El ser humano como reservorio de Pneumocystis

High prevalence of pneumocystis pneumonia in interstitial lung disease: a retrospective study

BACKGROUND

Interstitial lung disease (ILD) is a new risk category for pneumocystis pneumonia (PCP) with a high mortality rate. The definite diagnostic criteria of PCP in ILD patients have not been established until now. The aims of this study were to identify potential risk factors of PCP in patients with ILD, and to evaluate the performance of metagenomic next-generation sequencing (mNGS), CD4 + T cell count, (1-3)-β-D-Glucan (BG) and lactate dehydrogenase (LDH) in the diagnosis of PCP in ILD patients.

METHODS

This is a retrospective, single-center, case-control study. ILD patients who underwent mNGS from December 2018 to December 2022 were included in the study. Based on the diagnosis criteria of PCP, these patients were divided into PCP-ILD and non-PCP-ILD groups. The potential risk factors for PCP occurrence in ILD patients were analysed via logistic regression. The diagnostic efficacy of mNGS was compared with serological biomarkers.

RESULTS

92 patients with ILD were enrolled, 31 of which had a definite PCP and were assigned to the PCP-ILD group while 61 were to the non-PCP-ILD group. The infection rate of PJ in ILD patients was 33.7% (31/92). The history of glucocorticoid therapy, CD4 + T cell count, BG level and traction bronchiectasis on HRCT were associated with PCP occurrence in ILD patients. LDH level did not reach statistical significance in the logistic regression analysis. mNGS was confirmed as the most accurate test for PCP diagnosis in ILD patients.

CONCLUSION

ILD is a new risk group of PCP with high PCP prevalence. Clinicians should pay close attention to the occurrence of PCP in ILD patients who possess the risk factors of previous glucocorticoid therapy, decreased CD4 + T cell count, increased BG level and absence of traction bronchiectasis on HRCT. mNGS showed the most excellent performance for PCP diagnosis in ILD patients. Peripheral blood CD4 + T cell count and BG level are alternative diagnostic methods for PCP in ILD patients. However, the diagnostic value of serum LDH level was limited in ILD patients.

Prevention and treatment of opportunistic infections and other coinfections in HIV-infected patients: May 2015

Despite the huge advance that antiretroviral therapy represents for the prognosis of infection by the human immunodeficiency virus (HIV), opportunistic infections (OIs) continue to be a cause of morbidity and mortality in HIV-infected patients. OIs often arise because of severe immunosuppression resulting from poor adherence to antiretroviral therapy, failure of antiretroviral therapy, or unawareness of HIV infection by patients whose first clinical manifestation of AIDS is an OI. The present article updates our previous guidelines on the prevention and treatment of various OIs in HIV-infected patients, namely, infections by parasites, fungi, viruses, mycobacteria, and bacteria, as well as imported infections. The article also addresses immune reconstitution inflammatory syndrome.

Pneumocystis jirovecii colonization in Chronic Obstructive Pulmonary Disease (COPD)

Chronic obstructive pulmonary disease (COPD) is associated with a chronic inflammatory response in airways and lung parenchyma that results in significant morbidity and mortality worldwide. Cigarette smoking considered as an important risk factor plays a role in pathogenesis of disease. Pneumocystis jirovecii is an atypical opportunistic fungus that causes pneumonia in immunosuppressed host, although the low levels of its DNA in patients without signs and symptoms of pneumonia, which likely represents colonization. The increased prevalence of P. jirovecii colonization in COPD patients has led to an interest in understanding its role in the disease. P. jirovecii colonization in these patients could represent a problem for public health since colonized patients could act as a major reservoir and source of infection for susceptible subjects. Using sensitive molecular techniques, low levels of P. jirovecii DNA have been detected in the respiratory tract of certain individuals. It is necessary to elucidate the role of P. jirovecii colonization in the natural history of COPD patients in order to improve the clinical management of this disease. In the current review paper, we discuss P. jirovecii colonization in COPD patients.

High prevalence of Pneumocystis jirovecii colonization among HIV-positive patients in southern Brazil

A high prevalence of Pneumocystis jirovecii colonization was observed in patients positive for the human immunodeficiency virus (HIV) admitted to a tertiary hospital in southern Brazil between August 2012 and December 2012. Amplification of the mitochondrial large subunit ribosomal RNA gene in oropharyngeal samples through nested polymerase chain reaction identified P. jirovecii colonization in 26 of 58 (44.8%) HIV-positive patients admitted for causes other than Pneumocystis pneumonia. Colonization was more frequent among patients with an absolute CD4 count ≤200 cells/μl. These findings suggest that the HIV-infected population is a major reservoir and source of P. jirovecii infection and that identification of such individuals may contribute to future strategies for improving management of HIV-infected patients.

Pneumocystis jirovecii colonization in chronic pulmonary disease

Pneumocystis jirovecii causes pneumonia in immunosuppressed individuals. However, it has been reported the detection of low levels of Pneumocystis DNA in patients without signs and symptoms of pneumonia, which likely represents colonization. Several studies performed in animals models and in humans have demonstrated that Pneumocystis induces a local and a systemic response in the host. Since P. jirovecii colonization has been found in patients with chronic pulmonary diseases it has been suggested that P. jirovecii may play a role in the physiopathology and progression of those diseases. In this report we revise P. jirovecii colonization in different chronic pulmonary diseases such us, chronic obstructive pulmonary disease, interstitial lung diseases, cystic fibrosis and lung cancer.

Pneumocystis jirovecii and cystic fibrosis

Pneumocystis jirovecii is an atypical opportunistic fungus with lung tropism and worldwide distribution that causes pneumonia in immunosuppressed individuals. The development of sensitive molecular techniques has led to the recognition of a colonization or carrier state of P. jirovecii, in which low levels of the organism are detected in persons who do not have pneumonia. Pneumocystis colonization has been described in individuals with various lung diseases, and accumulating evidence suggests that it may be a relevant issue with potential clinical impact. Only a few published studies carried out in Europe have evaluated the prevalence of Pneumocystis colonization in patients with cystic fibrosis, reporting ranges from 1.3-21.6%. The evolution of P. jirovecii colonization in cystic fibrosis patients is largely unknown. In a longitudinal study, none of the colonized patients developed pneumonia during a 1-year follow-up. Since patients with cystic fibrosis could act as major reservoirs and sources of infection for susceptible individuals further research is thus warranted to assess the true scope of the problem and to design rational preventive strategies if necessary. Moreover, it's necessary to elucidate the role of P. jirovecii infection in the natural history of cystic fibrosis in order to improve the clinical management of this disease.