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The Journal of Infectious Diseases Aug 2022Respiratory syncytial virus (RSV) infections occur in human populations around the globe, causing disease of variable severity, disproportionately affecting infants and... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Respiratory syncytial virus (RSV) infections occur in human populations around the globe, causing disease of variable severity, disproportionately affecting infants and older adults (>65 years of age). Immune responses can be protective but also contribute to disease. Experimental studies in animals enable detailed investigation of immune responses, provide insights into clinical questions, and accelerate the development of passive and active vaccination. We aimed to review the role of antibody and T-cell responses in relation to RSV disease severity in animals.
METHODS
Systematic review and meta-analysis of animal studies examining the association between T-cell responses/phenotype or antibody titers and severity of RSV disease. The PubMed, Zoological Record, and Embase databases were screened from January 1980 to May 2018 to identify animal studies of RSV infection that assessed serum antibody titer or T lymphocytes with disease severity as an outcome. Sixty-three studies were included in the final review.
RESULTS
RSV-specific antibody appears to protect from disease in mice, but such an effect was less evident in bovine RSV. Strong T-cell, Th1, Th2, Th17, CD4/CD8 responses, and weak Treg responses accompany severe disease in mice.
CONCLUSIONS
Murine studies suggest that measures of T-lymphocyte activity (particularly CD4 and CD8 T cells) may be predictive biomarkers of severity. Further inquiry is merited to validate these results and assess relevance as biomarkers for human disease.
Topics: Aged; Animals; Antibodies, Viral; Biomarkers; CD8-Positive T-Lymphocytes; Cattle; Humans; Infant; Mice; Mice, Inbred BALB C; Respiratory Syncytial Virus Infections; Respiratory Syncytial Viruses
PubMed: 34522970
DOI: 10.1093/infdis/jiab370 -
Translational Gastroenterology and... 2022Spontaneous bacterial peritonitis (SBP) is a common bacterial infection in cirrhotic patients associated with a high mortality rate. Prompt diagnosis and early...
BACKGROUND
Spontaneous bacterial peritonitis (SBP) is a common bacterial infection in cirrhotic patients associated with a high mortality rate. Prompt diagnosis and early antibiotic administration are crucial in minimizing adverse outcomes. Although detection of ≥250 polymorphonuclear leukocytes (PMN) in ascitic fluid is the current gold standard to diagnose SBP, consideration for rapid detection with biomarkers is warranted.
METHODS
A literature search for studies evaluating ascitic calprotectin and lactoferrin for detection of SBP was performed using PubMed, Embase, Scopus, Google Scholar, Cochrane library, and Clinical Trial Registries. Summary sensitivity, specificity, log diagnostic odds ratio (LDOR), and area under the summary receiver operating curve (AUC) were calculated.
RESULTS
In total, 12 and 13 studies evaluated ascitic calprotectin and lactoferrin, respectively, for detection of SBP. Summary sensitivity, specificity, and LDOR for calprotectin were 0.942 (95% CI, 0.916, 0.967), 0.860 (95% CI, 0.799, 0.935), and 4.250 (95% CI, 3.504, 4.990), respectively. AUC for calprotectin was 0.91. Summary sensitivity, specificity, and LDOR for lactoferrin were 0.954 (95% CI, 0.930, 0.979), 0.890 (95% CI, 0.836, 0.945), and 4.630 (95% CI, 3.800, 5.452), respectively. AUC for lactoferrin was 0.958.
CONCLUSIONS
The overall performance of ascitic calprotectin and lactoferrin was substantial, potentially serving as a screening tool or an alternative to manual cell count. However, a variety of manufacturers, cut-off values, and significant heterogeneity between studies should be noted. Point-of-care testing for calprotectin and lactoferrin may resolve disadvantages associated with the current methods. Future studies on this topic are, therefore, needed.
PubMed: 36300150
DOI: 10.21037/tgh-20-323 -
JDR Clinical and Translational Research Oct 2022Although healing abutments are designated for single use by most implant manufacturers, it is common practice for clinicians to reuse healing abutments. However, there... (Review)
Review
INTRODUCTION
Although healing abutments are designated for single use by most implant manufacturers, it is common practice for clinicians to reuse healing abutments. However, there is a lack of adequate references that describe detailed sterilization protocols for reuse of healing abutments.
