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Dellière S, Amar Y, Hamane S, Aissaoui N, Denis B, Bergeron A, Tazi A, Alanio A. Bronchial aspirate obtained during bronchoscopy yields increased fungal load compared to bronchoalveolar lavage fluid in patients at risk of invasive aspergillosis and Pneumocystis pneumonia. Med Mycol 2023; 61:myad120. [PMID: 37996394 DOI: 10.1093/mmy/myad120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Revised: 11/13/2023] [Accepted: 11/22/2023] [Indexed: 11/25/2023] Open
Abstract
Bronchoalveolar lavage fluid (BALF) is a standard respiratory sample for diagnosing invasive fungal diseases like Pneumocystis pneumonia (PCP) and invasive pulmonary aspergillosis (IPA). However, procedural variations exist across medical centers and wards. This study aimed to compare the diagnostic potential of BALF and bronchial aspirate (BA) obtained during bronchoscopy in 173 patients suspected of fungal infections. A prospective observational study was conducted from April 2020 to November 2021. BALF and BA were collected during bronchoscopy and subjected to direct examination, fungal culture, Aspergillus fumigatus qPCR (AfqPCR), and Pneumocystis jirovecii qPCR (PjqPCR). Galactomannan detection was performed on BALF. Patients were classified based on established European Organization for Research and Treatment of Cancer (EORTC) criteria. Out of 173 patients, 75 tested positive for at least one test in BA or BALF. For Aspergillus, proportion of positive AfqPCR (14.5% vs. 9.2%; P < 0.0001) and fungal loads (Cq of 31.3 vs. 32.8; P = 0.0018) were significantly higher in BA compared to BALF. For Pneumocystis, fungal loads by PjqPCR was also higher in BA compared to BALF (Cq of 34.2 vs. 35.7; P = 0.003). BA only detected A. fumigatus and P. jirovecii in 12 (42.9%) and 8 (19.5%) patients, respectively. BA obtained during a BAL procedure can be a suitable sample type for increased detection of P. jirovecii and A. fumigatus by qPCR. The use of BA in diagnostic algorithms requires further investigation in prospective studies.
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Affiliation(s)
- Sarah Dellière
- Laboratoire de parasitologie-mycologie, AP-HP, Hôpital Saint-Louis, Paris, France
- Institut Pasteur, Université de Paris Cité, Immunobiology d'Aspergillus, Paris, France
| | - Yaël Amar
- Service de pneumologie, AP-HP, Hôpital Saint-Louis, Paris, France
| | - Samia Hamane
- Laboratoire de parasitologie-mycologie, AP-HP, Hôpital Saint-Louis, Paris, France
| | - Nesrine Aissaoui
- Laboratoire de parasitologie-mycologie, AP-HP, Hôpital Saint-Louis, Paris, France
| | - Blandine Denis
- Service d'infectiologie, AP-HP, Hôpital Saint-Louis, Paris, France
| | - Anne Bergeron
- Hôpitaux Universitaire de Genève, University of Geneva, Genève, Switzerland
| | - Abdellatif Tazi
- Service de pneumologie, AP-HP, Hôpital Saint-Louis, Paris, France
| | - Alexandre Alanio
- Laboratoire de parasitologie-mycologie, AP-HP, Hôpital Saint-Louis, Paris, France
- Institut Pasteur, Université Paris Cité, National Reference Center for Invasive Mycoses and Antifungals, Translational Mycology research group, Mycology Department, Paris, France
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2
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Wills NK, Lawrence DS, Botsile E, Tenforde MW, Jarvis JN. The prevalence of laboratory-confirmed Pneumocystis jirovecii in HIV-infected adults in Africa: A systematic review and meta-analysis. Med Mycol 2021; 59:802-812. [PMID: 33578417 DOI: 10.1093/mmy/myab002] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 11/30/2020] [Accepted: 01/08/2021] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND The epidemiology of Pneumocystis jirovecii, known to colonize the respiratory tract and cause a life-threatening HIV-associated pneumonia (PCP), is poorly described in Africa. We conducted a systematic review to evaluate P. jirovecii prevalence in African HIV-positive adults with or without respiratory symptoms. METHODS We searched Medline, Embase, Cochrane library, Africa-Wide, and Web of Science for studies employing PCR and/or microscopy for P. jirovecii detection in respiratory samples from HIV-positive adults in Africa between 1995 and 2020. Prevalence with respiratory symptoms was pooled using random-effect meta-analysis, and stratified by laboratory method, sample tested, study setting, CD4 count, and trimethoprim/sulfamethoxazole prophylaxis. Colonization prevalence in asymptomatic adults and in adults with non-PCP respiratory disease was described, and quantitative PCR (qPCR) thresholds to distinguish colonization from microscopy-confirmed PCP reviewed. RESULTS Thirty-two studies were included, with 27 studies (87%) at high risk of selection bias. P. jirovecii was detected in 19% [95% confidence interval (CI): 12-27%] of 3583 symptomatic and in 9% [95% CI: 0-45%] of 140 asymptomatic adults. Among symptomatic adults, prevalence was 22% [95% CI: 12-35%] by PCR and 15% [95% CI: 9-23%] by microscopy. Seven percent of 435 symptomatic adults had PCR-detected Pneumocystis colonization without evidence of PCP [95% CI: 5-10%, four studies]. One study established a qPCR cutoff of 78 copies/5μl of DNA in 305 induced sputum samples to distinguish Pneumocystis colonization from microscopy-confirmed PCP. CONCLUSION Despite widened access to HIV services, P. jirovecii remains common in Africa. Prevalence estimates and qPCR-based definitions of colonization are limited, and overall quality of studies is low.
