Multi-omics reveals that alkaline mineral water improves the respiratory health and growth performance of transported calves.

BACKGROUND: Long-distance transportation, a frequent practice in the cattle industry, stresses calves and results in morbidity, mortality, and growth suppression, leading to welfare concerns and economic losses. Alkaline mineral water (AMW) is an electrolyte additive containing multiple mineral elements and shows stress-mitigating effects on humans and bovines. RESULTS: Here, we monitored the respiratory health status and growth performance of 60 Simmental calves subjected to 30 hours of road transportation using a clinical scoring system. Within the three days of commingling before the transportation and 30 days after the transportation, calves in the AMW group (n = 30) were supplied with AMW, while calves in the Control group (n = 29) were not. On three specific days, namely the day before transportation (day -3), the 30th day (day 30), and the 60th day (day 60) after transportation, sets of venous blood, serum, and nasopharyngeal swab samples were collected from 20 calves (10 from each group) for routine blood testing, whole blood transcriptomic sequencing, serology detection, serum untargeted metabolic sequencing, and 16S rRNA gene sequencing. The field data showed that calves in the AMW group displayed lower rectal temperatures (38.967 ℃ vs. 39.022 ℃; p = 0.004), respiratory scores (0.079 vs. 0.144; p < 0.001), appetite scores (0.024 vs. 0.055; p < 0.001), ocular and ear scores (0.185 vs. 0.338; p < 0.001), nasal discharge scores (0.143 vs. 0.241; p < 0.001), and higher body weight gains (30.870 kg vs. 7.552 kg; p < 0.001). The outcomes of laboratory and high throughput sequencing data revealed that the calves in the AMW group demonstrated higher cellular and humoral immunities, antioxidant capacities, lower inflammatory levels, and intestinal absorption and lipogenesis on days -3 and 60. The nasopharynx 16S rRNA gene microbiome analysis revealed the different composition and structure of the nasopharyngeal microflora in the two groups of calves on day 30. Joint analysis of multi-omics revealed that on days -3 and 30, bile secretion was a shared pathway enriched by differentially expressed genes and metabolites, and there were strong correlations between the differentially expressed metabolites and the main genera in the nasopharynx. CONCLUSIONS: These results suggest that AMW supplementation enhances peripheral immunity, nutrition absorption, and metabolic processes, subsequently affecting the nasopharyngeal microbiota and improving the respiratory health and growth performance of transported calves. This investigation provided a practical approach to mitigate transportation stress and explored its underlying mechanisms, which are beneficial for the development of the livestock industry. Video Abstract.

Effects of Meloxicam on the Welfare of Holstein Calves from 6 Weeks to 6 Months Old Undergoing Amputation Dehorning.

