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Ma L, Lin I, Hunter ST, Blasi B, Danesi P, Weissenbacher-Lang C, Cisse OH, Rothenburger JL, Kovacs JA. Development of Highly Efficient Universal Pneumocystis Primers and Their Application in Investigating the Prevalence and Genetic Diversity of Pneumocystis in Wild Hares and Rabbits. J Fungi (Basel) 2024; 10:355. [PMID: 38786710 PMCID: PMC11121927 DOI: 10.3390/jof10050355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2024] [Revised: 05/10/2024] [Accepted: 05/13/2024] [Indexed: 05/25/2024] Open
Abstract
Despite its ubiquitous infectivity to mammals with strong host specificity, our current knowledge about Pneumocystis has originated from studies of merely 4% of extant mammalian species. Further studies of Pneumocystis epidemiology across a broader range of animal species require the use of assays with high sensitivity and specificity. To this end, we have developed multiple universal Pneumocystis primers targeting different genetic loci with high amplification efficiency. Application of these primers to PCR investigation of Pneumocystis in free-living hares (Lepus townsendii, n = 130) and rabbits (Oryctolagus cuniculus, n = 8) in Canada revealed a prevalence of 81% (105/130) and 25% (2/8), respectively. Genotyping analysis identified five and two variants of Pneumocystis from hares and rabbits, respectively, with significant sequence divergence between the variants from hares. Based on phylogenetic analysis using nearly full-length sequences of the mitochondrial genome, nuclear rRNA operon and dihydropteroate synthase gene for the two most common variants, Pneumocystis in hares and rabbits are more closely related to each other than either are to Pneumocystis in other mammals. Furthermore, Pneumocystis in both hares and rabbits are more closely related to Pneumocystis in primates and dogs than to Pneumocystis in rodents. The high prevalence of Pneumocystis in hares (P. sp. 'townsendii') suggests its widespread transmissibility in the natural environment, similar to P. oryctolagi in rabbits. The presence of multiple distinct Pneumocystis populations in hares contrasts with the lack of apparent intra-species heterogeneity in P. oryctolagi, implying a unique evolution history of P. sp. 'townsendii' in hares.
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Affiliation(s)
- Liang Ma
- Critical Care Medicine Department, National Institutes of Health Clinical Center, Bethesda, MD 20892, USA; (I.L.); (O.H.C.); (J.A.K.)
| | - Isabella Lin
- Critical Care Medicine Department, National Institutes of Health Clinical Center, Bethesda, MD 20892, USA; (I.L.); (O.H.C.); (J.A.K.)
| | - Summer T. Hunter
- Faculty of Veterinary Medicine, University of Calgary, Canadian Wildlife Health Cooperative (Alberta Region), Calgary, AB T2N 1N4, Canada; (S.T.H.); (J.L.R.)
| | - Barbara Blasi
- Department of Biological Sciences and Pathobiology, Institute of Pathology, University of Veterinary Medicine Vienna, 1210 Wien, Austria; (B.B.); (C.W.-L.)
| | - Patrizia Danesi
- Laboratory of Parasitology, Mycology and Medical Enthomology, Istituto Zooprofilattico delle Venezie, 35020 Legnaro, Italy;
| | - Christiane Weissenbacher-Lang
- Department of Biological Sciences and Pathobiology, Institute of Pathology, University of Veterinary Medicine Vienna, 1210 Wien, Austria; (B.B.); (C.W.-L.)
| | - Ousmane H. Cisse
- Critical Care Medicine Department, National Institutes of Health Clinical Center, Bethesda, MD 20892, USA; (I.L.); (O.H.C.); (J.A.K.)
| | - Jamie L. Rothenburger
- Faculty of Veterinary Medicine, University of Calgary, Canadian Wildlife Health Cooperative (Alberta Region), Calgary, AB T2N 1N4, Canada; (S.T.H.); (J.L.R.)
| | - Joseph A. Kovacs
- Critical Care Medicine Department, National Institutes of Health Clinical Center, Bethesda, MD 20892, USA; (I.L.); (O.H.C.); (J.A.K.)
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Iturrieta-González I, Chahin C, Cabrera J, Concha C, Olivares-Ferretti P, Briones J, Vega F, Bustos-Medina L, Fonseca-Salamanca F. Molecular Study of Pneumocystis jirovecii in Respiratory Samples of HIV Patients in Chile. J Fungi (Basel) 2024; 10:117. [PMID: 38392789 PMCID: PMC10889964 DOI: 10.3390/jof10020117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 10/01/2023] [Accepted: 10/06/2023] [Indexed: 02/24/2024] Open
Abstract
Pneumocystis is an opportunistic fungus that causes potentially fatal pneumonia (PCP) in immunocompromised patients. The objective of this study was to determine the prevalence of P. jirovecii in HIV patients through phenotypic and molecular study, to investigate the genetic polymorphisms of P. jirovecii at the mitochondrial gene mtLSU and at the nuclear dihydropteroate synthase gene (DHPS), and by analysis of molecular docking to study the effect of DHPS mutations on the enzymatic affinity for sulfamethoxazole. A PCP prevalence of 28.3% was detected, with mtLSU rRNA genotypes 3 (33.3%) and 2 (26.6%) being the most common. A prevalence of 6.7% (1/15) mutations in the DHPS gene was detected, specifically at codon 55 of the amino acid sequence of dihydropteroate synthase. Molecular docking analysis showed that the combination of mutations at 55 and 98 codons is required to significantly reduce the affinity of the enzyme for sulfamethoxazole. We observed a low rate of mutations in the DHPS gene, and molecular docking analysis showed that at least two mutations in the DHPS gene are required to significantly reduce the affinity of dihydropteroate synthase for sulfamethoxazole.
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Affiliation(s)
- Isabel Iturrieta-González
- Department of Preclinic Sciences, Medicine Faculty, Laboratory of Infectology and Clinical Immunology, Center of Excellence in Translational Medicine-Scientific and Technological Nucleus (CEMT-BIOREN), Universidad de La Frontera, Temuco 4810296, Chile
- Jeffrey Modell Foundation for Diagnosis and Research in Primary Immunodeficiencies, Center of Excellence in Translational Medicine, Medicine Faculty, Universidad de La Frontera, Temuco 4810296, Chile
| | - Carolina Chahin
- Infectology Unit, Hospital Dr. Hernán Henríquez Aravena, Temuco 4781151, Chile
| | - Johanna Cabrera
- Infectology Unit, Hospital Dr. Hernán Henríquez Aravena, Temuco 4781151, Chile
| | - Carla Concha
- Infectology Unit, Hospital Dr. Hernán Henríquez Aravena, Temuco 4781151, Chile
| | | | - Javier Briones
- Infectology Unit, Hospital Dr. Hernán Henríquez Aravena, Temuco 4781151, Chile
| | - Fernando Vega
- Critical Patient Unit, Hospital Dr. Hernán Henríquez Aravena, Temuco 4781151, Chile
| | - Luis Bustos-Medina
- Department of Public Health and CIGES, Faculty of Medicine, Universidad de La Frontera, Temuco 4781176, Chile
| | - Flery Fonseca-Salamanca
- Department of Preclinic Sciences, Medicine Faculty, Laboratory of Molecular Immunoparasitology, Center of Excellence in Translational Medicine-Scientific and Technological Nucleus (CEMT-BIOREN), Universidad de La Frontera, Temuco 4810296, Chile
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Tsvetkova N, Harizanov R, Rainova I, Ivanova A, Yancheva-Petrova N. Molecular Analysis of Dihydropteroate Synthase Gene Mutations in Pneumocystis jirovecii Isolates among Bulgarian Patients with Pneumocystis Pneumonia. Int J Mol Sci 2023; 24:16927. [PMID: 38069248 PMCID: PMC10707730 DOI: 10.3390/ijms242316927] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 11/20/2023] [Accepted: 11/21/2023] [Indexed: 12/18/2023] Open
Abstract
Pneumocystis jirovecii pneumonia (PCP) is a significant cause of morbidity and mortality in immunocompromised people. The widespread use of trimethoprim-sulfamethoxazole (TMP-SMZ) for the treatment and prophylaxis of opportunistic infections (including PCP) has led to an increased selection of TMP-SMZ-resistant microorganisms. Sulfa/sulfone resistance has been demonstrated to result from specific point mutations in the DHPS gene. This study aims to investigate the presence of DHPS gene mutations among P. jirovecii isolates from Bulgarian patients with PCP. A total of 326 patients were examined via real-time PCR targeting the P. jirovecii mitochondrial large subunit rRNA gene and further at the DHPS locus. P. jirovecii DNA was detected in 50 (15.34%) specimens. A 370 bp DHPS locus fragment was successfully amplified in 21 samples from 19 PCP-positive patients, which was then purified, sequenced, and used for phylogenetic analysis. Based on the sequencing analysis, all (n = 21) P. jirovecii isolates showed DHPS genotype 1 (the wild type, with the nucleotide sequence ACA CGG CCT at codons 55, 56, and 57, respectively). In conclusion, infections caused by P. jirovecii mutants potentially resistant to sulfonamides are still rare events in Bulgaria. DHPS genotype 1 at codons 55 and 57 is the predominant P. jirovecii strain in the country.
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Affiliation(s)
- Nina Tsvetkova
- Department of Parasitology and Tropical Medicine, National Centre of Infectious and Parasitic Diseases, 26 Yanko Sakazov Blvd., 1504 Sofia, Bulgaria
| | - Rumen Harizanov
- Department of Parasitology and Tropical Medicine, National Centre of Infectious and Parasitic Diseases, 26 Yanko Sakazov Blvd., 1504 Sofia, Bulgaria
| | - Iskra Rainova
- Department of Parasitology and Tropical Medicine, National Centre of Infectious and Parasitic Diseases, 26 Yanko Sakazov Blvd., 1504 Sofia, Bulgaria
| | - Aleksandra Ivanova
- Department of Parasitology and Tropical Medicine, National Centre of Infectious and Parasitic Diseases, 26 Yanko Sakazov Blvd., 1504 Sofia, Bulgaria
| | - Nina Yancheva-Petrova
- Department for AIDS, Specialized Hospital for Active Treatment of Infectious and Parasitic Diseases, Ivan Geshev Blvd. 17, 1431 Sofia, Bulgaria
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Xue T, Kong X, Ma L. Trends in the Epidemiology of Pneumocystis Pneumonia in Immunocompromised Patients without HIV Infection. J Fungi (Basel) 2023; 9:812. [PMID: 37623583 PMCID: PMC10455156 DOI: 10.3390/jof9080812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 06/19/2023] [Accepted: 07/19/2023] [Indexed: 08/26/2023] Open
Abstract
The increasing morbidity and mortality of life-threatening Pneumocystis pneumonia (PCP) in immunocompromised people poses a global concern, prompting the World Health Organization to list it as one of the 19 priority invasive fungal diseases, calling for increased research and public health action. In response to this initiative, we provide this review on the epidemiology of PCP in non-HIV patients with various immunodeficient conditions, including the use of immunosuppressive agents, cancer therapies, solid organ and stem cell transplantation, autoimmune and inflammatory diseases, inherited or primary immunodeficiencies, and COVID-19. Special attention is given to the molecular epidemiology of PCP outbreaks in solid organ transplant recipients; the risk of PCP associated with the increasing use of immunodepleting monoclonal antibodies and a wide range of genetic defects causing primary immunodeficiency; the trend of concurrent infection of PCP in COVID-19; the prevalence of colonization; and the rising evidence supporting de novo infection rather than reactivation of latent infection in the pathogenesis of PCP. Additionally, we provide a concise discussion of the varying effects of different immunodeficient conditions on distinct components of the immune system. The objective of this review is to increase awareness and knowledge of PCP in non-HIV patients, thereby improving the early identification and treatment of patients susceptible to PCP.