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Affiliation(s)
- Nicola K Wills
- Welcome Centre for Infectious Diseases Research in Africa, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Cape Town, 7925, South Africa.,Department of Clinical Research, Faculty of infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK.,Department of Medicine, Groote Schuur Hospital University of Cape Town, Cape Town, 7925, South Africa
| | - David S Lawrence
- Department of Clinical Research, Faculty of infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK.,Botswana Harvard AIDS Institute Partnership, Gaborone, Botswana
| | - Elizabeth Botsile
- Department of Medicine, Princess Marina Hospital, Gaborone, Botswana
| | - Mark W Tenforde
- Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington School of Medicine, Seattle, WA, 98195, USA.,Department of Epidemiology, University of Washington School of Public Health, Seattle, 98195, WA, USA
| | - Joseph N Jarvis
- Department of Clinical Research, Faculty of infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK.,Botswana Harvard AIDS Institute Partnership, Gaborone, Botswana
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Ricci G, Santos DW, Kovacs JA, Nishikaku AS, de Sandes-Freitas TV, Rodrigues AM, Kutty G, Affonso R, Silva HT, Medina-Pestana JO, de Franco MF, Colombo AL. Genetic diversity of Pneumocystis jirovecii from a cluster of cases of pneumonia in renal transplant patients: Cross-sectional study. Mycoses 2018; 61:845-852. [PMID: 29992629 DOI: 10.1111/myc.12823] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Revised: 06/11/2018] [Accepted: 07/01/2018] [Indexed: 12/25/2022]
Abstract
Pneumocystis jirovecii can cause severe potentially life-threatening pneumonia (PCP) in kidney transplant patients. Prophylaxis of patients against PCP in this setting is usually performed during 6 months after transplantation. The aim of this study is to describe the molecular epidemiology of a cluster of PCP in renal transplant recipients in Brazil. Renal transplant patients who developed PCP between May and December 2011 had their formalin-fixed paraffin-embedded (FFPE) lung biopsy samples analysed. Pneumocystis jirovecii 23S mitochondrial large subunit of ribosomal RNA (23S mtLSU-rRNA), 26S rRNA, and dihydropteroate synthase (DHPS) genes were amplified by polymerase chain reaction (PCR), sequenced, and analysed for genetic variation. During the study period, 17 patients developed PCP (only four infections were documented within the first year after transplantation) and six (35.3%) died. Thirty FFPE samples from 11 patients, including one external control HIV-infected patient, had fungal DNA successfully extracted for further amplification and sequencing for all three genes. A total of five genotypes were identified among the 10 infected patients. Of note, four patients were infected by more than one genotype and seven patients were infected by the same genotype. DNA extracted from FFPE samples can be used for genotyping; this approach allowed us to demonstrate that multiple P. jirovecii strains were responsible for this cluster, and one genotype was found infecting seven patients. The knowledge of the causative agents of PCP may help to develop new initiatives for control and prevention of PCP among patients undergoing renal transplant and improve routine PCP prophylaxis.
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Affiliation(s)
- Giannina Ricci
- Special Mycology Laboratory, Division of Infectious Diseases, Department of Medicine, Universidade Federal de São Paulo (UNIFESP), São Paulo, SP, Brazil
| | - Daniel Wagner Santos
- Special Mycology Laboratory, Division of Infectious Diseases, Department of Medicine, Universidade Federal de São Paulo (UNIFESP), São Paulo, SP, Brazil.,Hospital do Rim, Fundação Oswaldo Ramos, São Paulo, SP, Brazil
| | - Joseph A Kovacs
- Critical Care Medicine Department, NIH Clinical Center, National Institutes of Health, Bethesda, Maryland
| | - Angela Satie Nishikaku
- Special Mycology Laboratory, Division of Infectious Diseases, Department of Medicine, Universidade Federal de São Paulo (UNIFESP), São Paulo, SP, Brazil
| | | | - Anderson Messias Rodrigues
- Molecular Biology Division, Department of Microbiology, Immunology and Parasitology (DMIP), Universidade Federal de São Paulo (UNIFESP), São Paulo, SP, Brazil
| | - Geetha Kutty
- Critical Care Medicine Department, NIH Clinical Center, National Institutes of Health, Bethesda, Maryland
| | - Regina Affonso
- Biotechnology Center, Nuclear and Energy Research Institute (IPEN), São Paulo, SP, Brazil
| | | | | | | | - Arnaldo Lopes Colombo
- Special Mycology Laboratory, Division of Infectious Diseases, Department of Medicine, Universidade Federal de São Paulo (UNIFESP), São Paulo, SP, Brazil
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4
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Dunaiski CM, Janssen L, Erzinger H, Pieper M, Damaschek S, Schildgen O, Schildgen V. Inter-Specimen Imbalance of Mitochondrial Gene Copy Numbers Predicts Clustering of Pneumocystis jirovecii Isolates in Distinct Subgroups. J Fungi (Basel) 2018; 4:jof4030084. [PMID: 29996561 PMCID: PMC6162491 DOI: 10.3390/jof4030084] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Revised: 07/04/2018] [Accepted: 07/09/2018] [Indexed: 12/11/2022] Open
Abstract
The molecular detection of Pneumocystis jirovecii is an important therapy-relevant tool in microbiological diagnostics. However, the quantification of this pathogen in the past has revealed discordant results depending on the target gene. As the clinical variety of P. jirovecii infections ranges between life-threatening infections and symptom-free colonization, the question arises if qPCRs are reliable tools for quantitative diagnostics of P. jirovecii. P. jirovecii positive BALs were quantitatively tested for the copy numbers of one mitochondrial (COX-1) and two nuclear single-copy genes (KEX1 and DHPS) compared to the mitochondrial large subunit (mtLSU) by qPCR. Independent of the overall mtLSU copy number P. jirovecii clustered into distinct groups based on the ratio patterns of the respective qPCRs. This study, which compared different mitochondrial to nuclear gene ratio patterns of independent patients, shows that the mtLSU gene represents a highly sensitive qPCR tool for the detection of P. jirovecii, but does not display a reliable target for absolute quantification.
