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Environmental Science & Technology Jun 2024Waterborne pathogens invariably present considerable threats to public health. The quorum sensing (QS) system is instrumental in coordinating bacterial growth and...
Waterborne pathogens invariably present considerable threats to public health. The quorum sensing (QS) system is instrumental in coordinating bacterial growth and metabolisms. However, the responses and regulatory mechanisms of bacteria to various disinfection technologies through quorum sensing are still unclear. This study examines the inactivation effect of chlorination and ozonation on biofilms and planktonic cells of QS signaling-deficient mutants of . Cell counting and viability assessment revealed that the combined disinfection of chlorine and ozone was the most effective for inactivating planktonic within 10 min of exposure. Additionally, microfluidic chip culture demonstrated that the secretion of quinolone signals escalated biofilms' disinfection resistance. Disinfection exposure significantly altered the gene expression of wild-type strains and QS signaling-deficient mutants. Moreover, the QS system triggered multilayered gene expression programs as a responsive protection to disinfectant exposure, including oxidative stress, ribosome synthesis, and the nutrient absorption of bacteria. These insights broaden our understanding of bacterial QS in response to disinfection, promising potential strategies toward efficient disinfection processes.
PubMed: 38937254
DOI: 10.1021/acs.est.3c08305 -
International Journal of Infectious... Jun 2024To clarify the infection route in maternal death due to invasive group A streptococcal (GAS) infection and toxic shock syndrome (TSS).
OBJECTIVE
To clarify the infection route in maternal death due to invasive group A streptococcal (GAS) infection and toxic shock syndrome (TSS).
METHODS
A retrospective study was conducted on maternal deaths due to GAS-TSS in Japan between January 2010 and March 2024. The final causal diagnosis of maternal death and the infection routes of GAS were analysed using medical records, laboratory data, and autopsy findings.
RESULTS
Among the 616 maternal deaths during the study period, 48 (8%) involved infectious diseases. The most common infection was invasive GAS (56%, n=27), 21 (78%) and six cases occurred during the antepartum and puerperium periods, respectively. In the GAS-TSS group, 71% (15/21) infections were originated the upper respiratory tract. However, in the puerperium cases, 67% (4/6) were infected from the genital tract. In addition, no maternal deaths due to GAS-TSS were reported during the COVID-19 pandemic period in Japan from 2020-2023.
CONCLUSION
Most antepartum GAS infections were from the upper respiratory tract. They may be reduced by preventive measures, including frequent disinfection, wearing masks, and isolation from persons at high risk of carrying GAS, such as symptomatic children. On the other hand, GAS-TSS during puerperium infection via the genital tract.
PubMed: 38936654
DOI: 10.1016/j.ijid.2024.107154 -
Chemosphere Jun 2024This research investigated the comparative efficacy of sulfamic acid (SA) and phytic acid (PA), both individually and in combination, for treating potential foodborne...
This research investigated the comparative efficacy of sulfamic acid (SA) and phytic acid (PA), both individually and in combination, for treating potential foodborne pathogens and pre-formed foulants. Pathogens studied included Listeria monocytogenes, E. coli DH5α, Salmonella Typhimurium, Staphylococcus aureus, and vegetative Bacillus cereus, in suspended aqueous solutions, as well as Pseudomonas aeruginosa biofilm on quartz glass surfaces. Inactivation kinetics for Listeria monocytogenes revealed concentration-dependent rate constants (k) of 6.6(±0.2)×10 M and 2.8(±0.1)×10 M for single treatments of SA and PA, respectively, and ranged from 6.9(±0.3) to 50.7(±2.3)×10 M for combined treatments with PA pre-treatment concentrations of 75-758 μM. Observable cellular abnormalities in Listeria monocytogenes, such as membrane vesiculation, chelation, cellular disruption, biomolecule leakage, and lipid peroxidation, were identified after exposure to PA or SA, either individually or in combination. The optimized combined treatment of PA and SA achieved significant removal (i.e., >3-log; 99.9%) of potential foodborne pathogens under simulated food-washing process conditions. Additionally, over 90% descaling efficacy was observed for pre-formed foulants such as CaCO precipitates and Pseudomonas aeruginosa biofilm on quartz glass surfaces with the combined treatment. These findings provide novel insights into the versatile utility of PA and SA for optimizing combinational water disinfection systems and addressing (in)organic foulant scaling on surfaces in the food processing industry.
