Haemophilus influenzae, formerly called Pfeiffer's bacillus or Bacillus influenzae, is a Gram-negative, rod-shaped bacterium first described in 1892 by Richard Pfeiffer during an influenza pandemic. A member of the Pasteurellaceae family, it is generally aerobic, but can grow as a facultative anaerobe.
H. influenzae was mistakenly considered to be the cause of influenza until 1933, when the viral etiology of the flu became apparent; the bacterium is colloquially known as bacterial influenza. Still, H. influenzae is responsible for a wide range of clinical diseases.
H. influenzae was the first free-living organism to have its entire genome sequenced. The sequencing project was completed and published in 1995.
Read more about Haemophilus Influenzae: Serotypes, Diseases, Diagnosis, Interaction With Streptococcus Pneumoniae, Treatment, Prevention, Sequencing