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Affiliation(s)
- Ting Xue
- NHC Key Laboratory of Pneumoconiosis, Key Laboratory of Prophylaxis and Treatment and Basic Research of Respiratory Diseases of Shanxi Province, Shanxi Province Key Laboratory of Respiratory, Department of Respiratory and Critical Care Medicine, First Hospital of Shanxi Medical University, Taiyuan 030001, China
| | - Xiaomei Kong
- NHC Key Laboratory of Pneumoconiosis, Key Laboratory of Prophylaxis and Treatment and Basic Research of Respiratory Diseases of Shanxi Province, Shanxi Province Key Laboratory of Respiratory, Department of Respiratory and Critical Care Medicine, First Hospital of Shanxi Medical University, Taiyuan 030001, China
| | - Liang Ma
- Critical Care Medicine Department, NIH Clinical Center, Bethesda, MD 20892, USA
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Apparent Absence of Selective Pressure on Pneumocystis jirovecii Organisms in Patients with Prior Methotrexate Exposure. Antimicrob Agents Chemother 2022; 66:e0099022. [PMID: 36317930 PMCID: PMC9765006 DOI: 10.1128/aac.00990-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Pneumocystis jirovecii infections occur in patients treated with methotrexate (MTX) because of immunosuppressive effects of this highly potent dihydrofolate reductase (DHFR) inhibitor. Conversely, MTX may act as an anti-P. jirovecii drug and consequently may exert a selective pressure on this fungus. In this context, we compared the sequences of the dhfr gene of P. jirovecii isolates obtained from two groups of patients with P. jirovecii infections. The first group, with systemic diseases or malignancies, had prior exposure to MTX (21 patients), whereas the second group (22 patients), the control group, did not. Three single nucleotide polymorphisms (SNPs) were observed at positions 278, 312, and 381. The first one was located in the intronic region and the two others were synonymous. Based on these SNPs, three P. jirovecii dhfr alleles, named A, B, and C, were specified. Allele A was the most frequent, as it was observed in 18 patients (85.7%) and in 16 patients (72.7%) of the first and second groups, respectively. No significant difference in P. jirovecii dhfr gene diversity in the two patient groups was observed. In conclusion, these original results suggest that MTX does not exert an overt selective pressure on P. jirovecii organisms.
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Xue T, Du WQ, Dai WJ, Li YS, Wang SF, Wang JL, Zhang XR. Genetic Polymorphisms of Pneumocystis jirovecii in HIV-Positive and HIV-Negative Patients in Northern China. Pol J Microbiol 2022; 71:27-34. [PMID: 35635165 PMCID: PMC9152919 DOI: 10.33073/pjm-2022-002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2021] [Accepted: 12/15/2021] [Indexed: 11/25/2022] Open
Abstract
Pneumocystis jirovecii is an opportunistic fungus that can cause severe and potentially fatal Pneumocystis pneumonia (PCP) in immunodeficient patients. In this study, we investigated the genetic polymorphisms of P. jirovecii at eight different loci, including six nuclear genes (ITS, 26S rRNA, sod, dhps, dhfr and β-Tub) and two mitochondrial genes (mtLSU-rRNA and cyb) in three PCP cases, including two patients with HIV infection and one without HIV infection in Shanxi Province, P.R. China. The gene targets were amplified by PCR followed by sequencing of plasmid clones. The HIV-negative patient showed a coinfection with two genotypes of P. jirovecii at six of the eight loci sequenced. Of the two HIV-positive patients, one showed a coinfection with two genotypes of P. jirovecii at the same two of the six loci as in the HIV-negative patient, while the other showed a single infection at all eight loci sequenced. None of the three drug target genes (dhfr, dhps and cyb) showed mutations known to be potentially associated with drug resistance. This is the first report of genetic polymorphisms of P. jirovecii in PCP patients in Shanxi Province, China. Our findings expand our understanding of the genetic diversity of P. jirovecii in China. ![]()
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Affiliation(s)
- Ting Xue
- NHC Key Laboratory of Pneumoconiosis, Key Laboratory of Prophylaxis and Treatment and Basic Research of Respiratory Diseases of Shanxi Province , Department of Respiratory and Critical Care Medicine , First Affiliated Hospital of Shanxi Medical University , Taiyuan , P.R. China
| | - Wei-Qin Du
- Department of clinical inspection , Eleventh Affiliated Hospital of Shanxi Medical University , Lvliang , P.R. China
| | - Wen-Juan Dai
- NHC Key Laboratory of Pneumoconiosis, Key Laboratory of Prophylaxis and Treatment and Basic Research of Respiratory Diseases of Shanxi Province , Department of Respiratory and Critical Care Medicine , First Affiliated Hospital of Shanxi Medical University , Taiyuan , P.R. China
| | - Yi-Shan Li
- NHC Key Laboratory of Pneumoconiosis, Key Laboratory of Prophylaxis and Treatment and Basic Research of Respiratory Diseases of Shanxi Province , Department of Respiratory and Critical Care Medicine , First Affiliated Hospital of Shanxi Medical University , Taiyuan , P.R. China
| | - Shu-Feng Wang
- Department of Clinical Inspection , First Affiliated Hospital of Shanxi Medical University , Taiyuan , P.R. China
| | - Jun-Ling Wang
- Department of Translation Medicine , Jinzhou Medical University , Jinzhou , P.R. China
| | - Xin-Ri Zhang
- NHC Key Laboratory of Pneumoconiosis, Key Laboratory of Prophylaxis and Treatment and Basic Research of Respiratory Diseases of Shanxi Province , Department of Respiratory and Critical Care Medicine , First Affiliated Hospital of Shanxi Medical University , Taiyuan , P.R. China
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de la Horra C, Friaza V, Morilla R, Delgado J, Medrano FJ, Miller RF, de Armas Y, Calderón EJ. Update on Dihydropteroate Synthase (DHPS) Mutations in Pneumocystis jirovecii. J Fungi (Basel) 2021; 7:jof7100856. [PMID: 34682277 PMCID: PMC8540849 DOI: 10.3390/jof7100856] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2021] [Revised: 09/28/2021] [Accepted: 10/10/2021] [Indexed: 12/21/2022] Open
Abstract
A Pneumocystis jirovecii is one of the most important microorganisms that cause pneumonia in immunosupressed individuals. The guideline for treatment and prophylaxis of Pneumocystis pneumonia (PcP) is the use of a combination of sulfa drug-containing trimethroprim and sulfamethoxazole. In the absence of a reliable method to culture Pneumocystis, molecular techniques have been developed to detect mutations in the dihydropteroate synthase gene, the target of sulfa drugs, where mutations are related to sulfa resistance in other microorganisms. The presence of dihydropteroate synthase (DHPS) mutations has been described at codon 55 and 57 and found almost around the world. In the current work, we analyzed the most common methods to identify these mutations, their geographical distribution around the world, and their clinical implications. In addition, we describe new emerging DHPS mutations. Other aspects, such as the possibility of transmitting Pneumocystis mutated organisms between susceptible patients is also described, as well as a brief summary of approaches to study these mutations in a heterologous expression system.
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Affiliation(s)
- Carmen de la Horra
- Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/Consejo Superior de Investigaciones Científicas/Universidad de Sevilla, 41013 Seville, Spain; (C.d.l.H.); (R.M.); (J.D.); (F.J.M.)
| | - Vicente Friaza
- Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/Consejo Superior de Investigaciones Científicas/Universidad de Sevilla, 41013 Seville, Spain; (C.d.l.H.); (R.M.); (J.D.); (F.J.M.)
- Centro de Investigación Biomédica en Red de Epidemiología y Salud Pública (CIBERESP), 28029 Madrid, Spain
- Correspondence: (V.F.); (E.J.C.); Tel.: +34-955923096 (E.J.C.)
| | - Rubén Morilla
- Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/Consejo Superior de Investigaciones Científicas/Universidad de Sevilla, 41013 Seville, Spain; (C.d.l.H.); (R.M.); (J.D.); (F.J.M.)
- Departamento de Enfermería, Universidad de Sevilla, 41009 Seville, Spain
| | - Juan Delgado
- Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/Consejo Superior de Investigaciones Científicas/Universidad de Sevilla, 41013 Seville, Spain; (C.d.l.H.); (R.M.); (J.D.); (F.J.M.)
| | - Francisco J. Medrano
- Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/Consejo Superior de Investigaciones Científicas/Universidad de Sevilla, 41013 Seville, Spain; (C.d.l.H.); (R.M.); (J.D.); (F.J.M.)
- Centro de Investigación Biomédica en Red de Epidemiología y Salud Pública (CIBERESP), 28029 Madrid, Spain
- Departamento de Medicina, Universidad de Sevilla, 41009 Seville, Spain
| | - Robert F. Miller
- Institute for Global Health, University College London, London WC1E 6JB, UK;
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London WC1E 7HT, UK
| | - Yaxsier de Armas
- Department of Clinical Microbiology Diagnostic, Hospital Center of Institute of Tropical Medicine “Pedro Kourí”, Havana 11400, Cuba;
- Pathology Department, Hospital Center of Institute of Tropical Medicine “Pedro Kourí,” Havana 11400, Cuba
| | - Enrique J. Calderón
- Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/Consejo Superior de Investigaciones Científicas/Universidad de Sevilla, 41013 Seville, Spain; (C.d.l.H.); (R.M.); (J.D.); (F.J.M.)
- Centro de Investigación Biomédica en Red de Epidemiología y Salud Pública (CIBERESP), 28029 Madrid, Spain
- Departamento de Medicina, Universidad de Sevilla, 41009 Seville, Spain
- Correspondence: (V.F.); (E.J.C.); Tel.: +34-955923096 (E.J.C.)
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Jitmuang A, Nititammaluk A, Boonsong T, Sarasombath PT, Sompradeekul S, Chayakulkeeree M. A novel droplet digital polymerase chain reaction for diagnosis of Pneumocystis pneumonia (PCP)-a clinical performance study and survey of sulfamethoxazole-trimethoprim resistant mutations. J Infect 2021; 83:701-708. [PMID: 34562541 DOI: 10.1016/j.jinf.2021.09.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2021] [Revised: 09/14/2021] [Accepted: 09/19/2021] [Indexed: 10/20/2022]
Abstract
Objectives To determine the performance of droplet digital polymerase chain reaction (ddPCR) assays in diagnosing Pneumocystis pneumonia (PCP), and to survey the sulfamethoxazole-trimethoprim (SMX-TMP) resistant mutations in our PCP cohort. Methods A prospective study was conducted from January 2017 to June 2018. Adult immunocompromised subjects with pneumonia were enrolled. Bronchoalveolar lavage fluid samples were obtained for standard microscopic testing and ddPCR to quantify the Pneumocystis MSG gene. DHPS and DHFR gene sequencings were performed to detect SMX-TMP resistance. Results Of 54 subjects, 12 had definite PCP, 7 had probable PCP, and 35 were non-PCP. In the PCP cohort, 10 (53%) had HIV infections. Using a cutoff value of ≥ 1.94 copies/µL, the ddPCR exhibited an overall sensitivity of 91.7% (61.5-99.8%) and specificity of 88.1% (74.4-96%). It showed a better performance when different cutoff values were used in subjects with HIV (≥ 1.80 copies/µL) and non-HIV (≥ 4.5 copies/µL). ROC curves demonstrated an AUC of 0.80 (95% CI, 0.56-1.0) for the HIV group, and 0.99 (95% CI, 0.95-1.0) for the non-HIV group. Of 16 PCP samples tested for DHPS- and DHFR-mutations, only DHPS mutations were detected (2). Most of the subjects, including those with DHPS mutations, demonstrated favorable outcomes. Conclusions The ddPCR exhibited a satisfactory diagnostic performance for PCP. Based on very limited data, the treatment outcomes of PCP did not seem to be affected by the DHPS mutations.
