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Verma R, Moreira FMF, do Prado Morais AO, Walter KS, Dos Santos PCP, Kim E, Soares TR, de Araujo RCP, da Silva BO, da Silva Santos A, Croda J, Andrews JR. Detection of M. tuberculosis in the environment as a tool for identifying high-risk locations for tuberculosis transmission. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 843:156970. [PMID: 35760168 DOI: 10.1016/j.scitotenv.2022.156970] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 06/21/2022] [Accepted: 06/21/2022] [Indexed: 06/15/2023]
Abstract
Tuberculosis (TB) remains a leading cause of infectious mortality globally, yet most cases cannot be epidemiologically linked even with extensive contact investigations and whole genome sequencing. Consequently, there remain major gaps in our understanding of where and when M. tuberculosis (Mtb) exposures occur. We aimed to investigate whether Mtb can be detected in environments where TB patients were recently present, which could serve as a tool for characterizing exposure risk. We collected 389 environment surface (ES) swabs from two high TB burden prisons in Brazil, sampling 41 (n = 340) cells occupied by individuals with active TB and 7 (n = 49) cells from individuals without TB. In a subset of pooled swabs (n = 6) and a swab from a cigarette lighter from the cell with active TB patients, we enriched Mtb DNA using RNA-bait hybrid capture assays and performed whole genome sequencing. In prison cells, Mtb DNA was detected in 55/340 (16 %) of ES swabs from cells occupied by active TB patients and none (0/49) from cells in which no active TB patients were present. Mtb was detected in 13/16 (81 %) prison cells occupied by the individuals with high/medium sputum Xpert Mtb load and 8/25 (32 %) with low/very low sputum Mtb load (p = 0.003). Seven hybrid capture samples had a median genomic coverage of 140×. rpoB mutations conferring high-level rifampin resistance were detected in 3/7 ES swabs. Mtb was frequently detectable in environments recently occupied by individuals with active TB. This approach could be applied in congregate environments to identify and characterize high-risk settings for Mtb exposure.
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Affiliation(s)
- Renu Verma
- Division of Infectious Diseases and Geographic Medicine, Stanford University School of Medicine, Stanford, CA, USA.
| | | | - Agne Oliveira do Prado Morais
- Postgraduate Program in Infectious and Parasitic Diseases, Federal University of Mato Grosso do Sul, Mato Grosso do Sul, Brazil
| | - Katharine S Walter
- Division of Infectious Diseases and Geographic Medicine, Stanford University School of Medicine, Stanford, CA, USA
| | - Paulo César Pereira Dos Santos
- Postgraduate Program in Infectious and Parasitic Diseases, Federal University of Mato Grosso do Sul, Mato Grosso do Sul, Brazil
| | - Eugene Kim
- Division of Infectious Diseases and Geographic Medicine, Stanford University School of Medicine, Stanford, CA, USA
| | - Thiego Ramon Soares
- Faculty of Health Sciences, Federal University of Grande Dourados, Dourados, MS, Brazil
| | | | | | | | - Julio Croda
- Oswaldo Cruz Foundation Mato Grosso do Sul, Mato Grosso do Sul, Brazil; Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, USA; Federal University of Mato Grosso do Sul - UFMS, Campo Grande, MS, Brazil
| | - Jason R Andrews
- Division of Infectious Diseases and Geographic Medicine, Stanford University School of Medicine, Stanford, CA, USA
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Environmental air sampling for detection and quantification of Mycobacterium tuberculosis in clinical settings: Proof of concept. Infect Control Hosp Epidemiol 2022; 44:774-779. [DOI: 10.1017/ice.2022.162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Abstract
Objective:
Novel approaches are needed to understand and disrupt Mycobacterium tuberculosis transmission. In this proof-of-concept study, we investigated the use of environmental air samplings to detect and quantify M. tuberculosis in different clinic settings in a high-burden area.
Design:
Cross-sectional, environmental sampling.
Setting:
Primary-care clinic.
Methods:
A portable, high-flow dry filter unit (DFU) was used to draw air through polyester felt filters for 2 hours. Samples were collected in the waiting area and TB room of a primary care clinic. Controls included sterile filters placed directly into collection tubes at the DFU sampling site, and filter samplings performed outdoors. DNA was extracted from the filters, and droplet digital polymerase chain reaction (ddPCR) was used to quantify M. tuberculosis DNA copies. Carbon dioxide (CO2) data loggers captured CO2 concentrations in the sampled areas.
Results:
The median sampling time was 123 minutes (interquartile range [IQR], 121–126). A median of 121 (IQR, 35–243) M. tuberculosis DNA copies were obtained from 74 clinic samplings, compared to a median of 3 (IQR, 1–33; P < .001) obtained from 47 controls. At a threshold of 320 DNA copies, specificity was 100%, and 18% of clinic samples would be classified as positive.
Conclusions:
This proof-of-concept study suggests that the potential for airborne M. tuberculosis detection based on M. tuberculosis DNA copy yield to enable the identification of high-risk transmission locations. Further optimization of the M. tuberculosis extraction technique and ddPCR data analysis would improve detection and enable robust interpretation of these data.
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Fan Y, Chen J, Liu M, Xu X, Zhang Y, Yue P, Cao W, Ji Z, Su X, Wen S, Kong J, Zhou G, Li B, Dong Y, Liu A, Bao F. Application of Droplet Digital PCR to Detection of Mycobacterium tuberculosis and Mycobacterium leprae Infections: A Narrative Review. Infect Drug Resist 2022; 15:1067-1076. [PMID: 35313727 PMCID: PMC8934166 DOI: 10.2147/idr.s349607] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Accepted: 01/25/2022] [Indexed: 12/15/2022] Open
Abstract
Tuberculosis (TB) is a chronic infectious disease caused by Mycobacterium tuberculosis (MTB) infection, which has seriously endangered human health for many years. With the emergence of multidrug-resistant and extensively drug-resistant MTB, the prevention and treatment of TB has become a pressing need. Early diagnosis, drug resistance monitoring, and control of disease transmission are critical aspects in the prevention and treatment of TB. However, the currently available diagnostic technologies and drug sensitivity tests are time consuming, and thus, it is difficult to achieve the goal of early diagnosis and detection drug sensitivity, which results in limited control of disease transmission. The development of molecular testing technology has gradually achieved the vision of rapid and accurate diagnosis of TB. Droplet digital PCR (ddPCR) is an excellent nucleic acid quantification method with high sensitivity and no need for a calibration curve. Herein, we review the application of ddPCR in TB diagnosis and drug resistance detection and transmission monitoring.
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Affiliation(s)
- Yuxin Fan
- The Institute for Tropical Medicine, Faculty of Basic Medical Sciences, Kunming Medical University, Kunming, 650500, People’s Republic of China
- Department of Microbiology and Immunology, Kunming Medical University, Kunming, 650030, People’s Republic of China
- Yunnan Province Key Laboratory of Children’s Major Diseases Research, The Affiliated Children Hospital, Kunming Medical University, Kunming, 650030, People’s Republic of China
| | - Jingjing Chen
- The Institute for Tropical Medicine, Faculty of Basic Medical Sciences, Kunming Medical University, Kunming, 650500, People’s Republic of China
- Department of Biochemistry and Molecular Biology, Kunming Medical University, Kunming, 650030, People’s Republic of China
| | - Meixiao Liu
- The Institute for Tropical Medicine, Faculty of Basic Medical Sciences, Kunming Medical University, Kunming, 650500, People’s Republic of China
- Department of Microbiology and Immunology, Kunming Medical University, Kunming, 650030, People’s Republic of China
| | - Xin Xu
- The Institute for Tropical Medicine, Faculty of Basic Medical Sciences, Kunming Medical University, Kunming, 650500, People’s Republic of China
- Department of Microbiology and Immunology, Kunming Medical University, Kunming, 650030, People’s Republic of China
| | - Yu Zhang
- The Institute for Tropical Medicine, Faculty of Basic Medical Sciences, Kunming Medical University, Kunming, 650500, People’s Republic of China
- Department of Microbiology and Immunology, Kunming Medical University, Kunming, 650030, People’s Republic of China
- Yunnan Province Key Laboratory of Children’s Major Diseases Research, The Affiliated Children Hospital, Kunming Medical University, Kunming, 650030, People’s Republic of China
| | - Peng Yue
- The Institute for Tropical Medicine, Faculty of Basic Medical Sciences, Kunming Medical University, Kunming, 650500, People’s Republic of China
- Department of Biochemistry and Molecular Biology, Kunming Medical University, Kunming, 650030, People’s Republic of China
| | - Wenjing Cao
- The Institute for Tropical Medicine, Faculty of Basic Medical Sciences, Kunming Medical University, Kunming, 650500, People’s Republic of China
- Department of Biochemistry and Molecular Biology, Kunming Medical University, Kunming, 650030, People’s Republic of China
| | - Zhenhua Ji
- The Institute for Tropical Medicine, Faculty of Basic Medical Sciences, Kunming Medical University, Kunming, 650500, People’s Republic of China
- Department of Microbiology and Immunology, Kunming Medical University, Kunming, 650030, People’s Republic of China
| | - Xuan Su
- The Institute for Tropical Medicine, Faculty of Basic Medical Sciences, Kunming Medical University, Kunming, 650500, People’s Republic of China
- Department of Microbiology and Immunology, Kunming Medical University, Kunming, 650030, People’s Republic of China
| | - Shiyuan Wen
