Polymorphisms inPneumocystis jiroveciiStrains in Spanish Children with Cystic Fibrosis

Pneumocystis jirovecii in Patients With Cystic Fibrosis: A Review

Pneumocystis pneumonia (PCP) remains the most frequent AIDS-defining illness in developed countries. This infection also occurs in non-AIDS immunosuppressed patients, e.g., those who have undergone an organ transplantation. Moreover, mild Pneumocystis jirovecii infections related to low pulmonary fungal burden, frequently designated as pulmonary colonization, occurs in patients with chronic pulmonary diseases, e.g., cystic fibrosis (CF). Indeed, this autosomal recessive disorder alters mucociliary clearance leading to bacterial and fungal colonization of the airways. This mini-review compiles and discusses available information on P. jirovecii and CF. It highlights significant differences in the prevalence of P. jirovecii pulmonary colonization in European and Brazilian CF patients. It also describes the microbiota associated with P. jirovecii in CF patients colonized by P. jirovecii. Furthermore, we have described P. jirovecii genomic diversity in colonized CF patients. In addition of pulmonary colonization, it appears that PCP can occur in CF patients specifically after lung transplantation, thus requiring preventive strategies. In other respects, Pneumocystis primary infection is a worldwide phenomenon occurring in non-immunosuppressed infants within their first months. The primary infection is mostly asymptomatic but it can also present as a benign self-limiting infection. It probably occurs in the same manner in CF infants. Nonetheless, two cases of severe Pneumocystis primary infection mimicking PCP in CF infants have been reported, the genetic disease appearing in these circumstances as a risk factor of PCP while the host-pathogen interaction in older children and adults with pulmonary colonization remains to be clarified.

Prospective multicenter study of Pneumocystis jirovecii colonization among cystic fibrosis patients in France

Pneumocystis carriage was detected in 12.5% of 104 cystic fibrosis (CF) patients during a prospective multicenter French study, with a prevalence of genotype 85C/248C and geographic variations. It was significantly associated with the absence of Pseudomonas aeruginosa colonization and a greater forced expiratory volume in 1 s. Results are discussed considering the natural history of CF.

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.

High prevalence of Pneumocystis jiroveci colonization among young HIV-infected patients

BACKGROUND

Pneumocystis colonization in young HIV-infected patients has been poorly studied. The aim of this study was to analyze the prevalence of P jiroveci colonization in a cohort of young HIV-infected patients.

MATERIAL AND METHODS

We designed a basal cross-sectional study in 20 young HIV-infected patients to determine the prevalence of P jiroveci colonization in oropharyngeal wash samples studied by nested polymerase chain reaction (PCR). Subsequently, patients were followed up during 50 weeks to observe the development of Pneumocystis pneumonia (PCP).

RESULTS

P jiroveci colonization was detected in eight (40%) of the 20 oropharyngeal wash samples. Genotype 85C/248C was the most frequent. After 50 weeks of follow-up, one colonized patient with advanced immunodepression developed PCP.

CONCLUSIONS

We have found a high prevalence of P jiroveci colonization in young HIV-infected patients with a major prevalence of genotype 1 (85C/248C). Further studies are necessary to clarify if Pneumocystis colonization could be a potential risk factor of developing PCP in young HIV infected patients.

Dynamic colonisation by different Pneumocystis jirovecii genotypes in cystic fibrosis patients

Although asymptomatic carriers of Pneumocystis jirovecii with cystic fibrosis (CF) have been described previously, the molecular epidemiology of P. jirovecii in CF patients has not yet been clarified. This study identified the distribution and dynamic evolution of P. jirovecii genotypes based on the mitochondrial large-subunit (mt LSU) rRNA gene. The mt LSU rRNA genotypes of P. jirovecii isolates in 33 respiratory samples from CF patients were investigated using nested PCR and direct sequencing. Three different genotypes were detected: 36.3% genotype 1 (85C/248C); 15.1% genotype 2 (85A/248C); 42.4% genotype 3 (85T/248C); and 6% mixed genotypes. Patients studied during a 1-year follow-up period showed a continuous colonisation/clearance cycle involving P. jirovecii and an accumulative tendency to be colonised with genotype 3.