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Affiliation(s)
- Cara Mia Dunaiski
- Kliniken der Stadt Köln gGmbH, Institut für Pathologie, Klinikum der Privaten Universität Witten/Herdecke, 51109 Köln, Germany.
| | - Lena Janssen
- Kliniken der Stadt Köln gGmbH, Institut für Pathologie, Klinikum der Privaten Universität Witten/Herdecke, 51109 Köln, Germany.
| | - Hannah Erzinger
- Kliniken der Stadt Köln gGmbH, Institut für Pathologie, Klinikum der Privaten Universität Witten/Herdecke, 51109 Köln, Germany.
| | - Monika Pieper
- Kliniken der Stadt Köln gGmbH, Institut für Pathologie, Klinikum der Privaten Universität Witten/Herdecke, 51109 Köln, Germany.
| | - Sarah Damaschek
- Kliniken der Stadt Köln gGmbH, Institut für Pathologie, Klinikum der Privaten Universität Witten/Herdecke, 51109 Köln, Germany.
| | - Oliver Schildgen
- Kliniken der Stadt Köln gGmbH, Institut für Pathologie, Klinikum der Privaten Universität Witten/Herdecke, 51109 Köln, Germany.
| | - Verena Schildgen
- Kliniken der Stadt Köln gGmbH, Institut für Pathologie, Klinikum der Privaten Universität Witten/Herdecke, 51109 Köln, Germany.
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5
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Copete AR, Aguilar YA, Rueda ZV, Vélez LA. Genotyping and macrolide resistance of Mycoplasma pneumoniae identified in children with community-acquired pneumonia in Medellín, Colombia. Int J Infect Dis 2017; 66:113-120. [PMID: 29155089 PMCID: PMC7129344 DOI: 10.1016/j.ijid.2017.11.019] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Revised: 11/07/2017] [Accepted: 11/09/2017] [Indexed: 01/19/2023] Open
Abstract
The majority of the Mycoplasma pneumoniae isolates obtained from the children with community-acquired pneumonia in this study were a variant of type 2. There was an absence of the mutations in the 23S rRNA gene related to macrolide resistance. Induced sputum sample has higher percentage of positive PCR to diagnose Mycoplasma pneumoniae compared to nasopharyngeal swab.
Objectives The aim of this study was to describe the genotypes and the main characteristics of community-acquired pneumonia (CAP) caused by Mycoplasma pneumoniae in hospitalized children in Medellín and neighboring municipalities during the period 2011–2012. Methods The M. pneumoniae genotype was determined by PCR and sequencing of the p1 and 23S rRNA genes from induced sputum samples and nasopharyngeal swabs (NPS). Samples were obtained from children with CAP who were hospitalized in 13 healthcare centers. In addition, a spatio-temporal analysis was performed to identify the potential risk areas and clustering of the cases over time. Results A variant of type 2 was the dominant genotype in the induced sputum (96.1%) and NPS (89.3%) samples; the type 1 variant was identified in 3.9% and 10.7% of these samples, respectively. No strains with mutations in the 23S rRNA gene associated with macrolide resistance were found. The cases in Medellín were mainly concentrated in the northeastern areas and western districts. However, no temporal relationship was found among these cases. Conclusions A variant of type 2 of M. pneumoniae prevailed among children with CAP during the study period. No strains with mutations associated with macrolide resistance were found.
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Affiliation(s)
- Angela Rocio Copete
- Research Group of Problems in Infectious Diseases (GRIPE), School of Medicine, Universidad de Antioquia UdeA, Medellín, Colombia.
| | - Yudy Alexandra Aguilar
- Research Group of Problems in Infectious Diseases (GRIPE), School of Medicine, Universidad de Antioquia UdeA, Medellín, Colombia.
| | | | - Lázaro Agustín Vélez
- Research Group of Problems in Infectious Diseases (GRIPE), School of Medicine, Universidad de Antioquia UdeA, Medellín, Colombia; Unit of Infectious Diseases, Hospital Universitario San Vicente Fundación, Medellín, Colombia.
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6
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Vargas SL, Ponce C, Bustamante R, Calderón E, Nevez G, De Armas Y, Matos O, Miller RF, Gallo MJ. Importance of tissue sampling, laboratory methods, and patient characteristics for detection of Pneumocystis in autopsied lungs of non-immunosuppressed individuals. Eur J Clin Microbiol Infect Dis 2017; 36:1711-1716. [PMID: 28584896 PMCID: PMC5602097 DOI: 10.1007/s10096-017-3006-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2017] [Accepted: 05/03/2017] [Indexed: 11/29/2022]
Abstract
To understand the epidemiological significance of Pneumocystis detection in a lung tissue sample of non-immunosuppressed individuals, we examined sampling procedures, laboratory methodology, and patient characteristics of autopsy series reported in the literature. Number of tissue specimens, DNA-extraction procedures, age and underlying diagnosis highly influence yield and are critical to understand yield differences of Pneumocystis among reports of pulmonary colonization in immunocompetent individuals.
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Affiliation(s)
- S L Vargas
- Programa de Microbiología y Micología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Independencia 1027, 8380453, Santiago, Chile.
| | - C Ponce
- Programa de Microbiología y Micología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Independencia 1027, 8380453, Santiago, Chile
| | - R Bustamante
- Programa de Microbiología y Micología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Independencia 1027, 8380453, Santiago, Chile
| | - E Calderón
- Centro de Investigación Biomédica en Red de Epidemiología y Salud Pública (CIBERESP) and Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain
| | - G Nevez
- Laboratory of Parasitology and Mycology, Brest University Hospital, & University of Brest, GEIHP, EA 3142, Brest, France
| | - Y De Armas
- Hospital Microbiology Department, Institute of Tropical Medicine "Pedro Kourí" Pathology Department, Institute of Tropical Medicine "Pedro Kourí" Hospital, Havana, Cuba
| | - O Matos
- Unidade de Parasitología Médica, Grupo de Protozoários Oportunistas/VIH e Outros Protozoarios, Global Health and Tropical Medicine, Instituto de Higiene e Medicina Tropical, Universidade NOVA de Lisboa, 1349-008, Lisbon, Portugal
| | - R F Miller
- Research Department of Infection and Population Health, Institute of Global Health, University College London, Mortimer Market Street, London, WC1E 6BT, UK
- Clinical Research Department, London School of Hygiene and Tropical Medicine, London, UK
| | - M J Gallo
- Servicio Médico Legal, Av. La Paz 1012, 8380454, Santiago, Chile
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7
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Abstract
Pneumocystis jirovecii is an unusual ascomycetous fungus that can be detected in the lungs of healthy individuals. Transmission from human to human is one of its main characteristics in comparison with other fungi responsible for invasive infections.
