Did you know that there are microbes living in our airways, just like in the gut and on the skin?
The human respiratory tract is a complex and dynamic environment, harbouring a diverse community of microorganisms collectively known as the respiratory tract microbiota.
Far from being sterile, this microbial ecosystem plays a crucial role in maintaining respiratory health.
Among its many inhabitants, Streptococcus pneumoniae, commonly referred to as pneumococcus, stands out as a frequent coloniser of the upper respiratory tract, particularly the nasopharynx.
In fact, it is estimated that up to 40-50% of healthy children and 20-30% of healthy adults are asymptomatic carriers of pneumococcus.
While often living harmlessly as part of the respiratory tract microbiota, pneumococcus is also a notorious opportunistic pathogen capable of causing a range of severe diseases.
The composition and stability of the respiratory tract microbiota are influenced by a myriad of factors, both intrinsic and environmental:
- Age and genetics: These inherent factors play a role in shaping an individual’s unique microbial profile.
- Environmental exposures: Air pollution – most notably, exposure to cigarette smoke (both active and passive) – significantly alters the balance of the respiratory tract microbiota.
Smoking, for instance, has been shown to reduce the diversity of microbial species and promote the colonisation of potential pathogens like Haemophilus influenzae and Moraxella catarrhalis, alongside pneumococcus, thereby increasing susceptibility to respiratory infections.
- Lifestyle factors: Diet and antibiotic use can also impact the microbial community.
- Viral infections: Infections such as influenza can temporarily disrupt the microbiota, creating a window of opportunity for bacterial superinfections.
The effects of dysbiosis
Dysbiosis, an imbalance in the composition or function of the respiratory tract microbiota, is increasingly being recognised as a contributing factor to various respiratory diseases.
While a healthy microbiota can protect against pathogen invasion, dysbiosis can compromise these defences.
This disruption has been linked to some common respiratory illnesses, including:
- Pneumonia: An altered microbiota can facilitate the overgrowth of pathogenic bacteria, leading to inflammation and impaired lung function.
- Bronchitis: Dysbiosis can contribute to inflammation of the bronchial tubes.
- Chronic obstructive pulmonary disease (COPD): Persist-ent dysbiosis may exacerbate symptoms and contribute to disease progression.
- Asthma and cystic fibrosis: Emerging research also suggests a connection between respiratory tract microbiota dysbiosis and these conditions.
Sustaining the balance
Maintaining the delicate balance of the respiratory tract microbiota is paramount for preventing respiratory infections and promoting overall respiratory health.
Ways to do this include:
- Lifestyle interventions: Avoiding exposure to cigarette smoke and air pollutants can significantly contribute to a healthier microbial environment.
- Dietary approaches: A balanced diet, rich in prebiotics and probiotics, may also play a role in supporting a diverse and robust microbiota, although more research is needed in this specific area for respiratory health.
Crucially, vaccination stands as one of the most effective strategies for preventing infections caused by specific respiratory pathogens.
In the context of pneumococcus, the pneumococcal vaccine significantly reduces the incidence of pneumococcal diseases such as pneumonia, meningitis and otitis media (inflammation of the middle ear).
While vaccination primarily targets the pathogen, it indirectly contributes to maintaining the balance of the respiratory tract microbiota by preventing the overgrowth and pathogenic activity of a common coloniser that can severely disrupt the delicate ecosystem.
By reducing the burden of pneumococcal disease, vaccination helps preserve the overall health and resilience of the respiratory tract microbiota.
Datuk Dr Zulkifli Ismail is a consultant paediatrician and paediatric cardiologist. This article is courtesy of the Malaysian Paediatric Association’s Positive Parenting programme in collaboration with expert partners. For further information, please email starhealth@thestar.com.my. The information provided is for educational and communication purposes only, and it should not be construed as personal medical advice. Information published in this article is not intended to replace, supplant or augment a consultation with a health professional regarding the reader’s own medical care. The Star does not give any warranty on accuracy, completeness, functionality, usefulness or other assurances as to the content appearing in this column. The Star disclaims all responsibility for any losses, damage to property or personal injury suffered directly or indirectly from reliance on such information.
