Early Acquisition of
            <i>Pneumocystis carinii</i>
            in Neonatal Rats as Evidenced by PCR and Oral Swabs

Icenhour, Crystal R.; Rebholz, Sandra; Collins, Margaret S.; Cushion, Melanie T.

doi:10.1128/ec.1.3.414-419.2002

Cited by 53 publications

(30 citation statements)

References 34 publications

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“…Moreover, most of these fungi have a primary environmental niche in which sex, if it does occur, takes place. P. jirovecii have been reported to “colonize” certain sectors of the human population [19], [70] and P. carinii are frequently detected in the lungs of healthy adult rodents [30], [71] and within hours after birth in neonatal rats [72]. The serological responses to P. jirovecii antigens early in life are also indicative of their role as normal flora [73].…”

Section: Discussionmentioning

confidence: 99%

Transcriptome of Pneumocystis carinii during Fulminate Infection: Carbohydrate Metabolism and the Concept of a Compatible Parasite

et al. 2007

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Members of the genus Pneumocystis are fungal pathogens that cause pneumonia in a wide variety of mammals with debilitated immune systems. Little is known about their basic biological functions, including life cycle, since no species can be cultured continuously outside the mammalian lung. To better understand the pathological process, about 4500 ESTS derived from sequencing of the poly(A) tail ends of P. carinii mRNAs during fulminate infection were annotated and functionally characterized as unassembled reads, and then clustered and reduced to a unigene set with 1042 members. Because of the presence of sequences from other microbial genomes and the rat host, the analysis and compression to a unigene set was necessarily an iterative process. BLASTx analysis of the unassembled reads (UR) vs. the Uni-Prot and TREMBL databases revealed 56% had similarities to existing polypeptides at E values of≤10−6, with the remainder lacking any significant homology. The most abundant transcripts in the UR were associated with stress responses, energy production, transcription and translation. Most (70%) of the UR had similarities to proteins from filamentous fungi (e.g., Aspergillus, Neurospora) and existing P. carinii gene products. In contrast, similarities to proteins of the yeast-like fungi, Schizosaccharomyces pombe and Saccharomyces cerevisiae, predominated in the unigene set. Gene Ontology analysis using BLAST2GO revealed P. carinii dedicated most of its transcripts to cellular and physiological processes (∼80%), molecular binding and catalytic activities (∼70%), and were primarily derived from cell and organellar compartments (∼80%). KEGG Pathway mapping showed the putative P. carinii genes represented most standard metabolic pathways and cellular processes, including the tricarboxylic acid cycle, glycolysis, amino acid biosynthesis, cell cycle and mitochondrial function. Several gene homologs associated with mating, meiosis, and sterol biosynthesis in fungi were identified. Genes encoding the major surface glycoprotein family (MSG), heat shock (HSP70), and proteases (PROT/KEX) were the most abundantly expressed of known P. carinii genes. The apparent presence of many metabolic pathways in P. carinii, sexual reproduction within the host, and lack of an invasive infection process in the immunologically intact host suggest members of the genus Pneumocystis may be adapted parasites and have a compatible relationship with their mammalian hosts. This study represents the first characterization of the expressed genes of a non-culturable fungal pathogen of mammals during the infective process.

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Section: Discussionmentioning

confidence: 99%

Transcriptome of Pneumocystis carinii during Fulminate Infection: Carbohydrate Metabolism and the Concept of a Compatible Parasite

et al. 2007

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“…PCR was positive in all oral swabs of pups by 48 hours and was negative in fetuses and their placentas, indicating that P. carinii is acquired just after birth, but is not transplacental [21]. …”

Section: Discussionmentioning

confidence: 99%

“…Sensitivity of the PCR was determined as described [21,22,26,34]. Briefly, the number of P. carinii organisms was counted in stained slides prepared from 20 μl lung homogenates of infected rats.…”

Section: Methodsmentioning

confidence: 99%

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Detection of Pneumocystis in the nasal swabs of immune-suppressed rats by use of PCR and microscopy

Can

Caner

Döşkaya

et al. 2013

Med Sci Monit Basic Res

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BackgroundDetection of Pneumocystis jiroveci colonization in lungs or oral samples due to high sensitivity of PCR methods results in undue treatment of patients without any symptoms of Pneumocystis pneumonia. The aim of the present study is to demonstrate Pneumocystis carinii in rats, immune suppressed by oral and subcutaneous administration of dexamethasone.Material/MethodsBlood, oral, nasal and eye swabs were collected prior to immune suppression and 2, 6, 12 weeks after administration of dexamethasone. Also, samples were collected from lung, heart, liver, kidney, diaphragm, brain, spleen, tongue, muscle, eye, intestine, and feces. Cysts and trophozoites were investigated in stained slides and MSG gene was detected by PCR.ResultsThe results showed that weight loss is significantly higher in rats administered oral dexamethasone (P<0.05). Microscopy was positive only in lungs of rats orally administered dexamethasone. PCR was positive in lungs and oral swabs of rats prior to the administration of dexamethasone. After the administration of dexamethasone, the MSG gene was detected in oral swabs, lungs, spleen, kidney and (for the first time) in nasal swabs. PCR was positive in nasal swabs during the second and sixth weeks of oral and subcutaneous administration of dexamethasone, respectively.ConclusionsPresence of P. jiroveci in nasopharyngeal aspirate, oropharyngeal wash, oral swab, induced sputum or BAL, and absence in nasal swab in a patient without symptoms of PCP may support clinician’s decision regarding colonization. Overall, detection of P. carinii in nasal swabs of rats by PCR demonstrated that nasal sampling can be used for the diagnosis of Pneumocystis pneumonia.

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“…Furthermore, this colonization occurs within hours of birth [74]. To our knowledge, all commercial rats that are available generally have some low level of Pc colonization.…”

Section: Discussionmentioning

confidence: 99%

Chitinases in Pneumocystis carinii pneumonia

Villegas

Kottom

Limper

2012

Med Microbiol Immunol

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Pneumocystis pneumonia remains an important complication of immune suppression. The cell wall of Pneumocystis has been demonstrated to potently stimulate host inflammatory responses, with most studies focusing on β-glucan components of the Pneumocystis cell wall. In the current study, we have elaborated the potential role of chitins and chitinases in Pneumocystis pneumonia. We demonstrated differential host mammalian chitinase expression during Pneumocystis pneumonia. We further characterized a chitin synthase gene in Pneumocystis carinii termed Pcchs5, a gene with considerable homolog to the fungal chitin biosynthesis protein Chs5. We also observed the impact of chitinase digestion on Pneumocystis-induced host inflammatory responses by measuring TNFα release and mammalian chitinase expression by cultured lung epithelial and macrophage cells stimulated with Pneumocystis cell wall isolates in the presence and absence of exogenous chitinase digestion. These findings provide evidence supporting a chitin biosynthetic pathway in Pneumocystis organisms and that chitinases modulate inflammatory responses in lung cells. We further demonstrate lung expression of chitinase molecules during Pneumocystis pneumonia.

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Early Acquisition of Pneumocystis carinii in Neonatal Rats as Evidenced by PCR and Oral Swabs

Cited by 53 publications

References 34 publications

Transcriptome of Pneumocystis carinii during Fulminate Infection: Carbohydrate Metabolism and the Concept of a Compatible Parasite

Transcriptome of Pneumocystis carinii during Fulminate Infection: Carbohydrate Metabolism and the Concept of a Compatible Parasite

Detection of Pneumocystis in the nasal swabs of immune-suppressed rats by use of PCR and microscopy

Chitinases in Pneumocystis carinii pneumonia

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