- The Institute for Tropical Medicine, Faculty of Basic Medical Sciences, Kunming Medical University, Kunming, 650500, People’s Republic of China
- Department of Microbiology and Immunology, Kunming Medical University, Kunming, 650030, People’s Republic of China
- Yunnan Province Key Laboratory of Children’s Major Diseases Research, The Affiliated Children Hospital, Kunming Medical University, Kunming, 650030, People’s Republic of China
| | - Jing Kong
- The Institute for Tropical Medicine, Faculty of Basic Medical Sciences, Kunming Medical University, Kunming, 650500, People’s Republic of China
- Department of Microbiology and Immunology, Kunming Medical University, Kunming, 650030, People’s Republic of China
| | - Guozhong Zhou
- The Institute for Tropical Medicine, Faculty of Basic Medical Sciences, Kunming Medical University, Kunming, 650500, People’s Republic of China
- Department of Microbiology and Immunology, Kunming Medical University, Kunming, 650030, People’s Republic of China
| | - Bingxue Li
- The Institute for Tropical Medicine, Faculty of Basic Medical Sciences, Kunming Medical University, Kunming, 650500, People’s Republic of China
- Department of Microbiology and Immunology, Kunming Medical University, Kunming, 650030, People’s Republic of China
| | - Yan Dong
- The Institute for Tropical Medicine, Faculty of Basic Medical Sciences, Kunming Medical University, Kunming, 650500, People’s Republic of China
- Department of Microbiology and Immunology, Kunming Medical University, Kunming, 650030, People’s Republic of China
| | - Aihua Liu
- The Institute for Tropical Medicine, Faculty of Basic Medical Sciences, Kunming Medical University, Kunming, 650500, People’s Republic of China
- Yunnan Province Key Laboratory of Children’s Major Diseases Research, The Affiliated Children Hospital, Kunming Medical University, Kunming, 650030, People’s Republic of China
- Department of Biochemistry and Molecular Biology, Kunming Medical University, Kunming, 650030, People’s Republic of China
- Correspondence: Aihua Liu; Fukai Bao, The Institute for Tropical Medicine, Faculty of Basic Medical Sciences, Kunming Medical University, Kunming, 650500, People’s Republic of China, Email ;
| | - Fukai Bao
- The Institute for Tropical Medicine, Faculty of Basic Medical Sciences, Kunming Medical University, Kunming, 650500, People’s Republic of China
- Department of Microbiology and Immunology, Kunming Medical University, Kunming, 650030, People’s Republic of China
- Yunnan Province Key Laboratory of Children’s Major Diseases Research, The Affiliated Children Hospital, Kunming Medical University, Kunming, 650030, People’s Republic of China
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Bunyasi EW, Middelkoop K, Koch A, Hoosen Z, Mulenga H, Luabeya AKK, Shenje J, Mendelsohn SC, Tameris M, Scriba TJ, Warner DF, Wood R, Andrews JR, Hatherill M. Molecular Detection of Airborne Mycobacterium tuberculosis in South African High Schools. Am J Respir Crit Care Med 2022; 205:350-356. [PMID: 34752730 PMCID: PMC8886998 DOI: 10.1164/rccm.202102-0405oc] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Rationale: South African adolescents carry a high tuberculosis disease burden. It is not known if schools are high-risk settings for Mycobacterium tuberculosis (MTB) transmission. Objectives: To detect airborne MTB genomic DNA in classrooms. Methods: We studied 72 classrooms occupied by 2,262 students in two South African schools. High-volume air filtration was performed for median 40 (interquartile range [IQR], 35-54) minutes and assayed by droplet digital PCR (ddPCR)-targeting MTB region of difference 9 (RD9), with concurrent CO2 concentration measurement. Classroom data were benchmarked against public health clinics. Students who consented to individual tuberculosis screening completed a questionnaire and sputum collection (Xpert MTB/RIF Ultra) if symptom positive. Poisson statistics were used for MTB RD9 copy quantification. Measurements and Main Results: ddPCR assays were positive in 13/72 (18.1%) classrooms and 4/39 (10.3%) clinic measurements (P = 0.276). Median ambient CO2 concentration was 886 (IQR, 747-1223) ppm in classrooms versus 490 (IQR, 405-587) ppm in clinics (P < 0.001). Average airborne concentration of MTB RD9 was 3.61 copies per 180,000 liters in classrooms versus 1.74 copies per 180,000 liters in clinics (P = 0.280). Across all classrooms, the average risk of an occupant inhaling one MTB RD9 copy was estimated as 0.71% during one standard lesson of 35 minutes. Among 1,836/2,262 (81.2%) students who consented to screening, 21/90 (23.3%) symptomatic students produced a sputum sample, of which one was Xpert MTB/RIF Ultra positive. Conclusions: Airborne MTB genomic DNA was detected frequently in high school classrooms. Instantaneous risk of classroom exposure was similar to the risk in public health clinics.
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Affiliation(s)
- Erick W. Bunyasi
- South African Tuberculosis Vaccine Initiative, Institute of Infectious Disease and Molecular Medicine,,Department of Pathology
| | | | - Anastasia Koch
- SAMRC/NHLS/UCT Molecular Mycobacteriology Research Unit, Institute of Infectious Disease and Molecular Medicine, and
| | | | - Humphrey Mulenga
- South African Tuberculosis Vaccine Initiative, Institute of Infectious Disease and Molecular Medicine,,Department of Pathology
| | - Angelique K. K. Luabeya
- South African Tuberculosis Vaccine Initiative, Institute of Infectious Disease and Molecular Medicine,,Department of Pathology
| | - Justin Shenje
- South African Tuberculosis Vaccine Initiative, Institute of Infectious Disease and Molecular Medicine,,Department of Pathology
| | - Simon C. Mendelsohn
- South African Tuberculosis Vaccine Initiative, Institute of Infectious Disease and Molecular Medicine,,Department of Pathology
| | - Michele Tameris
- South African Tuberculosis Vaccine Initiative, Institute of Infectious Disease and Molecular Medicine,,Department of Pathology
| | - Thomas J. Scriba
- South African Tuberculosis Vaccine Initiative, Institute of Infectious Disease and Molecular Medicine,,Department of Pathology
| | - Digby F. Warner
- SAMRC/NHLS/UCT Molecular Mycobacteriology Research Unit, Institute of Infectious Disease and Molecular Medicine, and,Wellcome Centre for Infectious Diseases Research in Africa (CIDRI-Africa), University of Cape Town, Cape Town, South Africa; and
| | | | - Jason R. Andrews
- Division of Infectious Diseases and Geographic Medicine, Stanford University, Stanford, California
| | - Mark Hatherill
- South African Tuberculosis Vaccine Initiative, Institute of Infectious Disease and Molecular Medicine,,Department of Pathology
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5
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Matuka DO, Duba T, Ngcobo Z, Made F, Muleba L, Nthoke T, Singh TS. Occupational Risk of Airborne Mycobacterium tuberculosis Exposure: A Situational Analysis in a Three-Tier Public Healthcare System in South Africa. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph181910130. [PMID: 34639431 PMCID: PMC8508202 DOI: 10.3390/ijerph181910130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Revised: 09/15/2021] [Accepted: 09/18/2021] [Indexed: 11/23/2022]
Abstract
This study aimed to detect airborne Mycobacterium tuberculosis (MTB) at nine public health facilities in three provinces of South Africa and determine possible risk factors that may contribute to airborne transmission. Personal samples (n = 264) and stationary samples (n = 327) were collected from perceived high-risk areas in district, primary health clinics (PHCs) and TB facilities. Quantitative real-time (RT) polymerase chain reaction (PCR) was used for TB analysis. Walkabout observations and work practices through the infection prevention and control (IPC) questionnaire were documented. Statistical analysis was carried out using Stata version 15.2 software. Airborne MTB was detected in 2.2% of samples (13/572), and 97.8% were negative. District hospitals and Western Cape province had the most TB-positive samples and identified risk areas included medical wards, casualty, and TB wards. MTB-positive samples were not detected in PHCs and during the summer season. All facilities reported training healthcare workers (HCWs) on TB IPC. The risk factors for airborne MTB included province, type of facility, area or section, season, lack of UVGI, and ineffective ventilation. Environmental monitoring, PCR, IPC questionnaire, and walkabout observations can estimate the risk of TB transmission in various settings. These findings can be used to inform management and staff to improve the TB IPC programmes.
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Affiliation(s)
- Dikeledi O. Matuka
- National Institute for Occupational Health (NIOH), National Health Laboratory Service (NHLS), Johannesburg 2000, South Africa; (D.O.M.); (T.D.); (Z.N.); (F.M.); (L.M.); (T.N.)
| | - Thabang Duba
- National Institute for Occupational Health (NIOH), National Health Laboratory Service (NHLS), Johannesburg 2000, South Africa; (D.O.M.); (T.D.); (Z.N.); (F.M.); (L.M.); (T.N.)
| | - Zethembiso Ngcobo
- National Institute for Occupational Health (NIOH), National Health Laboratory Service (NHLS), Johannesburg 2000, South Africa; (D.O.M.); (T.D.); (Z.N.); (F.M.); (L.M.); (T.N.)
| | - Felix Made
- National Institute for Occupational Health (NIOH), National Health Laboratory Service (NHLS), Johannesburg 2000, South Africa; (D.O.M.); (T.D.); (Z.N.); (F.M.); (L.M.); (T.N.)
| | - Lufuno Muleba
- National Institute for Occupational Health (NIOH), National Health Laboratory Service (NHLS), Johannesburg 2000, South Africa; (D.O.M.); (T.D.); (Z.N.); (F.M.); (L.M.); (T.N.)
| | - Tebogo Nthoke
- National Institute for Occupational Health (NIOH), National Health Laboratory Service (NHLS), Johannesburg 2000, South Africa; (D.O.M.); (T.D.); (Z.N.); (F.M.); (L.M.); (T.N.)
| | - Tanusha S. Singh
- National Institute for Occupational Health (NIOH), National Health Laboratory Service (NHLS), Johannesburg 2000, South Africa; (D.O.M.); (T.D.); (Z.N.); (F.M.); (L.M.); (T.N.)
