## Distinguishing Campylobacter jejuni from Helicobacter pylori ### Structural and Morphological Comparison | Feature | Campylobacter jejuni | Helicobacter pylori | |---------|----------------------|---------------------| | **Flagella** | Multiple polar flagella (sheathed) | 4–6 unsheathed flagella | | **Morphology** | S-shaped or spiral curved rod | Tightly coiled spiral | | **Growth atmosphere** | Microaerophilic (5% O₂, 10% CO₂) | Microaerophilic (5% O₂, 5% CO₂) | | **Temperature optimum** | 42–43°C | 37°C | | **Urease production** | Negative | Positive (key virulence factor) | | **Primary site** | Small intestine (ileum/jejunum) | Gastric antrum and fundus | **Key Point:** While both are gram-negative, microaerophilic, curved rods, Campylobacter's **multiple polar flagella** and obligate microaerophilic growth at 42–43°C are the most reliable structural discriminators. H. pylori's urease production is biochemical, not strictly structural. ### Why This Matters Clinically **High-Yield:** Campylobacter's flagella enable motility in the small intestine and are essential for pathogenesis. H. pylori's tight spiral and urease allow it to burrow through gastric mucus and neutralize acid — entirely different ecological strategies. **Clinical Pearl:** Campylobacter grows at 42°C (chicken body temperature) — a practical lab clue. H. pylori prefers 37°C and requires more exacting CO₂ control. **Mnemonic:** **CAMP** = **C**ampylobacter **A**t **M**ultiple **P**oles (flagella). H. pylori = **H**elical in **H**omogeneous gastric habitat. [cite:Textbook of Microbiology Ananthanarayan 10e Ch 45]
Sign up free to access AI-powered MCQ practice with detailed explanations and adaptive learning.