Amputation dehorning (AD) is a common practice performed on calves, causing harmful effects such as pain, distress, anxiety, and fear. These effects extend to behavioral, physiological, and hematological responses, prompting serious ethical concerns regarding animal welfare, even when performed with local anesthesia. Meloxicam, a non-steroidal anti-inflammatory drug, has been widely used to mitigate the side effects of dehorning and disbudding in calves. However, there is a notable gap in research regarding the effects of meloxicam on calves aged 6 weeks to 6 mo undergoing AD procedures. This study was designed to assess the effectiveness of co-administering meloxicam with lidocaine, a cornual nerve anesthetic, in alleviating the adverse effects caused by the AD procedure in calves within this age range, compared with the use of lidocaine alone. Thirty Holstein calves were enrolled and randomly divided into 2 groups. The first group (Placebo) received a subcutaneous injection of 5 mL of lidocaine in the horn area and a subcutaneous injection of 0.9% saline at a dose of 0.025 mL/kg in the neck, administered 10 min before the AD procedure. The second group (MX) received a combination of lidocaine and meloxicam: a subcutaneous injection of 5 mL of lidocaine in the horn area and a subcutaneous injection of 20 mg/mL meloxicam at a dose of 0.025 mL/kg in the neck, also administered 10 min before the AD procedure. To avoid subjective bias, the researchers were blinded to the treatment groups. Pain-related behaviors, including tail flicking, head shaking, ear flicking, head rubbing, head crossing bar, and kicking, were observed, and physiological parameters, including heart rate, rectal temperature, respiration rate, mechanical nociceptive threshold (MNT), daily active steps, and food intake were monitored. Hematological conditions were determined using enzyme-linked immunosorbent assays and routine blood tests. The data were processed using a generalized linear mixed model (GLMM). The outcomes demonstrated that the AD procedure increased the frequencies of ear flicking and resulted in rises in the respiration rate, heart rate, rectal temperature, and daily active steps. It also led to decreases in total food intake, forage intake, hay intake, MNT, and increased concentrations of prostaglandin E2 (PgE2), interleukin-1ß (IL-1ß), tumor necrosis factor-α (TNF-α), nitric oxide (NO), and malondialdehyde, as well as glutathione peroxidase activity. However, calves that received meloxicam treatment showed significant improvements in response to the AD procedure, including lower respiration rates, heart rates, and rectal temperatures; higher MNTs; and lower intermediate cell ratio. They also had higher red blood counts, hemoglobin levels, hematocrit values; larger mean platelet volumes; and lower concentrations of PgE2, IL-1ß, TNF-α, and NO. These results suggest that co-administration of lidocaine and meloxicam may aid in mitigating the adverse impacts induced by the AD procedure on these calves, thereby supporting the use of meloxicam in conjunction with a local anesthetic in AD procedures for calves aged 6 weeks to 6 mo.

XAV939 Improves the Prognosis of Myocardial Infarction by Blocking the Wnt/ß-Catenin Signalling Pathway.

Myocardial infarction (MI) is closely related to the Wnt signalling pathway, but the role of XAV939 (a Wnt/ß-catenin signalling pathway blocker) in MI has not been elucidated. The purpose of this study was to explore the role of XAV939 in mouse hearts and to provide a new and feasible treatment for improving the prognosis of MI. C57BL/6 (male, 8 weeks old, 20-25 g) mice were selected for our study. The MI model was made by ligating the left anterior descending coronary artery. On day 28 after the operation, cardiac function was examined by echocardiography. Infarct size, fibrosis, and angiogenesis were individually measured by TTC assays, Masson's trichrome staining, and CD31 analysis, respectively. Apoptosis was examined by TdT-mediated dUTP nick-end labelling (TUNEL) staining. The expression of Wnt, ß-catenin, caspase 3, Bax, and Bcl-2 was determined by western blotting. XAV939 successfully blocked Wnt/ß-catenin signalling pathway activation in cardiomyocytes after MI by promoting the degradation of ß-catenin. XAV939 suppressed fibrosis and apoptosis, promoted angiogenesis, reduced myocardial infarct size and improved cardiac function after MI. XAV939 can reduce myocardial infarct size and improve cardiac function by blocking the Wnt/ß-catenin signalling pathway, which may provide a new strategy for improving the prognosis of MI.

A Clinical Trial on the Welfare Effects of Administering Meloxicam to 10 to 21 Day Dairy Calves Following Caustic Paste Disbudding.