- Department of Clinical Microbiology and Infectious Disease, School of Pathology, University of the Witwatersrand, Johannesburg 2000, South Africa
- Department of Environmental Health, School of Health Sciences, University of Johannesburg, Johannesburg 2028, South Africa
- Correspondence:
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6
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Hoover AG, Heiger-Bernays W, Ojha S, Pennell KG. Balancing incomplete COVID-19 evidence and local priorities: risk communication and stakeholder engagement strategies for school re-opening. REVIEWS ON ENVIRONMENTAL HEALTH 2021; 36:27-37. [PMID: 33001857 PMCID: PMC7933073 DOI: 10.1515/reveh-2020-0092] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Accepted: 09/08/2020] [Indexed: 05/09/2023]
Abstract
In the midst of the COVID-19 pandemic, United States (U.S.) educational institutions must weigh incomplete scientific evidence to inform decisions about how best to re-open schools without sacrificing public health. While many communities face surging case numbers, others are experiencing case plateaus or even decreasing numbers. Simultaneously, some U.S. school systems face immense infrastructure challenges and resource constraints, while others are better positioned to resume face-to-face instruction. In this review, we first examine potential engineering controls to reduce SARS-CoV-2 exposures; we then present processes whereby local decision-makers can identify and partner with scientists, faculty, students, parents, public health officials, and others to determine the controls most appropriate for their communities. While no solution completely eliminates risks of SARS-CoV-2 exposure and illness, this mini-review discusses engaged decision and communication processes that incorporate current scientific knowledge, school district constraints, local tolerance for health risk, and community priorities to help guide schools in selecting and implementing re-opening strategies that are acceptable, feasible, and context-specific.
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Affiliation(s)
- Anna G. Hoover
- University of Kentucky, College of Public Health, Department of Preventive Medicine and Environmental Health, Lexington, KY 40506, USA
| | - Wendy Heiger-Bernays
- Boston University, School of Public Health, Department of Environmental Health, Boston, MA 02118, USA
| | - Sweta Ojha
- University of Kentucky, College of Engineering, Department of Civil Engineering, Lexington, KY 40506, USA
| | - Kelly G. Pennell
- University of Kentucky, College of Engineering, Department of Civil Engineering, Lexington, KY 40506, USA
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7
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Rufino de Sousa N, Sandström N, Shen L, Håkansson K, Vezozzo R, Udekwu KI, Croda J, Rothfuchs AG. A fieldable electrostatic air sampler enabling tuberculosis detection in bioaerosols. Tuberculosis (Edinb) 2020; 120:101896. [PMID: 32090857 PMCID: PMC7049907 DOI: 10.1016/j.tube.2019.101896] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 11/05/2019] [Accepted: 12/15/2019] [Indexed: 01/03/2023]
Abstract
Tuberculosis (TB) infects about 25% of the world population and claims more human lives than any other infectious disease. TB is spread by inhalation of aerosols containing viable Mycobacterium tuberculosis expectorated or exhaled by patients with active pulmonary disease. Air-sampling technology could play an important role in TB control by enabling the detection of airborne M. tuberculosis, but tools that are easy to use and scalable in TB hotspots are lacking. We developed an electrostatic air sampler termed the TB Hotspot DetectOR (THOR) and investigated its performance in laboratory aerosol experiments and in a prison hotspot of TB transmission. We show that THOR collects aerosols carrying microspheres, Bacillus globigii spores and M. bovis BCG, concentrating these microparticles onto a collector piece designed for subsequent detection analysis. The unit was also successfully operated in the complex setting of a prison hotspot, enabling detection of a molecular signature for M. tuberculosis in the cough of inmates. Future deployment of this device may lead to a measurable impact on TB case-finding by screening individuals through the aerosols they generate.
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Affiliation(s)
- Nuno Rufino de Sousa
- Department of Microbiology, Tumor and Cell Biology (MTC), Karolinska Institutet, Stockholm, Sweden
| | - Niklas Sandström
- Department of Microbiology, Tumor and Cell Biology (MTC), Karolinska Institutet, Stockholm, Sweden
| | - Lei Shen
- Department of Microbiology, Tumor and Cell Biology (MTC), Karolinska Institutet, Stockholm, Sweden
| | - Kathleen Håkansson
- Department of Microbiology, Tumor and Cell Biology (MTC), Karolinska Institutet, Stockholm, Sweden
| | - Rafaella Vezozzo
- Faculty of Health Sciences, Federal University of Grande Dourados, Dourados, Brazil
| | - Klas I Udekwu
- Department of Molecular Biosciences, Wenner-Gren Institutet, Stockholms Universitet, Stockholm, Sweden
| | - Julio Croda
- School of Medicine, Federal University of Mato Grosso do Sul, Campo Grande, Brazil; Oswaldo Cruz Foundation, Mato Grosso do Sul, Campo Grande, Brazil
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8
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Shaikh A, Sriraman K, Vaswani S, Oswal V, Mistry N. Detection of Mycobacterium tuberculosis RNA in bioaerosols from pulmonary tuberculosis patients. Int J Infect Dis 2019; 86:5-11. [PMID: 31202909 DOI: 10.1016/j.ijid.2019.06.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2019] [Revised: 06/04/2019] [Accepted: 06/09/2019] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Bioaerosols from pulmonary tuberculosis (PTB) patients are a quantitative predictor of transmission. Current methods involve sophisticated instruments and time-consuming techniques to assess viable TB bacteria in bioaerosols. We tested the feasibility of detecting Mycobacterium tuberculosis (Mtb) specific RNA from bioaerosols retained on TB patients' masks. METHODS Adult PTB patients (n=33) were recruited at diagnosis before GeneXpert confirmation between April-2017 to February-2019 from private TB clinics in Mumbai. Face mask worn for 1 or 3h or N95 mask containing a cellulose acetate membrane worn for 5min by the patients were tested for the presence of Mtb RNA by quantitative PCR and bacterial load was estimated. RESULTS Quantitative PCR targeting rpoB, sigA,16S and fgd1 and sequencing of rpoB confirmed the presence of Mtb specific RNA in mask samples including masks of two patients with unproductive sputum. Membrane samples had seven-fold higher RNA and bacterial load that correlated to bacterial load estimated by sputum GeneXpert. CONCLUSION The study demonstrates that patient masks can be used to sample bioaerosols for detection of viable Mtb. The findings have translational value in the diagnosis of TB and monitoring Mtb variations between and within patients useful for assessing infectiousness and treatment response.
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Affiliation(s)
- Ambreen Shaikh
- The Foundation for Medical Research, Dr. Kantilal J. Sheth Memorial Building, 84-A, RG Thadani Marg, Worli, Mumbai, Maharashtra 400018, India
| | - Kalpana Sriraman
- The Foundation for Medical Research, Dr. Kantilal J. Sheth Memorial Building, 84-A, RG Thadani Marg, Worli, Mumbai, Maharashtra 400018, India
| | - Smriti Vaswani
- The Foundation for Medical Research, Dr. Kantilal J. Sheth Memorial Building, 84-A, RG Thadani Marg, Worli, Mumbai, Maharashtra 400018, India
| | - Vikas Oswal
- Sai Hospital, 90 Feet Rd., Masiha Islampura Co-op Hsg. Soc. Ltd., Dharavi, Mumbai, Maharashtra 400017, India; Vikas Nursing Home, Plot no. 18/U/1/2, Shivaji Nagar, Govandi East, Mumbai, Maharashtra 400043, India
| | - Nerges Mistry
- The Foundation for Medical Research, Dr. Kantilal J. Sheth Memorial Building, 84-A, RG Thadani Marg, Worli, Mumbai, Maharashtra 400018, India.
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9
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Martinez L, Verma R, Croda J, Horsburgh CR, Walter KS, Degner N, Middelkoop K, Koch A, Hermans S, Warner DF, Wood R, Cobelens F, Andrews JR. Detection, survival and infectious potential of Mycobacterium tuberculosis in the environment: a review of the evidence and epidemiological implications. Eur Respir J 2019; 53:1802302. [PMID: 31048345 PMCID: PMC6753378 DOI: 10.1183/13993003.02302-2018] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Accepted: 04/18/2019] [Indexed: 11/05/2022]
Abstract
Much remains unknown about Mycobacterium tuberculosis transmission. Seminal experimental studies from the 1950s demonstrated that airborne expulsion of droplet nuclei from an infectious tuberculosis (TB) patient is the primary route of transmission. However, these findings did not rule out other routes of M. tuberculosis transmission. We reviewed historical scientific evidence from the late 19th/early 20th century and contemporary studies investigating the presence, persistence and infectiousness of environmental M. tuberculosis We found both experimental and epidemiological evidence supporting the presence and viability of M. tuberculosis in multiple natural and built environments for months to years, presumably following contamination by a human source. Furthermore, several studies confirm M. tuberculosis viability and virulence in the environment using guinea pig and mouse models. Most of this evidence was historical; however, several recent studies have reported consistent findings of M. tuberculosis detection and viability in the environment using modern methods. Whether M. tuberculosis in environments represents an infectious threat to humans requires further investigation; this may represent an untapped source of data with which to further understand M. tuberculosis transmission. We discuss potential opportunities for harnessing these data to generate new insights into TB transmission in congregate settings.