PubMed: 38936490
DOI: 10.1016/j.chemosphere.2024.142706 -
Environmental Pollution (Barking, Essex... Jun 2024The environmental transmission of antibiotic resistance genes (ARGs) and metal resistance genes (MRGs) exerted devastating threats to global public health, and their...
The environmental transmission of antibiotic resistance genes (ARGs) and metal resistance genes (MRGs) exerted devastating threats to global public health, and their interactions with other emerging contaminants (ECs) have raised increasing concern. This study investigated that the abundances of ARGs and MRGs with the predominant type of efflux pump were simultaneously increased (8.4-59.1%) by disinfectant polyhexamethylene guanidine (PHMG) during waste activated sludge (WAS) anaerobic digestion. The aggregation of the same microorganisms (i.e., Hymenobacter and Comamonas) and different host bacteria (i.e., Azoarcus and Thauera) were occurred upon exposure to PHMG, thereby increasing the co-selection and propagation of MRGs and ARGs by vertical gene transfer. Moreover, PHMG enhanced the process of horizontal gene transfer (HGT), facilitating their co-transmission by the same mobile genetic elements (20.2-223.7%). Additionally, PHMG up-regulated the expression of critical genes (i.e., glnB, trpG and gspM) associated with the HGT of ARGs and MRGs (i.e., two-component regulatory system and quorum sensing) and exocytosis system (i.e., bacterial secretion system). Structural equation model analysis further verified that the key driver for the simultaneous enrichment of ARGs and MRGs under PHMG stress was microbial community structure. The study gives new insights into the aggravated environmental risks and mechanisms of ECs in sludge digestion system, providing guidance for subsequent regulation and control of ECs.
PubMed: 38936038
DOI: 10.1016/j.envpol.2024.124453 -
Journal of Water and Health Jun 2024Ferrate (Fe(VI): HFeO /FeO), a potent oxidant, has been investigated as an alternative chemical disinfectant in water treatment due to its reduced production of...
Ferrate (Fe(VI): HFeO /FeO), a potent oxidant, has been investigated as an alternative chemical disinfectant in water treatment due to its reduced production of disinfection by-products. In this study, we assessed the disinfecting ability of potassium ferrate against a variety of microorganisms, including waterborne pathogens, under varying pH and water temperature conditions. We presented CT values, a metric of ferrate concentrations (C) and contact time (T), to quantify microbial inactivation rates. Among the tested microorganisms, human adenovirus was the least resistant to ferrate, followed by waterborne bacteria such as and , and finally, the protozoan parasite . We further investigated the impact of two pH values (7 and 8) and two temperatures (5 and 25 °C) on microbial inactivation rates, observing that inactivation rates increased with lower pH and higher temperature. In addition to showcasing ferrate's capacity to effectively inactivate a range of the tested microorganisms, we offer a ferrate CT table to facilitate the comparison of the effectiveness of various disinfection methods.
Topics: Hydrogen-Ion Concentration; Temperature; Disinfectants; Giardia lamblia; Adenoviruses, Human; Potassium Compounds; Water Microbiology; Disinfection; Water Purification; Iron Compounds; Humans; Escherichia coli
PubMed: 38935460
DOI: 10.2166/wh.2024.087 -
Journal of Water and Health Jun 2024We characterized concentrations of trihalomethanes (THMs), a measure of disinfection byproducts (DBPs), in tap water samples collected from households with...