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Affiliation(s)
- Anupop Jitmuang
- Department of Medicine, Faculty of Medicine Siriraj Hospital, Mahidol University, 2 Wanglang Road, Bangkoknoi, Bangkok 10700, Thailand
| | - Anapat Nititammaluk
- Department of Medicine, Faculty of Medicine Siriraj Hospital, Mahidol University, 2 Wanglang Road, Bangkoknoi, Bangkok 10700, Thailand
| | - Thitaya Boonsong
- Department of Internal Medicine, Hatyai Hospital, Songkhla, Thailand
| | | | - Suree Sompradeekul
- Department of Medicine, Faculty of Medicine Siriraj Hospital, Mahidol University, 2 Wanglang Road, Bangkoknoi, Bangkok 10700, Thailand
| | - Methee Chayakulkeeree
- Department of Medicine, Faculty of Medicine Siriraj Hospital, Mahidol University, 2 Wanglang Road, Bangkoknoi, Bangkok 10700, Thailand.
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Arastehfar A, Gabaldón T, Garcia-Rubio R, Jenks JD, Hoenigl M, Salzer HJF, Ilkit M, Lass-Flörl C, Perlin DS. Drug-Resistant Fungi: An Emerging Challenge Threatening Our Limited Antifungal Armamentarium. Antibiotics (Basel) 2020; 9:antibiotics9120877. [PMID: 33302565 PMCID: PMC7764418 DOI: 10.3390/antibiotics9120877] [Citation(s) in RCA: 91] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 11/02/2020] [Accepted: 12/03/2020] [Indexed: 12/14/2022] Open
Abstract
The high clinical mortality and economic burden posed by invasive fungal infections (IFIs), along with significant agricultural crop loss caused by various fungal species, has resulted in the widespread use of antifungal agents. Selective drug pressure, fungal attributes, and host- and drug-related factors have counteracted the efficacy of the limited systemic antifungal drugs and changed the epidemiological landscape of IFIs. Species belonging to Candida, Aspergillus, Cryptococcus, and Pneumocystis are among the fungal pathogens showing notable rates of antifungal resistance. Drug-resistant fungi from the environment are increasingly identified in clinical settings. Furthermore, we have a limited understanding of drug class-specific resistance mechanisms in emerging Candida species. The establishment of antifungal stewardship programs in both clinical and agricultural fields and the inclusion of species identification, antifungal susceptibility testing, and therapeutic drug monitoring practices in the clinic can minimize the emergence of drug-resistant fungi. New antifungal drugs featuring promising therapeutic profiles have great promise to treat drug-resistant fungi in the clinical setting. Mitigating antifungal tolerance, a prelude to the emergence of resistance, also requires the development of effective and fungal-specific adjuvants to be used in combination with systemic antifungals.
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Affiliation(s)
- Amir Arastehfar
- Center for Discovery and Innovation, Hackensack Meridian Health, Nutley, NJ 07110, USA; (A.A.); (R.G.-R.)
| | - Toni Gabaldón
- Life Sciences Programme, Supercomputing Center (BSC-CNS), Jordi Girona, 08034 Barcelona, Spain;
- Mechanisms of Disease Programme, Institute for Research in Biomedicine (IRB), 08024 Barcelona, Spain
- Catalan Institution for Research and Advanced Studies. Pg. Lluís Companys 23, 08010 Barcelona, Spain
| | - Rocio Garcia-Rubio
- Center for Discovery and Innovation, Hackensack Meridian Health, Nutley, NJ 07110, USA; (A.A.); (R.G.-R.)
| | - Jeffrey D. Jenks
- Department of Medicine, University of California San Diego, San Diego, CA 92103, USA;
- Clinical and Translational Fungal-Working Group, University of California San Diego, La Jolla, CA 92093, USA;
- Division of Infectious Diseases and Global Public Health, Department of Medicine, University of California San Diego, La Jolla, CA 92093, USA
| | - Martin Hoenigl
- Clinical and Translational Fungal-Working Group, University of California San Diego, La Jolla, CA 92093, USA;
- Division of Infectious Diseases and Global Public Health, Department of Medicine, University of California San Diego, La Jolla, CA 92093, USA
- Section of Infectious Diseases and Tropical Medicine, Department of Internal Medicine, Medical University of Graz, 8036 Graz, Austria
| | | | - Macit Ilkit
- Division of Mycology, University of Çukurova, 01330 Adana, Turkey
- Correspondence: (M.I.); (D.S.P.); Tel.: +90-532-286-0099 (M.I.); +1-201-880-3100 (D.S.P.)
| | - Cornelia Lass-Flörl
- Institute of Hygiene and Medical Microbiology, Medical University of Innsbruck, 6020 Innsbruck, Austria;
| | - David S. Perlin
- Center for Discovery and Innovation, Hackensack Meridian Health, Nutley, NJ 07110, USA; (A.A.); (R.G.-R.)
- Correspondence: (M.I.); (D.S.P.); Tel.: +90-532-286-0099 (M.I.); +1-201-880-3100 (D.S.P.)
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Consensus Multilocus Sequence Typing Scheme for Pneumocystis jirovecii. J Fungi (Basel) 2020; 6:jof6040259. [PMID: 33143112 PMCID: PMC7711988 DOI: 10.3390/jof6040259] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 10/10/2020] [Accepted: 10/18/2020] [Indexed: 12/26/2022] Open
Abstract
Pneumocystis jirovecii is an opportunistic human pathogenic fungus causing severe pneumonia mainly in immunocompromised hosts. Multilocus sequence typing (MLST) remains the gold standard for genotyping of this unculturable fungus. However, the lack of a consensus scheme impedes a global comparison, large scale population studies and the development of a global MLST database. To overcome this problem this study compared all genetic regions (19 loci) currently used in 31 different published Pneumocystis MLST schemes. The most diverse/commonly used eight loci, β-TUB, CYB, DHPS, ITS1, ITS1/2, mt26S and SOD, were further assess for their ability to be successfully amplified and sequenced, and for their discriminatory power. The most successful loci were tested to identify genetically related and unrelated cases. A new consensus MLST scheme consisting of four genetically independent loci: β-TUB, CYB, mt26S and SOD, is herein proposed for standardised P. jirovecii typing, successfully amplifying low and high fungal burden specimens, showing adequate discriminatory power, and correctly identifying suspected related and unrelated isolates. The new consensus MLST scheme, if accepted, will for the first time provide a powerful tool to investigate outbreak settings and undertake global epidemiological studies shedding light on the spread of this important human fungal pathogen.
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Epps QJ, Epps KL, Young DC, Zobell JT. State of the art in cystic fibrosis pharmacology-Optimization of antimicrobials in the treatment of cystic fibrosis pulmonary exacerbations: I. Anti-methicillin-resistant Staphylococcus aureus (MRSA) antibiotics. Pediatr Pulmonol 2020; 55:33-57. [PMID: 31609097 DOI: 10.1002/ppul.24537] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2019] [Accepted: 09/19/2019] [Indexed: 12/22/2022]
Abstract
Acute pulmonary exacerbations (APE) are a complication of cystic fibrosis (CF) and are associated with morbidity and mortality. Methicillin-resistant Staphylococcus aureus (MRSA) is one of many organisms that has been detected in the airways of patients with CF. This review provides an evidence-based summary of pharmacokinetic/pharmacodynamic (PK/PD), tolerability, and efficacy studies utilizing anti-MRSA antibiotics (ie, ceftaroline, clindamycin, fluoroquinolone derivatives (ciprofloxacin, levofloxacin), glycopeptide derivatives (telavancin, vancomycin), linezolid, rifampin, sulfamethoxazole/trimethoprim (SMZ/TMP), and tetracycline derivatives (doxycycline, minocycline, tigecycline) in the treatment of APE and identifies areas where further study is warranted. A recent utilization study of antimicrobials for anti-MRSA has shown some CF Foundation accredited care centers and affiliate programs are using doses higher than the FDA-approved doses. Further studies are needed to determine the PK/PD properties in CF patients with clindamycin, minocycline, rifampin, SMZ/TMP, telavancin, and tigecycline; as well as, efficacy and tolerability studies with ciprofloxacin, clindamycin, doxycycline, levofloxacin, minocycline, rifampin, SMZ/TMP, in CF patients with MRSA.
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Affiliation(s)
- Quovadis J Epps
- Florida Agricultural and Mechanical University College of Pharmacy and Pharmaceutical Sciences, Jacksonville, Florida
| | - Kevin L Epps
- Department of Pharmacy, The Mayo Clinic, Jacksonville, Florida
| | - David C Young
- L.S. Skaggs Pharmacy Institute, University of Utah College of Pharmacy, Salt Lake City, Utah
- University of Utah Adult Cystic Fibrosis Center, Salt Lake City, Utah
| | - Jeffery T Zobell
- Department of Pharmacy, Intermountain Primary Children's Hospital, Salt Lake City, Utah
- Primary Children's Cystic Fibrosis Center, Salt Lake City, Utah
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Wang M, Xu X, Guo Y, Tao R, Hu C, Dong X, Huang Y, Zhu B. Polymorphisms involving the Pneumocystis jirovecii-related genes in AIDS patients in eastern China. INFECTION GENETICS AND EVOLUTION 2019; 75:103955. [PMID: 31284044 DOI: 10.1016/j.meegid.2019.103955] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 06/25/2019] [Accepted: 07/05/2019] [Indexed: 11/18/2022]
Abstract
OBJECTIVE To investigate the genetic polymorphisms of mitochondrial large ribosomal subunit (mtLSU)-rRNA, dihydrofolate reductase (DHFR), dihydropteroate synthase (DHPS), cytochrome b (CYB), and superoxide dismutase (SOD) genes and its correlation with clinical outcomes of Pneumocystis jirovecii pneumonia in acquired immune deficiency(AIDS) patients. METHODS Eighty AIDS patients with P. jirovecii pneumonia that were admitted to our hospital from 2016 to 2018 were included in this study. Their demographic information and clinical data were collected, as well as corresponding saliva specimens for PCR and sequencing of mtLSU-rRNA, DHFR, DHPS, CYB, and SOD genes to analyze genetic polymorphisms, different polymorphic combinations, and clinical outcomes. RESULTS Of the 80 saliva specimens, mtLSU-rRNA was successfully amplified and sequenced in 30 cases; CYB was successfully amplified and sequenced in 26 cases; and SOD, DHFR, and DHPS were successfully amplified and sequenced in 18 cases. These results indicate that The mtLSU-rRNA, CYB, and SOD genes were highly polymorphic. mt85T and CYB1 were the variants dominantly detected at the mtLSU-rRNA and CYB loci, respectively. The SOD1 and SOD2 variants (each in 50% of the cases) were detected at the SOD locus. Among the 18 cases that were successfully amplified and sequenced for DHFR and DHPS, three DHFR nonsense mutations and no DHPS mutation were observed. The mt85C, CYB1, SOD1, and DHFR312T genes harbored common polymorphisms (n = 4; 22.22%) and the mt85T, CYB1, SOD1, DHFR312T genes were associated with poor clinical outcomes. CONCLUSION The types of genetic polymorphisms and polymorphic combinations of mtLSU-rRNA, DHFR, DHPS, CYB, and SOD in P. jirovecii were related to the clinical outcomes of patients with P. jirovecii pneumonia in Zhejiang Province, China.
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Affiliation(s)
- Mengyan Wang
- The Department of Infectious Diseases, State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, the First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China.
| | - Xiaoke Xu
- The Department of Infectious Diseases, State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, the First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China.
| | - Yongzheng Guo
- The Department of Infectious Diseases, State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, the First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China.
| | - Ran Tao
- The Department of Infectious Diseases, State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, the First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - Caiqin Hu
- The Department of Infectious Diseases, State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, the First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China.
| | - Xiaotian Dong
- The Department of Infectious Diseases, State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, the First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China.
| | - Ying Huang
- The Department of Infectious Diseases, State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, the First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China.
| | - Biao Zhu
- The Department of Infectious Diseases, State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, the First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China.
