Abstract
A 5-month-old male harbour seal was admitted for rehabilitation to the Sealcentre Pieterburen on November 16th, 2015. During the initial veterinary examination parasitic pneumonia and secondary bacterial pneumonia were suspected. Therefore, the seal received antiparasitic and antibiotic treatment and appeared to be recovering but died unexpectedly after several weeks. The main necropsy findings were a large amount of blood in the pericardial space and two perforating lesions: one in the aortic wall and the second in the tricuspid valve. Histopathological examination of the aorta revealed mural necrosis with haemorrhage, suppurative to mixed inflammation and presence of granular cystic structures. The latter structures were considered as microsporidia as the most likely micro-organisms by the pathologist but could not be confirmed by PCR. Bacterial culture resulted in the isolation of a methicillin resistant Staphylococcus aureus (MRSA) from the pericardial effusion. Subsequent culture of rectal swabs collected at arrival and during the seal rehabilitation process revealed that the animal was already colonized when admitted to the Sealcentre. MRSA has been isolated from marine mammals before, including from two harbour seals (Phoca vitulina), two pilot whales (Globicephala macrorhynchus) and five bottlenose dolphins (Tursiops truncatus).1-6 In addition, Staphylococcus aureus has been related to endocarditis in a harp seal.7 However, to our knowledge this is the first report of MRSA associated endocarditis in seals. Also, the isolation of an MRSA in rectal swabs of this seal strengthens the idea to use seals as bio-indicators for antimicrobial resistance prevalence in marine ecosystems.
Acknowledgements
The authors wish to thank Izore, UMCG and Sophie Maes for the support with the analysis of the samples. The authors wish to thank also the staff and volunteers of the Sealcentre Pieterburen that helped with the sample collection.
*Presenting author
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