CHEST Guidelines-Blurred-Lines-on-the-Dysbiosis-Spectrum

Blurred-Lines-on-the-Dysbiosis-Spectrum_chest

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The article "Blurred Lines on the Dysbiosis Spectrum" explores the differentiation between Pneumocystis jirovecii colonization (PJC) and infection, particularly the implications for pneumonia outcomes. Historically, colonization was seen as benign, but much like territorial invasions, it may have adverse effects. In clinical settings, colonization and infection have been treated as distinct, with colonization viewed as innocuous and infection causing inflammation and damage. However, recent studies show a broader spectrum of microbiota deviations from health, known as dysbiosis.<br /><br />The article discusses a study by Jiang et al., which focused on P. jirovecii, a fungal pathogen causing severe pneumonia in immunocompromised individuals, such as those with HIV. The study involved 1,787 patients with severe pneumonia and used bronchoalveolar lavage fluid and metagenomics to screen for LRT microbiota. The results showed a 9.2% detection rate for P. jirovecii DNA in non-HIV-infected patients. These were categorized into PJP and PJC, revealing a continuum of host defense impairments and varying illness severities.<br /><br />The study underscores the complexities in distinguishing between PJP and PJC due to the lack of a definitive reference standard. It found that patients with PJP and PJC had higher fungal and viral dysbiosis, exhibiting increased mortality rates and higher prevalence of immunosuppressive conditions. Both groups had higher detection of Candida, Aspergillus, and latent viruses compared to pneumonia control patients.<br /><br />Despite its limitations, the study promotes understanding of LRT ecology and challenges the perception of PJC as harmless. It suggests ongoing colonization should not be overlooked even if not directly causal for adverse prognosis. Future longitudinal studies are needed to further explore the dynamics of LRT microbiota and refine diagnostic tools to improve pneumonia management.

Keywords

Pneumocystis jirovecii

colonization

infection

pneumonia

dysbiosis

microbiota

immunocompromised

bronchoalveolar lavage

metagenomics

fungal pathogens