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Affiliation(s)
- Leonardo Martinez
- Division of Infectious Diseases and Geographic Medicine, School of Medicine, Stanford University, Stanford, CA, USA
| | - Renu Verma
- Division of Infectious Diseases and Geographic Medicine, School of Medicine, Stanford University, Stanford, CA, USA
| | - Julio Croda
- Oswaldo Cruz Foundation, Campo Grande and Salvador, Brazil
- School of Medicine, Federal University of Mato Grosso do Sul, Campo Grande, Brazil
| | - C Robert Horsburgh
- Dept of Medicine, Boston University School of Medicine, Boston, MA, USA
- Dept of Epidemiology, Biostatistics and Global Health, Boston University School of Public Health, Boston, MA, USA
| | - Katharine S Walter
- Division of Infectious Diseases and Geographic Medicine, School of Medicine, Stanford University, Stanford, CA, USA
| | - Nicholas Degner
- Division of Infectious Diseases and Geographic Medicine, School of Medicine, Stanford University, Stanford, CA, USA
| | - Keren Middelkoop
- The Desmond Tutu HIV Centre, Institute for Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- Dept of Medicine, University of Cape Town, Cape Town, South Africa
| | - Anastasia Koch
- SAMRC/NHLS/UCT Molecular Mycobacteriology Research Unit, Dept of Pathology and Institute of Infectious Diseases and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Sabine Hermans
- The Desmond Tutu HIV Centre, Institute for Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- Dept of Global Health, Amsterdam Institute for Global Health and Development, Academic Medical Center, Amsterdam, The Netherlands
| | - Digby F Warner
- SAMRC/NHLS/UCT Molecular Mycobacteriology Research Unit, Dept of Pathology and Institute of Infectious Diseases and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- Wellcome Center for Infectious Diseases Research in Africa, Institute of Infectious Diseases and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Robin Wood
- The Desmond Tutu HIV Centre, Institute for Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Frank Cobelens
- Dept of Global Health, Amsterdam Institute for Global Health and Development, Academic Medical Center, Amsterdam, The Netherlands
| | - Jason R Andrews
- Division of Infectious Diseases and Geographic Medicine, School of Medicine, Stanford University, Stanford, CA, USA
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10
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Patterson B, Morrow C, Singh V, Moosa A, Gqada M, Woodward J, Mizrahi V, Bryden W, Call C, Patel S, Warner D, Wood R. Detection of Mycobacterium tuberculosis bacilli in bio-aerosols from untreated TB patients. Gates Open Res 2018; 1:11. [PMID: 29355225 PMCID: PMC5757796 DOI: 10.12688/gatesopenres.12758.2] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/05/2018] [Indexed: 12/02/2022] Open
Abstract
Background: Tuberculosis (TB) is predominantly an airborne disease. However, quantitative and qualitative analysis of bio-aerosols containing the aetiological agent, Mycobacterium tuberculosis (Mtb), has proven very challenging. Our objective is to sample bio-aerosols from newly diagnosed TB patients for detection and enumeration of Mtb bacilli. Methods: We monitored each of 35 newly diagnosed, GeneXpert sputum-positive, TB patients during 1 hour confinement in a custom-built Respiratory Aerosol Sampling Chamber (RASC). The RASC (a small clean-room of 1.4m ) incorporates aerodynamic particle size detection, viable and non-viable sampling devices, real-time CO 2 monitoring, and cough sound-recording. Microbiological culture and droplet digital polymerase chain reaction (ddPCR) were used to detect Mtb in each of the bio-aerosol collection devices. Results: Mtb was detected in 27/35 (77.1%) of aerosol samples; 15/35 (42.8%) samples were positive by mycobacterial culture and 25/27 (92.96%) were positive by ddPCR. Culturability of collected bacilli was not predicted by radiographic evidence of pulmonary cavitation, sputum smear positivity. A correlation was found between cough rate and culturable bioaerosol. Mtb was detected on all viable cascade impactor stages with a peak at aerosol sizes 2.0-3.5μm. This suggests a median of 0.09 CFU/litre of exhaled air (IQR: 0.07 to 0.3 CFU/l) for the aerosol culture positives and an estimated median concentration of 4.5x10 CFU/ml (IQR: 2.9x10 -5.6x10 ) of exhaled particulate bio-aerosol. Conclusions: Mtb was identified in bio-aerosols exhaled by the majority of untreated TB patients using the RASC. Molecular detection was more sensitive than mycobacterial culture on solid media, suggesting that further studies are required to determine whether this reflects a significant proportion of differentially detectable bacilli in these samples.
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Affiliation(s)
- Benjamin Patterson
- Division of Infectious Diseases, Department of Medicine, Columbia University, College of Physicians and Surgeons, New York, NY, USA
| | - Carl Morrow
- Institute of Infectious Disease and Molecular Medicine (IDM), Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- Desmond Tutu HIV Centre,Institute of Infectious Disease and Molecular Medicine (IDM), University of Cape Town, Cape Town, South Africa
| | - Vinayak Singh
- Institute of Infectious Disease and Molecular Medicine (IDM), Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- MRC/NHLS/UCT Molecular Mycobacteriology Research Unit & DST/NRF Centre of Excellence for Biomedical TB Research, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Atica Moosa
- Institute of Infectious Disease and Molecular Medicine (IDM), Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- MRC/NHLS/UCT Molecular Mycobacteriology Research Unit & DST/NRF Centre of Excellence for Biomedical TB Research, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Melitta Gqada
- Desmond Tutu HIV Centre,Institute of Infectious Disease and Molecular Medicine (IDM), University of Cape Town, Cape Town, South Africa
| | - Jeremy Woodward
- Department of Integrative Biomedical Sciences, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Valerie Mizrahi
- Institute of Infectious Disease and Molecular Medicine (IDM), Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- MRC/NHLS/UCT Molecular Mycobacteriology Research Unit & DST/NRF Centre of Excellence for Biomedical TB Research, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | | | | | - Shwetak Patel
- Computer Science and Engineering, Electrical Engineering DUB group, University of Washington, Seattle, USA
| | - Digby Warner
- Institute of Infectious Disease and Molecular Medicine (IDM), Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- MRC/NHLS/UCT Molecular Mycobacteriology Research Unit & DST/NRF Centre of Excellence for Biomedical TB Research, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Robin Wood
- Institute of Infectious Disease and Molecular Medicine (IDM), Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- Desmond Tutu HIV Centre,Institute of Infectious Disease and Molecular Medicine (IDM), University of Cape Town, Cape Town, South Africa
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11
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Patterson B, Morrow C, Singh V, Moosa A, Gqada M, Woodward J, Mizrahi V, Bryden W, Call C, Patel S, Warner D, Wood R. Detection of Mycobacterium tuberculosis bacilli in bio-aerosols from untreated TB patients. Gates Open Res 2017; 1:11. [PMID: 29355225 PMCID: PMC5757796 DOI: 10.12688/gatesopenres.12758.1] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/30/2017] [Indexed: 11/20/2022] Open
Abstract
Background: Tuberculosis (TB) is predominantly an airborne disease. However, quantitative and qualitative analysis of bio-aerosols containing the aetiological agent, Mycobacterium tuberculosis (Mtb), has proven very challenging. Our objective is to sample bio-aerosols from newly diagnosed TB patients for detection and enumeration of Mtb bacilli. Methods: We monitored each of 35 newly diagnosed, GeneXpert sputum-positive, TB patients during 1 hour confinement in a custom-built Respiratory Aerosol Sampling Chamber (RASC). The RASC (a small clean-room of 1.4m ) incorporates aerodynamic particle size detection, viable and non-viable sampling devices, real-time CO 2 monitoring, and cough sound-recording. Microbiological culture and droplet digital polymerase chain reaction (ddPCR) were used to detect Mtb in each of the bio-aerosol collection devices. Results: Mtb was detected in 27/35 (77.1%) of aerosol samples; 15/35 (42.8%) samples were positive by mycobacterial culture and 25/27 (92.96%) were positive by ddPCR. Culturability of collected bacilli was not predicted by radiographic evidence of pulmonary cavitation, sputum smear positivity, or cough rate. Mtb was detected on all viable cascade impactor stages with a peak at aerosol sizes 2.0-3.5μm. This suggests a median of 0.09 CFU/litre of exhaled air (IQR: 0.07 to 0.3 CFU/l) for the aerosol culture positives and an estimated median concentration of 4.5x10 CFU/ml (IQR: 2.9x10 -5.6x10 ) of exhaled particulate bio-aerosol. Conclusions: Mtb was identified in bio-aerosols exhaled by the majority of untreated TB patients using the RASC. Molecular detection was more sensitive than mycobacterial culture on solid media, suggesting that further studies are required to determine whether this reflects a significant proportion of differentially detectable bacilli in these samples.
