Use of repetitive sequence-based polymerase chain reaction for molecular epidemiologic analysis of Streptococcus equi subspecies equi.
OBJECTIVE
To determine whether repetitive sequence-based polymerase chain reaction (rep-PCR) could be used to differentiate Streptococcus equi isolates, to examine S equi isolates from throughout the world, and to determine whether a horse had > 1 subtype of S equi during an outbreak of disease.


METHODS
An initial group of 32 S equi isolates, 63 S equi isolates from various geographic areas, and 17 S equi isolates obtained during outbreaks of disease.


METHODS
An aliquot of S equi genomic DNA was amplified, using enterobacterial repetitive intergenic consensus primers. Gel electrophoresis was performed on 1.5% agarose gels, and a computed-assisted program was used to compare rep-PCR results.


RESULTS
Use of these primers to analyze 100 ng of S equi genomic DNA resulted in patterns of 6 to 14 bands. The 32 initial isolates were separated into 7 rep-PCR subtypes. There were 30 rep-PCR subtypes found among 29 S equi isolates obtained from Minnesota, Michigan, Canada, and Australia and 34 S equi isolates obtained from Kentucky and other sources. Furthermore, the same clone was identified in several horses during an outbreak of disease. Infected horses on the same farm all had a single clone of S equi.


CONCLUSIONS
Analysis of these results suggests that rep-PCR is useful for delineating S equi into rep-PCR subtypes. Results revealed that isolates with the same geographic source or similar date of collection did not always have the same rep-PCR subtype. A single clone of S equi usually predominated during an outbreak of disease.
Al-Ghamdi
G M
GM
Department of Clinical and Population Sciences, College of Veterinary Medicine, University of Minnesota, St Paul 55108, USA.
Kapur
V
V
Ames
T R
TR
Timoney
J F
JF
Love
D N
DN
Mellencamp
M A
MA
D000818:Animals; D001315:Australia / Q000453:epidemiology; D016172:DNA Fingerprinting / Q000662:veterinary; D017931:DNA Primers / Q000737:chemistry; D004269:DNA, Bacterial / Q000737:chemistry / Q000302:isolation & purification; D004196:Disease Outbreaks / Q000145:classification / Q000662:veterinary*; D004587:Electrophoresis, Agar Gel / Q000662:veterinary; D005060:Europe / Q000453:epidemiology; D006734:Horse Diseases / Q000453:epidemiology / Q000382:microbiology*; D006736:Horses; D015146:Midwestern United States / Q000453:epidemiology; D009864:Ontario / Q000453:epidemiology; D010802:Phylogeny; D016133:Polymerase Chain Reaction / Q000662:veterinary; D013290:Streptococcal Infections / Q000453:epidemiology / Q000382:microbiology / Q000662:veterinary*; D018502:Streptococcus equi / Q000737:chemistry / Q000145:classification* / Q000235:genetics
D017931:DNA Primers; D004269:DNA, Bacterial