Clinical and prognostic differences between methicillin-resistant and methicillin-susceptible Staphylococcus aureus infective endocarditis

• Main Authors: Carmen Hidalgo-Tenorio, Juan Gálvez, Francisco Javier Martínez-Marcos, Antonio Plata-Ciezar, Javier De La Torre-Lima, Luis Eduardo López-Cortés, Mariam Noureddine, José M. Reguera, David Vinuesa, Maria Victoria García, Guillermo Ojeda, Rafael Luque, José Manuel Lomas, Jose Antonio Lepe, Arístides de Alarcón
• Format: Article
• Language: English
• Published: BMC 2020-02-01
• Series: BMC Infectious Diseases
• Subjects: Endocarditis; Staphylococcus aureus; Vancomycin; Methicillin resistance
• Online Access: http://link.springer.com/article/10.1186/s12879-020-4895-1

Abstract Background S. aureus (SA) infective endocarditis (IE) has a very high mortality, attributed to the age and comorbidities of patients, inadequate or delayed antibiotic treatment, and methicillin resistance, among other causes. The main study objective was to analyze epidemiological and clinical differences between IE by methicillin-resistant versus methicillin-susceptible SA (MRSA vs. MSSA) and to examine prognostic factors for SA endocarditis, including methicillin resistance and vancomycin minimum inhibitory concentration (MIC) values > 1 μg/mL to MRSA. Methods Patients with SA endocarditis were consecutively and prospectively recruited from the Andalusia endocarditis cohort between 1984 and January 2017. Results We studied 437 patients with SA endocarditis, which was MRSA in 13.5% of cases. A greater likelihood of history of COPD (OR 3.19; 95% CI 1.41–7.23), invasive procedures, or recognized infection focus in the 3 months before IE onset (OR 2.9; 95% CI 1.14–7.65) and of diagnostic delay (OR 3.94; 95% CI 1.64–9.5) was observed in patients with MRSA versus MSSA endocarditis. The one-year mortality rate due to SA endocarditis was 44.3% and associated with decade of endocarditis onset (1985–1999) (OR 8.391; 95% CI (2.82–24.9); 2000–2009 (OR 6.4; 95% CI 2.92–14.06); active neoplasm (OR 6.63; 95% CI 1.7–25.5) and sepsis (OR 2.28; 95% CI 1.053–4.9). Methicillin resistance was not associated with higher IE-related mortality (49.7 vs. 43.1%; p = 0.32). Conclusion MRSA IE is associated with COPD, previous invasive procedure or recognized infection focus, and nosocomial or healthcare-related origin. Methicillin resistance does not appear to be a decisive prognostic factor for SA IE.