Exploring the complex relationship between the lung microbiome and ventilator-associated pneumonia

ABSTRACTIntroduction Understanding the presence and function of a diverse lung microbiome in acute lung infections, particularly ventilator-associated pneumonia (VAP), is still limited, evidencing significant gaps in our knowledge.Areas covered In this comprehensive narrative review, we aim to elucidate the contribution of the respiratory microbiome in the development of VAP by examining the current knowledge on the interactions among microorganisms. By exploring these intricate connections, we endeavor to enhance our understanding of the disease’s pathophysiology and pave the way for novel ideas and interventions in studying the respiratory tract microbiome.Expert opinion The conventional perception of lungs as sterile is deprecated since it is currently recognized the existence of a diverse microbial community within them. However, despite extensive research on the role of the respiratory microbiome in healthy lungs, respiratory chronic diseases and acute lung infections such as pneumonia are not fully understood. It is crucial to investigate further the relationship between the pathophysiology of VAP and the pulmonary microbiome, elucidating the mechanisms underlying the interactions between the microbiome, host immune response and mechanical ventilation for the development of VAP.KEYWORDS: Lung microbiomelung microbiotaDysbiosisimmune responseventilator-associated pneumoniamechanical ventilationDisclaimerAs a service to authors and researchers we are providing this version of an accepted manuscript (AM). Copyediting, typesetting, and review of the resulting proofs will be undertaken on this manuscript before final publication of the Version of Record (VoR). During production and pre-press, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal relate to these versions also. Articles highlightsThe lung microbiome is a diverse and dynamic ecosystem unique to everyone. Current knowledge is based on the description of bacterial communities. Still, it is crucial to characterize the virome and mycobiome, connecting the clinical outcomes associated with each patient with VAP.Ventilator-associated pneumonia (VAP) is a serious complication in intensive care units, but identifying its causative agent is challenging due to limitations in traditional tests. Exploring the dynamics of microbial communities during VAP development through techniques like DNA sequencing offers new opportunities for understanding its relevance.The oral microbiome plays a pivotal role in developing VAP, primarily through the microaspiration of microorganisms during mechanical ventilation. Additionally, the role of respiratory colonization by Candida spp. may have clinical implications in VAP, although its precise role remains intricate and multifaceted.The development of VAP involves complex interactions between the lung microbiome and host immune responses. Multifaceted interactions suggest that several factors influence the development of VAP beyond the presence of a single pathogen.To gain a deeper understanding of the microbial communities linked to ventilator-associated pneumonia (VAP), adopting a comprehensive multibiome approach is crucial by integrating several omics techniques. These robust methodologies will enable us to unravel the essential characteristics of the VAP-associated microbiome.Probiotics have emerged as a promising strategy for preventing and treating VAP. Their administration can aid in restoring the balance of the lung microbiome, thereby reducing the colonization of pathogenic bacteria in the lungs and modulating the immune response.Declaration of interestThe authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.Reviewer disclosuresPeer reviewers on this manuscript have no relevant financial or other relationships to disclose.Additional informationFundingThis paper was not funded.