Role of Helicobacter pylori in pathogenesis of upper respiratory system diseases.

Helicobacter pylori (H. pylori) is one of the frequently encountered micro-organisms in the aerodigestive tract. Although infections caused by H. pylori are this common, the exact mode of transmission has not been fully understood yet. Oral-oral, fecal-oral and gastrointestinal-oral routes are the possible modes of transmission. This infection is usually acquired in childhood and may persist for the whole life of the patient. However, about 80% of the infected humans are asymptomatic. Human stomach was considered to be the only reservoir of H. pylori until bacteria were discovered in human dental plaque, in oral lesions, in saliva, in tonsil and adenoid tissue. It is suggested that H. pylori enters the nasopharyngeal cavity by gastroesophageal reflux and colonize in the dental plaques, adenoid tissues and tonsils. From these localizations, the bacteria ascend to the middle ear and to the paranasal sinuses directly or by the reflux again and may trigger some diseases, including otitis, sinusitis, phyrangitis, laryngitis and glossitis. But still, the exact mechanism remains unclear.