OBJECTIVES
The purpose of this systematic review was to compile, organize, and describe the most common techniques for the sterilization of healing abutments and their efficiency in eliminating traces of microorganisms.
METHODS
An electronic search in 5 different databases was performed, including the National Library of Medicine (MEDLINE via PubMed), Embase, Cochrane Central Register of Controlled Trials, Web of Science, and Google Scholar from January 2000 to December 2020. Search variables included were dental implant, healing abutment, contaminate, contamination, reuse, and sterilization. Studies reporting with a minimum sample size of 10 healing abutments (5 per group) published in the English language were evaluated. Risk of bias assessment was elaborated for included investigations.
RESULTS
In total, 812 articles were identified, of which 8 were included in the analysis. Steam autoclave was the most widely used form of resterilization. Not a single protocol, however, was able to achieve 100% virgin surface of the healing abutments.
CONCLUSION
Although reuse of dental implant healing abutments is a cost-effective measure in dental practice, thorough surface decontamination followed by resterilization is highly recommended before reuse.
KNOWLEDGE TRANSFER STATEMENT
With consideration of cost and patient preference, results of this review would be useful in knowing various sterilization protocols for reusing healing abutments that could lead to more appropriate therapeutic decisions.
Topics: Dental Abutments; Dental Implants; Equipment Reuse; Humans; Steam; Sterilization; Surface Properties; United States
PubMed: 34617805
DOI: 10.1177/23800844211045897 -
The Cochrane Database of Systematic... Oct 2020Antiphospholipid syndrome (APS) is a systemic autoimmune disease characterized by arterial or venous thrombosis (or both), and/or pregnancy morbidity in association with... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Antiphospholipid syndrome (APS) is a systemic autoimmune disease characterized by arterial or venous thrombosis (or both), and/or pregnancy morbidity in association with the presence of antiphospholipid antibodies. The prevalence of APS is estimated at 40 to 50 cases per 100,000 people. The most common sites of thrombosis are cerebral arteries and deep veins of the lower limbs. People with a definite APS diagnosis have an increased lifetime risk of recurrent thrombotic events.
OBJECTIVES
To assess the effects of antiplatelet (AP) or anticoagulant agents, or both, for the secondary prevention of recurrent thrombosis, particularly ischemic stroke, in people with APS.
SEARCH METHODS
We last searched the MEDLINE, Embase, CENTRAL, Cochrane Stroke Group Trials Register, and ongoing trials registers on 22 November 2019. We checked reference lists of included studies, systematic reviews, and practice guidelines. We also contacted experts in the field.
SELECTION CRITERIA
We included randomized controlled trials (RCTs) that evaluated any anticoagulant or AP agent, or both, in the secondary prevention of thrombosis in people with APS, according to the criteria valid when the study took place. We did not include studies specifically addressing women with obstetrical APS.
DATA COLLECTION AND ANALYSIS
Pairs of review authors independently worked on each step of the review, following Cochrane methods. We summarized the evidence using the GRADE approach.
