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Rockey NC, Le Sage V, Marr LC, Lakdawala SS. Seasonal influenza viruses decay more rapidly at intermediate humidity in droplets containing saliva compared to respiratory mucus. Appl Environ Microbiol 2024; 90:e0201023. [PMID: 38193683 PMCID: PMC10880610 DOI: 10.1128/aem.02010-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Accepted: 11/27/2023] [Indexed: 01/10/2024] Open
Abstract
Expulsions of virus-laden aerosols or droplets from the oral and nasal cavities of an infected host are an important source of onward respiratory virus transmission. However, the presence of infectious influenza virus in the oral cavity during infection has not been widely considered, and thus, little work has explored the environmental persistence of influenza virus in oral cavity expulsions. Using the ferret model, we detected infectious virus in the nasal and oral cavities, suggesting that the virus can be expelled into the environment from both anatomical sites. We also assessed the stability of two influenza A viruses (H1N1 and H3N2) in droplets of human saliva or respiratory mucus over a range of relative humidities. We observed that influenza virus infectivity decays rapidly in saliva droplets at intermediate relative humidity, while viruses in airway surface liquid droplets retain infectivity. Virus inactivation was not associated with bulk protein content, salt content, or droplet drying time. Instead, we found that saliva droplets exhibited distinct inactivation kinetics during the wet and dry phases at intermediate relative humidity, and droplet residue morphology may lead to the elevated first-order inactivation rate observed during the dry phase. Additionally, distinct differences in crystalline structure and nanobead localization were observed between saliva and airway surface liquid droplets. Together, our work demonstrates that different respiratory fluids exhibit unique virus persistence profiles and suggests that influenza viruses expelled from the oral cavity may contribute to virus transmission in low- and high-humidity environments.IMPORTANCEDetermining how long viruses persist in the environment is important for mitigating transmission risk. Expelled infectious droplets and aerosols are composed of respiratory fluids, including saliva and complex mucus mixtures, but how well influenza viruses survive in such fluids is largely unknown. Here, we find that infectious influenza virus is present in the oral cavity of infected ferrets, suggesting that saliva-containing expulsions can play a role in onward transmission. Additionally, influenza virus in droplets composed of saliva degrades more rapidly than virus within respiratory mucus. Droplet composition impacts the crystalline structure and virus localization in dried droplets. These results suggest that viruses from distinct sites in the respiratory tract could have variable persistence in the environment, which will impact viral transmission fitness.
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Affiliation(s)
- Nicole C. Rockey
- Department of Microbiology and Molecular Genetics, The University of Pittsburgh, Pittsburgh, Pennsylvania, USA
- Department of Civil and Environmental Engineering, Duke University, Durham, North Carolina, USA
| | - Valerie Le Sage
- Department of Microbiology and Molecular Genetics, The University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Linsey C. Marr
- Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, Virginia, USA
| | - Seema S. Lakdawala
- Department of Microbiology and Molecular Genetics, The University of Pittsburgh, Pittsburgh, Pennsylvania, USA
- Department of Microbiology and Immunology, Emory University, Atlanta, Georgia, USA
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French AJ, Rockey NC, Le Sage V, Mueller Brown K, Shephard MJ, Frizzell S, Myerburg MM, Hiller NL, Lakdawala SS. Detection of influenza virus and Streptococcus pneumoniae in air sampled from co-infected ferrets and analysis of their influence on pathogen stability. mSphere 2023; 8:e0003923. [PMID: 37255295 PMCID: PMC10449498 DOI: 10.1128/msphere.00039-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Accepted: 04/12/2023] [Indexed: 06/01/2023] Open
Abstract
Secondary infection with Streptococcus pneumoniae has contributed significantly to morbidity and mortality during multiple influenza virus pandemics and remains a common threat today. During a concurrent infection, both pathogens can influence the transmission of each other, but the mechanisms behind this are unclear. In this study, condensation air sampling and cyclone bioaerosol sampling were performed using ferrets first infected with the 2009 H1N1 pandemic influenza virus (H1N1pdm09) and secondarily infected with S. pneumoniae strain D39 (Spn). We detected viable pathogens and microbial nucleic acid in expelled aerosols from co-infected ferrets, suggesting that these microbes could be present in the same respiratory expulsions. To assess whether microbial communities impact pathogen stability within an expelled droplet, we performed experiments measuring viral and bacterial