We characterized concentrations of trihalomethanes (THMs), a measure of disinfection byproducts (DBPs), in tap water samples collected from households with utility-supplied water in two rural counties in Appalachian Virginia, and assessed associations with pH, free chlorine, and metal ions which can impact THM formation. Free chlorine concentrations in all samples ( = 27 homes) complied with EPA drinking water guidelines, though 7% ( = 2) of first draw samples and 11% ( = 3) of 5-min flushed-tap water samples exceeded the US Safe Drinking Water Act (SDWA) maximum contaminant level (MCL) for THM (80 ppb). Regression analyses showed that free chlorine and pH were positively associated with the formation of THM levels above SDWA MCLs (OR = 1.04, = 0.97 and OR = 1.74, = 0.79, respectively), while temperature was negatively associated (OR = 0.78, = 0.38). Of the eight utilities serving study households, samples from water served by three different utilities exceeded the EPA MCL for THM. Overall, these findings do not indicate substantial exposures to DBPs for rural households with utility-supplied water in this region of southwest Virginia. However, given the observed variability in THM concentrations between and across utilities, and established adverse health impacts associated with chronic and acute DBP exposure, more research on DBPs in rural Central Appalachia is warranted.
Topics: Virginia; Chlorine; Rural Population; Drinking Water; Water Pollutants, Chemical; Water Supply; Trihalomethanes; Water Purification; Disinfection; Humans; Disinfectants; Appalachian Region; Family Characteristics
PubMed: 38935457
DOI: 10.2166/wh.2024.054 -
European Endodontic Journal Jun 2024Evaluate the bacterial reduction effect of disinfection protocols used in lower molars infected by Enterococcus faecalis.
OBJECTIVE
Evaluate the bacterial reduction effect of disinfection protocols used in lower molars infected by Enterococcus faecalis.
METHODS
Eighty extracted lower molars were prepared and inoculated with E. faecalis for 2 months. The teeth were then distributed into 2 control groups (n = 4) and 4 experimental groups (n = 18) in function of the disinfection protocol utilized: G1. WaveOne Gold (WOG), passive ultrasonic irrigation (PUI) and Ultracal; G2. WOG, PUI and calcium hydroxide (CH); G3. WOG, XP-Endo Finisher (XPF) and Ultracal; G4. WOG, XPF and CH. Bacteriological samples were collected previously (S1), after preparation (S2), final agitation (S3) and intracanal dressing (S4). Microbial growth was assessed according to culture turbidity and UV spectrophotometry. Statistical analyses used the Friedman test for paired samples and Kruskal-Wallis test for non-paired data (p<0.05).
RESULTS
No protocol eliminated E. faecalis effectively. The S2, S3 and S4 samples were statistically different from the S1 samples in G1, G2, G3 and G4 (p<0.05). Statistical differences were observed in bacterial reduction between G1 and G2 and G1 and G3 after the intracanal medicament (S4) (p<0.05).
CONCLUSION
The WOG + PUI + CH disinfection protocol showed higher percentages of bacterial reduction.
PubMed: 38935107
DOI: 10.14744/hnhj.2024.47450 -
Indian Journal of Public Health Oct 2023The augmentation of precautionary behaviors through the application of health belief model (HBM) constructs could help in curbing the current pandemic.
BACKGROUND
The augmentation of precautionary behaviors through the application of health belief model (HBM) constructs could help in curbing the current pandemic.
OBJECTIVES
The objectives are to assess adherence to CAB and to evaluate its predictors using the constructs of HBM among COVID-19 vaccinees in Himachal Pradesh.
MATERIALS AND METHODS
A cross-sectional study using a telephone survey, with two-step stratified random sampling, was employed to acquire a sample of 441 respondents from Himachal Pradesh. Formal interviews were conducted using pretested, structured, self-administered questionnaires.
RESULTS
The mean age of respondents was 32.16 years (standard deviation = 12.77; range = 18-78 years). Maximum adherence was seen for wearing masks at 83% (95% confidence interval [CI]: 79.3%-86.3%), followed by maintenance of respiratory hygiene at 72.3% (95% CI 68%-78.4%). Nearly 42.2% (95% CI 37.6%-47.8%) conformed to social distancing norms. We observed minimum adherence for handwashing practices of 12.9% (95% CI 10%-16.3.0%). On bivariate analyses, except for perceived severity, all HBM constructs were significantly associated with CAB. However, after adjusting for gender, age, education, area of residence, and reduced income in multivariate analysis, perceived susceptibility, perceived barriers, and exposure to cues to action remained significant predictors of CAB.