MAIN RESULTS
We identified eight studies including 811 participants that compared different AP or anticoagulant agents. NOAC (non-VKA oral anticoagulant: rivaroxaban 15 or 20 mg/d) versus standard-dose VKA (vitamin K antagonist: warfarin at moderate International Normalized Ratio [INR] - 2.5) or adjusted [INR 2.0-3.0] dose): In three studies there were no differences in any thromboembolic event (including death) and major bleeding (moderate-certainty evidence), but an increased risk of stroke (risk ratio [RR] 14.13, 95% confidence interval [CI] 1.87 to 106.8; moderate-certainty evidence). One of the studies reported a small benefit of rivaroxaban in terms of quality of life at 180 days measured as health state on Visual Analogue Scale (mean difference [MD] 7 mm, 95% CI 2.01 to 11.99; low-certainty evidence), but not measured as health utility on a scale from 0 to 1 (MD 0.04, 95% CI -0.02 to 0.10; low-certainty evidence). High-dose VKA (warfarin with a target INR of 3.1 to 4.0 [mean 3.3] or 3.5 [mean 3.2]) versus standard-dose VKA (warfarin with a target INR of 2.0 to 3.0 [mean 2.3] or 2.5 [mean 2.5]): In two studies there were no differences in the rates of thrombotic events and major bleeding (RR 2.22, 95% CI 0.79 to 6.23, low-certainty evidence), but an increased risk of minor bleeding in one study during a mean of 3.4 years (standard deviation [SD] 1.2) of follow-up (RR 2.55, 95% CI 1.07 to 6.07). In both trials there was evidence of a higher risk of any bleeding (hazard ratio [HR] 2.03 95% CI 1.12 to 3.68; low-certainty evidence) in the high-dose VKA group, and for this outcome (any bleeding) the incidence is not different, only the time to event is showing an effect. Standard-dose VKA plus a single AP agent (warfarin at a target INR of 2.0 to 3.0 plus aspirin 100 mg/d) versus standard-dose VKA (warfarin at a target INR of 2.0 to 3.0): One high-risk-of-bias study showed an increased risk of any thromboembolic event with combined treatment (RR 2.14, 95% CI 1.04 to 4.43; low-certainty evidence) and reported on major bleeding with five cases in the combined treatment group and one case in the standard-dose VKA treatment group, resulting in RR 7.42 (95% CI 0.91 to 60.7; low-certainty evidence) and no differences for secondary outcomes (very low- to low-certainty evidence). Single/dual AP agent and standard-dose VKA (pooled results): Two high-risk-of-bias studies compared a combination of AP and VKA (aspirin 100 mg/d plus warfarin or unspecified VKA at a target INR of 2.0 to 3.0 or 2.0 to 2.5) with a single AP agent (aspirin 100 mg/d), but did not provide any conclusive evidence regarding the effects of those drugs in people with APS (very low-certainty evidence). One of the above-mentioned studies was a three-armed study that compared a combination of AP and VKA (aspirin 100 mg/d plus warfarin at a target INR of 2.0 to 2.5) with dual AP therapy (aspirin 100 mg/d plus cilostazol 200 mg/d) and dual AP therapy (aspirin 100 mg/d plus cilostazol 200 mg/d) versus a single AP treatment (aspirin 100 mg/d). This study reported on stroke (very low-certainty evidence) but did not report on any thromboembolic events, major bleeding, or any secondary outcomes. We identified two ongoing studies and three studies are awaiting classification.
AUTHORS' CONCLUSIONS
The evidence identified indicates that NOACs compared with standard-dose VKAs may increase the risk of stroke and do not appear to alter the risk of other outcomes (moderate-certainty evidence). Using high-dose VKA versus standard-dose VKA did not alter the risk of any thromboembolic event or major bleeding but may increase the risk of any form of bleeding (low-certainty evidence). Standard-dose VKA combined with an AP agent compared with standard-dose VKA alone may increase the risk of any thromboembolic event and does not appear to alter the risk of major bleeding or other outcomes (low-certainty evidence). The evidence is very uncertain about the benefit or harm of using standard-dose VKA plus AP agents versus single or dual AP therapy, or dual versus single AP therapy, for the secondary prevention of recurrent thrombosis in people with APS (very low-certainty evidence).
