Distribution of<i>Pneumocystis carinii f. sp. hominis</i>Types in the Lung of a Child Dying of<i>Pneumocystis</i>Pneumonia

Ambrose, Helen E.; Ponce, Carolina A.; Wakefield, Ann E.; Miller, R F; Vargas, Sergio L.

doi:10.1086/322690

Cited by 11 publications

(8 citation statements)

References 10 publications

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“…This difference may be partially due to the fact that the sequencing of only one clone in one colonized patient (A.6) did not allow the detection of a mixed infection. Nonetheless, our results establish that mixed infections may occur in patients with pulmonary colonization and that this form of P. jiroveci infection may not be necessarily clonal as previously suggested for PCP (2,38).…”

Section: Discussionsupporting

confidence: 81%

Pneumocystis jiroveci Internal Transcribed Spacer Types in Patients Colonized by the Fungus and in Patients with Pneumocystosis from the Same French Geographic Region

Nevez¹,

Totet²,

Jounieaux

et al. 2003

J Clin Microbiol

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Pneumocystis jiroveci (human-derived Pneumocystis) infections can display a broad spectrum of clinical presentations, of which pulmonary colonization with the fungus may represent an important part, occurring frequently in patients with various underlying diseases and presenting alternative diagnoses of acute pneumocystosis (Pneumocystis carinii pneumonia [PCP]). There are few data concerning the P. jiroveci genotypes involved in pulmonary colonization, whereas several genotypes responsible for PCP in immunocompromised patients have been described. In this study, P. jiroveci genotypes have retrospectively been investigated and compared in 6 colonized patients and in 11 patients with PCP who were in the same hospital. Seventeen archival bronchoalveolar lavage samples were genotyped at internal-transcribed spacer 1 (ITS1) and ITS2 of the nuclear rRNA operon. Fourteen different genotypes were identified, of which 1 was found only in colonized patients, 10 were found only in patients with PCP, and 3 were found in both patient populations. Mixed infections were diagnosed in 2 of the 6 colonized patients and in 6 of the 11 patients with PCP. The results show that similar genotypes can be responsible for PCP as well as pulmonary colonization. There is a high diversity of genotypes in colonized patients and in patients with PCP. Mixed infections may occur in these two patient populations. These shared features of P. jiroveci ITS genotypes in colonized patients and patients with PCP suggest that human populations infected by P. jiroveci, whatever the clinical manifestation, may play a role as a common reservoir for the fungus.Over the past decade, the use of PCR has led to the detection of low numbers of Pneumocystis jiroveci (human-derived Pneumocystis) (9, 36) organisms in bronchoalveolar lavage (BAL) specimens from patients, showing an alternative diagnosis of acute Pneumocystis carinii pneumonia (PCP) (24,30,40). These low levels of P. jiroveci organisms were considered to reflect pulmonary colonization. These cases of colonization that have been described have occurred mainly in immunocompromised patients (24, 30) and less frequently in immunocompetent patients; nevertheless, cases of colonization in immunocompromised patients presenting with underlying pulmonary diseases have been described (4, 34). Cases of pulmonary colonization with P. jiroveci are frequently missed since PCR assays are not usually used for the routine detection of P. jiroveci in pulmonary specimens. Moreover, the small numbers of P. jiroveci organisms carried by colonized patients render molecular typing of the organisms difficult. For these reasons, little is known concerning the types of P. jiroveci carried by colonized patients whereas several types of P. jiroveci isolates obtained from patients developing PCP have been described (5, 14-17, 19-23, 25, 27, 28, 32, 37-39). Two different molecular studies, one using single-strand conformation polymorphism analysis (10) and another using sequencing of internaltranscribed spacer 1 (ITS1) and ITS2...

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Section: Discussionsupporting

confidence: 81%

Pneumocystis jiroveci Internal Transcribed Spacer Types in Patients Colonized by the Fungus and in Patients with Pneumocystosis from the Same French Geographic Region

Nevez¹,

Totet²,

Jounieaux

et al. 2003

J Clin Microbiol

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“…In all three cases, the pairs were genetically close, but not identical, similar to past observations (61). This finding could be explained in multiple ways, including the following: (i) these patients may have been infected with multiple P. jirovecii strains, which were differentially detected at different time points (90), or (ii) after clinical resolution of their initial PcP case, these patients returned home and were subsequently colonized by genetically related-though not identical-organisms. Importantly, these data show that this method provides high discriminatory power between infections: other than those isolate pairs expected to be related, there were no identical isolates and only two related isolates ( Fig.…”

Section: Discussionsupporting

confidence: 73%

Multilocus Microsatellite Genotyping Array for Investigation of Genetic Epidemiology of Pneumocystis jirovecii

et al. 2014

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Pneumocystis jirovecii is a symbiotic respiratory fungus that causes pneumonia (PcP) in immunosuppressed patients. Because P. jirovecii cannot be reliably cultured in vitro, it has proven difficult to study and gaps in our understanding of the organism persist. The release of a draft genome for the organism opens the door for the development of new genotyping approaches for studying its molecular epidemiology and global population structure. We identified and validated 8 putatively neutral microsatellite markers and 1 microsatellite marker linked to the dihydropteroate synthase gene (dhps), the enzymatic target of sulfa drugs used for PcP prevention and treatment. Using these tools, we analyzed P. jirovecii isolates from HIV-infected patients from three geographically distant populations: Uganda, the United States, and Spain. Among the 8 neutral markers, we observed high levels of allelic heterozygosity (average H e , 0.586 to 0.842). Consistent with past reports, we observed limited global population structuring, with only the Ugandan isolates showing minor differentiation from the other two populations. In Ugandan isolates that harbored mutations in dhps, the microsatellite locus linked to dhps demonstrated a depressed H e , consistent with positive directional selection for sulfa resistance mutations. Using a subset of these microsatellites, analyses of individual and paired samples from infections in San Francisco, CA, showed reliable typeability within a single infection and high discriminatory power between infections. These features suggest that this novel microsatellite typing approach will be an effective tool for molecularepidemiological investigations into P. jirovecii population structure, transmission, and drug resistance.

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“…The homogenate was then filtered using sterile gauze; the stirring flasks were washed with sterile PBS to collect any remnants of the specimens; centrifugation was performed at 4ЊC for 10 min at 2900 g; the supernatant was discarded; and the pellet was reconstituted in 700 mL of sterile PBS (pH 7.2) and stored at Ϫ20ЊC until processing. DNA was extracted and purified from 200 mL of this solution, using the QIAamp DNA Mini kit (Qiagen) as described elsewhere [28]. Liver tissue was processed in the same fashion as lung tissue during DNA extraction and purification, to monitor for cross-contamination.…”

Section: Ethics the Ethics Commission Of The North Metropolitanmentioning

confidence: 99%

PneumocystisColonization Is Highly Prevalent in the Autopsied Lungs of the General Population

Gallo²,

et al. 2010

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Distribution ofPneumocystis carinii f. sp. hominisTypes in the Lung of a Child Dying ofPneumocystisPneumonia

Cited by 11 publications

References 10 publications

Pneumocystis jiroveci Internal Transcribed Spacer Types in Patients Colonized by the Fungus and in Patients with Pneumocystosis from the Same French Geographic Region

Pneumocystis jiroveci Internal Transcribed Spacer Types in Patients Colonized by the Fungus and in Patients with Pneumocystosis from the Same French Geographic Region

Multilocus Microsatellite Genotyping Array for Investigation of Genetic Epidemiology of Pneumocystis jirovecii

PneumocystisColonization Is Highly Prevalent in the Autopsied Lungs of the General Population

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