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Affiliation(s)
- Benjamin Patterson
- Division of Infectious Diseases, Department of Medicine, Columbia University, College of Physicians and Surgeons, New York, NY, USA
| | - Carl Morrow
- Institute of Infectious Disease and Molecular Medicine (IDM), Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- Desmond Tutu HIV Centre,Institute of Infectious Disease and Molecular Medicine (IDM), University of Cape Town, Cape Town, South Africa
| | - Vinayak Singh
- Institute of Infectious Disease and Molecular Medicine (IDM), Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- MRC/NHLS/UCT Molecular Mycobacteriology Research Unit & DST/NRF Centre of Excellence for Biomedical TB Research, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Atica Moosa
- Institute of Infectious Disease and Molecular Medicine (IDM), Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- MRC/NHLS/UCT Molecular Mycobacteriology Research Unit & DST/NRF Centre of Excellence for Biomedical TB Research, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Melitta Gqada
- Desmond Tutu HIV Centre,Institute of Infectious Disease and Molecular Medicine (IDM), University of Cape Town, Cape Town, South Africa
| | - Jeremy Woodward
- Department of Integrative Biomedical Sciences, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Valerie Mizrahi
- Institute of Infectious Disease and Molecular Medicine (IDM), Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- MRC/NHLS/UCT Molecular Mycobacteriology Research Unit & DST/NRF Centre of Excellence for Biomedical TB Research, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | | | | | - Shwetak Patel
- Computer Science and Engineering, Electrical Engineering DUB group, University of Washington, Seattle, USA
| | - Digby Warner
- Institute of Infectious Disease and Molecular Medicine (IDM), Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- MRC/NHLS/UCT Molecular Mycobacteriology Research Unit & DST/NRF Centre of Excellence for Biomedical TB Research, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Robin Wood
- Institute of Infectious Disease and Molecular Medicine (IDM), Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- Desmond Tutu HIV Centre,Institute of Infectious Disease and Molecular Medicine (IDM), University of Cape Town, Cape Town, South Africa
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12
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Yates TA, Khan PY, Knight GM, Taylor JG, McHugh TD, Lipman M, White RG, Cohen T, Cobelens FG, Wood R, Moore DAJ, Abubakar I. The transmission of Mycobacterium tuberculosis in high burden settings. THE LANCET. INFECTIOUS DISEASES 2016; 16:227-38. [PMID: 26867464 DOI: 10.1016/s1473-3099(15)00499-5] [Citation(s) in RCA: 118] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Revised: 11/03/2015] [Accepted: 11/26/2015] [Indexed: 01/06/2023]
Abstract
Unacceptable levels of Mycobacterium tuberculosis transmission are noted in high burden settings and a renewed focus on reducing person-to-person transmission in these communities is needed. We review recent developments in the understanding of airborne transmission. We outline approaches to measure transmission in populations and trials and describe the Wells-Riley equation, which is used to estimate transmission risk in indoor spaces. Present research priorities include the identification of effective strategies for tuberculosis infection control, improved understanding of where transmission occurs and the transmissibility of drug-resistant strains, and estimates of the effect of HIV and antiretroviral therapy on transmission dynamics. When research is planned and interventions are designed to interrupt transmission, resource constraints that are common in high burden settings-including shortages of health-care workers-must be considered.
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Affiliation(s)
- Tom A Yates
- Centre for Infectious Disease Epidemiology, Research Department of Infection and Population Health, University College London, London, UK; Wellcome Trust Africa Centre for Population Health, Mtubatuba, South Africa, London School of Hygiene & Tropical Medicine, London, UK.
| | - Palwasha Y Khan
- Department of Infectious Disease Epidemiology, Faculty of Epidemiology and Population Health, London School of Hygiene & Tropical Medicine, London, UK; Tuberculosis Centre, London School of Hygiene & Tropical Medicine, London, UK; Karonga Prevention Study, Chilumba, Malawi
| | - Gwenan M Knight
- Tuberculosis Centre, London School of Hygiene & Tropical Medicine, London, UK; Tuberculosis Modelling Group, London School of Hygiene & Tropical Medicine, London, UK; National Institute for Health Research Health Protection Research Unit in Healthcare Associated Infection and Antimicrobial Resistance, Imperial College London, London, UK
| | - Jonathon G Taylor
- UCL Institute for Environmental Design and Engineering, Bartlett School of Environment, Energy and Resources, University College London, London, UK
| | - Timothy D McHugh
- Centre for Clinical Microbiology, University College London, London, UK
| | - Marc Lipman
- Division of Medicine, University College London, London, UK
| | - Richard G White
- Tuberculosis Centre, London School of Hygiene & Tropical Medicine, London, UK; Tuberculosis Modelling Group, London School of Hygiene & Tropical Medicine, London, UK
| | - Ted Cohen
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, USA
| | - Frank G Cobelens
- Department of Global Health, Academic Medical Center, Amsterdam, Netherlands; KNCV Tuberculosis Foundation, The Hague, Netherlands
| | - Robin Wood
- Department of Infectious Disease Epidemiology, Faculty of Epidemiology and Population Health, London School of Hygiene & Tropical Medicine, London, UK; Tuberculosis Centre, London School of Hygiene & Tropical Medicine, London, UK; The Desmond Tutu HIV Centre, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Cape Town, South Africa
| | - David A J Moore
- Tuberculosis Centre, London School of Hygiene & Tropical Medicine, London, UK; Department of Clinical Research, London School of Hygiene & Tropical Medicine, London, UK
| | - Ibrahim Abubakar
- Centre for Infectious Disease Epidemiology, Research Department of Infection and Population Health, University College London, London, UK; MRC Clinical Trials Unit at University College London, University College London, London, UK
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13
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Wood R, Morrow C, Barry CE, Bryden WA, Call CJ, Hickey AJ, Rodes CE, Scriba TJ, Blackburn J, Issarow C, Mulder N, Woodward J, Moosa A, Singh V, Mizrahi V, Warner DF. Real-Time Investigation of Tuberculosis Transmission: Developing the Respiratory Aerosol Sampling Chamber (RASC). PLoS One 2016; 11:e0146658. [PMID: 26807816 PMCID: PMC4726558 DOI: 10.1371/journal.pone.0146658] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Accepted: 12/21/2015] [Indexed: 11/18/2022] Open
Abstract
Knowledge of the airborne nature of respiratory disease transmission owes much to the pioneering experiments of Wells and Riley over half a century ago. However, the mechanical, physiological, and immunopathological processes which drive the production of infectious aerosols by a diseased host remain poorly understood. Similarly, very little is known about the specific physiological, metabolic and morphological adaptations which enable pathogens such as Mycobacterium tuberculosis (Mtb) to exit the infected host, survive exposure to the external environment during airborne carriage, and adopt a form that is able to enter the respiratory tract of a new host, avoiding innate immune and physical defenses to establish a nascent infection. As a first step towards addressing these fundamental knowledge gaps which are central to any efforts to interrupt disease transmission, we developed and characterized a small personal clean room comprising an array of sampling devices which enable isolation and representative sampling of airborne particles and organic matter from tuberculosis (TB) patients. The complete unit, termed the Respiratory Aerosol Sampling Chamber (RASC), is instrumented to provide real-time information about the particulate output of a single patient, and to capture samples via a suite of particulate impingers, impactors and filters. Applying the RASC in a clinical setting, we demonstrate that a combination of molecular and microbiological assays, as well as imaging by fluorescence and scanning electron microscopy, can be applied to investigate the identity, viability, and morphology of isolated aerosolized particles. Importantly, from a preliminary panel of active TB patients, we observed the real-time production of large numbers of airborne particles including Mtb, as confirmed by microbiological culture and polymerase chain reaction (PCR) genotyping. Moreover, direct imaging of captured samples revealed the presence of multiple rod-like Mtb organisms whose physical dimensions suggested the capacity for travel deep into the alveolar spaces of the human lung.
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Affiliation(s)
- Robin Wood
- Institute of Infectious Disease and Molecular Medicine (IDM), Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- Desmond Tutu HIV Centre, IDM, University of Cape Town, Cape Town, South Africa
| | - Carl Morrow
- Institute of Infectious Disease and Molecular Medicine (IDM), Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- Desmond Tutu HIV Centre, IDM, University of Cape Town, Cape Town, South Africa
- * E-mail:
| | - Clifton E. Barry
- Institute of Infectious Disease and Molecular Medicine (IDM), Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- Laboratory of Clinical Infectious Diseases, National Institute of Allergy and Infectious Diseases, US National Institutes of Health, Bethesda, Maryland, United States of America
| | - Wayne A. Bryden
- Zeteo Tech LLC, Ellicott City, Maryland, United States of America
| | - Charles J. Call
- Zeteo Tech LLC, Ellicott City, Maryland, United States of America
| | - Anthony J. Hickey
- RTI International, Research Triangle Park, North Carolina, United States of America
| | - Charles E. Rodes
- Aerosol Exposure Dimensions, Cary, North Carolina, United States of America
| | - Thomas J. Scriba
- Institute of Infectious Disease and Molecular Medicine (IDM), Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- South African Tuberculosis Vaccine Initiative, Department of Paediatrics and Child Health, University of Cape Town, Cape Town, South Africa
| | - Jonathan Blackburn
- Institute of Infectious Disease and Molecular Medicine (IDM), Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- Structural Biology Research Unit, Department of Integrative Biomedical Sciences, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Chacha Issarow
- Institute of Infectious Disease and Molecular Medicine (IDM), Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- Structural Biology Research Unit, Department of Integrative Biomedical Sciences, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Nicola Mulder
- Institute of Infectious Disease and Molecular Medicine (IDM), Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- Structural Biology Research Unit, Department of Integrative Biomedical Sciences, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Jeremy Woodward
- Structural Biology Research Unit, Department of Integrative Biomedical Sciences, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Atica Moosa
- Institute of Infectious Disease and Molecular Medicine (IDM), Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- MRC/NHLS/UCT Molecular Mycobacteriology Research Unit & DST/NRF Centre of Excellence for Biomedical TB Research, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Vinayak Singh
- Institute of Infectious Disease and Molecular Medicine (IDM), Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- MRC/NHLS/UCT Molecular Mycobacteriology Research Unit & DST/NRF Centre of Excellence for Biomedical TB Research, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Valerie Mizrahi
- Institute of Infectious Disease and Molecular Medicine (IDM), Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- MRC/NHLS/UCT Molecular Mycobacteriology Research Unit & DST/NRF Centre of Excellence for Biomedical TB Research, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Digby F. Warner
- Institute of Infectious Disease and Molecular Medicine (IDM), Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- MRC/NHLS/UCT Molecular Mycobacteriology Research Unit & DST/NRF Centre of Excellence for Biomedical TB Research, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
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14
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Matuka O, Singh TS, Bryce E, Yassi A, Kgasha O, Zungu M, Kyaw K, Malotle M, Renton K, O'Hara L. Pilot study to detect airborne Mycobacterium tuberculosis exposure in a South African public healthcare facility outpatient clinic. J Hosp Infect 2014; 89:192-6. [PMID: 25623206 DOI: 10.1016/j.jhin.2014.11.013] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Accepted: 11/19/2014] [Indexed: 11/17/2022]
Abstract
BACKGROUND Airborne transmission of Mycobacterium tuberculosis remains an occupational health hazard, particularly in crowded and resource-limited healthcare settings. AIM To quantify airborne M. tuberculosis in a busy outpatient clinic in Gauteng, South Africa. METHODS Stationary air samples and samples from healthcare workers (HCWs) were collected in the polyclinic and administrative block. Quantitative real-time polymerase chain reaction (PCR) was used to detect airborne M. tuberculosis. Walkthrough observations and work practices of HCWs were also recorded. FINDINGS In total, M. tuberculosis was detected in 11 of 49 (22.4%) samples: nine of 25 (36%) HCW samples and two of 24 (8.3%) stationary air samples. Samples from five of 10 medical officers (50%) and three of 13 nurses (23%) were positive. Repeat measurements on different days showed variable results. Most of the HCWs (87.5%) with positive results had been in contact with coughing patients and had not worn respiratory masks despite training. CONCLUSION The use of air sampling coupled with quantitative real-time PCR is a simple and effective tool to demonstrate the risk of M. tuberculosis exposure. The findings provide an impetus for hospital management to strengthen infection prevention and control measures for tuberculosis.
