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The Use of Probiotics in Head and Neck Infections
1ENT Department, Lundby Hospital, Wieselgrensplatesen 2A, 41717 Göteborg, Sweden. Kristian.roos@lundbysjukhus.se
Abstract:
Recurrent episodes of infections in the upper respiratory tract are very common. The pathogenesis behind these recurrences is still not well understood, but much attention has been paid to the adherence of the microorganisms to epithelial structures and to the protective function of the normal bacterial flora (bacterial interference). Thus, in vitro as well as in vivo studies have shown that both aerobic and anaerobic bacteria of the normal flora in the upper respiratory tract can hinder the growth of pathogens and the establishment of a renewed infection. Studies have shown that lack of interfering bacteria facilitates recurrence of these diseases. Recolonization with interfering alpha-streptococci has been performed successfully in acute streptococcal pharyngotonsillitis, as well as in acute otitis media. The number of recurrences has significantly been lowered in these diseases after recolonization with alpha-streptococci, which is the dominating normal bacteria in the upper respiratory tract. Several mechanisms have been proposed to be responsible for this interaction, such as competition of the adhering sites at the epithelial cells, production of hydrogen peroxide, competition for nutritients, and production of specific growth inhibiting factors such as bacteriocins. Other human components like lactoferrin are also important in the defense against microorganisms, and are important parts of the unspecific and specific immune system.
Insights
Normal upper respiratory tract bacteria prevent pathogen growth and recurrent infections. Restoring these beneficial bacteria, like alpha-streptococci, significantly reduces infection recurrences by outcompeting pathogens.
Area of Science:
- Microbiology
- Immunology
- Infectious Diseases
Background:
- Recurrent upper respiratory tract infections (URTIs) are common but poorly understood.
- The role of normal bacterial flora in preventing pathogen colonization and reinfection is a key area of research.
- Disruption of this protective flora is linked to increased infection frequency.
Purpose of the Study:
- To investigate the protective mechanisms of normal respiratory tract bacteria against pathogens.
- To evaluate the efficacy of recolonization with interfering bacteria in reducing recurrent URTIs.
- To understand the interactions between normal flora, pathogens, and the host immune system.
Main Methods:
- In vitro and in vivo studies examining bacterial adherence and growth inhibition.
- Clinical application of recolonization with alpha-streptococci in patients with recurrent infections.
- Analysis of proposed mechanisms including competition for adhesion sites and production of inhibitory substances.
Main Results:
- Normal aerobic and anaerobic bacteria of the upper respiratory tract inhibit pathogen growth and colonization.
- Recolonization with alpha-streptococci successfully reduced recurrence rates in acute streptococcal pharyngotonsillitis and acute otitis media.
- Proposed mechanisms include competition for epithelial binding sites, hydrogen peroxide production, nutrient competition, and bacteriocin production.
Conclusions:
- The normal bacterial flora of the upper respiratory tract plays a crucial role in preventing recurrent infections.
- Alpha-streptococci are effective in reducing URTI recurrences through mechanisms like bacterial interference.
- Further research into host-microbe interactions and immune components like lactoferrin is important for understanding URTI pathogenesis.