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Bacterium

Haemophilus influenzae

Small Gram-negative coccobacillus with X/V factors

hee-MOFF-ih-lus in-floo-EN-zee

Gram negativebacteriagram-negativecoccobacilluscapsulerespiratoryx-factor

High-yield clue

Coccobacillus + chocolate agar/X and V factor vocabulary + Hib capsule concept.

Overview

A small Gram-negative coccobacillus used to connect respiratory flora vocabulary, capsule serotype concepts, and X/V growth-factor coursework clues.

Classification

  • Gram-negative
  • Coccobacillus
  • Facultative anaerobe
  • Encapsulated strains emphasized in coursework

Lab & identification clues

  • Chocolate agar vocabulary
  • X factor and V factor terms
  • Satellitism teaching concept

Associations

  • Otitis/sinusitis vocabulary
  • Epiglottitis and meningitis historical Hib vaccine framing
  • Respiratory flora contrast

Commonly confused with

  • Moraxella catarrhalis
  • Bordetella pertussis
  • Streptococcus pneumoniae

Frequently asked questions

What is Haemophilus influenzae?

A small Gram-negative coccobacillus used to connect respiratory flora vocabulary, capsule serotype concepts, and X/V growth-factor coursework clues.

What is the Gram stain of Haemophilus influenzae?

Haemophilus influenzae is Gram negative.

What are the lab clues for Haemophilus influenzae?

Lab clues for Haemophilus influenzae include Chocolate agar vocabulary, X factor and V factor terms, and Satellitism teaching concept.

What is Haemophilus influenzae commonly confused with?

Haemophilus influenzae is commonly confused with Moraxella catarrhalis, Bordetella pertussis, and Streptococcus pneumoniae.

Original student-study summary. Sources checked: OpenStax Microbiology 2e, NCBI Bookshelf Medical Microbiology, and CDC topic pages where applicable; reviewed 2026-06. Educational only; no diagnosis, treatment, dosing, or specimen-handling guidance.

OpenStax: Microbiology 2e organism classification foundations - sourceNCBI Bookshelf: Medical Microbiology organism chapters - sourceCDC: CDC disease and public-health topic pages - source