Topics: Anticoagulants; Antiphospholipid Syndrome; Cause of Death; Factor Xa Inhibitors; Hemorrhage; Humans; Platelet Aggregation Inhibitors; Randomized Controlled Trials as Topic; Rivaroxaban; Secondary Prevention; Stroke; Thromboembolism; Warfarin
PubMed: 33045766
DOI: 10.1002/14651858.CD012169.pub3 -
Towards smart sustainable development through value stream mapping - a systematic literature review.Heliyon May 2023Value Stream Mapping (VSM) is a standard Lean tool for identifying and reducing waste. It is used to create value and improve the performance of any industry. The value... (Review)
Review
Value Stream Mapping (VSM) is a standard Lean tool for identifying and reducing waste. It is used to create value and improve the performance of any industry. The value of the VSM has greatly expanded from conventional to smart over time; hence, researchers and practitioners in this sector are paying more emphasis. Comprehensive review research is needed to understand VSM-based smart, sustainable development from a triple-bottom-line perspective. The primary goal of this research is to look at various insights from the historical literature that can help with the adoption of smart, sustainable development through VSM. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) with a fifteen-year time range (2008-2022) is being considered to study various insights and gaps in value stream mapping. Analysis of the significant outcomes presents an eight-point study agenda: year, national context, research method, sector, wastes, VSM type, applied tools, and analysis indicators. The critical finding implies that empirical qualitative research dominates the research sector. Effective VSM implementation requires balancing the three sustainable dimensions of economic, environmental, and social through digitalization. The circular economy should also bolster research on the intersection of sustainability applications and new digital paradigms such as industry revolution 4.0.
PubMed: 37215771
DOI: 10.1016/j.heliyon.2023.e15852 -
Journal of Chromatography. A Jan 2021Following the consolidation of therapeutic proteins in the fight against cancer, autoimmune, and neurodegenerative diseases, recent advancements in biochemistry and...
Following the consolidation of therapeutic proteins in the fight against cancer, autoimmune, and neurodegenerative diseases, recent advancements in biochemistry and biotechnology have introduced a host of next-generation biotherapeutics, such as CRISPR-Cas nucleases, stem and car-T cells, and viral vectors for gene therapy. With these drugs entering the clinical pipeline, a new challenge lies ahead: how to manufacture large quantities of high-purity biotherapeutics that meet the growing demand by clinics and biotech companies worldwide. The protein ligands employed by the industry are inadequate to confront this challenge: while featuring high binding affinity and selectivity, these ligands require laborious engineering and expensive manufacturing, are prone to biochemical degradation, and pose safety concerns related to their bacterial origin. Peptides and pseudopeptides make excellent candidates to form a new cohort of ligands for the purification of next-generation biotherapeutics. Peptide-based ligands feature excellent target biorecognition, low or no toxicity and immunogenicity, and can be manufactured affordably at large scale. This work presents a comprehensive and systematic review of the literature on peptide-based ligands and their use in the affinity purification of established and upcoming biological drugs. A comparative analysis is first presented on peptide engineering principles, the development of ligands targeting different biomolecular targets, and the promises and challenges connected to the industrial implementation of peptide ligands. The reviewed literature is organized in (i) conventional (α-)peptides targeting antibodies and other therapeutic proteins, gene therapy products, and therapeutic cells; (ii) cyclic peptides and pseudo-peptides for protein purification and capture of viral and bacterial pathogens; and (iii) the forefront of peptide mimetics, such as β-/γ-peptides, peptoids, foldamers, and stimuli-responsive peptides for advanced processing of biologics.
Topics: Antibodies; Biological Products; Chemistry, Pharmaceutical; Chromatography, Affinity; Family Characteristics; Humans; Ligands; Peptides; Peptoids; Proteins
PubMed: 33333349
DOI: 10.1016/j.chroma.2020.461632 -
Dental and Medical Problems 2020At present, new acrylic plastic technologies are being developed in dentistry. Although this kind of material has been used for dental prostheses for over 80 years, it... (Review)
Review
At present, new acrylic plastic technologies are being developed in dentistry. Although this kind of material has been used for dental prostheses for over 80 years, it has been produced in the form of disks with the computer-aided design/computer-aided manufacturing (CAD/CAM) technology for over 15 years. The purpose of the article was to collect information from the literature on acrylic materials processed through the milling technology (CAD/CAM). The publicly available databases PubMed, Google Scholar and Scopus were searched using the key word "acrylic resins, CAD/CAM". All articles describing the application and testing of CAD/CAM disks were selected. Duplicate articles were removed. More than 100 articles that described the use of materials machined using the milling equipment were found. These included works comparing the mechanical properties, biocompatibility and clinical use of the materials. After the initial selection, 36 papers on this subject were included in this review. The number of studies on the processing of acrylic materials with the use of the CAD/CAM technology has been increasing worldwide. Since such materials have better mechanical properties, no polymerization shrinkage occurs during processing, the amount of residual monomer material is very low and they have better color stability than self-curing materials.
