foals aged up to 6 months via tracheobronchial aspiration or necropsy
- •Plasmid profiling and pulsed-field gel electrophoresis were used for genotyping of isolates