P. jirovecii is transmitted through the air between healthy individuals, who are considered to be the natural reservoir, at least transiently. In immunocompromised patients,
P. jirovecii multiplies, leading to subacute infections and acute life-threatening pneumonia, called Pneumocystis pneumonia [PCP]. PCP is caused by genotypically distinct mixtures of organisms in more than 90% of cases, reinforcing the hypothesis that there is constant inhalation of
P. jirovecii from different contacts over time, although reactivation of latent organisms from previous exposures may be possible. Detection of
P. jirovecii DNA without any symptoms or related radiological signs has been called “colonization”. This situation could be considered as the result of recent exposure to
P. jirovecii that could evolve towards PCP, raising the issue of cotrimoxazole prophylaxis for at-risk quantitative polymerase chain reaction (qPCR)-positive immunocompromised patients. The more accurate way to diagnose PCP is the use of real-time quantitative PCR, which prevents amplicon contamination and allows determination of the fungal load that is mandatory to interpret the qPCR results and manage the patient appropriately. The detection of
P. jirovecii in respiratory samples of immunocompromised patients should be considered for potential risk of developing PCP. Many challenges still need to be addressed, including a better description of transmission, characterization of organisms present at low level, and prevention of environmental exposure during immunodepression.
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Affiliation(s)
- Alexandre Alanio
- Parasitology-Mycology Laboratory, Lariboisière Saint-Louis Fernand Widal Hospitals, Assistance Publique-Hôpitaux de Paris, Paris, France.,Paris-Diderot, Sorbonne Paris Cité University, Paris, France.,Molecular Mycology Unit, CNRS, Institut Pasteur, URA 3012, Paris, France
| | - Stéphane Bretagne
- Parasitology-Mycology Laboratory, Lariboisière Saint-Louis Fernand Widal Hospitals, Assistance Publique-Hôpitaux de Paris, Paris, France.,Paris-Diderot, Sorbonne Paris Cité University, Paris, France.,Molecular Mycology Unit, CNRS, Institut Pasteur, URA 3012, Paris, France
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8
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Alanio A, Gits-Muselli M, Mercier-Delarue S, Dromer F, Bretagne S. Diversity of Pneumocystis jirovecii during Infection Revealed by Ultra-Deep Pyrosequencing. Front Microbiol 2016; 7:733. [PMID: 27252684 PMCID: PMC4877386 DOI: 10.3389/fmicb.2016.00733] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 05/02/2016] [Indexed: 01/05/2023] Open
Abstract
Pneumocystis jirovecii is an uncultivable fungal pathogen responsible for Pneumocystis pneumonia (PCP) in immunocompromised patients, the physiopathology of which is only partially understood. The diversity of the Pneumocystis strains associated with acute infection has mainly been studied by Sanger sequencing techniques precluding any identification of rare genetic events (< 20% frequency). We used next-generation sequencing to detect minority variants causing infection, and analyzed the complexity of the genomes of infection-causing P. jirovecii. Ultra-deep pyrosequencing (UDPS) of PCR amplicons of two nuclear target region [internal transcribed spacer 2 (ITS2) and dihydrofolate reductase (DHFR)] and one mitochondrial DNA target region [the mitochondrial ribosomal RNA large subunit gene (mtLSU)] was performed on 31 samples from 25 patients. UDPS revealed that almost all patients (n = 23/25, 92%) were infected with mixtures of strains. An analysis of repeated samples from six patients showed that the proportion of each variant change significantly (by up to 30%) over time on treatment in three of these patients. A comparison of mitochondrial and nuclear UDPS data revealed heteroplasmy in P. jirovecii. The recognition site for the homing endonuclease I-SceI was recovered from the mtLSU gene, whereas its two conserved motifs of the enzyme were not. This suggests that heteroplasmy may result from recombination induced by unidentified homing endonucleases. This study sheds new light on the biology of P. jirovecii during infection. PCP results from infection not with a single microorganism, but with a complex mixture of different genotypes, the proportions of which change over time due to intricate selection and reinfection mechanisms that may differ between patients, treatments, and predisposing diseases.