Topics: Acrylic Resins; Computer-Aided Design; Dental Materials; Humans; Materials Testing; Polymethyl Methacrylate
PubMed: 33444491
DOI: 10.17219/dmp/124697 -
Pharmaceutics May 2024Andrographolide (ADG) has poor aqueous solubility and low bioavailability. This study systematically reviews the use of solid dispersion (SD) techniques to enhance the... (Review)
Review
Andrographolide (ADG) has poor aqueous solubility and low bioavailability. This study systematically reviews the use of solid dispersion (SD) techniques to enhance the solubility and absorption of ADG, with a focus on the methods and polymers utilized. We searched electronic databases including PubMed, Web of Science, Scopus, Embase and ScienceDirect Elsevier up to November 2023 for studies on the solubility or absorption of ADG in SD formulations. Two reviewers independently reviewed the retrieved articles and extracted data using a standardized form and synthesized the data qualitatively. SD significantly improved ADG solubility with up to a 4.7-fold increase and resulted in a decrease in 50% release time (T) to less than 5 min. SD could also improve ADG absorption, as evidenced by higher C and AUC and reduced T. Notably, Soluplus-based SDs showed marked solubility and absorption enhancements. Among the five SD techniques (rotary evaporation, spray drying, hot-melt extrusion, freeze drying and vacuum drying) examined, spray drying emerged as the most effective, enabling a one-step process without the need for post-milling. SD techniques, particularly using Soluplus and spray drying, effectively enhance the solubility and absorption of ADG. This insight is vital for the future development of ADG-SD matrices.
PubMed: 38794350
DOI: 10.3390/pharmaceutics16050688 -
The Cochrane Database of Systematic... Apr 2020Disease-modifying pharmacological agents for transthyretin (TTR)-related familial amyloid polyneuropathy (FAP) have become available in the last decade, but evidence on...
BACKGROUND
Disease-modifying pharmacological agents for transthyretin (TTR)-related familial amyloid polyneuropathy (FAP) have become available in the last decade, but evidence on their efficacy and safety is limited. This review focuses on disease-modifying pharmacological treatment for TTR-related and other FAPs, encompassing amyloid kinetic stabilisers, amyloid matrix solvents, and amyloid precursor inhibitors.
OBJECTIVES
To assess and compare the efficacy, acceptability, and tolerability of disease-modifying pharmacological agents for familial amyloid polyneuropathies (FAPs).
SEARCH METHODS
On 18 November 2019, we searched the Cochrane Neuromuscular Specialised Register, the Cochrane Central Register of Controlled Trials, MEDLINE, and Embase. We reviewed reference lists of articles and textbooks on peripheral neuropathies. We also contacted experts in the field. We searched clinical trials registries and manufacturers' websites.
SELECTION CRITERIA
We included randomised clinical trials (RCTs) or quasi-RCTs investigating any disease-modifying pharmacological agent in adults with FAPs. Disability due to FAP progression was the primary outcome. Secondary outcomes were severity of peripheral neuropathy, change in modified body mass index (mBMI), quality of life, severity of depression, mortality, and adverse events during the trial.
DATA COLLECTION AND ANALYSIS
We followed standard Cochrane methodology.
