Endocarditis by Staphylococcus sp. in Cow and Sheep Leading to Osteoarthritis and Sepsis as Unusual Outcomes

Abstract

Background: Endocarditis is one of the most important heart diseases in cattle and a rare disease in sheep. This illness could be caused by any bacteria when related to bacteremia, being Staphylococcus aureus one uncommon cause for this disorder in ruminants. The clinical sings at the early stages are unspecific and many cases are only diagnosed just at the
final stages of the disease, resulting in heart insufficiency with bad prognosis. The aim of this study is to report two cases of endocarditis caused by Staphylococcus spp. leading to sepsis in a sheep and osteoarthritis in a cow, showing the importance of this bacteria in the pathogenesis of this disease.
Cases: Case 1. A 8-month-old sheep, female, Texel showed lameness in the left thoracic limb, and even treated with nonsteroidal anti-inflammatory drug had anorexia, locomotion difficulty and on the day before of death showed neurological sings, with less than one week of total clinical course. At necropsy, in the heart was observed thrombus in the tricuspid,
mitral and aortic valves and pale areas in the myocardium. Multiples abscesses were observed in the lungs, liver and kidneys and infarcts in kidneys, spleen and brain. At the histopathology exam was observed in the tricuspid, mitral and aortic valves subacute endocarditis with intralesional coccoids bacteria Gram positives. There were multifocal fibrinonecrotic myocarditis, abscess in lung, liver and kidney with intralesional bacterial myriads. In kidneys, spleen and brain was observed
thrombosis associated to multiple infarct areas. Samples of cardiac thrombus, heart, spleen, kidney and meningeal swabs were submitted for bacterial cultivation and was isolated Staphylococcus aureus in all samples, in pure culture.
Case 2. A 2-year-old cow, female, mixed breed Angus and Charolais showed a wound in the distal part of the thoracic limb that was done topical treatment. After a month, was noted submandibular and dewlap edema, prostration, lethargy and fever. Antibiotic treatment was performed having remission of edema and fever, however being lethargic yet. After
a month post antibiotic treatment, the animal showed bilateral increased of joint volume and a new antibiotic treatment was performed. The X-ray and cytology of the synovial fluid presented septic osteoarthritis in both radiocarpal joint. At necropsy was observed a thrombus in the tricuspid valve of approximately 20x4cm ascending to caudal and cranial cava
veins and a pulmonary abscess. In the left carpometacarpal joint, right antebrachiocarpal joint and stifle joint were observed severe purulent exudation and erosions. At histopathology evaluation of the heart was noted subacute septic endocarditis in tricuspid valve and in the joints was observed subacute fibrinopurulent osteoarthritis. In the swabs of joints and thrombus was identified Staphylococcus coagulase positive.
Discussion: Despite the fact of to be skin commensal, S. aureus can enter in the bloodstream and to cause endocarditis, sepsis, abscesses and arthritis. Regard to possible entryways, interdigital pododermatitis and skin superficial lesions can be the entrance of the agent. In both cases the animals showed lesions on the limbs, as possible cause. The relationship
between endocarditis and osteoarticular infections is not fully known. In cattle with heart disease was noted that lameness is an important clinical sign and osteoarthritis could be related with endocarditis. Staphylococcus aureus rarely is reported in endocarditis cases in ruminants and the outcomes showed here are uncommon and poorly studied.
Descritores: estafilococose, doença cardíaca, poliartrite, bacteremia, ruminantes.