Streptococcus equi subsp. zooepidemicus isolates from equine infectious endometritis belong to a distinct genetic group
1 Department of Large Animal Sciences, Section of Veterinary Reproduction and Obstetrics, Faculty of Health and Medical Sciences, University of Copenhagen, Dyrlaegevej 68, Frederiksberg C DK-1870, Denmark
2 Department of Large Animal Sciences, Section of Medicine and Surgery, Faculty of Health and Medical Sciences, University of Copenhagen, Hoejbakkegaard Allé 5, Taastrup DK-2630, Denmark
3 Fertility Clinic, Rigshospitalet, Section 4071, University Hospital of Copenhagen, Blegdamsvej 9, Copenhagen DK-2100, Denmark
4 Ansager Dyrehospital (Ansager Large Animal Hospital), Gartnerhaven 5, Ansager DK-6823, Denmark
5 Department of Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen, Stigboejlen 4, Frederiksberg C DK-1870, Denmark
Veterinary Research 2013, 44:26 doi:10.1186/1297-9716-44-26Published: 18 April 2013
Streptococcus equi subsp. zooepidemicus is the pathogen most commonly isolated from the uterus of mares. S. zooepidemicus is an opportunistic pathogen and part of the resident flora in the caudal reproductive tract. The aim of this study was to investigate whether a genotypically distinct subpopulation of S. zooepidemicus is associated with endometritis in the mare, by genotyping and comparing uterine S. zooepidemicus strains with isolates from the vagina and clitoral fossa. Mares with (n = 18) or without (n = 11) clinical symptoms of endometritis were included. Uterine samples were obtained using a guarded endometrial biopsy punch, whereas a swab was used to recover samples from the cranial vagina and the clitoral fossa. If S. zooepidemicus was present, up to three colonies were selected from each anatomical location (max. 9 isolates per mare). Bacterial isolates were characterized by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). S. zooepidemicus was isolated from the endometrium of 12 mares. A total of 88 isolates were analyzed by PFGE: 31 from the endometrium, 26 from the cranial vagina and 31 isolates from the clitoral fossa. For MLST 21 isolates were chosen. Results demonstrated a higher genetic similarity of the isolates obtained from infectious endometritis compared to isolates obtained from the caudal reproductive tract. In conclusion, we demonstrate for the first time that a genetically distinct group of S. zooepidemicus is associated with infectious endometritis in the mare.