MAIN RESULTS
The review included four RCTs involving 655 people with TTR-FAP. The manufacturers of the drugs under investigation funded three of the studies. The trials investigated different drugs versus placebo and we did not conduct a meta-analysis. One RCT compared tafamidis with placebo in early-stage TTR-FAP (128 randomised participants). The trial did not explore our predetermined disability outcome measures. After 18 months, tafamidis might reduce progression of peripheral neuropathy slightly more than placebo (Neuropathy Impairment Score (NIS) in the lower limbs; mean difference (MD) -3.21 points, 95% confidential interval (CI) -5.63 to -0.79; P = 0.009; low-certainty evidence). However, tafamidis might lead to little or no difference in the change of quality of life between groups (Norfolk Quality of Life-Diabetic Neuropathy (Norfolk QOL-DN) total score; MD -4.50 points, 95% CI -11.27 to 2.27; P = 0.19; very low-certainty evidence). No clear between-group difference was found in the numbers of participants who died (risk ratio (RR) 0.65, 95% CI 0.11 to 3.74; P = 0.63; very low-certainty evidence), who dropped out due to adverse events (RR 1.29, 95% CI 0.30 to 5.54; P = 0.73; very low-certainty evidence), or who experienced at least one severe adverse event during the trial (RR 1.16, 95% CI 0.37 to 3.62; P = 0.79; very low-certainty evidence). One RCT compared diflunisal with placebo (130 randomised participants). At month 24, diflunisal might reduce progression of disability (Kumamoto Score; MD -4.90 points, 95% CI -7.89 to -1.91; P = 0.002; low-certainty evidence) and peripheral neuropathy (NIS plus 7 nerve tests; MD -18.10 points, 95% CI -26.03 to -10.17; P < 0.001; low-certainty evidence) more than placebo. After 24 months, changes from baseline in the quality of life measured by the 36-Item Short-Form Health Survey score showed no clear difference between groups for the physical component (MD 6.10 points, 95% CI 2.56 to 9.64; P = 0.001; very low-certainty evidence) and the mental component (MD 4.40 points, 95% CI -0.19 to 8.99; P = 0.063; very low-certainty evidence). There was no clear between-group difference in the number of people who died (RR 0.46, 95% CI 0.15 to 1.41; P = 0.17; very low-certainty evidence), in the number of dropouts due to adverse events (RR 2.06, 95% CI 0.39 to 10.87; P = 0.39; very low-certainty evidence), and in the number of people who experienced at least one severe adverse event (RR 0.77, 95% CI 0.18 to 3.32; P = 0.73; very low-certainty evidence) during the trial. One RCT compared patisiran with placebo (225 randomised participants). After 18 months, patisiran reduced both progression of disability (Rasch-built Overall Disability Scale; least-squares MD 8.90 points, 95% CI 7.00 to 10.80; P < 0.001; moderate-certainty evidence) and peripheral neuropathy (modified NIS plus 7 nerve tests - Alnylam version; least-squares MD -33.99 points, 95% CI -39.86 to -28.13; P < 0.001; moderate-certainty evidence) more than placebo. At month 18, the change in quality of life between groups favoured patisiran (Norfolk QOL-DN total score; least-squares MD -21.10 points, 95% CI -27.20 to -15.00; P < 0.001; low-certainty evidence). There was little or no between-group difference in the number of participants who died (RR 0.61, 95% CI 0.21 to 1.74; P = 0.35; low-certainty evidence), dropped out due to adverse events (RR 0.33, 95% CI 0.13 to 0.82; P = 0.017; low-certainty evidence), or experienced at least one severe adverse event (RR 0.91, 95% CI 0.64 to 1.28; P = 0.58; low-certainty evidence) during the trial. One RCT compared inotersen with placebo (172 randomised participants). The trial did not explore our predetermined disability outcome measures. From baseline to week 66, inotersen reduced progression of peripheral neuropathy more than placebo (modified NIS plus 7 nerve tests - Ionis version; MD -19.73 points, 95% CI -26.50 to -12.96; P < 0.001; moderate-certainty evidence). At week 65, the change in quality of life between groups favoured inotersen (Norfolk QOL-DN total score; MD -10.85 points, 95% CI -17.25 to -4.45; P < 0.001; low-certainty evidence). Inotersen may slightly increase mortality (RR 5.94, 95% CI 0.33 to 105.60; P = 0.22; low-certainty evidence) and occurrence of severe adverse events (RR 1.48, 95% CI 0.85 to 2.57; P = 0.16; low-certainty evidence) compared to placebo. More dropouts due to adverse events were observed in the inotersen than in the placebo group (RR 8.57, 95% CI 1.16 to 63.07; P = 0.035; low-certainty evidence). There were no studies addressing apolipoprotein AI-FAP, gelsolin-FAP, and beta-2-microglobulin-FAP.
