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Ji S, Xiao S, Wang H, Lei H. Increasing contributions of airborne route in SARS-CoV-2 omicron variant transmission compared with the ancestral strain. BUILDING AND ENVIRONMENT 2022; 221:109328. [PMID: 35784591 PMCID: PMC9233747 DOI: 10.1016/j.buildenv.2022.109328] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/24/2022] [Revised: 06/14/2022] [Accepted: 06/17/2022] [Indexed: 06/15/2023]
Abstract
The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron variant has become the dominant lineage worldwide. Experimental studies have shown that SARS-CoV-2 Omicron variant is more stable on various environmental surfaces than the ancestral strains of SARS-CoV-2. However, the influences on the role of the contact route in SARS-CoV-2 transmission are still unknown. In this study, we built a Markov chain model to simulate the transmission of the Omicron and ancestral strains of SARS-CoV-2 within a household over a 1-day period from multiple pathways; that is, airborne, droplet, and contact routes. We assumed that there were two adults and one child in the household, and that one of the adults was infected with SARS-CoV-2. We assumed two scenarios. (1) Asymptomatic/presymptomatic infection, and (2) symptomatic infection. During asymptomatic/presymptomatic infection, the contact route contributing the most (37%-45%), followed by the airborne (34%-38%) and droplet routes (21%-28%). During symptomatic infection, the droplet route was the dominant pathway (48%-71%), followed by the contact route (25%-42%), with the airborne route playing a negligible role (<10%). Compared to the ancestral strain, although the contribution of the contact route increased in Omicron variant transmission, the increase was slight, from 25%-41% to 30%-45%. With the growing concern about the increase in the proportion of asymptomatic/presymptomatic infection in Omicron strain transmissions, the airborne route, rather than the fomite route, should be of focus. Our findings suggest the importance of ventilation in the SARS-CoV-2 Omicron variant prevention in building environment.
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Affiliation(s)
- Shuyi Ji
- School of Public Health, Zhejiang University, Hangzhou, 310058, PR China
| | - Shenglan Xiao
- School of Public Health (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Shenzhen, 518107, PR China
| | - Huaibin Wang
- School of Public Health (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Shenzhen, 518107, PR China
| | - Hao Lei
- School of Public Health, Zhejiang University, Hangzhou, 310058, PR China
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Gregory TV, Ellis K, Valeriani R, Khan F, Wu X, Murin L, Alibayov B, Vidal AGJ, Zhao T, Vidal JE. MoWa: A Disinfectant for Hospital Surfaces Contaminated With Methicillin-Resistant Staphylococcus aureus (MRSA) and Other Nosocomial Pathogens. Front Cell Infect Microbiol 2021; 11:676638. [PMID: 34295834 PMCID: PMC8291128 DOI: 10.3389/fcimb.2021.676638] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Accepted: 05/13/2021] [Indexed: 11/13/2022] Open
Abstract
Introduction Staphylococcus aureus strains, including methicillin-resistant S. aureus (MRSA) and methicillin-sensitive S. aureus (MSSA), are a main cause of nosocomial infection in the world. The majority of nosocomial S. aureus-infection are traced back to a source of contaminated surfaces including surgery tables. We assessed the efficacy of a mixture of levulinic acid (LA) and sodium dodecyl sulfate (SDS), hereafter called MoWa, to eradicate nosocomial pathogens from contaminated surfaces. Methods and Results A dose response study demonstrated that MoWa killed 24 h planktonic cultures of S. aureus strains starting at a concentration of (LA) 8.2/(SDS) 0.3 mM while 24 h preformed biofilms were eradicated with 32/1.3 mM. A time course study further showed that attached MRSA bacteria were eradicated within 4 h of incubation with 65/2 mM MoWa. Staphylococci were killed as confirmed by bacterial counts, and fluorescence micrographs that were stained with the live/dead bacterial assay. We then simulated contamination of hospital surfaces by inoculating bacteria on a surface prone to contamination. Once dried, contaminated surfaces were sprayed with MoWa or mock-treated, and treated contaminated surfaces were swabbed and bacteria counted. While bacteria in the mock-treated samples grew at a density of ~104 cfu/cm2, those treated for ~1 min with MoWa (1.0/0.04 M) had been eradicated below limit of detection. A similar eradication efficacy was obtained when surfaces were contaminated with other nosocomial pathogens, such as Klebsiella pneumoniae, Pseudomonas aeruginosa, Acinetobacter baumannii, or Staphylococcus epidermidis. Conclusions MoWa kills planktonic and biofilms made by MRSA and MSSA strains and showed great efficacy to disinfect MRSA-, and MSSA-contaminated, surfaces and surfaces contaminated with other important nosocomial pathogens.
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Affiliation(s)
- Tyler V Gregory
- Department of Microbiology and Immunology, University of Mississippi Medical Center, Jackson, MS, United States.,Biomedical Sciences Master of Science Program, University of Mississippi Medical Center, Jackson, MS, United States
| | - Karen Ellis
- Rollins School of Public Health, Emory University, Atlanta, GA, United States
| | - Renzo Valeriani
- Rollins School of Public Health, Emory University, Atlanta, GA, United States
| | - Faidad Khan
- Department of Microbiology and Immunology, University of Mississippi Medical Center, Jackson, MS, United States
| | - Xueqing Wu
- Department of Infectious Disease, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - Landon Murin
- Base Pair Program Murrah- University of Mississippi Medical Center, Jackson, MS, United States
| | - Babek Alibayov
- Department of Microbiology and Immunology, University of Mississippi Medical Center, Jackson, MS, United States
| | - Ana G Jop Vidal
- Department of Microbiology and Immunology, University of Mississippi Medical Center, Jackson, MS, United States
| | - Tong Zhao
- Center for Food Safety, University of Georgia, Griffin, GA, United States
| | - Jorge E Vidal
- Department of Microbiology and Immunology, University of Mississippi Medical Center, Jackson, MS, United States
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