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Bongiovanni A, Colazingari V, Messineo A, Del Cimmuto A, De Giusti M, La Torre G. Can legionellosis be considered an occupational risk in the healthcare sector? A systematic review and meta-analysis. Public Health 2023; 214:31-37. [PMID: 36463752 DOI: 10.1016/j.puhe.2022.10.027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2022] [Revised: 10/26/2022] [Accepted: 10/28/2022] [Indexed: 12/03/2022]
Abstract
OBJECTIVES According to current knowledge about legionella transmission, healthcare workers (HCWs) are at an increased risk of exposure. The aim of this research was to systematically review the literature about HCWs' exposure to legionella and establish whether there is an occupational risk. STUDY DESIGN This was a systematic review and meta-analysis. METHODS PubMed, Scopus and Web of Science were searched to identify studies regarding the occupational risk of legionellosis for HCWs. Keywords used in the search were 'Legionella pneumophila', 'occupational medicine', 'occupational' and 'risk'. Selected studies were reviewed to assess the quality and meta-analysed. Finally, the nine epidemiological principles of Bradford-Hill criteria were used to assess whether legionellosis could be considered an occupational risk for HCWs. RESULTS The search strategy retrieved 124 studies, and 10 studies were included in the present review. The overall study quality was low. The pooled odds ratio estimate was 2.45 (95% confidence interval: 1.52-3.96). The assessment using Bradford-Hill criteria showed that only two criteria (plausibility and coherence) were met, which is insufficient to establish an occupational risk. CONCLUSIONS This systematic review suggests that there is a higher risk of legionella exposure for HCWs, but there is currently no clinical evidence. Further studies with appropriate study design are needed to determine whether legionella infection is an occupational risk for HCWs.
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Affiliation(s)
- A Bongiovanni
- Department of Public Health and Infectious Diseases, University of Rome "Sapienza", Rome, Italy
| | - V Colazingari
- Department of Public Health and Infectious Diseases, University of Rome "Sapienza", Rome, Italy
| | - A Messineo
- Section of Legal Medicine, Social Security and Forensic Toxicology, Department of Biomedicine and Prevention, Tor Vergata University, Rome, Italy
| | - A Del Cimmuto
- Department of Public Health and Infectious Diseases, University of Rome "Sapienza", Rome, Italy
| | - M De Giusti
- Department of Public Health and Infectious Diseases, University of Rome "Sapienza", Rome, Italy
| | - G La Torre
- Department of Public Health and Infectious Diseases, University of Rome "Sapienza", Rome, Italy.
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Kermani M, Chegini Z, Mirkalantari S, Norzaee S. Assessment of the risk of Legionella pneumophila in water distribution systems in hospitals of Tehran city. ENVIRONMENTAL MONITORING AND ASSESSMENT 2022; 194:842. [PMID: 36175694 DOI: 10.1007/s10661-022-10469-y] [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: 05/30/2022] [Accepted: 09/10/2022] [Indexed: 06/16/2023]
Abstract
When a sensitive host inhales aerosols containing these bacteria, Legionella infection occurs. Therefore, monitoring and assessing Legionella in the environment and water distribution systems of such places are critical due to the prone population in hospitals. However, the health risks of Legionella bacteria in the environment are not adequately evaluated. In this study, for hospitalized patients, we performed a quantitative health risk assessment of Legionella in selected hospitals in Tehran city using two scenarios of shower and toilet faucet exposure. This study identified Legionella in 38 cases (38%) out of 100 samples collected from toilet faucets and showers in 8 hospitals. The information gathered was used for quantitative microbial risk assessment (QMRA). The microbial load transmitted by inhalation was calculated using the concentration of Legionella in water. Other exposure parameters (inhalation rate and exposure time) were obtained using information from other studies and the median length of hospital stay (3.6 days). The exponential model was used to estimate the risk of infection (γ = 0.06) due to Legionella pneumophila (L. pneumophila) inhalation for each exposure event. For the mean concentration obtained for Legionella (103 CFU/L), the risk of infection for toilet faucets and showers was in the range of 0.23-2.3 and 3.5-21.9, respectively, per 10,000 hospitalized patients. The results were compared with the tolerable risk level of infection determined by the US EPA and WHO. The risk values exceeded the WHO values for waterborne pathogens in hospitals in both exposure scenarios. As a result, our QMRA results based on monitoring data showed that despite using treated water (from distribution networks in the urban areas) by hospitals, 38% of the samples were contaminated with Legionella, and faucets and showers can be sources of Legionella transmission. Hence, to protect the health of hospitalized patients, the risk of Legionella infection should be considered.