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13
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Singh Y, Mirdha BR, Guleria R, Kabra SK, Mohan A, Chaudhry R, Kumar L, Dwivedi SN, Agarwal SK. Genetic polymorphisms associated with treatment failure and mortality in pediatric Pneumocystosis. Sci Rep 2019; 9:1192. [PMID: 30718779 PMCID: PMC6361943 DOI: 10.1038/s41598-018-38052-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Accepted: 12/19/2018] [Indexed: 12/15/2022] Open
Abstract
Data on the genetic diversity of Pneumocystis jirovecii causing Pneumocystis pneumonia (PCP) among children are still limited, and there are no available data from the Indian subcontinent, particularly associations between genotypes and clinical characteristics. A total of 37 children (62 days-12 years [median 5.5 years]) were included in this study. Pneumocystis was diagnosed by microscopy using Grocott-Gomori methenamine silver stain in 12 cases and by nested PCR using mtLSUrRNA in 25 cases. Genotyping was performed using three different genes, mitochondrial large subunit ribosomal RNA (mtLSUrRNA), dihydropteroate synthase (DHPS) and dihydrofolate reductase (DHFR). mtLSUrRNA genotype 3 and novel mutations at the gene target DHFR (401 T > C) and DHPS 96/98 were frequently observed and clinically associated with severe PCP and treatment failure. Phylogenetic analyses revealed 13 unique sequence types (STs). Two STs (i) 3-DHFR 401 T > C-DHPS 96/98 – PJ1 and (ii) 3-DHFR 401 T > C-DHPS 96- PJ3 were significantly associated with treatment failure and high mortality among PCP-positive patients. In conclusion, the present study strongly suggests the emergence of virulent P. jirovecii strains or genetic polymorphisms, leading to treatment failure and high mortality. Our study is the first of its kind from the Indian subcontinent and has highlighted the genetic diversity of Pneumocystis jirovecii among children and their clinical outcomes. These findings emphasize the need to focus more on genotypes to better understand the epidemiology of Pneumocystis pneumonia.
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Affiliation(s)
- Yogita Singh
- All India Institute of Medical Sciences, Department of Microbiology, New Delhi, 110029, India
| | - Bijay Ranjan Mirdha
- All India Institute of Medical Sciences, Department of Microbiology, New Delhi, 110029, India.
| | - Randeep Guleria
- All India Institute of Medical Sciences, Department of Pulmonary Medicine and Sleep Disorders, New Delhi, 110029, India
| | - Sushil K Kabra
- All India Institute of Medical Sciences, Department of Pediatrics, New Delhi, 110029, India
| | - Anant Mohan
- All India Institute of Medical Sciences, Department of Pulmonary Medicine and Sleep Disorders, New Delhi, 110029, India
| | - Rama Chaudhry
- All India Institute of Medical Sciences, Department of Microbiology, New Delhi, 110029, India
| | - Lalit Kumar
- All India Institute of Medical Sciences, Department of Medical Oncology, New Delhi, 110029, India
| | - Sada Nand Dwivedi
- All India Institute of Medical Sciences, Department of Biostatistics, New Delhi, 110029, India
| | - Sanjay K Agarwal
- All India Institute of Medical Sciences, Department of Nephrology, New Delhi, 110029, India
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Koshy R, Chen T. Combination therapy with trimethoprim-sulfamethoxazole and caspofungin in a case of severe pneumocystis pneumonia. IDCases 2019; 15:e00496. [PMID: 30828545 PMCID: PMC6384316 DOI: 10.1016/j.idcr.2019.e00496] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Revised: 01/21/2019] [Accepted: 01/21/2019] [Indexed: 01/15/2023] Open
Abstract
Bactrim failure adverse effects. Alternative echinocandin target. Combination echinocandin therapy.
Trimethoprim-sulfamethoxazole (TMP-SMX, co-trimoxazole, or bactrim) has been the standard first-line treatment against Pneumocystis jirovecii pneumonia (PCP) for decades. However, adverse effects and cases of treatment failure have led to a search for alternative agents. We present a case of a 50 year old immune compromised female whose course of PCP did not improve until Caspofungin was added to TMP-SMX.
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Affiliation(s)
- Robin Koshy
- Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, Department of Infectious Disease, United States
| | - Thomas Chen
- Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, Department of Infectious Disease, United States
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15
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Site-Directed Mutagenesis of the 1,3-β-Glucan Synthase Catalytic Subunit of Pneumocystis jirovecii and Susceptibility Assays Suggest Its Sensitivity to Caspofungin. Antimicrob Agents Chemother 2018; 62:AAC.01159-18. [PMID: 30249686 DOI: 10.1128/aac.01159-18] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Accepted: 09/11/2018] [Indexed: 12/26/2022] Open
Abstract
The echinocandin caspofungin inhibits the catalytic subunit Gsc1 of the enzymatic complex synthesizing 1,3-β-glucan, an essential compound of the fungal wall. Studies with rodents showed that caspofungin is effective against Pneumocystis asci. However, its efficacy against asci of Pneumocystis jirovecii, the species infecting exclusively humans, remains controversial. The aim of this study was to assess the sensitivity to caspofungin of the P. jirovecii Gsc1 subunit, as well as of those of Pneumocystis carinii and Pneumocystis murina infecting, respectively, rats and mice. In the absence of an established in vitro culture method for Pneumocystis species, we used functional complementation of the Saccharomyces cerevisiae gsc1 deletant. In the fungal pathogen Candida albicans, mutations leading to amino acid substitutions in Gsc1 confer resistance to caspofungin. We introduced the corresponding mutations into the Pneumocystis gsc1 genes using site-directed mutagenesis. In spot dilution tests, the sensitivity to caspofungin of the complemented strains decreased with the number of mutations introduced, suggesting that the wild-type enzymes are sensitive. The MICs of caspofungin determined by Etest and YeastOne for strains complemented with Pneumocystis enzymes (respectively, 0.125 and 0.12 μg/ml) were identical to those upon complementation with the enzyme of C. albicans, for which caspofungin presents low MICs. However, they were lower than the MICs upon complementation with the enzyme of the resistant species Candida parapsilosis (0.19 and 0.25 μg/ml). Sensitivity levels of Gsc1 enzymes of the three Pneumocystis species were similar. Our results suggest that P. jirovecii is sensitive to caspofungin during infections, as are P. carinii and P. murina.
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Ma L, Cissé OH, Kovacs JA. A Molecular Window into the Biology and Epidemiology of Pneumocystis spp. Clin Microbiol Rev 2018; 31:e00009-18. [PMID: 29899010 PMCID: PMC6056843 DOI: 10.1128/cmr.00009-18] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Pneumocystis, a unique atypical fungus with an elusive lifestyle, has had an important medical history. It came to prominence as an opportunistic pathogen that not only can cause life-threatening pneumonia in patients with HIV infection and other immunodeficiencies but also can colonize the lungs of healthy individuals from a very early age. The genus Pneumocystis includes a group of closely related but heterogeneous organisms that have a worldwide distribution, have been detected in multiple mammalian species, are highly host species specific, inhabit the lungs almost exclusively, and have never convincingly been cultured in vitro, making Pneumocystis a fascinating but difficult-to-study organism. Improved molecular biologic methodologies have opened a new window into the biology and epidemiology of Pneumocystis. Advances include an improved taxonomic classification, identification of an extremely reduced genome and concomitant inability to metabolize and grow independent of the host lungs, insights into its transmission mode, recognition of its widespread colonization in both immunocompetent and immunodeficient hosts, and utilization of strain variation to study drug resistance, epidemiology, and outbreaks of infection among transplant patients. This review summarizes these advances and also identifies some major questions and challenges that need to be addressed to better understand Pneumocystis biology and its relevance to clinical care.
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Affiliation(s)
- Liang Ma
- Critical Care Medicine Department, NIH Clinical Center, Bethesda, Maryland, USA
| | - Ousmane H Cissé
- Critical Care Medicine Department, NIH Clinical Center, Bethesda, Maryland, USA
| | - Joseph A Kovacs
- Critical Care Medicine Department, NIH Clinical Center, Bethesda, Maryland, USA
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17
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Cissé OH, Ma L, Wei Huang D, Khil PP, Dekker JP, Kutty G, Bishop L, Liu Y, Deng X, Hauser PM, Pagni M, Hirsch V, Lempicki RA, Stajich JE, Cuomo CA, Kovacs JA. Comparative Population Genomics Analysis of the Mammalian Fungal Pathogen Pneumocystis. mBio 2018; 9:e00381-18. [PMID: 29739910 PMCID: PMC5941068 DOI: 10.1128/mbio.00381-18] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Accepted: 04/19/2018] [Indexed: 01/14/2023] Open
Abstract
Pneumocystis species are opportunistic mammalian pathogens that cause severe pneumonia in immunocompromised individuals. These fungi are highly host specific and uncultivable in vitro Human Pneumocystis infections present major challenges because of a limited therapeutic arsenal and the rise of drug resistance. To investigate the diversity and demographic history of natural populations of Pneumocystis infecting humans, rats, and mice, we performed whole-genome and large-scale multilocus sequencing of infected tissues collected in various geographic locations. Here, we detected reduced levels of recombination and variations in historical demography, which shape the global population structures. We report estimates of evolutionary rates, levels of genetic diversity, and population sizes. Molecular clock estimates indicate that Pneumocystis species diverged before their hosts, while the asynchronous timing of population declines suggests host shifts. Our results have uncovered complex patterns of genetic variation influenced by multiple factors that shaped the adaptation of Pneumocystis populations during their spread across mammals.IMPORTANCE Understanding how natural pathogen populations evolve and identifying the determinants of genetic variation are central issues in evolutionary biology. Pneumocystis, a fungal pathogen which infects mammals exclusively, provides opportunities to explore these issues. In humans, Pneumocystis can cause a life-threatening pneumonia in immunosuppressed individuals. In analysis of different Pneumocystis species infecting humans, rats, and mice, we found that there are high infection rates and that natural populations maintain a high level of genetic variation despite low levels of recombination. We found no evidence of population structuring by geography. Our comparisons of the times of divergence of these species to their respective hosts suggest that Pneumocystis may have undergone recent host shifts. The results demonstrate that Pneumocystis strains are widely disseminated geographically and provide a new understanding of the evolution of these pathogens.