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Affiliation(s)
- O Matuka
- National Institute for Occupational Health, National Health Laboratory Service, Johannesburg, South Africa; Department of Clinical Microbiology and Infectious Diseases, School of Pathology, University of Witwatersrand, Johannesburg, South Africa
| | - T S Singh
- National Institute for Occupational Health, National Health Laboratory Service, Johannesburg, South Africa; Department of Clinical Microbiology and Infectious Diseases, School of Pathology, University of Witwatersrand, Johannesburg, South Africa.
| | - E Bryce
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada
| | - A Yassi
- School of Population and Public Health, University of British Columbia, Vancouver, BC, Canada
| | - O Kgasha
- National Institute for Occupational Health, National Health Laboratory Service, Johannesburg, South Africa
| | - M Zungu
- National Institute for Occupational Health, National Health Laboratory Service, Johannesburg, South Africa; Department of Public Health Medicine, School of Health Systems and Public Health, University of Pretoria, Pretoria, South Africa
| | - K Kyaw
- National Institute for Occupational Health, National Health Laboratory Service, Johannesburg, South Africa
| | - M Malotle
- National Institute for Occupational Health, National Health Laboratory Service, Johannesburg, South Africa
| | - K Renton
- National Institute for Occupational Health, National Health Laboratory Service, Johannesburg, South Africa
| | - L O'Hara
- School of Population and Public Health, University of British Columbia, Vancouver, BC, Canada
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15
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Effects of various antibiotics alone or in combination with doripenem against Klebsiella pneumoniae strains isolated in an intensive care unit. BIOMED RESEARCH INTERNATIONAL 2014; 2014:397421. [PMID: 25530961 PMCID: PMC4228717 DOI: 10.1155/2014/397421] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/04/2014] [Accepted: 09/01/2014] [Indexed: 11/17/2022]
Abstract
Colistin, tigecycline, levofloxacin, tobramycin, and rifampin alone and in combination with doripenem were investigated for their in vitro activities and postantibiotic effects (PAEs) on Klebsiella pneumoniae. The in vitro activities of tested antibiotics in combination with doripenem were determined using a microbroth checkerboard technique. To determine the PAEs, K. pneumoniae strains in the logarithmic phase of growth were exposed for 1 h to antibiotics, alone and in combination. Recovery periods of test cultures were evaluated using viable counting after centrifugation. Colistin, tobramycin, and levofloxacin produced strong PAEs ranging from 2.71 to 4.23 h, from 1.31 to 3.82 h, and from 1.35 to 4.72, respectively, in a concentration-dependent manner. Tigecycline and rifampin displayed modest PAEs ranging from 1.18 h to 1.55 h and 0.92 to 1.19, respectively. Because it is a beta-lactam, PAEs were not exactly induced by doripenem (ranging from 0.10 to 0.18 h). In combination, doripenem scarcely changed the duration of PAE of each tested antibiotic alone. The findings of this study may have important implications for the timing of doses during K. pneumoniae therapy with tested antibiotics.
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16
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Tuberculosis in patients with haematological malignancies. Mediterr J Hematol Infect Dis 2014; 6:e2014026. [PMID: 24803999 PMCID: PMC4010605 DOI: 10.4084/mjhid.2014.026] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2013] [Accepted: 03/10/2014] [Indexed: 02/01/2023] Open
Abstract
Tuberculosis (TB) is an infectious disease that causes more than 1 million deaths worldwide every year. In addition, it is estimated that one third of the world population is infected with M. tuberculosis in a latent state, which involves an eventual risk of progressing to active TB disease. Patients with immunodeficiencies, such as those suffering from haematological malignancies, have a greater risk of progressing to TB disease once infected. It is estimated that the Relative Risk of TB disease in patients with hematologic malignancies is 2–40 times that of the general population. The diagnosis of TB in these patients is often challenging as they often present clinical characteristics that are distinct to those of patients without any other underlying disease. Mortality due to TB is higher. Therefore, it is recommended to diagnose latent TB infection and consider preventive therapy that could avoid the progression from a latent state to active TB disease. There are currently two methods for diagnosing latent TB infection: the Tuberculin Skin Test (TST) and the Interferon-Gamma Release Assays (IGRA). Due to the lack of sensitivity in patients with immunodeficient conditions, a combined TST-IGRA testing is probably the best way for latent TB diagnosis in order to gain sensitivity. Treatment of latent TB infection and TB disease should follow the general principles to that in the general population.
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17
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Xu Z, Xu H, Yao M. Applicability of a modified MCE filter method with Button Inhalable Sampler for monitoring personal bioaerosol inhalation exposure. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2013; 20:2963-72. [PMID: 23054771 DOI: 10.1007/s11356-012-1204-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2012] [Accepted: 09/14/2012] [Indexed: 05/16/2023]
Abstract
In this study, a "modified" mixed cellulose ester (MCE) filter culturing method (directly placing filter on agar plate for culturing without extraction) was investigated in enumerating airborne culturable bacterial and fungal aerosol concentration and diversity both in different environments. A Button Inhalable Sampler loaded with a MCE filter was operated at a flow rate of 5 L/min to collect indoor and outdoor air samples using different sampling times: 10, 20, and 30 min in three different time periods of the day. As a comparison, a BioStage impactor, regarded as the gold standard, was operated in parallel at a flow rate of 28.3 L/min for all tests. The air samples collected by the Button Inhalable Sampler were directly placed on agar plates for culturing, and those collected by the BioStage impactor were incubated directly at 26 °C. The colony forming units (CFUs) were manually counted and the culturable concentrations were calculated both for bacterial and fungal aerosols. The bacterial CFUs developed were further washed off and subjected to polymerase chain reaction-denaturing gradient gel electrophoresis (DGGE) for diversity analysis. For fungal CFUs, microscopy method was applied to studying the culturable fungal diversity obtained using different methods. Experimental results showed that the performance of two investigated methods varied with sampling environments and microbial types (culturable bacterial and fungal aerosols). For bacterial aerosol sampling, both methods were shown to perform equally well, and in contrast the "modified" MCE filter method was demonstrated to enumerate more culturable fungal aerosols than the BioStage impactor. In general, the microbial species richness (number of gel bands) was observed to increase with increasing collection time. For both methods, the DGGE gel patterns were observed to vary with sampling time and environment despite of similar number of gel bands. In addition, an increase in sampling time from 20 to 30 min was found not to substantially alter the species richness. Regardless of the sampling methods, more species richness was observed in the outdoor environment than the indoor environment. This study described a new personal bioaerosol exposure assessment protocol, and it was demonstrated applicable in monitoring the personal bioaerosol exposure in replace of an Andersen-type impactor.