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Affiliation(s)
- Majid Kermani
- Research Center for Environmental Health Technology, Iran University of Medical Sciences, Tehran, Iran
- Department of Environmental Health Engineering, School of Public Health, Iran University of Medical Sciences, Tehran, Iran
| | - Zahra Chegini
- Department of Microbiology, School of Medicine, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Shiva Mirkalantari
- Department of Microbiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran.
| | - Samira Norzaee
- Research Center for Environmental Health Technology, Iran University of Medical Sciences, Tehran, Iran.
- Department of Environmental Health Engineering, School of Public Health, Iran University of Medical Sciences, Tehran, Iran.
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Factors Influencing Legionella Contamination of Domestic Household Showers. Pathogens 2019; 8:pathogens8010027. [PMID: 30813532 PMCID: PMC6470800 DOI: 10.3390/pathogens8010027] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Revised: 02/19/2019] [Accepted: 02/20/2019] [Indexed: 01/27/2023] Open
Abstract
Legionnaires’ disease is a potentially fatal pneumonia like infection caused by inhalation or aspiration of water particles contaminated with pathogenic Legionella spp. Household showers have been identified as a potential source of sporadic, community-acquired Legionnaires’ disease. This study used qPCR to enumerate Legionella spp. and Legionella pneumophila in water samples collected from domestic showers across metropolitan Adelaide, South Australia. A survey was used to identify risk factors associated with contamination and to examine awareness of Legionella control in the home. The hot water temperature was also measured. A total of 74.6% (50/68) and 64.2% (43/68) showers were positive for Legionella spp. and L. pneumophila, respectively. Statistically significant associations were found between Legionella spp. concentration and maximum hot water temperature (p = 0.000), frequency of shower use (p = 0.000) and age of house (p = 0.037). Lower Legionella spp. concentrations were associated with higher hot water temperatures, showers used at least every week and houses less than 5 years old. However, examination of risk factors associated with L. pneumophila found that there were no statistically significant associations (p > 0.05) with L. pneumophila concentrations and temperature, type of hot water system, age of system, age of house or frequency of use. This study demonstrated that domestic showers were frequently colonized by Legionella spp. and L. pneumophila and should be considered a potential source of sporadic Legionnaires’ disease. Increasing hot water temperature and running showers every week to enable water sitting in pipes to be replenished by the municipal water supply were identified as strategies to reduce the risk of Legionella in showers. The lack of public awareness in this study identified the need for public health campaigns to inform vulnerable populations of the steps they can take to reduce the risk of Legionella contamination and exposure.
