[Gram-positive cocci isolated from blood]

Area of Science:

• Medical Microbiology
• Infectious Diseases
• Clinical Bacteriology

Context:

• Bloodstream infections are a significant clinical concern.
• Staphylococci, including Staphylococcus aureus and Staphylococcus epidermidis, are common causes of hospital-acquired infections.
• Infective endocarditis remains a serious condition, particularly affecting native heart valves.

Purpose:

• To identify the predominant microorganisms isolated from patient blood cultures between 1994 and 1997.
• To analyze the prevalence of specific staphylococcal species, including Methicillin-Resistant Staphylococcus aureus (MRSA).
• To review the causative agents of native valve endocarditis over a ten-year period (1987-1997).

Summary:

• Staphylococci were the main organisms isolated from blood cultures (1994-1997), with 216 strains of S. epidermidis and 194 strains of S. aureus identified.
• MRSA strains predominated among S. aureus isolates (140 strains).
• S. epidermidis and MRSA were frequently associated with patients having indwelling intravenous catheters, though contamination is a possibility for S. epidermidis.
• Streptococci, specifically viridans streptococci (18 of 33 cases), were the primary cause of native valve endocarditis (1987-1997).

Impact:

• Highlights the significant role of staphylococci, especially MRSA and S. epidermidis, in bloodstream infections, often linked to medical devices.
• Underscores the persistent threat of streptococcal infections in native valve endocarditis.
• Provides crucial epidemiological data for guiding infection control strategies and antimicrobial therapy in clinical settings.