AUTHORS' CONCLUSIONS
Evidence on the pharmacological treatment of FAPs from RCTs is limited to TTR-FAP. No studies directly compare disease-modifying pharmacological treatments for TTR-FAP. Results from placebo-controlled trials indicate that tafamidis, diflunisal, patisiran, and inotersen may be beneficial in TTR-FAP, but further investigations are needed. Since direct comparative studies for TTR-FAP will be hampered by sample size and costs required to demonstrate superiority of one drug over another, long-term non-randomised open-label studies monitoring their efficacy and safety are needed.
Topics: Amyloid Neuropathies, Familial; Benzoxazoles; Diflunisal; Disease Progression; Humans; Oligonucleotides; Patient Dropouts; Quality of Life; RNA, Small Interfering; Randomized Controlled Trials as Topic
PubMed: 32311072
DOI: 10.1002/14651858.CD012395.pub2 -
Water Research Aug 2024Legionella is an opportunistic waterborne pathogen that causes Legionnaires' disease. It poses a significant public health risk, especially to vulnerable populations in...
Legionella is an opportunistic waterborne pathogen that causes Legionnaires' disease. It poses a significant public health risk, especially to vulnerable populations in health care facilities. It is ubiquitous in manufactured water systems and is transmitted via inhalation or aspiration of aerosols/water droplets generated from water fixtures (e.g., showers and hand basins). As such, the effective management of premise plumbing systems (building water systems) in health care facilities is essential for reducing the risk of Legionnaires' disease. Chemical disinfection is a commonly used control method and chlorine-based disinfectants, including chlorine, chloramine, and chlorine dioxide, have been used for over a century. However, the effectiveness of these disinfectants in premise plumbing systems is affected by various interconnected factors that can make it challenging to maintain effective disinfection. This systematic literature review identifies all studies that have examined the factors impacting the efficacy and decay of chlorine-based disinfectant within premise plumbing systems. A total of 117 field and laboratory-based studies were identified and included in this review. A total of 20 studies directly compared the effectiveness of the different chlorine-based disinfectants. The findings from these studies ranked the typical effectiveness as follows: chloramine > chlorine dioxide > chlorine. A total of 26 factors were identified across 117 studies as influencing the efficacy and decay of disinfectants in premise plumbing systems. These factors were sorted into categories of operational factors that are changed by the operation of water devices and fixtures (such as stagnation, temperature, water velocity), evolving factors which are changed in-directly (such as disinfectant concentration, Legionella disinfectant resistance, Legionella growth, season, biofilm and microbe, protozoa, nitrification, total organic carbon(TOC), pH, dissolved oxygen(DO), hardness, ammonia, and sediment and pipe deposit) and stable factors that are not often changed(such as disinfectant type, pipe material, pipe size, pipe age, water recirculating, softener, corrosion inhibitor, automatic sensor tap, building floor, and construction activity). A factor-effect map of each of these factors and whether they have a positive or negative association with disinfection efficacy against Legionella in premise plumbing systems is presented. It was also found that evaluating the effectiveness of chlorine disinfection as a water risk management strategy is further complicated by varying disinfection resistance of Legionella species and the form of Legionella (culturable/viable but non culturable, free living/biofilm associated, intracellular replication within amoeba hosts). Future research is needed that utilises sensors and other approaches to measure these key factors (such as pH, temperature, stagnation, water age and disinfection residual) in real time throughout premise plumbing systems. This information will support the development of improved models to predict disinfection within premise plumbing systems. The findings from this study will inform the use of chlorine-based disinfection within premise plumbing systems to reduce the risk of Legionnaires disease.
Topics: Disinfectants; Chlorine; Legionella; Disinfection; Chlorine Compounds; Water Microbiology; Chloramines; Water Supply; Oxides; Water Purification
PubMed: 38824796
DOI: 10.1016/j.watres.2024.121794