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Affiliation(s)
- Ousmane H Cissé
- Critical Care Medicine Department, NIH Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
| | - Liang Ma
- Critical Care Medicine Department, NIH Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
| | - Da Wei Huang
- Lymphoid Malignancies Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Pavel P Khil
- Department of Laboratory Medicine, NIH Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
| | - John P Dekker
- Department of Laboratory Medicine, NIH Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
| | - Geetha Kutty
- Critical Care Medicine Department, NIH Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
| | - Lisa Bishop
- Critical Care Medicine Department, NIH Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
| | - Yueqin Liu
- Critical Care Medicine Department, NIH Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
| | - Xilong Deng
- Critical Care Medicine Department, NIH Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
| | - Philippe M Hauser
- Institute of Microbiology, Lausanne University Hospital, Lausanne, Switzerland
| | - Marco Pagni
- Vital-IT Group, SIB Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Vanessa Hirsch
- Laboratory of Molecular Microbiology, National Institute of Allergy and Infectious Disease, National Institutes of Health, Bethesda, Maryland, USA
| | - Richard A Lempicki
- Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, Maryland, USA
| | - Jason E Stajich
- Department of Plant Pathology and Microbiology and Institute for Integrative Genome Biology, University of California, Riverside, Riverside, California, USA
| | - Christina A Cuomo
- Infectious Disease and Microbiome Program, Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Joseph A Kovacs
- Critical Care Medicine Department, NIH Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
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18
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In vitro and in vivo activity of iclaprim, a diaminopyrimidine compound and potential therapeutic alternative against Pneumocystis pneumonia. Eur J Clin Microbiol Infect Dis 2018; 37:409-415. [DOI: 10.1007/s10096-018-3184-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Accepted: 01/02/2018] [Indexed: 01/30/2023]
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Low prevalence of DHFR and DHPS mutations in Pneumocystis jirovecii strains obtained from a German cohort. Infection 2017; 45:341-347. [PMID: 28303545 DOI: 10.1007/s15010-017-1005-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Accepted: 03/07/2017] [Indexed: 12/30/2022]
Abstract
BACKGROUND Pneumocystis pneumonia (PCP) is an opportunistic and potentially life-threatening infection of immunocompromised individuals. A combination of trimethoprim-sulfamethoxazole is widely used for prophylaxis and treatment of PCP. Polymorphisms in the drug targets, the dihydropteroate synthase (DHPS) or the dihydrofolate reductase (DHFR) are presumably a reason for treatment failure. METHODS We retrospectively examined the prevalence of DHPS and DHFR mutations in Pneumocystis jirovecii isolates obtained from HIV-infected and non-HIV-infected PCP patients. DHFR and DHPS genes were amplified using semi-nested PCR followed by sequencing. Obtained data were correlated with clinical findings. RESULTS Sequencing of the DHPS gene was achieved in 81 out of 128 isolates (63%), the DHFR-gene was successfully sequenced in 96 isolates (75%). The vast majority of DHFR and DHPS sequences were either wild-type or showed synonymous single nucleotide polymorphisms. Only one sample contained a double mutation at DHPS codon 55 and codon 57 which was associated with treatment failure in some studies. No linkage of treatment failure to a DHFR or DHPS genotype was observed. In our cohort, 35 of 95 Patients (37%) were HIV-positive and 60 (63%) were HIV-negative. The overall mortality rate was 24% with a much higher rate among non-HIV patients. CONCLUSION DHPS and DHFR mutations exist but are infrequent in our cohort. The contribution of gene polymorphisms to treatment failure needs further research. In immunocompromised HIV-negative patients PCP is associated with high mortality rates. Prophylactic treatment is warranted in this patient subset.
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Abstract
This Special Issue is designed to highlight the latest research and development on new antifungal compounds with mechanisms of action different from the ones of polyenes, azoles, and echinocandins. The papers presented here highlight new pathways and targets that could be exploited for the future development of new antifungal agents to be used alone or in combination with existing antifungals. A computational model for better predicting antifungal drug resistance is also presented.
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Luraschi A, Cissé OH, Pagni M, Hauser PM. Identification and Functional Ascertainment of the Pneumocystis jirovecii Potential Drug Targets Gsc1 and Kre6 Involved in Glucan Synthesis. J Eukaryot Microbiol 2016; 64:481-490. [PMID: 27859907 DOI: 10.1111/jeu.12385] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Revised: 11/11/2016] [Accepted: 11/11/2016] [Indexed: 12/23/2022]
Abstract
The most efficient drug against the human pathogenic fungus Pneumocystis jirovecii is cotrimoxazole targeting the folate biosynthesis. However, resistance toward it is emerging and adverse effects occur in some patients. Studies in rodent models suggested that echinocandins could be useful to treat Pneumocystis pneumonia. Echinocandins inhibit the catalytic subunit Gsc1 of the enzymatic complex ensuring the synthesis of 1,3-β glucan, an essential constituent of cell walls of most fungi. Besides, inhibitors of the enzyme Kre6 involved in the synthesis of 1,6-β glucan, another essential component of fungal walls, were recently described. We identified and functionally characterized these two potential drug targets in the human pathogen P. jirovecii by rescue of the null allele of the orthologous gene in Saccharomyces cerevisiae. The P. jirovecii proteins Gsc1 and Kre6 identified using those of the relative Pneumocystis carinii as the query sequence showed high sequence identity to the putative fungal orthologs (53-97% in conserved functional domains). The expression of their encoding genes on plasmid rescued the increased sensitivity to, respectively, caspofungin or calcofluor white of the corresponding S. cerevisiae null allele. The uniqueness and likely essentiality of these proteins suggest that they are potential good drug targets.
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Affiliation(s)
- Amanda Luraschi
- Institute of Microbiology, Lausanne University Hospital and University of Lausanne, Lausanne, 1011, Switzerland
| | - Ousmane H Cissé
- Institute of Microbiology, Lausanne University Hospital and University of Lausanne, Lausanne, 1011, Switzerland.,Vital-IT Group, SIB Swiss Institute of Bioinformatics, Lausanne, 1015, Switzerland
| | - Marco Pagni
- Vital-IT Group, SIB Swiss Institute of Bioinformatics, Lausanne, 1015, Switzerland
| | - Philippe M Hauser
- Institute of Microbiology, Lausanne University Hospital and University of Lausanne, Lausanne, 1011, Switzerland
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Evaluation of a new commercial real-time PCR assay for diagnosis of Pneumocystis jirovecii pneumonia and identification of dihydropteroate synthase (DHPS) mutations. Diagn Microbiol Infect Dis 2016; 87:32-36. [PMID: 27789058 DOI: 10.1016/j.diagmicrobio.2016.10.005] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Revised: 08/22/2016] [Accepted: 10/04/2016] [Indexed: 12/14/2022]
Abstract
The PneumoGenius® real-time PCR assay is a new commercial multiplex real-time PCR method, which detects the Pneumocystis mitochondrial ribosomal large subunit (mtLSU) and two dihydropteroate synthase (DHPS) point mutations. To evaluate the clinical performance of this new real-time PCR assay we tested 120 extracted DNA samples from bronchoalveolar lavage specimens. These set of extracted DNA samples had already tested positive for Pneumocystis and patients had been classified in probable and unlikely PCP in a previous study. To evaluate de accuracy of the DHPS mutant's identification, an "in house" PCR and sequencing was performed. The sensitivity and specificity of PneumoGenius® PCR in discriminating between probable and unlikely Pneumocystis pneumonia (PCP) were 70% and 82% respectively. PneumoGenius® PCR was able to genotype more samples than "in house" DHPS PCR and sequencing. The same DHPS mutations were observed by both methods in four patients: two patients with a single mutation in position 171 (Pro57Ser) and two patients with a double mutation in position 165 (Thr55Ala) and in position 171 (Pro57Ser). A low rate of P. jirovecii (4.5%) harboring DHPS mutations was found, comparable to rates observed in other European countries. The PneumoGenius® real-time PCR is a suitable real-time PCR for PCP diagnosis and detection of DHPS mutants. The added value of DHPS mutation identification can assist in understanding the role of these mutations in prophylaxis failure or treatment outcome.
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Abstract
Pneumocystis carinii pneumonia (PCP) remains a serious infection in the immunocompromised host (in the absence of HIV infection) and presents significant management and diagnostic challenges to ICU physicians. Non-HIV PCP is generally abrupt in onset, and follows a fulminate course with high rates of hospitalization, ICT admission, respiratory failure, and requirement for intubation. Mortality is generally high, especially if mechanical ventilation is required. Non-invasive ventilatory support may be considered, although the rapid progression to respiratory failure often necessitates intubation at the time of presentation. Bronchoscopy is often required to establish the diagnosis, and empirical antimicrobial treatment specifically targeted to P. carinii should be initiated while awaiting confirmation. Adjunctive corticosteroids may accelerate recovery, although their use has not yet been established in non-HIV PCP. For the ICU physicians to diagnose PCP, the non-specific presentation of an acute febrile illness and respiratory distress with diffuse pulmonary infiltrates requires a high clinical index of suspician, familiarity with clinical conditions associated with increased risk for PCP, and a low threshold for bronchoscopy to establish the diagnosis.
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Affiliation(s)
- Geoffrey S. Gilmartin
- Division of Pulmonary and Critical Care, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA
| | - Henry Koziel
- Division of Pulmonary and Critical Care, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA.,
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Esteves F, de Sousa B, Calderón E, Huang L, Badura R, Maltez F, Bassat Q, de Armas Y, Antunes F, Matos O. Multicentre study highlighting clinical relevance of new high-throughput methodologies in molecular epidemiology of Pneumocystis jirovecii pneumonia. Clin Microbiol Infect 2016; 22:566.e9-566.e19. [DOI: 10.1016/j.cmi.2016.03.013] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2015] [Revised: 02/19/2016] [Accepted: 03/13/2016] [Indexed: 11/17/2022]
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Alanio A, Hauser PM, Lagrou K, Melchers WJG, Helweg-Larsen J, Matos O, Cesaro S, Maschmeyer G, Einsele H, Donnelly JP, Cordonnier C, Maertens J, Bretagne S. ECIL guidelines for the diagnosis of Pneumocystis jirovecii pneumonia in patients with haematological malignancies and stem cell transplant recipients. J Antimicrob Chemother 2016; 71:2386-96. [PMID: 27550991 DOI: 10.1093/jac/dkw156] [Citation(s) in RCA: 165] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The Fifth European Conference on Infections in Leukaemia (ECIL-5) convened a meeting to establish evidence-based recommendations for using tests to diagnose Pneumocystis jirovecii pneumonia (PCP) in adult patients with haematological malignancies. Immunofluorescence assays are recommended as the most sensitive microscopic method (recommendation A-II: ). Real-time PCR is recommended for the routine diagnosis of PCP ( A-II: ). Bronchoalveolar lavage (BAL) fluid is recommended as the best specimen as it yields good negative predictive value ( A-II: ). Non-invasive specimens can be suitable alternatives ( B-II: ), acknowledging that PCP cannot be ruled out in case of a negative PCR result ( A-II: ). Detecting β-d-glucan in serum can contribute to the diagnosis but not the follow-up of PCP ( A-II: ). A negative serum β-d-glucan result can exclude PCP in a patient at risk ( A-II: ), whereas a positive test result may indicate other fungal infections. Genotyping using multilocus sequence markers can be used to investigate suspected outbreaks ( A-II: ). The routine detection of dihydropteroate synthase mutations in cases of treatment failure is not recommended ( B-II: ) since these mutations do not affect response to high-dose co-trimoxazole. The clinical utility of these diagnostic tests for the early management of PCP should be further assessed in prospective, randomized interventional studies.
