Detection and differentiation of wild-type and a vaccine strain of Streptococcus equi ssp. equi using pyrosequencing.
Streptococcus equi subspecies equi (S. equi), the causative agent of strangles, is an important equine pathogen. Strangles is a highly contagious disease and a commercial modified live vaccine (MLV) is used for protection, which although effective, may also result in clinical signs of the disease. A rapid means to differentiate between the MLV and wild-type infection is crucial for quarantine release and limiting the disease spread. This study describes the use of a pyrosequencing assay targeting a single nucleotide deletion upstream of the SzPSe gene to distinguish between the wild-type and vaccine strains. A set of 96 characterized clinical specimens and isolates were tested using the assay. The assay was successful in differentiating between wild-type S. equi and the vaccine strains and in discriminating S. equi from other Streptococci. The vaccine strain was identified in 61.7% (29/47) of the strangles cases in horses with a history of MLV vaccination.
Pennsylvania Veterinary Laboratory, 2305 N Cameron Street, Harrisburg 17110, United States.
Julia L
JL
Livengood
Veterinary Diagnostic Laboratory, University of Illinois College of Veterinary Medicine, 2001 S. Lincoln Avenue, Urbana, IL 61802, United States.
Saraswathi
S
Lanka
Pathobiology Department, University of Illinois College of Veterinary Medicine, 2001 S. Lincoln Avenue, Urbana, IL 61802, United States.
Carol
C
Maddox
Pennsylvania Veterinary Laboratory, 2305 N Cameron Street, Harrisburg 17110, United States. Electronic address: dtewari@pa.gov.
Deepanker
D
Tewari
D000818:Animals; D015373:Bacterial Typing Techniques / Q000662:veterinary*; D001428:Bacterial Vaccines / Q000382:microbiology*; D006734:Horse Diseases / Q000382:microbiology*; D006736:Horses; D020641:Polymorphism, Single Nucleotide; D017422:Sequence Analysis, DNA; D017384:Sequence Deletion; D013290:Streptococcal Infections / Q000382:microbiology / Q000662:veterinary*; D022541:Streptococcal Vaccines / Q000627:therapeutic use; D018502:Streptococcus equi / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*
D001428:Bacterial Vaccines; D022541:Streptococcal Vaccines
Modified live vaccine; Pyrosequencing; Strangles vaccine; Strep. zooepidemicus-like protein (SzPSe); Streptococcus equi ssp. equi