New sequence type ST3756 of Staphylococcus aureus subspecies anaerobius as the causative agent of abscessing lymphadenitis in sheep.

ABSTRACT

Morel's disease is a form of abscessing lymphadenitis of sheep and goats caused by Staphylococcus aureus subspecies anaerobius. In Europe and Africa, the disease is linked to S. aureus of multilocus sequence type 1464. In an outbreak recorded in 2015 in a flock of 530 animals in the district of Nymburk, Czech Republic, Europe, the causative agent was cultured and subsequently confirmed by Maldi-TOF. Neither antibiotic therapy nor surgical interventions met any success, although the strain isolated was found to be sensitive to antibiotics used. Vaccination and revaccination with inactivated autogenous vaccine administered subcutaneously was relatively successful. Subsequent multilocus sequence typing revealed the presence of new S. aureus sequence type 3756, different from 1464 in three out of seven genes typed. The isolate thus represents a new sequence type of Staphylococcus aureus ssp. anaerobius which should be considered as a causative agent of Morel's disease.