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Affiliation(s)
- Alexandre Alanio
- Parasitology-Mycology Laboratory, Groupe Hospitalier Lariboisière Saint-Louis Fernand Widal, Assistance Publique-Hôpitaux de Paris (AP-HP), Université Paris-Diderot, Sorbonne Paris Cité, and Institut Pasteur, Unité de Mycologie Moléculaire, CNRS URA3012, Centre National de Référence Mycoses Invasives et Antifongiques, Paris, France
| | - Philippe M Hauser
- Institute of Microbiology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Katrien Lagrou
- Department of Microbiology and Immunology, Catholic University Leuven, Leuven, Belgium and National Reference Center for Mycosis, Department of Laboratory Medicine, University Hospitals Leuven, Leuven, Belgium
| | - Willem J G Melchers
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Jannik Helweg-Larsen
- Department of Infectious Diseases, Rigshospitalet-Copenhagen University Hospital, Copenhagen, Denmark
| | - Olga Matos
- Medical Parasitology Unit, Group of Opportunistic Protozoa/HIV and Other Protozoa, Global Health and Tropical Medicine, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Portugal Universidade Nova de Lisboa, Lisboa, Portugal
| | - Simone Cesaro
- Hematology Department, Oncoematologia Pediatrica, Policlinico G. B. Rossi, Verona, Italy
| | - Georg Maschmeyer
- Department of Hematology, Oncology and Palliative Care, Ernst-von-Bergmann Klinikum, Potsdam, Germany
| | - Hermann Einsele
- Medizinische Klinik und Poliklinik II, Julius Maximilians Universitaet, Würzburg, Germany
| | - J Peter Donnelly
- Department of Hematology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Catherine Cordonnier
- Hematology Department, Henri Mondor Hospital, APHP and Université Paris-Est-Créteil, Créteil, France
| | - Johan Maertens
- Hematology Department, University Hospital Leuven, Campus Gasthuisberg, Leuven, Belgium
| | - Stéphane Bretagne
- Parasitology-Mycology Laboratory, Groupe Hospitalier Lariboisière Saint-Louis Fernand Widal, Assistance Publique-Hôpitaux de Paris (AP-HP), Université Paris-Diderot, Sorbonne Paris Cité, and Institut Pasteur, Unité de Mycologie Moléculaire, CNRS URA3012, Centre National de Référence Mycoses Invasives et Antifongiques, Paris, France
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Mogoye BK, Du Plessis D, Poonsamy B, Frean J. Characterisation of Pneumocystis jiroveciiDHPS genotypes using a simple, inexpensive restriction fragment length polymorphism analysis. S Afr J Infect Dis 2015. [DOI: 10.1080/23120053.2015.1054180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
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Functional characterization of the Pneumocystis jirovecii potential drug targets dhfs and abz2 involved in folate biosynthesis. Antimicrob Agents Chemother 2015; 59:2560-6. [PMID: 25691634 DOI: 10.1128/aac.05092-14] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Accepted: 02/07/2015] [Indexed: 01/12/2023] Open
Abstract
Pneumocystis species are fungal parasites colonizing mammal lungs with strict host specificity. Pneumocystis jirovecii is the human-specific species and can turn into an opportunistic pathogen causing severe pneumonia in immunocompromised individuals. This disease is currently the second most frequent life-threatening invasive fungal infection worldwide. The most efficient drug, cotrimoxazole, presents serious side effects, and resistance to this drug is emerging. The search for new targets for the development of new drugs is thus of utmost importance. The recent release of the P. jirovecii genome sequence opens a new era for this task. It can now be carried out on the actual targets to be inhibited instead of on those of the relatively distant model Pneumocystis carinii, the species infecting rats. We focused on the folic acid biosynthesis pathway because (i) it is widely used for efficient therapeutic intervention, and (ii) it involves several enzymes that are essential for the pathogen and have no human counterparts. In this study, we report the identification of two such potential targets within the genome of P. jirovecii, the dihydrofolate synthase (dhfs) and the aminodeoxychorismate lyase (abz2). The function of these enzymes was demonstrated by the rescue of the null allele of the orthologous gene of Saccharomyces cerevisiae.
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Sheikholeslami MF, Sadraei J, Farnia P, Forozandeh Moghadam M, Emadikochak H. Dihydropteroate synthase gene mutation rates in Pneumocystis jirovecii strains obtained from Iranian HIV-positive and non-HIV-positive patients. Med Mycol 2015; 53:361-8. [PMID: 25631478 DOI: 10.1093/mmy/myu095] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Accepted: 12/15/2014] [Indexed: 12/17/2022] Open
Abstract
The dihydropteroate sulfate (DHPS) gene is associated with resistance to sulfa/sulfone drugs in Pneumocystis jirovecii. We investigated the DHPS mutation rate in three groups of Iranian HIV-positive and HIV-negative patients by polymerase chain reaction-restricted fragment length polymorphism analysis. Furthermore, an association between P. jirovecii DHPS mutations and strain typing was investigated based on direct sequencing of internal transcribed spacer region 1 (ITS1) and ITS2. The overall P. jirovecii DHPS mutation rate was (5/34; 14.7%), the lowest rate identified was in HIV-positive patients (1/16; 6.25%) and the highest rate was in malignancies patients (3/11; 27.3%). A moderate rate of mutation was detected in chronic obstructive pulmonary disease (COPD) patients (1/7; 14.3%). Most of the isolates were wild type (29/34; 85.3%). Double mutations in DHPS were detected in patients with malignancies, whereas single mutations at codons 55 and 57 were identified in the HIV-positive and COPD patients, respectively. In this study, two new and rare haplotypes were identified with DHPS mutations. Additionally, a positive relationship between P. jirovecii strain genotypes and DHPS mutations was identified. In contrast, no DHPS mutations were detected in the predominant (Eg) haplotype. This should be regarded as a warning of an increasing incidence of drug-resistant P. jirovecii strains.
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Affiliation(s)
- Maryam-Fatemeh Sheikholeslami
- Mycobacteriology Research Center, National Research Institute of Tuberculosis and Lung Disease (NRITLD), Shahid Beheshti University of Medical Sciences, Tehran, Iran Tarbiat Modares University, Medical Faculty, Parasitology Department, Tehran, Iran
| | - Javid Sadraei
- Tarbiat Modares University, Medical Faculty, Parasitology Department, Tehran, Iran
| | - Parisa Farnia
- Mycobacteriology Research Center, National Research Institute of Tuberculosis and Lung Disease (NRITLD), Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | | | - Hamid Emadikochak
- Iranian HIV/AIDS Research Center, Imam Khomini Hospital, Tehran University of Medical Sciences, Tehran, Iran
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Khodavaisy S, Mortaz E, Mohammadi F, Aliyali M, Fakhim H, Badali H. Pneumocystis jirovecii colonization in Chronic Obstructive Pulmonary Disease (COPD). Curr Med Mycol 2015; 1:42-48. [PMID: 28680980 PMCID: PMC5490321 DOI: 10.18869/acadpub.cmm.1.1.42] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
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.
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Affiliation(s)
- S Khodavaisy
- Department of Medical Parasitology and Mycology, Kurdistan University of Medical Sciences, Sanandaj, Iran.,Department of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - E Mortaz
- Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Faculty of Science, Utrecht University, Utrecht, The Netherlands
| | - F Mohammadi
- Department of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - M Aliyali
- Pulmonary and Critical Care Division, Mazandaran University of Medical Sciences, Sari, Iran
| | - H Fakhim
- Student Research Committee, Mazandaran University of Medical Sciences, Sari, Iran
| | - H Badali
- Department of Medical Mycology and Parasitology/Invasive Fungi Research Center, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran
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Pneumocystis jirovecii infection and the associated dihydropteroate synthase (DHPS) and dihydrofolate reductase (DHFR) mutations in HIV-positive individuals from Pune, India. Mycopathologia 2014; 179:141-5. [PMID: 25266324 DOI: 10.1007/s11046-014-9818-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Accepted: 09/23/2014] [Indexed: 10/24/2022]
Abstract
The present study was undertaken to detect Pneumocystis jirovecii infection among HIV-positive patients presenting with symptoms of lower respiratory tract infection and analyze the associated dihydropteroate synthase (DHPS) and dihydrofolate reductase (DHFR) mutations. P. jirovecii infection was detected in 12.6% cases. We did not find DHPS gene mutations at the commonest positions of codon 55 and 57; however, mutation at codon 171 was detected in two cases. No mutations in DHFR gene were detected. The results indicate low prevalence of DHPS and DHFR mutations in Indian P. jirovecii isolates, suggesting that the selective pressure of sulfa drugs on the local strains has probably not reached the levels found in developed nations.
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Mutational analysis of Pneumocystis jirovecii dihydropteroate synthase and dihydrofolate reductase genes in HIV-infected patients in China. J Clin Microbiol 2014; 52:4017-9. [PMID: 25122865 DOI: 10.1128/jcm.01848-14] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We investigated Pneumocystis jirovecii dihydropteroate synthase (DHPS) and dihydrofolate reductase (DHFR) genes for mutations in 25 Chinese HIV-infected patients with P. jirovecii pneumonia. We identified DHPS mutations in 3 (12%) patients and DHFR mutations in 1 (4%) patient. The prevalence of DHPS and DHFR mutations in China remains low, as it does in other developing countries.
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32
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Roblot F. Management ofPneumocystispneumonia in patients with inflammatory disorders. Expert Rev Anti Infect Ther 2014; 3:435-44. [PMID: 15954859 DOI: 10.1586/14787210.3.3.435] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Pneumocystis jirovecii is an atypical fungus that causes Pneumocystis pneumonia in immunocompromised patients. Underlying diseases associated with Pneumocystis pneumonia mainly consist of hematologic malignancies, solid tumors, organ transplant recipients and inflammatory disorders. Currently, inflammatory disorders represent 20% of underlying diseases. Corticosteroids are considered as a major risk factor. Recently introduced immunosuppressive drugs, such as antitumor necrosis factor monoclonal antibodies, could enhance the risk of Pneumocystis pneumonia. In patients with inflammatory disorders, lymphopenia is probably a determining factor but CD4+ T-cell count associated with the risk of Pneumocystis pneumonia remains unassessed. The diagnosis is based upon clinical, radiologic and biologic data. The identification of P. jirovecii usually requires a lower respiratory tract specimen, even if oral washes samples seem to be promising. According to recent data, immunofluorescent stains should be considered as the new gold standard, and specialized techniques such as PCR should be applied for sputum samples or oral washes. Recommendations on prophylaxis remains controversial except in patients with Wegener's granulomatosis and systemic lupus erythematosus. Cotrimoxazole is the preferred agent for prophylaxis as well as for treatment. An adjunctive corticosteroid therapy is usually prescribed despite the lack of evidence for utility in patients with inflammatory disorders. As person-to-person transmission is the most likely mode of acquiring P. jirovecii, isolation precautions should be advised.
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Affiliation(s)
- F Roblot
- Department of Internal Medicine, University Hospital, Poitiers, France.
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Prevalence and genotype distribution of Pneumocystis jirovecii in Cuban infants and toddlers with whooping cough. J Clin Microbiol 2013; 52:45-51. [PMID: 24131683 DOI: 10.1128/jcm.02381-13] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
This study describes the prevalence and genotype distribution of Pneumocystis jirovecii obtained from nasopharyngeal (NP) swabs from immunocompetent Cuban infants and toddlers with whooping cough (WC). A total of 163 NP swabs from 163 young Cuban children with WC who were admitted to the respiratory care units at two pediatric centers were studied. The prevalence of the organism was determined by a quantitative PCR (qPCR) assay targeting the P. jirovecii mitochondrial large subunit (mtLSU) rRNA gene. Genotypes were identified by direct sequencing of mtLSU ribosomal DNA (rDNA) and restriction fragment length polymorphism (RFLP) analysis of the dihydropteroate synthase (DHPS) gene amplicons. qPCR detected P. jirovecii DNA in 48/163 (29.4%) samples. mtLSU rDNA sequence analysis revealed the presence of three different genotypes in the population. Genotype 2 was most common (48%), followed in prevalence by genotypes 1 (23%) and 3 (19%); mixed-genotype infections were seen in 10% of the cases. RFLP analysis of DHPS PCR products revealed four genotypes, 18% of which were associated with resistance to sulfa drugs. Only contact with coughers (prevalence ratio [PR], 3.51 [95% confidence interval {CI}, 1.79 to 6.87]; P = 0.000) and exposure to tobacco smoke (PR, 1.82 [95% CI, 1.14 to 2.92]; P = 0.009) were statistically associated with being colonized by P. jirovecii. The prevalence of P. jirovecii in infants and toddlers with WC and the genotyping results provide evidence that this population represents a potential reservoir and transmission source of P. jirovecii.
