Gram-Positive Diplococci: Identification, Examples & Diseases

Gram-positive diplococci (GPD) are bacteria appearing in pairs under microscope after Gram staining. Key species:

• Streptococcus pneumoniae: Pneumonia, meningitis; nasopharyngeal colonizer.
• Streptococcus pyogenes (Group A Strep): Strep throat, scarlet fever; throat/skin.
• Enterococcus faecalis: UTIs, endocarditis, intra-abdominal infections; GI tract.
• Staphylococcus aureus: Skin infections, pneumonia; skin/respiratory colonizer. (Note: typically clusters, but can appear as pairs.)
• Streptococcus agalactiae (Group B Strep): Neonatal infections, maternal; GI/GU tracts.
• Gemella, Lactococcus, Pediococcus, Aerococcus: Mostly commensal; rare pathogens in immunocompromised.

Accurate identification guides appropriate antibiotic therapy and infection control.