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Affiliation(s)
- Alexandre Alanio
- Laboratoire de Parasitologie-Mycologie, Groupe Hospitalier Saint-Louis-Lariboisière-Fernand-Widal, Assistance Publique Hôpitaux de Paris, Hôpital Saint-LouisParis, France; Université Paris Diderot, Sorbonne Paris CitéParis, France; Unité de Mycologie Moléculaire, Département de Mycologie, Centre National de Référence Mycoses Invasives et Antifongiques, Institut PasteurParis, France; Centre National de la Recherche Scientifique CNRS URA3012Paris, France
| | - Maud Gits-Muselli
- Laboratoire de Parasitologie-Mycologie, Groupe Hospitalier Saint-Louis-Lariboisière-Fernand-Widal, Assistance Publique Hôpitaux de Paris, Hôpital Saint-LouisParis, France; Université Paris Diderot, Sorbonne Paris CitéParis, France
| | - Séverine Mercier-Delarue
- Laboratoire de Microbiologie, Groupe Hospitalier Saint-Louis-Lariboisière-Fernand-Widal, Assistance Publique Hôpitaux de Paris, Hôpital Saint-Louis Paris, France
| | - Françoise Dromer
- Unité de Mycologie Moléculaire, Département de Mycologie, Centre National de Référence Mycoses Invasives et Antifongiques, Institut PasteurParis, France; Centre National de la Recherche Scientifique CNRS URA3012Paris, France
| | - Stéphane Bretagne
- Laboratoire de Parasitologie-Mycologie, Groupe Hospitalier Saint-Louis-Lariboisière-Fernand-Widal, Assistance Publique Hôpitaux de Paris, Hôpital Saint-LouisParis, France; Université Paris Diderot, Sorbonne Paris CitéParis, France; Unité de Mycologie Moléculaire, Département de Mycologie, Centre National de Référence Mycoses Invasives et Antifongiques, Institut PasteurParis, France; Centre National de la Recherche Scientifique CNRS URA3012Paris, France
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Skalski JH, Kottom TJ, Limper AH. Pathobiology of Pneumocystis pneumonia: life cycle, cell wall and cell signal transduction. FEMS Yeast Res 2015; 15:fov046. [PMID: 26071598 DOI: 10.1093/femsyr/fov046] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/08/2015] [Indexed: 12/28/2022] Open
Abstract
Pneumocystis is a genus of ascomycetous fungi that are highly morbid pathogens in immunosuppressed humans and other mammals. Pneumocystis cannot easily be propagated in culture, which has greatly hindered understanding of its pathobiology. The Pneumocystis life cycle is intimately associated with its mammalian host lung environment, and life cycle progression is dependent on complex interactions with host alveolar epithelial cells and the extracellular matrix. The Pneumocystis cell wall is a varied and dynamic structure containing a dominant major surface glycoprotein, β-glucans and chitins that are important for evasion of host defenses and stimulation of the host immune system. Understanding of Pneumocystis cell signaling pathways is incomplete, but much has been deduced by comparison of the Pneumocystis genome with homologous genes and proteins in related fungi. In this mini-review, the pathobiology of Pneumocystis is reviewed, with particular focus on the life cycle, cell wall components and cell signal transduction.
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Affiliation(s)
- Joseph H Skalski
- Thoracic Diseases Research Unit, Division of Pulmonary and Critical Care Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA
| | - Theodore J Kottom
- Thoracic Diseases Research Unit, Division of Pulmonary and Critical Care Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA
| | - Andrew H Limper
- Thoracic Diseases Research Unit, Division of Pulmonary and Critical Care Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA
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10
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Alanio A, Olivi M, Cabaret O, Foulet F, Bellanger AP, Millon L, Berceanu A, Cordonnier C, Costa JM, Bretagne S. Correlation Between Pneumocystis jirovecii Mitochondrial Genotypes and High and Low Fungal Loads Assessed by Single Nucleotide Primer Extension Assay and Quantitative Real-Time PCR. J Eukaryot Microbiol 2015; 62:650-6. [PMID: 25940946 DOI: 10.1111/jeu.12222] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Revised: 02/06/2015] [Accepted: 02/06/2015] [Indexed: 12/12/2022]
Abstract
We designed a single nucleotide primer extension (SNaPshot) assay for Pneumocystis jirovecii genotyping, targeting mt85 SNP of the mitochondrial large subunit ribosomal RNA locus, to improve minority allele detection. We then analyzed 133 consecutive bronchoalveolar lavage (BAL) fluids tested positive for P. jirovecii DNA by quantitative real-time PCR, obtained from two hospitals in different locations (Hospital 1 [n = 95] and Hospital 2 [n = 38]). We detected three different alleles, either singly (mt85C: 39.1%; mt85T: 24.1%; mt85A: 9.8%) or together (27%), and an association between P. jirovecii mt85 genotype and the patient's place of hospitalization (p = 0.011). The lowest fungal loads (median = 0.82 × 10(3) copies/μl; range: 15-11 × 10(3) ) were associated with mt85A and the highest (median = 1.4 × 10(6) copies/μl; range: 17 × 10(3) -1.3 × 10(7) ) with mt85CTA (p = 0.010). The ratios of the various alleles differed between the 36 mixed-genotype samples. In tests of serial BALs (median: 20 d; range 4-525) from six patients with mixed genotypes, allele ratio changes were observed five times and genotype replacement once. Therefore, allele ratio changes seem more frequent than genotype replacement when using a SNaPshot assay more sensitive for detecting minority alleles than Sanger sequencing. Moreover, because microscopy detects only high fungal loads, the selection of microscopy-positive samples may miss genotypes associated with low loads.