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Trimethoprim resistance of dihydrofolate reductase variants from clinical isolates of Pneumocystis jirovecii. Antimicrob Agents Chemother 2013; 57:4990-8. [PMID: 23896474 DOI: 10.1128/aac.01161-13] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Pneumocystis jirovecii is an opportunistic pathogen that causes serious pneumonia in immunosuppressed patients. Standard therapy and prophylaxis include trimethoprim (TMP)-sulfamethoxazole; trimethoprim in this combination targets dihydrofolate reductase (DHFR). Fourteen clinically observed variants of P. jirovecii DHFR were produced recombinantly to allow exploration of the causes of clinically observed failure of therapy and prophylaxis that includes trimethoprim. Six DHFR variants (S31F, F36C, L65P, A67V, V79I, and I158V) showed resistance to inhibition by trimethoprim, with Ki values for trimethoprim 4-fold to 100-fold higher than those for the wild-type P. jirovecii DHFR. An experimental antifolate with more conformational flexibility than trimethoprim showed strong activity against one trimethoprim-resistant variant. The two variants that were most resistant to trimethoprim (F36C and L65P) also had increased Km values for dihydrofolic acid (DHFA). The catalytic rate constant (kcat) was unchanged for most variant forms of P. jirovecii DHFR but was significantly lowered in F36C protein; one naturally occurring variant with two amino acid substitutions (S106P and E127G) showed a doubling of kcat, as well as a Km for NADPH half that of the wild type. The strongest resistance to trimethoprim occurred with amino acid changes in the binding pocket for DHFA or trimethoprim, and the strongest effect on binding of NADPH was linked to a mutation involved in binding the phosphate group of the cofactor. This study marks the first confirmation that naturally occurring mutations in the gene for DHFR from P. jirovecii produce variant forms of DHFR that are resistant to trimethoprim and may contribute to clinically observed failures of standard therapy or prophylaxis.
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Characterization of pneumocystis major surface glycoprotein gene (msg) promoter activity in Saccharomyces cerevisiae. EUKARYOTIC CELL 2013; 12:1349-55. [PMID: 23893080 DOI: 10.1128/ec.00122-13] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Major surface glycoprotein (Msg), the most abundant cell surface protein of Pneumocystis, plays an important role in the interaction of this opportunistic pathogen with host cells, and its potential for antigenic variation may facilitate evasion of host immune responses. In the present study, we have identified and characterized the promoter region of msg in 3 species of Pneumocystis: P. carinii, P. jirovecii, and P. murina. Because Pneumocystis cannot be cultured, promoter activity was measured in Saccharomyces cerevisiae, a related fungus, using a yeast vector modified to utilize the gene coding for Renilla luciferase as a reporter gene. The 5'-flanking sequences of msg from all three Pneumocystis species showed considerable promoter activity, with increases in luciferase activity up to 15- to 44-fold above baseline. Progressive deletions helped define an ∼13-bp sequence in each Pneumocystis species that appears to be critical for promoter activity. Electrophoretic mobility shift analysis using P. carinii-specific msg promoter sequences demonstrated binding of nuclear proteins of S. cerevisiae. The 144-bp 5'-flanking region of P. murina msg showed 72% identity to that of P. carinii. The 5'-flanking region of P. jirovecii msg showed 58 and 61% identity to those of P. murina and P. carinii, respectively. The msg promoter is a good candidate for inclusion in a construct designed for genetic manipulation of Pneumocystis species.
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Multilocus sequence typing of Pneumocystis jirovecii from clinical samples: how many and which loci should be used? J Clin Microbiol 2013; 51:2843-9. [PMID: 23784120 DOI: 10.1128/jcm.01073-13] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Pneumocystis jirovecii pneumonia (PCP) is an opportunistic infection with airborne transmission and remains a major cause of respiratory illness among immunocompromised individuals. In recent years, several outbreaks of PCP, occurring mostly in kidney transplant recipients, have been reported. Currently, multilocus sequence typing (MLST) performed on clinical samples is considered to be the gold standard for epidemiological investigations of nosocomial clusters of PCP. However, until now, no MLST consensus scheme has emerged. The aim of this study was to evaluate the discriminatory power of eight distinct loci previously used for the molecular typing of P. jirovecii (internal transcribed spacer 1 [ITS1], cytochrome b [CYB], mitochondrial rRNA gene [mt26S], large subunit of the rRNA gene [26S], superoxide dismutase [SOD], β-tubulin [β-TUB], dihydropteroate synthase [DHPS], and dihydrofolate reductase [DHFR]) using a cohort of 33 epidemiologically unrelated patients having respiratory samples that were positive for P. jirovecii and who were admitted to our hospital between 2006 and 2011. Our results highlight that the choice of loci for MLST is crucial, as the discriminatory power of the method was highly variable from locus to locus. In all, the eight-locus-based scheme we used displayed a high discriminatory power (Hunter [H] index, 0.996). Based on our findings, a simple and alternative MLST scheme relying on three loci only (mt26S, CYB, and SOD) provides enough discriminatory power (H-index, 0.987) to be used for preliminary investigations of nosocomial clusters of PCP.
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Dimonte S, Berrilli F, D’Orazi C, D’Alfonso R, Placco F, Bordi E, Perno C, Di Cave D. Molecular analysis based on mtLSU-rRNA and DHPS sequences of Pneumocystis jirovecii from immunocompromised and immunocompetent patients in Italy. INFECTION GENETICS AND EVOLUTION 2013. [DOI: 10.1016/j.meegid.2012.11.012] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Anti-folate combination therapies and their effect on the development of drug resistance in Plasmodium vivax. Sci Rep 2013; 3:1008. [PMID: 23301149 PMCID: PMC3538286 DOI: 10.1038/srep01008] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2012] [Accepted: 11/21/2012] [Indexed: 11/08/2022] Open
Abstract
Can we predict the rise and spread of resistance to multi-drug therapy in a more predictable manner? We raise this question after analyzing over 500 Plasmodium vivax isolates collected from different, geographically isolated regions of China for sequence variation in and around the dhfr and dhps genes. We find: that resistance lineages have arisen at least once in each region; that there appears to have been little movement of parasite populations between these areas; and that highly resistant parasites contain dhfr and dhps alleles that are in linkage disequilibrium. We show a direct relationship between this linkage disequilibrium and a parasite's fitness in the absence of drug pressure. Such fitness would increase the spread of drug resistant phenotypes and is thus a selectable trait. These conclusions raise questions about the appropriate use of some other drug combinations to prevent and treat infection.
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Jarboui MA, Mseddi F, Sellami H, Sellami A, Makni F, Ayadi A. Genetic diversity of Pneumocystis jirovecii strains based on sequence variation of different DNA region. Med Mycol 2012; 51:561-7. [PMID: 23210680 DOI: 10.3109/13693786.2012.744879] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Pneumocystis jirovecii is an important opportunistic pathogen that causes severe pneumonia in immunocompromised patients. The aim of the present study was to investigate the genetic diversity of P. jirovecii strains by direct sequencing and analysis of the Upstream Conserved Sequence (UCS) region, mitochondrial large-subunit (mtLSU) rRNA and dihydrofolate reductase (DHFR) genes. We identified the polymorphisms in P. jirovecii strains of 15 immunocompromised patients, as well as detecting a new tandem repeat of 5 nucleotides in UCS region. The following three different types of repeat unit were found: type a GCCCA; type b GCCCT; and type c GCCTT. In addition, we identified the repeat unit which consisted of 10 nucleotides and three different patterns of UCS repeats with 3 and 4 repeats, i.e., 1, 2, 3 (86.7%), 1, 2, 3, 3 (6.6%) and a new genotype 2, 2, 3, 3 (6.6%). The polymorphism in the mtLSUrRNA gene was seen primarily at position 85 where we detected three different genotypes. Genotype 3 and genotype 2 were the most abundant with frequencies of 53.3% and 40%, respectively. With regard to the DHFR gene, only two (20%) patients had nucleotide substitution in position 312. In conclusion, the multilocus analysis facilitated the typing of P. jirovecii strains and proved the important genetic biodiversity of this fungus.
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Affiliation(s)
- Mohamed Ali Jarboui
- Fungal and Parasitic Molecular Biology Laboratory, School of Medicine, University of Sfax, Sfax, Tunisia.
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Taylor SM, Meshnick SR, Worodria W, Andama A, Cattamanchi A, Davis JL, Yoo SD, Byanyima P, Kaswabuli S, Goodman CD, Huang L. Low prevalence of Pneumocystis pneumonia (PCP) but high prevalence of pneumocystis dihydropteroate synthase (dhps) gene mutations in HIV-infected persons in Uganda. PLoS One 2012; 7:e49991. [PMID: 23166805 PMCID: PMC3500344 DOI: 10.1371/journal.pone.0049991] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2012] [Accepted: 10/19/2012] [Indexed: 12/03/2022] Open
Abstract
Pneumocystis jirovecii pneumonia (PCP) is an important opportunistic infection in patients infected with HIV, but its burden is incompletely characterized in those areas of sub-Saharan Africa where HIV is prevalent. We explored the prevalence of both PCP in HIV-infected adults admitted with pneumonia to a tertiary-care hospital in Uganda and of putative P. jirovecii drug resistance by mutations in fungal dihydropteroate synthase (dhps) and dihydrofolate reductase (dhfr). In 129 consecutive patients with sputum smears negative for mycobacteria, 5 (3.9%) were diagnosed with PCP by microscopic examination of Giemsa-stained bronchoalveolar lavage fluid. Concordance was 100% between Giemsa stain and PCR (dhps and dhfr). PCP was more prevalent in patients newly-diagnosed with HIV (11.4%) than in patients with known HIV (1.1%; p = 0.007). Mortality at 2 months after discharge was 29% overall: 28% among PCP-negative patients, and 60% (3 of 5) among PCP-positive patients. In these 5 fungal isolates and an additional 8 from consecutive cases of PCP, all strains harbored mutant dhps haplotypes; all 13 isolates harbored the P57S mutation in dhps, and 3 (23%) also harbored the T55A mutation. No non-synonymous dhfr mutations were detected. PCP is an important cause of pneumonia in patients newly-diagnosed with HIV in Uganda, is associated with high mortality, and putative molecular evidence of drug resistance is prevalent. Given the reliability of field diagnosis in our cohort, future studies in sub-Saharan Africa can investigate the clinical impact of these genotypes.
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Affiliation(s)
- Steve M Taylor
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina, United States of America.
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Abstract
Although the incidence of Pneumocystis pneumonia (PCP) has decreased since the introduction of combination antiretroviral therapy, it remains an important cause of disease in both HIV-infected and non-HIV-infected immunosuppressed populations. The epidemiology of PCP has shifted over the course of the HIV epidemic both from changes in HIV and PCP treatment and prevention and from changes in critical care medicine. Although less common in non-HIV-infected immunosuppressed patients, PCP is now more frequently seen due to the increasing numbers of organ transplants and development of novel immunotherapies. New diagnostic and treatment modalities are under investigation. The immune response is critical in preventing this disease but also results in lung damage, and future work may offer potential areas for vaccine development or immunomodulatory therapy. Colonization with Pneumocystis is an area of increasing clinical and research interest and may be important in development of lung diseases such as chronic obstructive pulmonary disease. In this review, we discuss current clinical and research topics in the study of Pneumocystis and highlight areas for future research.
