From the Guidelines
Staphylococcus aureus is the bacteria that is a gram-positive cocci, often found in pairs and clusters, and can be an anaerobe under certain conditions, although it is typically a facultative anaerobe. This organism is known for its ability to grow with or without oxygen, though it prefers oxygen-rich environments. According to the study published in Clinical Infectious Diseases 1, Staphylococcus aureus is one of the pathogens that can be involved in intra-abdominal infections, and its identification is crucial for appropriate treatment. Some key points about Staphylococcus aureus include:
- It appears as grape-like clusters when viewed under a microscope after gram staining, where it retains the purple crystal violet dye due to its thick peptidoglycan cell wall.
- It's commonly found on human skin and mucous membranes, particularly in the nose and respiratory tract.
- While often harmless as part of normal flora, it can cause various infections ranging from minor skin infections like boils and impetigo to serious conditions such as pneumonia, endocarditis, and toxic shock syndrome.
- Staphylococcus aureus is clinically significant because many strains have developed antibiotic resistance, including methicillin-resistant Staphylococcus aureus (MRSA), which requires specific antibiotics like vancomycin for treatment, as mentioned in the guidelines for the diagnosis and management of complicated intra-abdominal infection in adults and children 1. The study also highlights the importance of considering local susceptibility patterns for S. aureus and enterococci, and the potential need for additional empiric antimicrobial therapy until definitive culture results are available 1.
From the Research
Bacterial Identification
- The bacteria that is an anaerobe, gram-positive cocci in pairs and clusters is Peptostreptococcus anaerobius 2, 3, 4, 5, 6.
Characteristics
- Peptostreptococcus anaerobius is a gram-positive anaerobic coccus (GPAC) found in the gastrointestinal and vaginal microbiota 2.
- GPAC are part of the normal flora of all mucocutaneous surfaces and are often isolated from infections such as deep organ abscesses, obstetric and gynecological sepsis, and intraoral infections 4.
Antimicrobial Susceptibility
- Peptostreptococcus anaerobius has shown to be more resistant to antimicrobials than other GPAC 2, 5.
- P. anaerobius is resistant to penicillin, ampicillin, ciprofloxacin, and levofloxacin, and displays intermediate susceptibility to ampicillin-sulbactam and amoxicillin-clavulanic acid 2.
- Antimicrobial susceptibility testing (AST) should be performed on P. anaerobius isolates due to their unpredictable AST patterns 2.