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Affiliation(s)
- Alexandre Alanio
- Laboratoire de Parasitologie-Mycologie, AP-HP, Groupe Hospitalier Saint-Louis-Lariboisière-Fernand-Widal, Paris, France.,Université Paris-Diderot, Sorbonne Cité, Paris, France.,Institut Pasteur, Unité de Mycologie Moléculaire, Centre National de Référence Mycologie et Antifongiques, Paris, France.,CNRS URA3012, Paris, France
| | - Martine Olivi
- Laboratoire Cerba, Cergy-Pontoise, Saint-Ouen-l'Aumône, France
| | - Odile Cabaret
- Laboratoire de Parasitologie-Mycologie, AP-HP, Groupe hospitalier Chenevier-Mondor, Créteil, France.,Université Paris-Est-Créteil, Créteil, France
| | - Françoise Foulet
- Laboratoire de Parasitologie-Mycologie, AP-HP, Groupe hospitalier Chenevier-Mondor, Créteil, France.,Université Paris-Est-Créteil, Créteil, France
| | - Anne-Pauline Bellanger
- Laboratoire de Parasitologie-Mycologie, Centre hospitalier universitaire, Besançon, France.,Laboratoire Chrono-Environnement, Université Franche-Comté, UMR CNRS 6249, Besançon, France
| | - Laurence Millon
- Laboratoire de Parasitologie-Mycologie, Centre hospitalier universitaire, Besançon, France.,Laboratoire Chrono-Environnement, Université Franche-Comté, UMR CNRS 6249, Besançon, France
| | - Ana Berceanu
- Service d'Hématologie, Centre Hospitalier Universitaire, Besançon, France
| | - Catherine Cordonnier
- Université Paris-Est-Créteil, Créteil, France.,Département d'Hématologie, APHP, Groupe Hospitalier Albert Chenevier-Henri Mondor, Creteil, France
| | - Jean-Marc Costa
- Laboratoire Cerba, Cergy-Pontoise, Saint-Ouen-l'Aumône, France.,Laboratoire de Parasitologie-Mycologie, AP-HP, Groupe hospitalier Chenevier-Mondor, Créteil, France
| | - Stéphane Bretagne
- Laboratoire de Parasitologie-Mycologie, AP-HP, Groupe Hospitalier Saint-Louis-Lariboisière-Fernand-Widal, Paris, France.,Université Paris-Diderot, Sorbonne Cité, Paris, France.,Institut Pasteur, Unité de Mycologie Moléculaire, Centre National de Référence Mycologie et Antifongiques, Paris, France.,CNRS URA3012, Paris, France
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11
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Gits-Muselli M, Peraldi MN, de Castro N, Delcey V, Menotti J, Guigue N, Hamane S, Raffoux E, Bergeron A, Valade S, Molina JM, Bretagne S, Alanio A. New Short Tandem Repeat-Based Molecular Typing Method for Pneumocystis jirovecii Reveals Intrahospital Transmission between Patients from Different Wards. PLoS One 2015; 10:e0125763. [PMID: 25933203 PMCID: PMC4416908 DOI: 10.1371/journal.pone.0125763] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Accepted: 03/26/2015] [Indexed: 12/26/2022] Open
Abstract
Pneumocystis pneumonia is a severe opportunistic infection in immunocompromised patients caused by the unusual fungus Pneumocystis jirovecii. Transmission is airborne, with both immunocompromised and immunocompetent individuals acting as a reservoir for the fungus. Numerous reports of outbreaks in renal transplant units demonstrate the need for valid genotyping methods to detect transmission of a given genotype. Here, we developed a short tandem repeat (STR)-based molecular typing method for P. jirovecii. We analyzed the P. jirovecii genome and selected six genomic STR markers located on different contigs of the genome. We then tested these markers in 106 P. jirovecii PCR-positive respiratory samples collected between October 2010 and November 2013 from 91 patients with various underlying medical conditions. Unique (one allele per marker) and multiple (more than one allele per marker) genotypes were observed in 34 (32%) and 72 (68%) samples, respectively. A genotype could be assigned to 55 samples (54 patients) and 61 different genotypes were identified in total with a discriminatory power of 0.992. Analysis of the allelic distribution of the six markers and minimum spanning tree analysis of the 61 genotypes identified a specific genotype (Gt21) in our hospital, which may have been transmitted between 10 patients including six renal transplant recipients. Our STR-based molecular typing method is a quick, cheap and reliable approach to genotype Pneumocystis jirovecii in hospital settings and is sensitive enough to detect minor genotypes, thus enabling the study of the transmission and pathophysiology of Pneumocystis pneumonia.
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Affiliation(s)
- Maud Gits-Muselli
- Laboratoire de Parasitologie-Mycologie, AP-HP, Groupe Hospitalier Saint-Louis-Lariboisière-Fernand-Widal, Paris, France
| | - Marie-Noelle Peraldi
- Service de transplantation rénale, AP-HP, Groupe Hospitalier Saint-Louis-Lariboisière-Fernand-Widal, Paris, France
- Université Paris-Diderot, Sorbonne Cité, Paris, France
| | - Nathalie de Castro
- Service de Maladie Infectieuses et tropicales, AP-HP, Groupe Hospitalier Saint-Louis-Lariboisière-Fernand-Widal, Paris, France
| | - Véronique Delcey
- Service de Médecine interne, AP-HP, Groupe Hospitalier Saint-Louis-Lariboisière-Fernand-Widal, Hôpital Lariboisière, Paris, France
| | - Jean Menotti
- Laboratoire de Parasitologie-Mycologie, AP-HP, Groupe Hospitalier Saint-Louis-Lariboisière-Fernand-Widal, Paris, France
- Université Paris-Diderot, Sorbonne Cité, Paris, France
- Institut Pasteur, Unité de Mycologie Moléculaire, Centre National de Référence Mycoses invasives et Antifongiques, Paris, France
- CNRS URA3012, Paris, France
| | - Nicolas Guigue
- Laboratoire de Parasitologie-Mycologie, AP-HP, Groupe Hospitalier Saint-Louis-Lariboisière-Fernand-Widal, Paris, France
- Université Paris-Diderot, Sorbonne Cité, Paris, France
| | - Samia Hamane
- Laboratoire de Parasitologie-Mycologie, AP-HP, Groupe Hospitalier Saint-Louis-Lariboisière-Fernand-Widal, Paris, France
| | - Emmanuel Raffoux
- Service d’Hématologie adulte, AP-HP, Groupe Hospitalier Saint-Louis-Lariboisière-Fernand-Widal, Paris, France
| | - Anne Bergeron
- Université Paris-Diderot, Sorbonne Cité, Paris, France
- Service de Pneumologie, AP-HP, Groupe Hospitalier Saint-Louis-Lariboisière-Fernand-Widal, Paris, France
| | - Sandrine Valade
- Service de Réanimation, AP-HP, Groupe Hospitalier Saint-Louis-Lariboisière-Fernand-Widal, Paris, France
| | - Jean-Michel Molina
- Université Paris-Diderot, Sorbonne Cité, Paris, France
- Service de Maladie Infectieuses et tropicales, AP-HP, Groupe Hospitalier Saint-Louis-Lariboisière-Fernand-Widal, Paris, France
| | - Stéphane Bretagne
- Laboratoire de Parasitologie-Mycologie, AP-HP, Groupe Hospitalier Saint-Louis-Lariboisière-Fernand-Widal, Paris, France
- Université Paris-Diderot, Sorbonne Cité, Paris, France
- Institut Pasteur, Unité de Mycologie Moléculaire, Centre National de Référence Mycoses invasives et Antifongiques, Paris, France
- CNRS URA3012, Paris, France
| | - Alexandre Alanio
- Laboratoire de Parasitologie-Mycologie, AP-HP, Groupe Hospitalier Saint-Louis-Lariboisière-Fernand-Widal, Paris, France
- Université Paris-Diderot, Sorbonne Cité, Paris, France
- Institut Pasteur, Unité de Mycologie Moléculaire, Centre National de Référence Mycoses invasives et Antifongiques, Paris, France
- CNRS URA3012, Paris, France
- * E-mail:
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12
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Zicklerova I, Uzlikova M, Nohynkova E. Molecular evidence of Pneumocystis jirovecii reinfection in a haemato-oncology patient. SCANDINAVIAN JOURNAL OF INFECTIOUS DISEASES 2012; 44:705-707. [PMID: 22668318 DOI: 10.3109/00365548.2012.677062] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
For many years Pneumocystis pneumonia was thought to be caused by the reactivation of a latent infection, but several studies have demonstrated that Pneumocystis jirovecii infection can be acquired de novo. On the basis of our results obtained from a patient with recurrent pneumocystosis, we support the hypothesis that recurrent episodes are caused by reinfection.