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Duquenne P. On the Identification of Culturable Microorganisms for the Assessment of Biodiversity in Bioaerosols. Ann Work Expo Health 2017; 62:139-146. [DOI: 10.1093/annweh/wxx096] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2017] [Accepted: 11/10/2017] [Indexed: 11/14/2022] Open
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Petti S, Vitali M. Occupational risk for Legionella infection among dental healthcare workers: meta-analysis in occupational epidemiology. BMJ Open 2017; 7:e015374. [PMID: 28710211 PMCID: PMC5734417 DOI: 10.1136/bmjopen-2016-015374] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
OBJECTIVE The occupational risk for Legionella infection among dental healthcare workers (DHCWs) is conjectured because of the risk of routine inhalation of potentially contaminated aerosols produced by the dental instruments. Nevertheless, occupational epidemiology studies are contrasting. This meta-analysis assessed the level of scientific evidence regarding the relative occupational risk for Legionella infection among DHCWs. METHODS Literature search was performed without time and language restrictions, using broad data banks (PubMed, Scopus, Web of Science, GOOGLE Scholar) and generic keywords ('legionella' AND 'dent*'). Analytical cross-sectional studies comparing prevalence of high serum Legionella antibody levels in DHCWs and occupationally unexposed individuals were considered. The relative occupational risk was assessed through prevalence ratio (PR) with 95% CI. Between-study heterogeneity was assessed (Cochran's Q test) and was used to choose the meta-analytic method. Study quality (modified Newcastle-Ottawa Scale) and publication bias (Begg and Mazumdar's test, Egger and colleagues' test, trim and fill R0 method) were assessed formally and considered for the sensitivity analysis. Sensitivity analysis to study inclusion, subgroup analyses (dental staff categories; publication year, before vs after 1998, ie, 5 years after the release by the Centers for Disease Control and Prevention of the infection control guidelines in dental healthcare setting) were performed. RESULTS Seven studies were included (2232 DHCWs, 1172 occupationally unexposed individuals). No evidence of publication bias was detected. The pooled PR estimate was statistically non-significant at 95% level (1.7; 95% CI 0.8 to 3.2), study-quality adjustment did not change the PR considerably (PR, 1.5; 95% CI 0.5 to 4.1). PR was statistically significant before 1998 and no longer significant after 1998. Subgroup analysis according to DHCW categories was inconclusive. CONCLUSIONS There is no scientific evidence that DHCWs are at high occupational risk. The differences between former and recent studies could be due to different characteristics of municipal water systems and the infection control guideline dissemination.
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Affiliation(s)
- Stefano Petti
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, Rome, Italy
| | - Matteo Vitali
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, Rome, Italy
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Airborne Infectious Agents and Other Pollutants in Automobiles for Domestic Use: Potential Health Impacts and Approaches to Risk Mitigation. JOURNAL OF ENVIRONMENTAL AND PUBLIC HEALTH 2016; 2016:1548326. [PMID: 28042302 PMCID: PMC5155087 DOI: 10.1155/2016/1548326] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Revised: 10/14/2016] [Accepted: 10/23/2016] [Indexed: 01/30/2023]
Abstract
The world total of passenger cars is expected to go from the current one billion to >2.5 billion by 2050. Cars for domestic use account for ~74% of the world's yearly production of motorized vehicles. In North America, ~80% of the commuters use their own car with another 5.6% travelling as passengers. With the current life-expectancy of 78.6 years, the average North American spends 4.3 years driving a car! This equates to driving 101 minutes/day with a lifetime driving distance of nearly 1.3 million km inside the confined and often shared space of the car with exposure to a mix of potentially harmful pathogens, allergens, endotoxins, particulates, and volatile organics. Such risks may increase in proportion to the unprecedented upsurge in the numbers of family cars globally. Though new technologies may reduce the levels of air pollution from car exhausts and other sources, they are unlikely to impact our in-car exposure to pathogens. Can commercial in-car air decontamination devices reduce the risk from airborne infections and other pollutants? We lack scientifically rigorous protocols to verify the claims of such devices. Here we discuss the essentials of a customized aerobiology facility and test protocols to assess such devices under field-relevant conditions.
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Whiley H, Keegan A, Fallowfield H, Ross K. Uncertainties associated with assessing the public health risk from Legionella. Front Microbiol 2014; 5:501. [PMID: 25309526 PMCID: PMC4174118 DOI: 10.3389/fmicb.2014.00501] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Accepted: 09/05/2014] [Indexed: 11/13/2022] Open
Abstract
Legionella is an opportunistic pathogen of public health concern. Current regulatory and management guidelines for the control of this organism are informed by risk assessments. However, there are many unanswered questions and uncertainties regarding Legionella epidemiology, strain infectivity, infectious dose, and detection methods. This review follows the EnHealth Risk Assessment Framework, to examine the current information available regarding Legionella risk and discuss the uncertainties and assumptions. This review can be used as a tool for understanding the uncertainties associated with Legionella risk assessment. It also serves to highlight the areas of Legionella research that require future focus. Improvement of these uncertainties will provide information to enhance risk management practices for Legionella, potentially improving public health protection and reducing the economic costs by streamlining current management practices.