persistence in 1 µL droplets. We observed that H1N1pdm09 stability was unchanged in the presence of Spn. Further, Spn stability was moderately increased in the presence of H1N1pdm09, although the degree of stabilization differed between airway surface liquid collected from individual patient cultures. These findings are the first to collect both pathogens from the air and in doing so, they provide insight into the interplay between these pathogens and their hosts.IMPORTANCEThe impact of microbial communities on transmission fitness and environmental persistence is under-studied. Environmental stability of microbes is crucial to identifying transmission risks and mitigation strategies, such as removal of contaminated aerosols and decontamination of surfaces. Co-infection with S. pneumoniae is very common during influenza virus infection, but little work has been done to understand whether S. pneumoniae alters stability of influenza virus, or vice versa, in a relevant system. Here, we demonstrate that influenza virus and S. pneumoniae are expelled by co-infected hosts. Our stability assays did not reveal any impact of S. pneumoniae on influenza virus stability, but did show a trend towards increased stability of S. pneumoniae in the presence of influenza viruses. Future work characterizing environmental persistence of viruses and bacteria should include microbially complex solutions to better mimic physiologically relevant conditions.
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Affiliation(s)
- Andrea J. French
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Nicole C. Rockey
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Valerie Le Sage
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Karina Mueller Brown
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA
| | - Meredith J. Shephard
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Sheila Frizzell
- Division of Pulmonary, Allergy, and Critical Care Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Mike M. Myerburg
- Division of Pulmonary, Allergy, and Critical Care Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - N. Luisa Hiller
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA
| | - Seema S. Lakdawala
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
- Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, Georgia, USA
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French AJ, Rockey NC, Sage VL, Brown KM, Shephard MJ, Frizzell S, Myerburg MM, Hiller NL, Lakdawala SS. Detection of Influenza virus and Streptococcus pneumoniae in air sampled from co-infected ferrets and analysis of their influence on pathogen stability. bioRxiv 2023:2023.02.24.529988. [PMID: 36865236 PMCID: PMC9980167 DOI: 10.1101/2023.02.24.529988] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/27/2023]
Abstract
Secondary infection with Streptococcus pneumoniae has contributed significantly to morbidity and mortality during multiple influenza virus pandemics and remains a common threat today. During a concurrent infection, both pathogens can influence the transmission of each other, but the mechanisms behind this are unclear. In this study, condensation air sampling and cyclone bioaerosol sampling were performed using ferrets first infected with the 2009 H1N1 pandemic influenza virus (H1N1pdm09) and secondarily infected with S. pneumoniae strain D39 (Spn). We detected viable pathogens and microbial nucleic acid in expelled aerosols from co-infected ferrets, suggesting that these microbes could be present in the same respiratory expulsions. To assess whether microbial communities impact pathogen stability within an expelled droplet, we performed experiments measuring viral and bacterial persistence in 1 μL droplets. We observed that H1N1pdm09 stability was unchanged in the presence of Spn. Further, Spn stability was moderately increased in the presence of H1N1pdm09, although the degree of stabilization differed between airways surface liquid collected from individual patient cultures. These findings are the first to collect both pathogens from the air and in doing so, they provide insight into the interplay between these pathogens and their hosts. Importance The impact of microbial communities on transmission fitness and environmental persistence is under-studied. Environmental stability of microbes is crucial to identifying transmission risks and mitigation strategies, such as removal of contaminated aerosols and decontamination of surfaces. Co-infection with S. pneumoniae is very common during influenza virus infection, but little work has been done to understand whether S. pneumoniae alters stability of influenza virus, or vice versa, in a relevant system. Here, we demonstrate that influenza virus and S. pneumoniae are expelled by co-infected hosts. Our stability assays did not reveal any impact of S. pneumoniae on influenza virus stability, and a trend towards increased stability of S. pneumoniae in the presence of influenza viruses. Future work characterizing environmental persistence of viruses and bacteria should include microbially-complex solutions to better mimic physiologically relevant conditions.
