Gram Positive Cocci Bacteria Quiz

Gram Positive Cocci

• Gram stain: Essential first step to identify bacteria in a sample.
• Staphylococcus aureus: Common skin and nasal flora; a leading cause of bacteremia (sepsis)
• Staphylococcus aureus (MRSA): 40% of the population carries it in their nasal cavity. Swabs are used to identify it.
• Diagnosis of Staph aureus: Use specific media like blood agar and mannitol salt agar.
• MRSA treatment: Ceftaroline or Ceftobiprole are direct inhibitors of PBP2a.
• S. lugdunensis: Is similar to S. aureus causing native valve endocarditis, bacteremia, and joint infections.
• Contamination: S. lugdunensis in one out of four blood cultures indicates contamination.
• S. saprophyticus: Common cause of UTIs in females (16-35 years) during late summer. Diagnosis is based on a positive urease test.
• Group A Streptococci (GAS): Causes strep throat, scarlet fever (red rash and strawberry tongue)
• Group B Streptococci (GBS): Can cause neonatal disease (early onset); preventing it involves chemoprophylaxis around birth.
• Streptococcus pneumoniae: Leading cause of community acquired pneumonia (CAP) and lower respiratory tract infections. Lobar pneumonia/acute fever/shortness of breath are prominent signs.
• Diagnosis via bile solubility test: Method for identifying Streptococcus pneumoniae.
• S. anginosus: Can be a source of bacteremia, endocarditis, and deep tissue abscesses; commonly associated with anaerobic bacteria.

Gram Positive Bacilli

• Listeria monocytogenes: Can cause late-onset neonatal listeriosis (30% mortality rate); affects both newborns during birth and also older adults and the elderly.
• Corynebacterium spp.: Can cause respiratory tract infections (sore throat, bull neck, neurological symptoms), and skin lesions (ulcers).
• Nocardia spp.: Shows pulmonary and systemic symptoms often presenting with an acute flu-like illness, with pneumonia or disseminated disease, that eventually progresses into necrosis and abscess formation . Chronic and relapsing bronchopneumonia is possible.
• Diagnosis: Gram stain reveals branching filaments; AFB (acid fast bacilli) smear is positive (similar to TB).
• C. difficile ribotype-27: Variant of C. difficile, prevalent in North America, and associated with increased virulence. It is resistant to fluoroquinolones.
• Cutibacterium spp.: Common culprit for acne and can also be involved in complications during shoulder revisions.
• Chlamydia spp.: C. trachomatis is a common sexually transmitted infection (STI) that is often asymptomatic. It can cause urethritis, conjunctivitis, and Reiter's syndrome.
• Legionella pneumophila: Not a normal part of the body’s flora (normal flora and normal skin flora) and serogroup 1 being the most common cause of Legionnaires' disease.

Test your knowledge on Gram positive cocci, including important types like Staphylococcus aureus and Streptococcus species. This quiz covers identification, diagnosis, and treatment options for these bacteria, essential for microbiology studies. Relevant for students in health sciences or microbiology classes.