Differential Diagnosis for Gram Positive Cocci in Pairs in Chains
- Single Most Likely Diagnosis
- Streptococcus pyogenes: This bacterium is commonly found in pairs or chains and is a frequent cause of pharyngitis and skin infections, making it the most likely diagnosis based on the gram stain morphology.
- Other Likely Diagnoses
- Streptococcus pneumoniae: Although typically seen in pairs (diplococci), some strains can form short chains, and it's a common cause of pneumonia and other invasive infections.
- Streptococcus agalactiae (Group B Streptococcus): This organism can appear in chains and is a significant cause of infections in newborns and pregnant women.
- Streptococcus oralis: Part of the viridans streptococci group, it can form chains and is often associated with endocarditis and other infections.
- Do Not Miss Diagnoses
- Streptococcus milleri group: Includes Streptococcus anginosus, Streptococcus constellatus, and Streptococcus intermedius. These bacteria can form chains and are known for causing abscesses and other serious infections.
- Enterococcus species: While typically seen in pairs, enterococci can occasionally form short chains. They are significant pathogens, especially in healthcare settings, causing urinary tract infections, bacteremia, and endocarditis.
- Rare Diagnoses
- Abiotrophia species: Previously known as nutritionally variant streptococci, these bacteria require special growth conditions and can appear in chains. They are rare causes of endocarditis and other infections.
- Gemella species: These are gram-positive cocci that can form chains and are part of the normal oral flora but can cause infections, particularly endocarditis, in rare instances.