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Affiliation(s)
- Andrea J French
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Nicole C Rockey
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Valerie Le Sage
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Karina Mueller Brown
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Meredith J Shephard
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Sheila Frizzell
- Division of Pulmonary, Allergy, and Critical Care Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Mike M Myerburg
- Division of Pulmonary, Allergy, and Critical Care Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - N Luisa Hiller
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Seema S Lakdawala
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
- Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, GA, USA
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Abstract
UV254 disinfection strategies are commonly applied to inactivate pathogenic viruses in water, food, air, and on surfaces. There is a need for methods that rapidly predict the kinetics of virus inactivation by UV254, particularly for emerging and difficult-to-culture viruses. We conducted a systematic literature review of inactivation rate constants for a wide range of viruses. Using these data and virus characteristics, we developed and evaluated linear and nonlinear models for predicting inactivation rate constants. Multiple linear regressions performed best for predicting the inactivation kinetics of (+) ssRNA and dsDNA viruses, with cross-validated root mean squared relative prediction errors similar to those associated with experimental rate constants. We tested the models by predicting and measuring inactivation rate constants of a (+) ssRNA mouse coronavirus and a dsDNA marine bacteriophage; the predicted rate constants were within 7% and 71% of the experimental rate constants, respectively, indicating that the prediction was more accurate for the (+) ssRNA virus than the dsDNA virus. Finally, we applied our models to predict the UV254 rate constants of several viruses for which high-quality UV254 inactivation data are not available. Our models will be valuable for predicting inactivation kinetics of emerging or difficult-to-culture viruses.
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Affiliation(s)
- Nicole C Rockey
- Department of Civil & Environmental Engineering, University of Michigan, Ann Arbor, MI 48109, United States
| | - James B Henderson
- Consulting for Statistics, Computing and Analytics Research, University of Michigan, Ann Arbor, MI 48109, United States
| | - Kaitlyn Chin
- Department of Civil & Environmental Engineering, University of Michigan, Ann Arbor, MI 48109, United States
| | - Lutgarde Raskin
- Department of Civil & Environmental Engineering, University of Michigan, Ann Arbor, MI 48109, United States
| | - Krista R Wigginton
- Department of Civil & Environmental Engineering, University of Michigan, Ann Arbor, MI 48109, United States
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Wigginton KR, Arts PJ, Clack HL, Fitzsimmons WJ, Gamba M, Harrison KR, LeBar W, Lauring AS, Li L, Roberts WW, Rockey NC, Torreblanca J, Young C, Anderegg LG, Cohn AM, Doyle JM, Meisenhelder CM, Raskin L, Love NG, Kaye KS. Validation of N95 Filtering Facepiece Respirator Decontamination Methods Available at a Large University Hospital. Open Forum Infect Dis 2021; 8:ofaa610. [PMID: 33575418 DOI: 10.1101/2020.04.28.20084038] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Accepted: 12/09/2020] [Indexed: 05/26/2023] Open
Abstract
BACKGROUND Due to unprecedented shortages in N95 filtering facepiece respirators, healthcare systems have explored N95 reprocessing. No single, full-scale reprocessing publication has reported an evaluation including multiple viruses, bacteria, and fungi along with respirator filtration and fit. METHODS We explored reprocessing methods using new 3M 1860 N95 respirators, including moist (50%-75% relative humidity [RH]) heat (80-82°C for 30 minutes), ethylene oxide (EtO), pulsed xenon UV-C (UV-PX), hydrogen peroxide gas plasma (HPGP), and hydrogen peroxide vapor (HPV). Respirator samples were analyzed using 4 viruses (MS2, phi6, influenza A virus [IAV], murine hepatitis virus [MHV)]), 3 bacteria (Escherichia coli, Staphylococcus aureus, Geobacillus stearothermophilus spores, and vegetative bacteria), and Aspergillus niger. Different application media were tested. Decontaminated respirators were evaluated for filtration integrity and fit. RESULTS Heat with moderate RH most effectively inactivated virus, resulting in reductions of >6.6-log10 MS2, >6.7-log10 Phi6, >2.7-log10 MHV, and >3.9-log10 IAV and prokaryotes, except for G stearothermohphilus. Hydrogen peroxide vapor was moderately effective at inactivating tested viruses, resulting in 1.5- to >4-log10 observable inactivation. Staphylococcus aureus inactivation by HPV was limited. Filtration efficiency and proper fit were maintained after 5 cycles of heat with moderate RH and HPV. Although it was effective at decontamination, HPGP resulted in decreased filtration efficiency, and EtO treatment raised toxicity concerns. Observed virus inactivation varied depending upon the application media used. CONCLUSIONS Both moist heat and HPV are scalable N95 reprocessing options because they achieve high levels of biological indicator inactivation while maintaining respirator fit and integrity.