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Affiliation(s)
- Ivana Zicklerova
- Department of Tropical Medicine, Hospital Bulovka, Prague, Czech Republic
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13
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Internal transcribed spacer region sequence heterogeneity in Rhizopus microsporus: implications for molecular diagnosis in clinical microbiology laboratories. J Clin Microbiol 2009; 48:208-14. [PMID: 19906897 DOI: 10.1128/jcm.01750-09] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Although internal transcribed spacer region (ITS) sequence heterogeneity has been reported in a few fungal species, it has very rarely been reported in pathogenic fungi and has never been described in Mucorales, causes of the highly fatal mucormycosis. In a recent outbreak investigation of intestinal mucormycosis due to Rhizopus microsporus infection in patients with hematological malignancies, PCR of the ITS of four of the 28 R. microsporus strains, P11, P12, D3-1, and D4-1, showed thick bands at about 700 bp. Direct sequencing of the purified bands showed frequent double peaks along all of the sequence traces and occasional triple peaks for P12, D3-1, and D4-1. The thick bands of the four R. microsporus strains were purified and cloned. Sequencing of 10 clones for each strain revealed two different ITS sequences for P11 and three different ITS sequences for P12, D3-1, and D4-1. Variations in ITS sequence among the different ribosomal DNA (rDNA) operons in the same strain were observed in only ITS1 and ITS2 and not the 5.8S rDNA region. One copy of P11, P12, and D4-1, respectively, and one copy of P11, P12, D3-1, and D4-1, respectively, showed identical sequences. This represents the first evidence of ITS sequence heterogeneity in Mucorales. ITS sequence heterogeneity is an obstacle to molecular identification and genotyping of fungi in clinical microbiology laboratories. When thick bands and double peaks are observed during PCR sequencing of a gene target, such a strain should be sent to reference laboratories proficient in molecular technologies for further identification and/or genotyping.
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14
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De la Horra C, Varela JM, Friaza V, Respaldiza N, Muñoz-Lobato F, Montes-Cano MA, Calderon E, Medrano FJ. Comparison of Single and Touchdown PCR Protocols for Detecting Pneumocystis jirovecii DNA in Paraffin-Embedded Lung Tissue Samples. J Eukaryot Microbiol 2006; 53 Suppl 1:S98-9. [PMID: 17169083 DOI: 10.1111/j.1550-7408.2006.00187.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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15
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Giner JL, Zhao H, Amit Z, Kaneshiro ES. Sterol composition of Pneumocystis jirovecii with blocked 14alpha-demethylase activity. J Eukaryot Microbiol 2005; 51:634-43. [PMID: 15666720 DOI: 10.1111/j.1550-7408.2004.tb00597.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Several drugs that interact with membrane sterols or inhibit their syntheses are effective in clearing a number of fungal infections. The AIDS-associated lung infection caused by Pneumocystis jirovecii is not cleared by many of these therapies. Pneumocystis normally synthesizes distinct C28 and C29 24-alkylsterols, but ergosterol, the major fungal sterol, is not among them. Two distinct sterol compositional phenotypes were previously observed in P. jirovecii. One was characterized by delta7 C28 and C29 24-alkylsterols with only low proportions of higher molecular mass components. In contrast, the other type was dominated by high C31 and C32 24-alkylsterols, especially pneumocysterol. In the present study, 28 molecular species were elucidated by nuclear magnetic resonance analysis of a human lung specimen containing P. jirovecii representing the latter sterol profile phenotype. Fifteen of the 28 had the methyl group at C-14 of the sterol nucleus and these represented 96% of the total sterol mass in the specimen (excluding cholesterol). These results strongly suggest that sterol 14alpha-demethylase was blocked in these organisms. Twenty-four of the 28 were 24-alkylsterols, indicating that methylation of the C-24 position of the sterol side chain by S-adenosyl-L-methionine:sterol C-24 methyl transferase was fully functional.
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Affiliation(s)
- José-Luis Giner
- Department of Chemistry, State University of New York-ESF, Syracuse, NY 13210, USA.
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Abstract
A major goal of molecular testing is to develop a cost-effective as well as sensitive and specific assay that can detect microbial DNA in clinical samples early in the course of disease. Additionally, the ability to analyze the genetic relatedness of fungi on a timelier basis using molecular methods will have a positive impact on epidemiologic investigating. As technology advances, it seems apparent that commercially available molecular assays will become available in the near future for the management of patients with suspected fungal infections.
