A comparative study of the behaviour of left-sided infective endocarditis (left-sided IE) due to Streptococcus agalactiae (GBS) with left-sided IE caused by Staphylococcus aureus (SA). A prospective, multicentre cohort study in eight public hospitals in Spain, from January 1984 to December 2015; comparative analysis and factors associated with mortality. In total, there were 1754 episodes of left-sided IE; 41 (2.3%) caused by GBS vs. 344 (19.6%) due to SA, definitive IE 39 vs. 324 cases, males, 25 vs. 213, respectively. There were no differences in age or comorbidity, and healthcare-associated acquirement was 10% vs. 43%, p 0.001. Transthoracic echocardiogram (TTE) was performed in 95% vs. 96.8% and a transesophageal echocardiogram (TEE) in 61% vs. 56%. Vegetations were detected in 80% and measured > 1 cm in a similar proportion. It affected native valves in 85.4% vs. 82.6% and late prosthetic valve in 14.6% vs. 9.6%. The course was acute in both groups. There were more skin manifestations in SA left-sided IE, 7.3% vs. 32%, p 0.001. Both groups had similar complications, but in SA, there was more renal failure, 24% vs. 45%, p 0.010. Surgical risk and operated patients were similar. Mortality was proportionally higher in the SA group, without significance 29% vs. 43% (150), p 0.09. Heart failure, septic shock and neurological deterioration conditioned mortality: HR 1.96, 1.69 and 1.37 (CI 95% 1.40-2.73; 1.19-2.39 and 0.99-1.88 respectively) and to a lesser degree SA as aetiology agent and age. Left-sided IE caused by GBS is similar in severity to left-sided IE caused by SA.
Keywords: Left-sided infective endocarditis; Staphylococcus aureus; Streptococcus agalactiae.