Campylobacter & Helicobacter

Campylobacter & Helicobacter General Characteristics Common to Superfamily  Gram-negative  Helical (spiral or curved) morphology; Tend to be pleomorphic  Characteristics that facilitate penetration and colonization of mucosal environments (e.g., motile by polar flagella; corkscrew shape)  Microaerophilic atmospheric requirements  Become coccoid when exposed to oxygen or upon prolonged culture  Neither ferment nor oxidize carbohydrates History of Campylobacter  First isolated as Vibrio fetus in 1909 from spontaneous abortions in livestock  Campylobacter enteritis was not recognized until the mid-1970s when selective isolation media were developed for culturing campylobacters from human feces  Most common form of acute infectious diarrhea in developed countries; Higher incidence than Salmonella & Shigella combined  In the U.S., 2 million cases annually, an annual incidence close to the 1.1% observed in the United Kingdom; Estimated 200-700 deaths Morphology & Physiology of Campylobacter Small, thin (0.2 - 0.5 um X 0.5 - 5.0 um), helical (spiral or curved) cells with typical gram-negative cell wall; “Gull-winged” appearance • Tendency to form coccoid & elongated forms on prolonged culture or when exposed to O2 Distinctive rapid darting motility • Long sheathed polar flagellum at one (polar) or both (bipolar) ends of the cell • Motility slows quickly in wet mount preparation Microaerophilic & capnophilic 5%O2,10%CO2,85%N2 Thermophilic (42-43C) (except C. fetus) • Body temperature of natural avian reservoir May become nonculturable in nature Campylobacter Species Associated with Human Diseas