What is the Difference Between Streptococcus Pneumoniae and Haemophilus Influenzae

The key difference between Streptococcus pneumoniae and Haemophilus influenzae is that Streptococcus pneumoniae is a Gram-positive pathogenic bacterium in humans, while Haemophilus influenzae is a Gram-negative pathogenic bacterium in humans.

Streptococcus pneumoniae and Haemophilus influenza are both commensal bacteria of the human nasopharynx and have the ability to become pathogenic. Both these bacteria predominantly affect children. They are the leading causes of childhood pneumonia and meningitis. Moreover, they are also major contributors to mortality in children younger than five years of age.

CONTENTS

1. Overview and Key Difference
2. What is Streptococcus Pneumoniae 
3. What is Haemophilus Influenzae
4. Similarities – Streptococcus Pneumoniae and Haemophilus Influenzae
5. Streptococcus Pneumoniae vs Haemophilus Influenzae in Tabular Form
6. Summary – Streptococcus Pneumoniae vs Haemophilus Influenzae

What is Streptococcus Pneumoniae?

Streptococcus pneumoniae is a Gram-positive and facultative anaerobic pathogenic bacterium in humans. It is a lancet or spherical-shaped bacterium with more than known serotypes. However, only a minority of serotypes cause pneumococcal infections. S. pneumoniae bacterium resides in the nasopharynx of the respiratory tract and infects both children as well as adults. S.pneumonia is alpha haemolytic in aerobic conditions and beta haemolytic in anaerobic conditions. It does not form spores and is non-motile. Moreover, in the 19^th century, it was identified that S. pneumonia was the main causative agent of pneumonia. It spreads from person to person through respiratory droplets and autoinoculation.

S. pneumonia is also a cause of neonatal infections. S. pneumonia has a closed circular DNA structure, which is around 2.1 million base pairs. Its genome has 1553 core sets of genes, 154 virulence genes, and 176 genes that maintain non-invasive phenotypes. Furthermore, other than pneumonia, S. pneumonia can also cause meningitis, sepsis, and organ failure. Pneumococcal infection is currently controlled by antibiotics and vaccines.

What is Haemophilus Influenzae?

Haemophilus influenzae is a Gram negative pathogenic bacterium in humans. H. influenza causes ear infections, pneumonia, and bloodstream infections. It is a non-motile, coccobacillary, facultatively anaerobic, and canophilic bacterium. H. influenza is a mesophilic bacterium, so it grows best in temperatures between 35 and 37℃. H. influenzae consists of a genome that is 1,830,138 base pairs in size. It is a single circular chromosome and contains 1604 protein-coding genes, 117 pseudogenes, 57 tRNA genes, and 23 other RNA genes.

This bacterium was first described in 1893 by Richard Pfeiffer during an influenza pandemic. H. influenzae is normally responsible for a wide range of infections that generally affect infants and children. H. influenzae is resistant to penicillin. The treatment regime for H. influenzae includes other antibiotics such as cefotaxime, ceftriaxone, ampicillin, subactum, cephalosporins, and fluoroquinolones. Furthermore, the Hib vaccine, boosters, and combined vaccines such as DTaP-IPV/Hib can control it.

What are the Similarities Between Streptococcus Pneumoniae and Haemophilus Influenzae?

• Streptococcus pneumoniae and Haemophilus influenza are both commensal bacteria of the human nasopharynx with the ability to become pathogenic.
• Both bacteria can affect children.
• Both bacteria are non-motile and facultative anaerobic in nature.
• Their infections are mainly controlled by antibiotics and vaccines.

What is the Difference Between Streptococcus Pneumoniae and Haemophilus Influenzae?

S. pneumoniae is a Gram-positive pathogenic bacterium found in humans, while H. influenzae is a Gram-negative pathogenic bacterium found in humans. Thus, this is the key difference between Streptococcus pneumoniae and Haemophilus influenza. Furthermore, Streptococcus pneumonia belongs to the genus Streptococcus, while Haemophilus influenza belongs to the genus Haemophilus.

The following table summarizes the difference between Streptococcus pneumoniae and Haemophilus influenza.

Summary – Streptococcus Pneumoniae vs Haemophilus Influenzae

Streptococcus pneumoniae and Haemophilus influenza are both commensal bacteria of the human nasopharynx in the upper respiratory tract. They have the ability to become pathogenic. Streptococcus pneumoniae is a Gram-positive pathogenic bacterium, while Haemophilus influenzae is a Gram-negative pathogenic bacterium. So, this is the key difference between Streptococcus pneumoniae and Haemophilus influenza.

Reference:

1. “Haemophilus Influenzae Disease (Including Hib).” Centers for Disease Control and Prevention, Centers for Disease Control and Prevention, 4 Mar. 2022.
2. Eduardo Sanchez. “Pneumococcal Infections (Streptococcus Pneumoniae).” Practice Essentials, Background, Pathophysiology, Medscape, 5 Jan. 2022.

Image Courtesy:

1. “Haemophilus influenza” By Stefan Walkowski – Own work (CC BY-SA 4.0) via Commons Wikimedia
2. “Streptococcus pneumoniae, bacteria, colonies, grown, primary, isolation, medium” (CC0) via Pixino