Contents lists available at ScienceDirect Comparative Immunology, Microbiology and Infectious Diseases journal homepage: www.elsevier.com/locate/cimid New sequence type ST3756 of Staphylococcus aureus subspecies anaerobius as the causative agent of abscessing lymphadenitis in sheep Sona Slosarkova a , Jaroslav Bzdil b , Katerina Nedbalcova a , Jan Matiasovic a, ⁎ , Petr Fleischer a , Stanislav Stanek c a Department of Immunology, Veterinary Research Institute, Hudcova 70, 621 00 Brno, Czech Republic b Department of Special Microbiology, State Veterinary Institute Olomouc, Jakoubka ze Stribra 1, 779 00 Olomouc, Czech Republic c Department of Technology and Breeding Technique of Farm Animals, Institute of Animal Science, Pratelstvi 815, 104 00 Prague, Czech Republic ARTICLE INFO Keywords: Autogenous vaccine Europe Morel's disease S. aureus Therapy ABSTRACT Morel's disease is a form of abscessing lymphadenitis of sheep and goats caused by Staphylococcus aureus sub- species 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. 1. Introduction Superficial abscessing lymphadenitis or caseous lymphadenitis (CLA) in small ruminants is commonly associated with Corynebacterium pseudotuberculosis and the disease is referred to as pseudotuberculosis [1]. However, diseases caused by other pyogenic microorganisms may also be present in the form of abscessing lymphadenitis. One of these microorganisms is Staphylococcus aureus and its subspecies, S. aureus ssp. anaerobius, which was identified as a causative agent of superficial abscessing lymphadenitis, known as Morel's disease [2]. It was also reported in human patients in South Australia [3]. Nowadays, this disease is described in sheep in African countries such as the Sudan, Ethiopia and Kenya, and also in Saudi Arabia. European countries have reported cases of this disease in Poland, Hungary, Croatia, Denmark and Spain [4–7]. Localization of abscesses is variable, but usually they are subcutaneous. Their content is viscous, yellowish and odorless [4]. S. aureus ssp. anaerobius strains can be identified in detail by Multilocus Sequence Typing (MLST). The sequence types may vary depending on the geographical or host origin of S. aureus ssp. anaerobius isolates. For example, Elbir et al. [5] published a diagram containing 22 different sequence types. Of these, 4 sequential types were isolated from sheep. In the Sudan, they defined a completely new sequence type (ST), ST1464, in 17 sheep isolates. De la Fuente et al. [8] examined 94 strains of S. aureus ssp. anaerobius isolated from abscesses of small ruminants in Spain, Denmark, Italy and the Sudan and detected in all cases the same sequence type ST1464. They conjectured that abscessing disease is caused by a single sequence type ST1464. However, this paper de- scribes a case of rapid spreading Morel's disease which affected most sheep in a big flock in the Czech Republic and was caused by the new sequence type S. aureus, ssp. anaerobius ST3756. 2. Materials and methods 2.1. Animals The affected flock consisted of 170 adult sheep (Romanov sheep, Romanov crossbred with Lacaune breed and purebred East Friesian sheep), 60 young sheep, approximately 300 lambs (in summer 2015) and 15 goats. All the animals were housed in pens in new wooden sheep shelters with deep straw bedding. Animals had free access to pasture and in winter were also fed with hay, haylage and 0.5–1.0 kg of a mixture of grounded barley, oats and lupine per animal and day. The commercial sheep farm was located in Nymburk district, Czech Republic. https://doi.org/10.1016/j.cimid.2019.01.008 Received 22 December 2017; Received in revised form 30 November 2018; Accepted 14 January 2019 ⁎ Corresponding author. E-mail address: matiasovic@vri.cz (J. Matiasovic). Comparative Immunology, Microbiology and Infectious Diseases 63 (2019) 112–116 0147-9571/ © 2019 Elsevier Ltd. All rights reserved. T