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Affiliation(s)
- Harriet Whiley
- Health and the Environment, Flinders UniversityAdelaide, SA, Australia
| | | | | | - Kirstin Ross
- Health and the Environment, Flinders UniversityAdelaide, SA, Australia
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Abstract
Nosocomial waterborne pathogens may reach patients through several modes of transmission. Colonization of healthcare facility waterworks can occur in the proximal infrastructure, in the distal water outlets, or both. Infections with waterborne organisms such as Legionella, mycobacteria, Pseudomonas, and others cause significant morbidity and mortality, particularly in immunocompromised patients. Hospitals should have prospective water safety plans that include preventive measures, as prevention is preferable to remediation of contaminated hospital water distribution systems. Whole-genome sequencing may provide more informative epidemiologic data to link patient infections with hospital water isolates.
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Affiliation(s)
- Brooke K Decker
- National Institutes of Health Clinical Center, 10 Center Drive, 12C103A, Bethesda, MD, 20892, USA
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Hines SA, Chappie DJ, Lordo RA, Miller BD, Janke RJ, Lindquist HA, Fox KR, Ernst HS, Taft SC. Assessment of relative potential for Legionella species or surrogates inhalation exposure from common water uses. WATER RESEARCH 2014; 56:203-13. [PMID: 24681377 DOI: 10.1016/j.watres.2014.02.013] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2013] [Revised: 01/07/2014] [Accepted: 02/03/2014] [Indexed: 05/22/2023]
Abstract
The Legionella species have been identified as important waterborne pathogens in terms of disease morbidity and mortality. Microbial exposure assessment is a tool that can be utilized to assess the potential of Legionella species inhalation exposure from common water uses. The screening-level exposure assessment presented in this paper developed emission factors to model aerosolization, quantitatively assessed inhalation exposures of aerosolized Legionella species or Legionella species surrogates while evaluating two generalized levels of assumed water concentrations, and developed a relative ranking of six common in-home uses of water for potential Legionella species inhalation exposure. Considerable variability in the calculated exposure dose was identified between the six identified exposure pathways, with the doses differing by over five orders of magnitude in each of the evaluated exposure scenarios. The assessment of exposure pathways that have been epidemiologically associated with legionellosis transmission (ultrasonic and cool mist humidifiers) produced higher estimated inhalation exposure doses than pathways where epidemiological evidence of transmission has been less strong (faucet and shower) or absent (toilets and therapy pool). With consideration of the large uncertainties inherent in the exposure assessment process used, a relative ranking of exposure pathways from highest to lowest exposure doses was produced using culture-based measurement data and the assumption of constant water concentration across exposure pathways. In this ranking, the ultrasonic and cool mist humidifier exposure pathways were estimated to produce the highest exposure doses, followed by the shower and faucet exposure pathways, and then the toilet and therapy pool exposure pathways.
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Affiliation(s)
| | | | | | | | - Robert J Janke
- U.S. Environmental Protection Agency, National Homeland Security Research Center, 26 West Martin Luther King Drive, Cincinnati, OH 45268, USA
| | - H Alan Lindquist
- U.S. Environmental Protection Agency, National Homeland Security Research Center, 26 West Martin Luther King Drive, Cincinnati, OH 45268, USA
| | - Kim R Fox
- U.S. Environmental Protection Agency, National Homeland Security Research Center, 26 West Martin Luther King Drive, Cincinnati, OH 45268, USA
| | - Hiba S Ernst
- U.S. Environmental Protection Agency, National Homeland Security Research Center, 26 West Martin Luther King Drive, Cincinnati, OH 45268, USA
| | - Sarah C Taft
- U.S. Environmental Protection Agency, National Homeland Security Research Center, 26 West Martin Luther King Drive, Cincinnati, OH 45268, USA.
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