Respiratory tract infections and pneumonia

McChlery, S., Ramage, G. and Bagg, J. (2009) Respiratory tract infections and pneumonia. Periodontology 2000, 49(1), pp. 151-165. (doi: 10.1111/j.1600-0757.2008.00278.x)

Abstract

Many organisms cause respiratory tract infections, and not all can be discussed in this review. Although many respiratory tract infections are nonlife-threatening, they are associated with a significant level of morbidity. The oral cavity acts as a portal of entry and as a reservoir for many bacterial, viral and fungal species. Here these microorganisms gain access to interlinked airways, composed of mucosal epithelia, which collectively comprise the respiratory tract. This large mucosal surface area acts as a reservoir for infectious particles that are inhaled. There is good evidence to show that improved oral hygiene and frequent professional healthcare can reduce the progression or occurrence of respiratory diseases, especially amongst high-risk patient groups (4). A formidable host defence system protects the lower respiratory tract. Organisms must first negotiate the nonspecific mechanisms in the upper respiratory tract, which include a mechanical washing mechanism, the cough response, anatomic barriers and the mucociliary tree. Additional barriers in the lower respiratory tract include the frequent branching of the pulmonary tree (to effect aerodynamic filtration) and the restrictive size (0.3–5.0 μm) of the alveolus opening. Once microorganisms reach the alveolus they must resist the activity of phagocytes, immune response cells and other antimicrobial defence factors. If these microorganisms can overcome or subvert the innate host defences, such as the mucociliary system, bronchoconstriction, cough reflex or acquired immunity (mucosal immunoglobulin A), then the infectious process can begin. Infections may be acute or chronic, and lower respiratory tract infections may be limited to the bronchial tree (bronchitis) or the lung alveoli (pneumonia), or involve both (broncho-pneumonia).

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Bagg, Professor Jeremy and Ramage, Professor Gordon and McChlery, Miss Susan
• Authors: McChlery, S., Ramage, G., and Bagg, J.
• College/School: College of Medical Veterinary and Life Sciences > School of Medicine, Dentistry & Nursing > Dental School
• Journal Name: Periodontology 2000
• ISSN: 09066713