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Gram-positive bacteria account for >80% of all cases of endocarditis. Currently, staphylococci are the leading cause of endocarditis worldwide. Daptomycin is the drug of choice for empirical antibiotic therapy of staphylococcal endocarditis due to its optimal activity both against meticillin-susceptible Staphylococcus aureus and meticillin-resistant S. aureus (MRSA) strains. Daptomycin has not been proven to be superior to vancomycin in the treatment of MRSA endocarditis. However, daptomycin should be considered the drug of choice for the treatment of MRSA endocarditis caused by strains with a vancomycin minimum inhibitory concentration (MIC) of 2μg/mL, for heterogeneous vancomycin-intermediate S. aureus (hVISA) phenotypes and for glycopeptide-intermediate S. aureus (GISA) strains. Daptomycin is the drug of choice for rescue therapy in cases of MRSA endocarditis in which vancomycin has failed. The appropriate dose of daptomycin has not yet been established; however, for treatment of left-sided endocarditis the dose of daptomycin should be higher than the recommended dose of 6mg/kg/day. Combination antibiotic therapy with daptomycin (e.g. combined with fosfomycin) is a promising treatment for MRSA endocarditis and warrants further investigation. In vivo studies show that daptomycin is superior to vancomycin in the treatment of meticillin-resistant coagulase-negative staphylococci experimental endocarditis, although clinical data are required. Daptomycin could represent an efficacious treatment for vancomycin-resistant Enterococcus faecium endocarditis. Finally, the pharmacokinetic profile of daptomycin makes it an excellent drug for outpatient parenteral antimicrobial therapy.

The incidence of Gram-positive bloodstream infections has been increasing steadily. The virulence of coagulase-negative staphylococci is based mainly on their ability to produce biofilms, and thus cause infections of intravascular devices and foreign bodies, which must be removed to resolve the infection. Staphylococcus aureus is the leading cause of endocarditis, and it is important to recognize patients at risk of the complications of S. aureus bloodstream infections. The rate of meticillin resistance is higher in healthcare-related infections, although clones of community-acquired meticillin-resistant S. aureus carrying the Panton-Valentine leukocidin have recently emerged. Vancomycin minimum inhibitory concentration (MIC) creep gives cause for concern, and MICs >1 microg/mL are associated with higher failure rates and mortality in patients with S. aureus bacteraemia treated with vancomycin. Daptomycin should be considered the optimal empirical treatment for S. aureus bloodstream infections in settings with medium to high prevalence of meticillin-resistant Staphylococcus aureus infections. Enterococci are the third leading cause of Gram-positive bacteraemia in our institution. Management of this disease is difficult because of its intrinsic resistance to antibiotics, mainly in Enterococcus faecium infections. The recently described synergism of ampicillin plus ceftriaxone is a good therapeutic option for Enterococcus faecalis bacteraemia and endocarditis caused by high-level aminoglycoside-resistant strains.

IE and 1,110 cases of IE due to other pathogens (non-SA NVIE). Twogroup comparisons and adjusted survival analysis were performed. Results: Compared to non-SA NVIE, SA NVIE occurred more frequently in older subjects (p = 0.01). It was less often community-acquired (p < 10 4), more frequently diagnosed within the first month of symptoms onset (p < 10 4) and associated with comorbidities (p < 10 4). SA NVIE was more often complicated with stroke (p = 0.0009) and emboli (p = 0.008). By contrast the frequencies of cardiac failure and intracardiac abscess were the same in the two groups. EVS and 60day in-hospital mortality rate were lower (34.2% vs. 50.1%, p < 10 4) and higher (26.5% vs. 11.9%, p < 10 4), respectively. In multivariate analysis, when compared to non-SA NVIE: (1) the probability of EVS was significantly lower in SA NVIE (HR 0.66, 95 CI 0.54 0.80, p < 0.0001); (2) the probability of in-hospital death was significantly higher (HR 1.68, 95 CI 1.28 2.22, p < 0.0001), which was true both in operated and non-operated patients. Conclusion: This study confirms that SA NVIE is associated with higher rates of comorbidities and mortality. It is also associated with a lower rate of EVS, which is neither explained by a higher frequency of comorbidities/complications that would contraindicate surgery nor by a lower frequency of conditions that would require surgery.