Molecular epidemiology of Streptococcus zooepidemicus isolated from the respiratory tracts of Thoroughbred racehorses in training

• Published in: The veterinary journal (1997) Vol. 183; no. 3; pp. 348 - 351
• Main Authors: Barquero, Nuria, Chanter, Neil, Laxton, Ross, Wood, James L.N., Richard Newton, J.
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.03.2010
• Subjects: Animals; bacterial infections; Bacterial Typing Techniques; DNA, Bacterial - analysis; Equine; genetic variation; horse diseases; Horse Diseases - epidemiology; Horse Diseases - microbiology; Horses; isolation; molecular epidemiology; PCR typing; polymerase chain reaction; Polymerase Chain Reaction - veterinary; Respiratory; respiratory system; Respiratory Tract Infections - epidemiology; Respiratory Tract Infections - microbiology; Respiratory Tract Infections - veterinary; Seasons; Streptococcal Infections - epidemiology; Streptococcal Infections - microbiology; Streptococcal Infections - veterinary; Streptococcus; Streptococcus equi - classification; Streptococcus equi - genetics; Streptococcus equi - isolation & purification; Streptococcus equi subsp. zooepidemicus; Streptococcus zooepidemicus; Thoroughbred; Thoroughbred racehorse; United Kingdom - epidemiology; Equine; Respiratory; PCR typing; Thoroughbred racehorse; Streptococcus zooepidemicus
• ISSN: 1090-0233; 1532-2971
• DOI: 10.1016/j.tvjl.2008.12.013

The objective of this study was to characterise the molecular epidemiology of Streptococcus zooepidemicus isolated from the respiratory tracts of 198 Thoroughbred racehorses based at three Newmarket training yards over a 10 month period. Typing utilised two separate PCR procedures targeting the M-like protein hypervariable and the 16S–23S RNA gene intergenic spacer regions of the bacterium. S. zooepidemicus, isolated from 23% (224/983) of study samples, comprised 24 different types of varying prevalence. The four most common types, A1HV4, A1HV2, C1HVu and D1HV1, accounted for 45% of all the typed isolates. Overall, the findings were similar to those reported in a study of Welsh Mountain ponies and confirm that in equids, S. zooepidemicus is not a homogeneous, clonal population but instead represents a wide diversity of strain types. This diversity also highlights potential difficulties in using vaccines to control S. zooepidemicus infections in horses as it is likely that the induction of a heterologous, cross-protective immunity will be required.