CONCLUSIONS
The study highlights the empirical evidence of the application of HBM constructs to enhance behavioral adherence to COVID-19 precautionary measures.
Topics: Humans; COVID-19; India; Adult; Cross-Sectional Studies; Male; Female; Middle Aged; Health Belief Model; Adolescent; Young Adult; Aged; SARS-CoV-2; Health Behavior; Health Knowledge, Attitudes, Practice; Socioeconomic Factors; Hand Disinfection
PubMed: 38934832
DOI: 10.4103/ijph.ijph_1525_22 -
ACS Catalysis May 2024Electrochemical ozone production (EOP), a six-electron water oxidation reaction, offers promising avenues for creating value-added oxidants and disinfectants. However,...
Electrochemical ozone production (EOP), a six-electron water oxidation reaction, offers promising avenues for creating value-added oxidants and disinfectants. However, progress in this field is slowed by a dearth of understanding of fundamental reaction mechanisms. In this work, we combine experimental electrochemistry, spectroscopic detection of reactive oxygen species (ROS), oxygen-anion chemical ionization mass spectrometry, and computational quantum chemistry calculations to determine a plausible reaction mechanism on nickel- and antimony-doped tin oxide (Ni/Sb-SnO, NATO), one of the most selective EOP catalysts. Antimony doping is shown to increase the conductivity of the catalyst, leading to improved electrochemical performance. Spectroscopic analysis and electrochemical experiments combined with quantum chemistry predictions reveal that hydrogen peroxide (HO) is a critical reaction intermediate. We propose that leached Ni cations catalyze hydrogen peroxide into solution phase hydroperoxyl radicals (OOH); these radicals are subsequently oxidized to ozone. Isotopic product analysis shows that ozone is generated catalytically from water and corrosively from the catalyst oxide lattice without regeneration of lattice oxygens. Further quantum chemistry calculations and thermodynamic analysis suggest that the electrochemical corrosion of tin oxide itself might generate hydrogen peroxide, which is then catalyzed to ozone. The proposed pathways explain both the roles of dopants in NATO and its lack of stability. Our study interrogates the possibility that instability and electrochemical activity are intrinsically linked through the formation of ROS. In doing so, we provide the first mechanism for EOP that is consistent with computational and experimental results and highlight the central challenge of instability as a target for future research efforts.
PubMed: 38933735
DOI: 10.1021/acscatal.4c01317 -
Fundamental Research May 2024Land public transport is an important link within and between cities, and how to control the transmission of COVID-19 in land public transport is a critical issue in our... (Review)
Review
Land public transport is an important link within and between cities, and how to control the transmission of COVID-19 in land public transport is a critical issue in our daily lives. However, there are still many inconsistent opinions and views about the spread of SARS-CoV-2 in land public transport, which limits our ability to implement effective interventions. The purpose of this review is to overview the literature on transmission characteristics and routes of the epidemic in land public transport, as well as to investigate factors affecting its spread and provide feasible measures to mitigate the infection risk of passengers. We obtained 898 papers by searching the Web of Science, Pubmed, and WHO global COVID database by keywords, and finally selected 45 papers that can address the purpose of this review. Land public transport is a high outbreak area for COVID-19 due to characteristics like crowding, inadequate ventilation, long exposure time, and environmental closure. Different from surface touch transmission and drop spray transmission, aerosol inhalation transmission can occur not only in short distances but also in long distances. Insufficient ventilation is the most important factor influencing long-distance aerosol transmission. Other transmission factors (e.g., interpersonal distance, relative orientation, and ambient conditions) should be noticed as well, which have been summarized in this paper. To address various influencing factors, it is essential to suggest practical and efficient preventive measures. Among these, increased ventilation, particularly the fresh air (i.e., natural ventilation), has proven to effectively reduce indoor infection risk. Many preventive measures are also effective, such as enlarging social distance, avoiding face-to-face orientation, setting up physical partitions, disinfection, avoiding talking, and so on. As research on the epidemic has intensified, people have broken down many perceived barriers, but more comprehensive studies on monitoring systems and prevention measures in land public transport are still needed.
PubMed: 38933205
DOI: 10.1016/j.fmre.2023.10.013