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Affiliation(s)
- Zhenqiang Xu
- State Key Joint Laboratory for Environmental Simulation and Pollution Control College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
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Bukka A, Price CTD, Kernodle DS, Graham JE. Mycobacterium tuberculosis RNA Expression Patterns in Sputum Bacteria Indicate Secreted Esx Factors Contributing to Growth are Highly Expressed in Active Disease. Front Microbiol 2012; 2:266. [PMID: 22291682 PMCID: PMC3254194 DOI: 10.3389/fmicb.2011.00266] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2011] [Accepted: 12/15/2011] [Indexed: 01/13/2023] Open
Abstract
To identify factors contributing to the ability of tubercle bacilli to grow in the lung during active infection, we analyzed RNA expression patterns in bacteria present in patient sputum. Prominent among bacterial transcripts identified were those encoding secreted peptides of the Esat-6 subfamily that includes EsxK and EsxL (Rv1197 and Rv1198). H37Rv esxKL and esxJI transcripts were differentially expressed under different growth conditions, and disruption of these genes altered growth phase kinetics in typical laboratory batch broth cultures. These growth defects, including the reduced intracellular growth of an ΔesxKL mutant in primary human macrophages, were reversed by either low multiplicity co-infection or co-culture with wild-type bacteria, demonstrating the ability of the secreted factors to rescue isogenic mutants. Complementing either only esxL or esxI alone (Rv1198 or Rv1037c) also reduced observed growth defects, indicating these genes encode factors capable of contributing to growth. Our studies indicate that the Mycobacterium tuberculosis Mtb9.9 family secreted factors EsxL and EsxI can act in trans to modulate growth of intracellular bacteria, and are highly expressed during active human lung infection.
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Affiliation(s)
- Archana Bukka
- Department of Microbiology and Immunology, University of Louisville School of Medicine Louisville, KY, USA
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Cardona PJ, Ivanyi J. The secret trumps, impelling the pathogenicity of tubercle bacilli. Enferm Infecc Microbiol Clin 2011; 29 Suppl 1:14-9. [DOI: 10.1016/s0213-005x(11)70013-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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20
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Fox K, Castanha E, Fox A, Feigley C, Salzberg D. Human K10 epithelial keratin is the most abundant protein in airborne dust of both occupied and unoccupied school rooms. ACTA ACUST UNITED AC 2007; 10:55-9. [PMID: 18175017 DOI: 10.1039/b714802j] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Previously it was demonstrated that the levels of large particles (>2 micron) and associated bacterial cell envelope markers increase greatly on occupation in schools; it was hypothesized that the source of both was shed human skin. In the current work to test this hypothesis, room air cleaners were used to collect airborne dust (>50-100 mg) from occupied and unoccupied school rooms which was then subjected to proteomic analysis. Proteins were extracted from the dust and separated using two dimensional gel electrophoresis (2D GE). In situ digestion of protein spots with trypsin released peptides, which were subsequently analyzed by matrix assisted laser desorption/deionization, time-of-flight mass spectrometry (MALDI-TOF-MS) and tandem mass spectrometry (MALDI-TOF-MS-MS). In Coomassie blue stained gels, a single spot generally dominated the 2D gels; this protein was identified by tandem mass spectrometry as K10 epithelial keratin. The results experimentally confirm previous anecdotal reports that human skin is readily shed into air and suggest that increased levels of microbial markers and large particles observed in occupied rooms are also derived from skin.
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Affiliation(s)
- Karen Fox
- Department of Pathology, Microbiology and Immunology, School of Medicine, University of South Carolina, Columbia, SC 29208, USA
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21
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Escombe AR, Oeser C, Gilman RH, Navincopa M, Ticona E, Martínez C, Caviedes L, Sheen P, Gonzalez A, Noakes C, Moore DAJ, Friedland JS, Evans CA. The detection of airborne transmission of tuberculosis from HIV-infected patients, using an in vivo air sampling model. Clin Infect Dis 2007; 44:1349-57. [PMID: 17443474 PMCID: PMC2912511 DOI: 10.1086/515397] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2006] [Accepted: 12/12/2006] [Indexed: 11/03/2022] Open
Abstract
BACKGROUND Nosocomial transmission of tuberculosis remains an important public health problem. We created an in vivo air sampling model to study airborne transmission of tuberculosis from patients coinfected with human immunodeficiency virus (HIV) and to evaluate environmental control measures. METHODS An animal facility was built above a mechanically ventilated HIV-tuberculosis ward in Lima, Peru. A mean of 92 guinea pigs were continuously exposed to all ward exhaust air for 16 months. Animals had tuberculin skin tests performed at monthly intervals, and those with positive reactions were removed for autopsy and culture for tuberculosis. RESULTS Over 505 consecutive days, there were 118 ward admissions by 97 patients with pulmonary tuberculosis, with a median duration of hospitalization of 11 days. All patients were infected with HIV and constituted a heterogeneous group with both new and existing diagnoses of tuberculosis. There was a wide variation in monthly rates of guinea pigs developing positive tuberculin test results (0%-53%). Of 292 animals exposed to ward air, 159 developed positive tuberculin skin test results, of which 129 had laboratory confirmation of tuberculosis. The HIV-positive patients with pulmonary tuberculosis produced a mean of 8.2 infectious quanta per hour, compared with 1.25 for HIV-negative patients with tuberculosis in similar studies from the 1950s. The mean monthly patient infectiousness varied greatly, from production of 0-44 infectious quanta per hour, as did the theoretical risk for a health care worker to acquire tuberculosis by breathing ward air. CONCLUSIONS HIV-positive patients with tuberculosis varied greatly in their infectiousness, and some were highly infectious. Use of environmental control strategies for nosocomial tuberculosis is therefore a priority, especially in areas with a high prevalence of both tuberculosis and HIV infection.
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Affiliation(s)
- A Roderick Escombe
- Department of Infectious Diseases and Immunity, Imperial College London, London, United Kingdom.
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Li Y, Leung GM, Tang JW, Yang X, Chao CYH, Lin JZ, Lu JW, Nielsen PV, Niu J, Qian H, Sleigh AC, Su HJJ, Sundell J, Wong TW, Yuen PL. Role of ventilation in airborne transmission of infectious agents in the built environment - a multidisciplinary systematic review. INDOOR AIR 2007; 17:2-18. [PMID: 17257148 DOI: 10.1111/j.1600-0668.2006.00445.x] [Citation(s) in RCA: 436] [Impact Index Per Article: 25.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
There have been few recent studies demonstrating a definitive association between the transmission of airborne infections and the ventilation of buildings. The severe acute respiratory syndrome (SARS) epidemic in 2003 and current concerns about the risk of an avian influenza (H5N1) pandemic, have made a review of this area timely. We searched the major literature databases between 1960 and 2005, and then screened titles and abstracts, and finally selected 40 original studies based on a set of criteria. We established a review panel comprising medical and engineering experts in the fields of microbiology, medicine, epidemiology, indoor air quality, building ventilation, etc. Most panel members had experience with research into the 2003 SARS epidemic. The panel systematically assessed 40 original studies through both individual assessment and a 2-day face-to-face consensus meeting. Ten of 40 studies reviewed were considered to be conclusive with regard to the association between building ventilation and the transmission of airborne infection. There is strong and sufficient evidence to demonstrate the association between ventilation, air movements in buildings and the transmission/spread of infectious diseases such as measles, tuberculosis, chickenpox, influenza, smallpox and SARS. There is insufficient data to specify and quantify the minimum ventilation requirements in hospitals, schools, offices, homes and isolation rooms in relation to spread of infectious diseases via the airborne route. PRACTICAL IMPLICATION: The strong and sufficient evidence of the association between ventilation, the control of airflow direction in buildings, and the transmission and spread of infectious diseases supports the use of negatively pressurized isolation rooms for patients with these diseases in hospitals, in addition to the use of other engineering control methods. However, the lack of sufficient data on the specification and quantification of the minimum ventilation requirements in hospitals, schools and offices in relation to the spread of airborne infectious diseases, suggest the existence of a knowledge gap. Our study reveals a strong need for a multidisciplinary study in investigating disease outbreaks, and the impact of indoor air environments on the spread of airborne infectious diseases.
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Affiliation(s)
- Y Li
- Department of Mechanical Engineering, The University of Hong Kong, Pokfulam, Hong Kong.
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Pea F, Viale P. The antimicrobial therapy puzzle: could pharmacokinetic-pharmacodynamic relationships be helpful in addressing the issue of appropriate pneumonia treatment in critically ill patients? Clin Infect Dis 2006; 42:1764-71. [PMID: 16705585 DOI: 10.1086/504383] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2005] [Accepted: 02/21/2006] [Indexed: 11/03/2022] Open
Abstract
Until recently, the in vitro susceptibility of microorganisms was considered the only fundamental aspect for antibiotic efficacy in treating pneumonia. However, the relevance of pharmacokinetic-pharmacodynamic relationships in optimizing drug exposure has been progressively highlighted. Antimicrobial agents were divided into concentration-dependent or time-dependent groups, with the most consistently relevant pharmacodynamic parameters for efficacy being either the ration of the plasma peak concentration to the minimum inhibitory concentration or the time the plasma concentration persists above the minimum inhibitory concentration of the etiological agent, respectively. For the adequate treatment of pneumonia, optimal pharmacodynamic exposure should be ensured also at the infection site. To investigate this, a methodologically correct approach may be to detect drug concentration levels in the epithelial lining fluid and in the alveolar macrophages for extracellular and intracellular pathogens, respectively. From this perspective, the pharmacokinetic factors--only in some instances--support the achievement of optimal exposure during the treatment of pneumonia with fixed standard dosing regimens of antimicrobials; conversely, in other instances, the pharmacokinetic factors suggest the need for an implemented dosage regimen or even the choice of a different drug.
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Affiliation(s)
- Federico Pea
- Institute of Clinical Pharmacology and Toxicology, Department of Experimental and Clinical Pathology and Medicine, University of Udine, Udine, Italy.