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Affiliation(s)
- Krista R Wigginton
- Department of Civil and Environmental Engineering, University of Michigan, Ann Arbor, Michigan, USA
| | - Peter J Arts
- Department of Civil and Environmental Engineering, University of Michigan, Ann Arbor, Michigan, USA
| | - Herek L Clack
- Department of Civil and Environmental Engineering, University of Michigan, Ann Arbor, Michigan, USA
| | - William J Fitzsimmons
- Division of Infectious Diseases, Department of Internal Medicine, University of Michigan Health System, Ann Arbor, Michigan, USA
| | - Mirko Gamba
- Department of Aerospace Engineering, University of Michigan, Ann Arbor, Michigan, USA
| | - Katherine R Harrison
- Department of Civil and Environmental Engineering, University of Michigan, Ann Arbor, Michigan, USA
| | - William LeBar
- Department of Pathology, Clinical Microbiology, University of Michigan Health System, Ann Arbor, Michigan, USA
| | - Adam S Lauring
- Division of Infectious Diseases, Department of Internal Medicine, University of Michigan Health System, Ann Arbor, Michigan, USA
| | - Lucinda Li
- Department of Civil and Environmental Engineering, University of Michigan, Ann Arbor, Michigan, USA
| | - William W Roberts
- Department of Urology, University of Michigan Health System, Ann Arbor, Michigan, USA
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan, USA
| | - Nicole C Rockey
- Department of Civil and Environmental Engineering, University of Michigan, Ann Arbor, Michigan, USA
| | - Jania Torreblanca
- Department of Pathology, Clinical Microbiology, University of Michigan Health System, Ann Arbor, Michigan, USA
| | - Carol Young
- Department of Pathology, Clinical Microbiology, University of Michigan Health System, Ann Arbor, Michigan, USA
| | - Loïc G Anderegg
- Department of Physics, Harvard University, Cambridge, Massachusetts, USA
- Harvard-MIT Center for Ultracold Atoms, Cambridge, Massachusetts, USA
| | - Amy M Cohn
- Department of Industrial & Operations Engineering, University of Michigan, Ann Arbor, Michigan, USA
| | - John M Doyle
- Department of Physics, Harvard University, Cambridge, Massachusetts, USA
- Harvard-MIT Center for Ultracold Atoms, Cambridge, Massachusetts, USA
| | | | - Lutgarde Raskin
- Department of Civil and Environmental Engineering, University of Michigan, Ann Arbor, Michigan, USA
| | - Nancy G Love
- Department of Civil and Environmental Engineering, University of Michigan, Ann Arbor, Michigan, USA
| | - Keith S Kaye
- Division of Infectious Diseases, Department of Internal Medicine, University of Michigan Health System, Ann Arbor, Michigan, USA
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6
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Wigginton KR, Arts PJ, Clack HL, Fitzsimmons WJ, Gamba M, Harrison KR, LeBar W, Lauring AS, Li L, Roberts WW, Rockey NC, Torreblanca J, Young C, Anderegg LG, Cohn AM, Doyle JM, Meisenhelder CM, Raskin L, Love NG, Kaye KS. Validation of N95 Filtering Facepiece Respirator Decontamination Methods Available at a Large University Hospital. Open Forum Infect Dis 2021; 8:ofaa610. [PMID: 33575418 PMCID: PMC7863868 DOI: 10.1093/ofid/ofaa610] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Accepted: 12/09/2020] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Due to unprecedented shortages in N95 filtering facepiece respirators, healthcare systems have explored N95 reprocessing. No single, full-scale reprocessing publication has reported an evaluation including multiple viruses, bacteria, and fungi along with respirator filtration and fit. METHODS We explored reprocessing methods using new 3M 1860 N95 respirators, including moist (50%-75% relative humidity [RH]) heat (80-82°C for 30 minutes), ethylene oxide (EtO), pulsed xenon UV-C (UV-PX), hydrogen peroxide gas plasma (HPGP), and hydrogen peroxide vapor (HPV). Respirator samples were analyzed using 4 viruses (MS2, phi6, influenza A virus [IAV], murine hepatitis virus [MHV)]), 3 bacteria (Escherichia coli, Staphylococcus aureus, Geobacillus stearothermophilus spores, and vegetative bacteria), and Aspergillus niger. Different application media were tested. Decontaminated respirators were evaluated for filtration integrity and fit. RESULTS Heat with moderate RH most effectively inactivated virus, resulting in reductions of >6.6-log10 MS2, >6.7-log10 Phi6, >2.7-log10 MHV, and >3.9-log10 IAV and prokaryotes, except for G stearothermohphilus. Hydrogen peroxide vapor was moderately effective at inactivating tested viruses, resulting in 1.5- to >4-log10 observable inactivation. Staphylococcus aureus inactivation by HPV was limited. Filtration efficiency and proper fit were maintained after 5 cycles of heat with moderate RH and HPV. Although it was effective at decontamination, HPGP resulted in decreased filtration efficiency, and EtO treatment raised toxicity concerns. Observed virus inactivation varied depending upon the application media used. CONCLUSIONS Both moist heat and HPV are scalable N95 reprocessing options because they achieve high levels of biological indicator inactivation while maintaining respirator fit and integrity.
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Affiliation(s)
- Krista R Wigginton
- Department of Civil and Environmental Engineering, University of Michigan, Ann Arbor, Michigan, USA
| | - Peter J Arts
- Department of Civil and Environmental Engineering, University of Michigan, Ann Arbor, Michigan, USA
| | - Herek L Clack
- Department of Civil and Environmental Engineering, University of Michigan, Ann Arbor, Michigan, USA
| | - William J Fitzsimmons
- Division of Infectious Diseases, Department of Internal Medicine, University of Michigan Health System, Ann Arbor, Michigan, USA
| | - Mirko Gamba
- Department of Aerospace Engineering, University of Michigan, Ann Arbor, Michigan, USA
| | - Katherine R Harrison
- Department of Civil and Environmental Engineering, University of Michigan, Ann Arbor, Michigan, USA
| | - William LeBar
- Department of Pathology, Clinical Microbiology, University of Michigan Health System, Ann Arbor, Michigan, USA
| | - Adam S Lauring
- Division of Infectious Diseases, Department of Internal Medicine, University of Michigan Health System, Ann Arbor, Michigan, USA
| | - Lucinda Li
- Department of Civil and Environmental Engineering, University of Michigan, Ann Arbor, Michigan, USA
| | - William W Roberts
- Department of Urology, University of Michigan Health System, Ann Arbor, Michigan, USA
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan, USA
| | - Nicole C Rockey
- Department of Civil and Environmental Engineering, University of Michigan, Ann Arbor, Michigan, USA
| | - Jania Torreblanca
- Department of Pathology, Clinical Microbiology, University of Michigan Health System, Ann Arbor, Michigan, USA
| | - Carol Young
- Department of Pathology, Clinical Microbiology, University of Michigan Health System, Ann Arbor, Michigan, USA
| | - Loïc G Anderegg
- Department of Physics, Harvard University, Cambridge, Massachusetts, USA
- Harvard-MIT Center for Ultracold Atoms, Cambridge, Massachusetts, USA
| | - Amy M Cohn
- Department of Industrial & Operations Engineering, University of Michigan, Ann Arbor, Michigan, USA
| | - John M Doyle
- Department of Physics, Harvard University, Cambridge, Massachusetts, USA
- Harvard-MIT Center for Ultracold Atoms, Cambridge, Massachusetts, USA
| | | | - Lutgarde Raskin
- Department of Civil and Environmental Engineering, University of Michigan, Ann Arbor, Michigan, USA
| | - Nancy G Love
- Department of Civil and Environmental Engineering, University of Michigan, Ann Arbor, Michigan, USA
| | - Keith S Kaye
- Division of Infectious Diseases, Department of Internal Medicine, University of Michigan Health System, Ann Arbor, Michigan, USA
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