What is the Difference Between Streptococcus Pneumoniae and Haemophilus Influenzae?

Streptococcus pneumoniae and Haemophilus influenzae are both commensal bacteria that inhabit the human nasopharynx and can cause various diseases, particularly in children. Here are the main differences between the two:

• Classification: Streptococcus pneumoniae is a Gram-positive pathogenic bacterium, while Haemophilus influenzae is a Gram-negative pathogenic bacterium.
• Carriage: Both bacteria are commensal bacteria of the human nasopharynx, with asymptomatic nasopharyngeal carriage in healthy children documented to range up to 80% for Haemophilus influenzae and at least 20% for Streptococcus pneumoniae.
• Diseases: Both bacteria can cause otitis media, bronchitis, pneumonia, meningitis, and sepsis. They are the leading causes of childhood pneumonia and meningitis, and major contributors to mortality in children younger than five years of age.
• Antibiotic Susceptibility: The majority of Streptococcus pneumoniae isolates are sensitive to most antimicrobials, but there are high levels of resistance to azithromycin (51.0%) and erythromycin (51.0%). In contrast, Haemophilus influenzae isolates are sensitive to almost all antimicrobials tested, although 12.2% of isolates are resistant to ampicillin.
• Biofilm Formation: Streptococcus pneumoniae and Haemophilus influenzae have been detected together in a multispecies biofilm in infected tissue, suggesting that they can work together to avoid the host immune response.

Comparative Table: Streptococcus Pneumoniae vs Haemophilus Influenzae

Streptococcus pneumoniae and Haemophilus influenzae are both commensal bacteria that inhabit the human nasopharynx and can cause various diseases, including pneumonia, otitis media, and meningitis. Here is a table highlighting the differences between the two:

Both bacteria can form biofilms in infected tissue, and they have been detected together in a multispecies biofilm. They can sense each other's presence in the niche and initiate polymicrobial biofilm formation, involving the expression of appropriate adhesins. While both bacteria can cause pneumonia, their carriage rates in healthy children differ, with S. pneumoniae carriage ranging from 20% to over 50% and H. influenzae carriage ranging up to 80%. Additionally, the two bacteria have different serotypes, with S. pneumoniae having over 90 serotypes and H. influenzae having mostly nontypeable strains.