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Affiliation(s)
- Peter C Iwen
- Department of Pathology and Microbiology, University of Nebraska Medical Center, 986495 Nebraska Medical Center Omaha, NE 68198-6495, USA.
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17
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Lee K, Lee WG, Uh Y, Ha GY, Cho J, Chong Y. VIM- and IMP-type metallo-beta-lactamase-producing Pseudomonas spp. and Acinetobacter spp. in Korean hospitals. Emerg Infect Dis 2003; 9:868-71. [PMID: 12890331 PMCID: PMC3023439 DOI: 10.3201/eid0907.020753] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
We determined the occurrence of acquired metallo-b-lactamase (MBL)-producing bacteria in Korean hospitals. Among the isolates nonsusceptible to imipenem that were collected from 28 hospitals from 2000 to 2001, 44 (11.4%) of 387 Pseudomonas spp. and 38 (14.2%) of 267 Acinetobacter spp. produced MBL and had alleles of blaVIM-2 or blaIMP-1. MBL-producing isolates were detected in 60.7% of the hospitals.
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Affiliation(s)
- Kyungwon Lee
- Yonsei University College of Medicine, Seoul, Korea
| | - Wee Gyo Lee
- Ajou University School of Medicine, Suwon, Korea
| | - Young Uh
- Yonsei University Wonju College of Medicine, Wonju, Korea
| | - Gyoung Yim Ha
- College of Medicine of Dongguk University, Kyongju, Korea
| | - Jihyun Cho
- Wonkwang University College of Medicine, Iksan, Korea
| | - Yunsop Chong
- Yonsei University College of Medicine, Seoul, Korea
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18
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Totet A, Pautard JC, Raccurt C, Roux P, Nevez G. Genotypes at the internal transcribed spacers of the nuclear rRNA operon of Pneumocystis jiroveci in nonimmunosuppressed infants without severe pneumonia. J Clin Microbiol 2003; 41:1173-80. [PMID: 12624048 PMCID: PMC150306 DOI: 10.1128/jcm.41.3.1173-1180.2003] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The frequency of Pneumocystis jiroveci (human-derived Pneumocystis) in immunocompetent infants developing acute respiratory syndromes has recently been evaluated and has been shown to be close to 25%. Until now, there have been no data on the genomic characteristics of the fungus in these patients, while molecular typing of P. jiroveci organisms was mostly performed with samples from immunosuppressed patients with pneumocystosis (Pneumocystis carinii pneumonia [PCP]). The present report describes the genotypes of P. jiroveci organisms in 26 nonimmunosuppressed infants developing a mild Pneumocystis infection contemporaneously with an episode of bronchioloalveolitis. The typing was based on sequence analysis of internal transcribed spacers (ITSs) 1 and 2 of the rRNA operon, followed by the use of two typing scores. By use of the first score, 11 P. jiroveci ITS types were identified: 10 were previously reported in immunosuppressed patients with PCP, while 1 was newly described. By use of the second score, 13 types were identified, of which 2 were newly described. The most frequent type was identified as type B(1)a(3) (first score), which corresponds to type Eg (second score). Mixed infections were diagnosed in three infants. The occurrence of such diversity of P. jiroveci ITS types, an identical main type, and mixed infections has previously been reported in immunosuppressed patients with PCP. Thus, the P. jiroveci ITS genotypes detected in immunocompetent infants and immunosuppressed patients developing different forms of Pneumocystis infection share characteristics, suggesting that both groups of individuals make up a common human reservoir for the fungus. Finally, the frequency of P. jiroveci in nonimmunosuppressed infants with acute respiratory syndromes and the genotyping results provide evidence that this infant population is an important reservoir for the fungus.
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Affiliation(s)
- Anne Totet
- Department of Parasitology, Mycology, and Travel Medicine, University Hospital Centre, Jules Verne University of Picardy, 80054 Amiens, France.
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Nevez G, Totet A, Jounieaux V, Schmit JL, Dei-Cas E, Raccurt C. Pneumocystis jiroveci internal transcribed spacer types in patients colonized by the fungus and in patients with pneumocystosis from the same French geographic region. J Clin Microbiol 2003; 41:181-6. [PMID: 12517845 PMCID: PMC149574 DOI: 10.1128/jcm.41.1.181-186.2003] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
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.
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Affiliation(s)
- Gilles Nevez
- Department of Parasitology, Mycology and Travel Medicine, University Hospital of Amiens, Jules Verne University of Picardy, 80054 Amiens, France.
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Abstract
Pneumocystis organisms can cause pneumonia in mammals that lack a strong immune defense. The genus Pneumocystis contains many different organisms that can be distinguished by DNA sequence analysis. These different organisms are different species of yeast-like fungi that are most closely related to the ascomycete, Schizosaccharomyces pombe. Each species of Pneumocystis appears to be specific for the mammal in which it is found. The species that infects humans is Pneumocystis jiroveci. P. jiroveci has not been found in any other mammal and the species of Pneumocystis found in other mammals have not been seen in humans. Genetic variation among P. jiroveci samples is common, suggesting that there are many strains. Strain analysis shows that adults can be infected by more than one strain, and suggests that pneumonia can be the result of infection occurring proximal to the time of disease, rather than to reactivation of dormant organisms acquired in early childhood. Nevertheless, long-term colonisation may be occurring. A large fraction of normal children and animals show evidence of infection. A Pneumocystis species that grows in rats has been shown to possess a complex genetic system for surface antigen variation, a strategy employed by other microbes that dwell in immunocompetent hosts. These findings, together with strong host specificity, suggest that Pneumocystis species may be obligate parasites. The source of infection is not clear. Pneumocystis DNA is detectable in the air, but is scarce except in environments occupied by individuals with Pneumocystis pneumonia. In a few cases, there is direct evidence of person to person transmission. In general, however, patients and their contacts have been found to have different strains of P. jiroveci.
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Affiliation(s)
- James R Stringer
- Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati, Cincinnati, OH 45220-0524, USA.
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