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Abstract
Bronchiectasis is a chronic condition of global relevance resulting in permanent and irreversible structural airway damage. Bacterial infection in bronchiectasis is well studied; however, recent molecular studies identify fungi as important pathogens, either independently or in association with bacteria. Aspergillus species are established fungal pathogens in cystic fibrosis and their role is now increasingly being recognized in noncystic fibrosis bronchiectasis. While the healthy airway is constantly exposed to ubiquitously present Aspergillus conidia in the environment, anatomically damaged airways appear more prone to colonization and subsequent infection by this fungal group. Aspergilli possess diverse immunopathological mechanistic capabilities and when coupled with innate immune defects in a susceptible host, such as that observed in bronchiectasis, it may promote a range of clinical manifestations including sensitization, allergic bronchopulmonary aspergillosis, Aspergillus bronchitis, and/or invasive aspergillosis. How such clinical states influence "endophenotypes" in bronchiectasis is therefore of importance, as each Aspergillus-associated disease state has overlapping features with bronchiectasis itself, and can evolve, depending on underlying host immunity from one type into another. Concurrent Aspergillus infection complicates the clinical course and exacerbations in bronchiectasis and therefore dedicated research to better understand the Aspergillus-host interaction in the bronchiectasis airway is now warranted.
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Affiliation(s)
- Tavleen Kaur Jaggi
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
| | - Soo Kai Ter
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
| | - Micheál Mac Aogáin
- Biochemical Genetics Laboratory, Department of Biochemistry, St. James's Hospital, Dublin, Ireland.,Clinical Biochemistry Unit, School of Medicine, Trinity College Dublin, Ireland
| | - Sanjay H Chotirmall
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
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Wang M, Li Q, Hou M, Chan LLY, Liu M, Ter SK, Dong T, Xia Y, Chotirmall SH, Fang M. Inactivation of common airborne antigens by perfluoroalkyl chemicals modulates early life allergic asthma. Proc Natl Acad Sci U S A 2021; 118:e2011957118. [PMID: 34099560 PMCID: PMC8214667 DOI: 10.1073/pnas.2011957118] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Allergic asthma, driven by T helper 2 cell-mediated immune responses to common environmental antigens, remains the most common respiratory disease in children. Perfluorinated chemicals (PFCs) are environmental contaminants of great concern, because of their wide application, persistence in the environment, and bioaccumulation. PFCs associate with immunological disorders including asthma and attenuate immune responses to vaccines. The influence of PFCs on the immunological response to allergens during childhood is unknown. We report here that a major PFC, perfluorooctane sulfonate (PFOS), inactivates house dust mite (HDM) to dampen 5-wk-old, early weaned mice from developing HDM-induced allergic asthma. PFOS further attenuates the asthma protective effect of the microbial product lipopolysaccharide (LPS). We demonstrate that PFOS prevents desensitization of lung epithelia by LPS, thus abolishing the latter's protective effect. A close mechanistic study reveals that PFOS specifically binds the major HDM allergen Der p1 with high affinity as well as the lipid A moiety of LPS, leading to the inactivation of both antigens. Moreover, PFOS at physiological human (nanomolar) concentrations inactivates Der p1 from HDM and LPS in vitro, although higher doses did not cause further inactivation because of possible formation of PFOS aggregates. This PFOS-induced neutralization of LPS has been further validated in primary human cell models and extended to an in vivo bacterial infection mouse model. This study demonstrates that early life exposure of mice to a PFC blunts airway antigen bioactivity to modulate pulmonary inflammatory responses, which may adversely affect early pulmonary health.
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Affiliation(s)
- Mengjing Wang
- School of Civil and Environmental Engineering, Nanyang Technological University, 639798 Singapore, Singapore
| | - Qianqian Li
- Key Laboratory of Environmental Nanotechnology and Health Effects, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 100085 Beijing, China
| | - Meifang Hou
- School of Ecological Technology and Engineering, Shanghai Institute of Technology, 201418 Shanghai, China
| | - Louisa L Y Chan
- Lee Kong Chian School of Medicine, Nanyang Technological University, 639798 Singapore, Singapore
| | - Meng Liu
- Lee Kong Chian School of Medicine, Nanyang Technological University, 639798 Singapore, Singapore
| | - Soo Kai Ter
- Lee Kong Chian School of Medicine, Nanyang Technological University, 639798 Singapore, Singapore
| | - Ting Dong
- School of Civil and Environmental Engineering, Nanyang Technological University, 639798 Singapore, Singapore
| | - Yun Xia
- Lee Kong Chian School of Medicine, Nanyang Technological University, 639798 Singapore, Singapore
| | - Sanjay H Chotirmall
- Lee Kong Chian School of Medicine, Nanyang Technological University, 639798 Singapore, Singapore
| | - Mingliang Fang
- School of Civil and Environmental Engineering, Nanyang Technological University, 639798 Singapore, Singapore;
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Ter SK, Rattanavong S, Roberts T, Sengduangphachanh A, Sihalath S, Panapruksachat S, Vongsouvath M, Newton PN, Simpson AJH, Robinson MT. Molecular Detection of Pathogens in Negative Blood Cultures in the Lao People's Democratic Republic. Am J Trop Med Hyg 2021; 104:1582-1585. [PMID: 33646978 PMCID: PMC8045604 DOI: 10.4269/ajtmh.20-1348] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Accepted: 12/20/2020] [Indexed: 12/29/2022] Open
Abstract
Bloodstream infections cause substantial morbidity and mortality. However, despite clinical suspicion of such infections, blood cultures are often negative. We investigated blood cultures that were negative after 5 days of incubation for the presence of bacterial pathogens using specific (Rickettsia spp. and Leptospira spp.) and a broad-range 16S rRNA PCR. From 190 samples, 53 (27.9%) were positive for bacterial DNA. There was also a high background incidence of dengue (90/112 patient serum positive, 80.4%). Twelve samples (6.3%) were positive for Rickettsia spp., including two Rickettsia typhi. The 16S rRNA PCR gave 41 positives; Escherichia coli and Klebsiella pneumoniae were identified in 11 and eight samples, respectively, and one Leptospira species was detected. Molecular investigation of negative blood cultures can identify potential pathogens that will otherwise be missed by routine culture. Patient management would have been influenced in all 53 patients for whom a bacterial organism was identified, and 2.3-6.1% of patients would likely have had an altered final outcome. These findings warrant further study, particularly to determine the cost-benefit for routine use, ways of implementation, and timing of PCR for organisms such as Rickettsia and Leptospira, which are important pathogens in rural Asia.
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Affiliation(s)
- Soo Kai Ter
- 1Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom.,2Royal Veterinary College, London, United Kingdom.,3Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao PDR
| | - Sayaphet Rattanavong
- 3Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao PDR
| | - Tamalee Roberts
- 3Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao PDR
| | - Amphonesavanh Sengduangphachanh
- 3Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao PDR
| | - Somsavanh Sihalath
- 3Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao PDR
| | - Siribun Panapruksachat
- 3Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao PDR
| | - Manivanh Vongsouvath
- 3Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao PDR
| | - Paul N Newton
- 1Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom.,3Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao PDR.,4Nuffield Department of Medicine, Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, United Kingdom
| | - Andrew J H Simpson
- 3Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao PDR.,4Nuffield Department of Medicine, Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, United Kingdom
| | - Matthew T Robinson
- 3Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao PDR.,4Nuffield Department of Medicine, Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, United Kingdom
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