The Impact of Cigarette Smoke on the Airways Microbiome in Children: New Research Findings

The airways microbiome refers to the microbial ecosystem that exists in the respiratory tract (including the nasal cavity, throat, trachea and lungs). It is composed of various bacteria, fungi, viruses and other microorganisms, forming an interacting microbial community. The respiratory microbiota is important in maintaining the health of the airways, immunomodulation and defense against pathogens. Normally, the respiratory microbiota should be balanced and stable, helping to inhibit the growth of pathogens and maintain the normal function of the immune system. However, various factors (such as environment, infection, disease, and drug use) can have an impact on the composition and balance of the respiratory microbiota, causing the microbiota to change and lose its normal balance, allowing pathogens to grow and cause respiratory infections and diseases.

In recent years, researchers have begun to notice the important physiological roles of the airway microbiota and have found associations between it and a variety of respiratory diseases such as asthma, chronic obstructive pulmonary disease and lung infections. Therefore, understanding the composition and function of the respiratory microbiota, as well as their interactions with health and disease, will help in-depth research on the pathogenesis of respiratory diseases and provide new strategies for prevention and treatment.

Children often inhale the residual chemicals from cigarette smoke from other people’s use (secondhand smoke) or from indirect exposure from clothing and other surfaces (thirdhand smoke). Cigarette smoke is the smoke and particulate matter produced by the combustion of cigarettes, which contains a variety of harmful components, including polycyclic aromatic hydrocarbons, hydrocarbons, aldehydes, heavy metals, volatile organic compounds and other harmful substances. These ingredients can cause multiple hazards to human health, including lung disease, cardiovascular disease, cancer and other health problems. In recent years, more and more studies have shown that cigarette smoke has a serious impact on children’s respiratory health and development. According to statistics, about 168,000 children worldwide die every year due to exposure to cigarette smoke, mainly due to the increased incidence and severity of lower respiratory tract infections. Cigarette smoke also increases the risk of diseases such as otitis media, sinusitis, asthma and obesity in children, new research shows. Health risks associated with cigarette smoke include effects on lung inflammation, immune response, infectious response and tissue damage. Recent studies indicate that some of these effects may be through or result in changes in the respiratory microbiota. In critically ill adult patients with severe blunt trauma, the relative amounts of microorganisms such as Hemophilus spp., Streptococcus spp., and Fusobacterium spp. in the lower respiratory tract of patients exposed to cigarette smoke were increased. In addition, microbial changes associated with cigarette smoke, particularly Enterobacteriaceae bacteria, were found to be associated with the development of acute respiratory distress syndrome.

In order to further understand the impact of cigarette smoke exposure on changes in the lower respiratory tract microbiota, a research team from the University of California and the University of Colorado School of Medicine conducted a study on 362 children who received ventilators between 31 days and 18 years old to maintain respiratory function for more than 72 hours.Analysis, and using 16S ribosomal RNA sequencing to analyze the respiratory microbial flora of tracheal aspirates from 298 patients, and to analyze creatinine-corrected nicotine metabolites in urine to represent their exposure to cigarette smoke. RESULTS: Seventy-four (20%) patients had a history of cigarette smoke exposure and exhibited reduced microbial richness and Shannon diversity index. Bacteria with higher relative abundances in children exposed to cigarette smoke were: Serratia spp., Moraxella spp., Haemophilus spp., and Staphylococcus aureus, and these differences were most pronounced in patients with bacterial and viral respiratory infections, in acute respiratory distress There were no differences in syndrome occurrence, number of ventilator days, 28-day intubation-free days, length of hospital stay, or mortality. CONCLUSIONS: Among critically ill children requiring prolonged ventilator support for respiratory function, exposure to cigarette smoke was associated with decreased respiratory microbial species richness and Shannon diversity and changes in microbiota structure.

This study is the first to assess the effects of cigarette smoke exposure on the lower respiratory microbiota in children, and helps to clarify the relationship between cigarette smoke exposure and the lower respiratory microbiota, and may provide insight into the increased risk of adverse outcomes in children mechanism.