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Ishimatsu S, Fukuda K, Ishidao T, Taniguchi H, Hori H. [Sampling and detection methods of bioaerosols for the risk assessment of microorganisms in work environments]. SANGYŌ EISEIGAKU ZASSHI = JOURNAL OF OCCUPATIONAL HEALTH 2006; 48:1-6. [PMID: 16511333 DOI: 10.1539/sangyoeisei.48.1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Bioaerosols including bacteria and fungi have been almost unrecognized as pollutants of work environments in Japan. The combination of filter sampling and DNA staining by ethidium bromide (EtBr) was examined for the detection and evaluation of total numbers of bioaerosols, including viable and dead microorganisms, for risk assessment in work environments. With direct counting of microorganisms by EtBr concentrations of total cells were obtained in a shorter time than plate culture, the traditional method for detection of microorganisms. Total cell concentrations (cells/m3) were about 100 times greater than colonized cell concentrations (CFU/m3) in all samples. In some microscopic fields, macro conidia produced from some kinds of fungi were observed, but they were not detected by plate culture. Airborne bacterial 16S rDNA amplified by PCR were determined for their base sequences by DNA sequence analysis and classified by sequence-based homologies. Base sequences from 2 samples each contained 6 common groups of phylum. The combination of filter sampling and direct counting by EtBr staining was shown to be a better method for detecting and evaluating total cell concentrations in the risk assessment of sick building syndrome and allergy.
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Affiliation(s)
- Sumiyo Ishimatsu
- Department of Environmental Management 1, School of Health Sciences, University of Occupational and Environmental Health, Japan.
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Vadrot C, Bex V, Mouilleseaux A, Squinazi F, Darbord JC. Detection of Mycobacterium tuberculosis complex by PCR in hospital air samples. J Hosp Infect 2005; 58:262-7. [PMID: 15564002 DOI: 10.1016/j.jhin.2004.04.026] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2003] [Accepted: 04/29/2004] [Indexed: 11/17/2022]
Abstract
Tuberculosis remains a health problem in many developed countries. After the development of a sedimentation method, a semi-quantitative approach for bioaerosol monitoring of Mycobacterium tuberculosis based on polymerase chain reaction (PCR) was adapted for direct detection in air. Bovine serum albumin was added to override airborne environmental particle PCR inhibitors. The method gave positive results in hospital rooms where tubercular pneumonia patients were hospitalized during the first days after their diagnosis.
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Affiliation(s)
- C Vadrot
- Hygiene Laboratory of Paris, 11 rue George Eastman, F 75013 Paris, France.
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26
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Nardell EA. Catching droplet nuclei: toward a better understanding of tuberculosis transmission. Am J Respir Crit Care Med 2004; 169:553-4. [PMID: 14982820 DOI: 10.1164/rccm.2401003] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Fennelly KP, Martyny JW, Fulton KE, Orme IM, Cave DM, Heifets LB. Cough-generated aerosols of Mycobacterium tuberculosis: a new method to study infectiousness. Am J Respir Crit Care Med 2003; 169:604-9. [PMID: 14656754 DOI: 10.1164/rccm.200308-1101oc] [Citation(s) in RCA: 201] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The concentration and size distribution of infectious aerosols produced by patients with pulmonary tuberculosis (TB) has never been directly measured. We aimed to assess the feasibility of a method that we developed to collect and quantify culturable cough-generated aerosols of Mycobacterium tuberculosis. Subjects were recruited from a referral hospital and most had multidrug-resistant TB. They coughed into a chamber containing microbial air samplers while cough frequency was measured during two 5-minute sessions. Cough-generated aerosol cultures were positive in 4 of 16 subjects (25%) with smear-positive pulmonary TB. There was a rapid decrease in the cough-generated aerosol cultures within the first 3 weeks of effective treatment. Culture-positive cough aerosols were associated with lack of treatment during the previous week (p = 0.007), and there was a trend in the association with cough frequency (p = 0.08). The size distributions of these aerosols were variable, but most particle sizes were in the respirable range. Quantification of viable cough-generated aerosols is feasible and offers a new approach to study infectiousness and transmission of M. tuberculosis and other airborne pathogens.
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MESH Headings
- Aerosols
- Air Microbiology
- Cough/microbiology
- DNA Fingerprinting
- DNA, Bacterial/analysis
- DNA, Bacterial/genetics
- Environmental Monitoring/methods
- Environmental Monitoring/standards
- Epidemiological Monitoring
- Feasibility Studies
- Female
- Humans
- Male
- Molecular Epidemiology
- Mycobacterium tuberculosis/genetics
- Mycobacterium tuberculosis/isolation & purification
- Mycobacterium tuberculosis/pathogenicity
- Particle Size
- Reproducibility of Results
- Selection Bias
- Sensitivity and Specificity
- Sputum/microbiology
- Tuberculosis, Multidrug-Resistant/complications
- Tuberculosis, Multidrug-Resistant/drug therapy
- Tuberculosis, Multidrug-Resistant/epidemiology
- Tuberculosis, Multidrug-Resistant/microbiology
- Tuberculosis, Multidrug-Resistant/transmission
- Tuberculosis, Pulmonary/complications
- Tuberculosis, Pulmonary/drug therapy
- Tuberculosis, Pulmonary/epidemiology
- Tuberculosis, Pulmonary/microbiology
- Tuberculosis, Pulmonary/transmission
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Affiliation(s)
- Kevin P Fennelly
- Department of Medicine, Center for the Study of Emerging and Re-Emerging Pathogens, New Jersey Medical School, University of Medicine and Dentistry of New Jersey, Newark, NJ 07103, USA.
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McCartney HA, Foster SJ, Fraaije BA, Ward E. Molecular diagnostics for fungal plant pathogens. PEST MANAGEMENT SCIENCE 2003; 59:129-142. [PMID: 12587866 DOI: 10.1002/ps.575] [Citation(s) in RCA: 97] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Accurate identification of fungal phytopathogens is essential for virtually all aspects of plant pathology, from fundamental research on the biology of pathogens to the control of the diseases they cause. Although molecular methods, such as polymerase chain reaction (PCR), are routinely used in the diagnosis of human diseases, they are not yet widely used to detect and identify plant pathogens. Here we review some of the diagnostic tools currently used for fungal plant pathogens and describe some novel applications. Technological advances in PCR-based methods, such as real-time PCR, allow fast, accurate detection and quantification of plant pathogens and are now being applied to practical problems. Molecular methods have been used to detect several pathogens simultaneously in wheat, and to study the development of fungicide resistance in wheat pathogens. Information resulting from such work could be used to improve disease control by allowing more rational decisions to be made about the choice and use of fungicides and resistant cultivars. Molecular methods have also been applied to the study of variation in plant pathogen populations, for example detection of different mating types or virulence types. PCR-based methods can provide new tools to monitor the exposure of a crop to pathogen inoculum that are more reliable and faster than conventional methods. This information can be used to improve disease control decision making. The development and application of molecular diagnostic methods in the future is discussed and we expect that new developments will increase the adoption of these new technologies for the diagnosis and study of plant disease.
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Affiliation(s)
- H Alastair McCartney
- Plant Pathogen Interactions Division, IACR-Rothamsted, Harpenden, Herts AL5 2JQ, UK
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Myatt TA, Johnston SL, Rudnick S, Milton DK. Airborne rhinovirus detection and effect of ultraviolet irradiation on detection by a semi-nested RT-PCR assay. BMC Public Health 2003; 3:5. [PMID: 12525263 PMCID: PMC140314 DOI: 10.1186/1471-2458-3-5] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2002] [Accepted: 01/13/2003] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Rhinovirus, the most common cause of upper respiratory tract infections, has been implicated in asthma exacerbations and possibly asthma deaths. Although the method of transmission of rhinoviruses is disputed, several studies have demonstrated that aerosol transmission is a likely method of transmission among adults. As a first step in studies of possible airborne rhinovirus transmission, we developed methods to detect aerosolized rhinovirus by extending existing technology for detecting infectious agents in nasal specimens. METHODS We aerosolized rhinovirus in a small aerosol chamber. Experiments were conducted with decreasing concentrations of rhinovirus. To determine the effect of UV irradiation on detection of rhinoviral aerosols, we also conducted experiments in which we exposed aerosols to a UV dose of 684 mJ/m2. Aerosols were collected on Teflon filters and rhinovirus recovered in Qiagen AVL buffer using the Qiagen QIAamp Viral RNA Kit (Qiagen Corp., Valencia, California) followed by semi-nested RT-PCR and detection by gel electrophoresis. RESULTS We obtained positive results from filter samples that had collected at least 1.3 TCID50 of aerosolized rhinovirus. Ultraviolet irradiation of airborne virus at doses much greater than those used in upper-room UV germicidal irradiation applications did not inhibit subsequent detection with the RT-PCR assay. CONCLUSION The air sampling and extraction methodology developed in this study should be applicable to the detection of rhinovirus and other airborne viruses in the indoor air of offices and schools. This method, however, cannot distinguish UV inactivated virus from infectious viral particles.
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Affiliation(s)
- Theodore A Myatt
- Department of Environmental Health, Harvard School of Public Health, 665 Huntington Ave, Boston MA USA 02115
| | - Sebastian L Johnston
- Department of Respiratory Medicine, National Heart and Lung Institute, Faculty of Medicine, Imperial College of Science, Technology and Medicine, Norfolk Place, London W2 1PG, UK
| | - Stephen Rudnick
- Department of Environmental Health, Harvard School of Public Health, 665 Huntington Ave, Boston MA USA 02115
| | - Donald K Milton
- Department of Environmental Health, Harvard School of Public Health, 665 Huntington Ave, Boston MA USA 02115
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Air Sampling for Tuberculosis— Homage to the Lowly Guinea Pig. Chest 1999. [DOI: 10.1016/s0012-3692(15)37190-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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