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Muñoz C, Zuluaga A, Restrepo A, Tobón A, Cano LE, Gonzalez A. Molecular diagnosis and detection of Pneumocystis jirovecii DHPS and DHFR genotypes in respiratory specimens from Colombian patients. Diagn Microbiol Infect Dis 2012; 72:204-13. [PMID: 22321995 DOI: 10.1016/j.diagmicrobio.2011.11.015] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2011] [Revised: 11/17/2011] [Accepted: 11/19/2011] [Indexed: 11/16/2022]
Abstract
A total of 98 respiratory specimens from 88 patients suspected of having Pneumocystis jirovecii pneumonia (PcP) were evaluated using a previously reported nested polymerase chain reaction (PCR) assay for mitochondrial large subunit rRNA (mtLSUrRNA). In addition, samples from patients with other pulmonary infections and a sizeable DNA collection from other fungal pathogens were studied. A panfungal PCR assay amplifying the ITS1-ITS2 regions were also used to identify all fungal DNAs. All samples positive for mtLSUrRNA-PCR were evaluated to determine mutations in dihydropteroate synthase (DHPS) and dihydrofolate reductase (DHFR) genes. All PCR-amplified products were sequenced. Of the 98 clinical specimens, 13 (13.2%) were positive by GMS stain and mtLSUrRNA-PCR, while 32 (32.6%) that were GMS stain-negative gave positive results with mtLSUrRNA-PCR. All the sequences corresponding to the 45 products amplified by mtLSUrRNA-PCR showed 99% or greater identity with P. jirovecii. The mtLSUrRNA-PCR exhibited 86% sensitivity and 98% and 96.6% specificity when results were compared to those corresponding to negative controls and other proven clinical entities, respectively. We found mutations in the DHPS gene in 3 (7.7%) patients, 2 located at codon 55 and 1 at codon 57. One patient showed a synonymous substitution at nucleotide position 312 in the DHFR gene. These results suggest that mtLSUrRNA-PCR is a useful test for diagnosing PcP. In contrast to other studies, this study found a low prevalence of mutations in the DHPS and DHFR genes in Colombian patients.
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Affiliation(s)
- Cesar Muñoz
- Medical and Experimental Mycology Group, Corporación para Investigaciones Biológicas, Medellín, Colombia
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Dihydropteroate synthase gene mutations in Pneumocystis jiroveci strains isolated from immunocompromised patients. ACTA ACUST UNITED AC 2011; 59:222-5. [DOI: 10.1016/j.patbio.2010.02.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2010] [Accepted: 02/05/2010] [Indexed: 12/21/2022]
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Cody V, Pace J, Piraino J, Queener SF. Crystallographic analysis reveals a novel second binding site for trimethoprim in active site double mutants of human dihydrofolate reductase. J Struct Biol 2011; 176:52-9. [PMID: 21684339 DOI: 10.1016/j.jsb.2011.06.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2011] [Revised: 05/19/2011] [Accepted: 06/01/2011] [Indexed: 11/29/2022]
Abstract
In order to produce a more potent replacement for trimethoprim (TMP) used as a therapy for Pneumocystis pneumonia and targets dihydrofolate reductase from Pneumocystis jirovecii (pjDHFR), it is necessary to understand the determinants of potency and selectivity against DHFR from the mammalian host and fungal pathogen cells. To this end, active site residues in human (h) DHFR were replaced with those from pjDHFR. Structural data are reported for two complexes of TMP with the double mutants Gln35Ser/Asn64Phe (Q35S/N64F) and Gln35Lys/Asn64Phe (Q35K/N64F) of hDHFR that unexpectedly show evidence for the binding of two molecules of TMP: one molecule that binds in the normal folate binding site and the second molecule that binds in a novel subpocket site such that the mutated residue Phe64 is involved in van der Waals contacts to the trimethoxyphenyl ring of the second TMP molecule. Kinetic data for the binding of TMP to hDHFR and pjDHFR reveal an 84-fold selectivity of TMP against pjDHFR (K(i) 49 nM) compared to hDHFR (K(i) 4093 nM). Two mutants that contain one substitution from pj--and one from the closely related Pneumocystis carinii DHFR (pcDHFR) (Q35K/N64F and Q35S/N64F) show K(i) values of 593 and 617 nM, respectively; these K(i) values are well above both the K(i) for pjDHFR and are similar to pcDHFR (Q35K/N64F and Q35S/N64F) (305nM). These results suggest that active site residues 35 and 64 play key roles in determining selectivity for pneumocystis DHFR, but that other residues contribute to the unique binding of inhibitors to these enzymes.
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Affiliation(s)
- Vivian Cody
- Structural Biology Department, Hauptman Woodward Medical Research Institute, 700 Ellicott St. Buffalo, NY 14203, USA.
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Huang L, Cattamanchi A, Davis JL, den Boon S, Kovacs J, Meshnick S, Miller RF, Walzer PD, Worodria W, Masur H. HIV-associated Pneumocystis pneumonia. PROCEEDINGS OF THE AMERICAN THORACIC SOCIETY 2011; 8:294-300. [PMID: 21653531 PMCID: PMC3132788 DOI: 10.1513/pats.201009-062wr] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2010] [Accepted: 11/26/2010] [Indexed: 11/20/2022]
Abstract
During the past 30 years, major advances have been made in our understanding of HIV/AIDS and Pneumocystis pneumonia (PCP), but significant gaps remain. Pneumocystis is classified as a fungus and is host-species specific, but an understanding of its reservoir, mode of transmission, and pathogenesis is incomplete. PCP remains a frequent AIDS-defining diagnosis and is a frequent opportunistic pneumonia in the United States and in Europe, but comparable epidemiologic data from other areas of the world that are burdened with HIV/AIDS are limited. Pneumocystis cannot be cultured, and bronchoscopy with bronchoalveolar lavage is the gold standard procedure to diagnose PCP, but noninvasive diagnostic tests and biomarkers show promise that must be validated. Trimethoprim-sulfamethoxazole is the recommended first-line treatment and prophylaxis regimen, but putative trimethoprim-sulfamethoxazole drug resistance is an emerging concern. The International HIV-associated Opportunistic Pneumonias (IHOP) study was established to address these knowledge gaps. This review describes recent advances in the pathogenesis, epidemiology, diagnosis, and management of HIV-associated PCP and ongoing areas of clinical and translational research that are part of the IHOP study and the Longitudinal Studies of HIV-associated Lung Infections and Complications (Lung HIV).
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Affiliation(s)
- Laurence Huang
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, San Francisco General Hospital, University of California, San Francisco, California 94110, USA.
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Clinical relevance of multiple single-nucleotide polymorphisms in Pneumocystis jirovecii Pneumonia: development of a multiplex PCR-single-base-extension methodology. J Clin Microbiol 2011; 49:1810-5. [PMID: 21389160 DOI: 10.1128/jcm.02303-10] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Pneumocystis jirovecii pneumonia (PcP) is a major cause of respiratory illness in patients with AIDS. The identification of multiple single-nucleotide polymorphisms (SNPs) at three distinct P. jirovecii loci encoding dihydrofolate reductase (DHFR), mitochondrial large-subunit rRNA (mtLSU rRNA), and superoxide dismutase (SOD) was achieved using multiplex-PCR (MPCR) followed by direct sequencing and two single-base extension (SBE) techniques. Four SNPs (DHFR312, mt85, SOD215, and SOD110), correlated previously with parameters of disease, were amplified and genotyped simultaneously. The concordance of results between the standard sequencing technique (direct sequencing) and SBE analysis was 96.9% for the acrylamide gel electrophoresis and 98.4% for the capillary electrophoresis. The cross-genetic analysis established several statistical associations among the SNPs studied: mt85C-SOD110T, SOD110T-SOD215C, and SOD110C-SOD215T. These results were confirmed by cluster analysis. Data showed that among the isolates with low to moderate parasite burden, the highest percentages of DHFR312C, mt85C, SOD110T, and SOD215C were detected, whereas for high parasite burden cases the highest frequencies were observed among isolates with DHFR312T, mt85T, SOD110C, and SOD215T. The polymorphisms studied were shown to be suitable genetic targets potentially correlated with PcP clinical data that can be used as predictors of outcome in further studies to help clinical decision-making in the management of PcP. The MPCR/SBE protocol described for the first time in the present study was shown to be a rapid, highly accurate method for genotyping P. jirovecii SNPs encoded by different loci that could be used for epidemiological studies and as an additional procedure for the prognostic classification and diagnosis of PcP.
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Kutty G, Achaz G, Maldarelli F, Varma A, Shroff R, Becker S, Fantoni G, Kovacs JA. Characterization of the meiosis-specific recombinase Dmc1 of pneumocystis. J Infect Dis 2010; 202:1920-9. [PMID: 21050123 DOI: 10.1086/657414] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
The life cycle of Pneumocystis, which causes life-threatening pneumonia in immunosuppressed patients, remains poorly defined. In the present study, we have identified and characterized an orthologue of dmc1, a gene specific for meiotic recombination in yeast, in 3 species of Pneumocystis. dmc1 is a single-copy gene that is transcribed as ∼1.2-kb messenger RNA, which encodes a protein of 336-337 amino acids. Pneumocystis Dmc1 was 61%-70% identical to those from yeast. Confocal microscopy results indicated that the expression of Dmc1 is primarily confined to the cyst form of Pneumocystis. By sequence analysis of 2 single-copy regions of the human Pneumocystis jirovecii genome, we can infer multiple recombination events, which are consistent with meiotic recombination in this primarily haploid organism. Taken together, these studies support the occurrence of a sexual phase in the life cycle of Pneumocystis.
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Affiliation(s)
- Geetha Kutty
- Critical Care Medicine Department, National Institutes of Health (NIH) Clinical Center, National Institutes of Allergy and Infectious Diseases, USA
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Matos O, Esteves F. Pneumocystis jirovecii multilocus gene sequencing: findings and implications. Future Microbiol 2010; 5:1257-67. [DOI: 10.2217/fmb.10.75] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Pneumocystis jirovecii pneumonia (PcP) remains a major cause of respiratory illness among immunocompromised patients, especially patients infected with HIV, but it has also been isolated from immunocompetent persons. This article discusses the application of multilocus genotyping analysis to the study of the genetic diversity of P. jirovecii and its epidemiological and clinical parameters, and the important concepts achieved to date with these approaches. The multilocus typing studies performed until now have shown that there is an important genetic diversity of stable and ubiquitous P. jirovecii genotypes; infection with P. jirovecii is not necessarily clonal, recombination between some P. jirovecii multilocus genotypes has been suggested. P. jirovecii-specific multilocus genotypes can be associated with severity of PcP. Patients infected with P. jirovecii, regardless of the form of infection they present with, are part of a common human reservoir for future infections. The CYB, DHFR, DHPS, mtLSU rRNA, SOD and the ITS loci are suitable genetic targets to be used in further epidemiological studies focused on the identification and characterization of P. jirovecii haplotypes correlated with drug resistance and PcP outcome.
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Affiliation(s)
| | - Francisco Esteves
- Unidade de Protozoários Oportunistas/VIH e Outras Protozooses, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Lisboa, Portugal
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Esteves F, Gaspar J, Marques T, Leite R, Antunes F, Mansinho K, Matos O. Identification of relevant single-nucleotide polymorphisms in Pneumocystis jirovecii: relationship with clinical data. Clin Microbiol Infect 2010; 16:878-84. [DOI: 10.1111/j.1469-0691.2009.03030.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Catherinot E, Lanternier F, Bougnoux ME, Lecuit M, Couderc LJ, Lortholary O. Pneumocystis jirovecii Pneumonia. Infect Dis Clin North Am 2010; 24:107-38. [PMID: 20171548 DOI: 10.1016/j.idc.2009.10.010] [Citation(s) in RCA: 140] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Pneumocystis jirovecii has gained attention during the last decade in the context of the AIDS epidemic and the increasing use of cytotoxic and immunosuppressive therapies. This article summarizes current knowledge on biology, pathophysiology, epidemiology, diagnosis, prevention, and treatment of pulmonary P jirovecii infection, with a particular focus on the evolving pathophysiology and epidemiology. Pneumocystis pneumonia still remains a severe opportunistic infection, associated with a high mortality rate.
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Affiliation(s)
- Emilie Catherinot
- Université Paris Descartes, Service de Maladies Infectieuses et Tropicales, 149 Rue de Sèvres, Centre d'Infectiologie Necker-Pasteur, Hôpital Necker-Enfants Malades, Paris 75015, France
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