Caustic paste disbudding (CPD) is widely utilized for calves, which has been known to result in adverse effects on the calves and ethical concerns related to animal welfare, despite the use of local anesthetics. The administration of meloxicam has been demonstrated to provide benefits in alleviating pain and inflammation in juvenile calves under 9 d old and subjected to CPD. Nonetheless, there is a scarcity of literature documenting the beneficial impact of meloxicam in alleviating pain in calves aged over 9 d that have undergone CPD. Therefore, the objective of this clinical trial was to evaluate the efficacy of administering meloxicam and lidocaine for cornual nerve block together in mitigating the deleterious effects of CPD, as opposed to using lidocaine alone in calves older than 9 d. Thirty Holstein calves, aged between 10 and 21 d, were enrolled and randomly assigned to 1 of 2 treatments: lidocaine alone (Placebo), lidocaine and normal saline treatment before CPD, and lidocaine plus meloxicam, lidocaine and 0.5 mg/kg of meloxicam treatment prior to CPD. The researchers were blind to the treatment of calves to control the subjective error. The occurrences of actions associated with pain, which included head shaking, head rubbing, ear flicking, tail flicking, kicking, and head passing through the fence, were recorded. Physiological performance, including the respiration rate, heart rate, rectal temperature, mechanical nociceptive threshold (MNT), food intake, and daily activity level, was monitored. Hematological conditions were ascertained through the use of routine blood tests and enzyme-linked immunosorbent assay. The generalized linear mixed model was employed to analyze the data. The research findings revealed that applying the CPD procedure significantly elevated the frequencies of tail flicking, head shaking, and kicking, resulted in increases in respiratory rate, heart rate, daily active steps, and food intake and a decrease in MNT, and led to alterations in hematological markers, including platelet counts, mean platelet volume, prostaglandin E2, constitutive nitric oxide synthase, and hydroxyl radical. Considerable benefits, such as lower heart rates, higher food intake, and MNTs, as well as lower levels of white blood cell counts, lymphocyte counts, hemoglobin, mean platelet volume, prostaglandin E2, tumor necrosis factor-α, constitutive nitric oxide synthase, malondialdehyde, and hydroxyl radical, were observed in the calves that received meloxicam treatment in response to CPD. The findings of the study indicate that the co-administration of lidocaine and meloxicam provides obvious benefits in mitigating pain, inflammation, and oxidative stress in calves aged over 9 d and undergoing CPD. This endorses the use of meloxicam during the disbudding and dehorning procedures of calves.

Caustic paste disbudding (CPD) is a widely used practice in the cattle industry, yet there is a shortage of literature on the effects of meloxicam on calves aged 10 to 21 d who have undergone this procedure. In this clinical trial, we conducted a comparative analysis of the pain-related behavioral, physiological, and hematological performance of calves that were administered with either lidocaine plus normal saline (n = 15) or lidocaine plus meloxicam (n = 15) before undergoing disbudding operations. The findings demonstrated that the CPD operation had a significant impact on the pain-related behavior, physiological functions, and serum anti-inflammatory and antioxidative markers of the calves. On the other hand, the administration of meloxicam had notable advantages for the calves by enhancing the physiological and hematological parameters.

Low Glucose plus ß-Hydroxybutyrate Induces an Enhanced Inflammatory Response in Yak Alveolar Macrophages via Activating the GPR109A/NF-κB Signaling Pathway.

Yaks are often subject to long-term starvation and a high prevalence of respiratory diseases and mortality in the withered season, yet the mechanisms that cause this remain unclear. Research has demonstrated that ß-hydroxybutyrate (BHB) plays a significant role in regulating the immune system. Hence, we hypothesize that the low glucose and high BHB condition induced by severe starvation might have an effect on the pro-inflammatory response of the alveolar macrophages (AMs) in yaks. To validate our hypothesis, we isolated and identified primary AMs from freshly slaughtered yaks and cultured them in a medium with 5.5 mM of glucose or 2.8 mM of glucose plus 1-4 mM of BHB. Utilizing a real-time quantitative polymerase chain reaction (RT-qPCR), immunoblot assay, and enzyme-linked immunosorbent assay (ELISA), we evaluated the gene and protein expression levels of GPR109A (G-protein-coupled receptor 109A), NF-κB p65, p38, and PPARγ and the concentrations of pro-inflammatory cytokines interleukin (IL)-1ß and IL-6 and tumor necrosis factor (TNF)-α in the supernatant. The results demonstrated that AMs exposed to low glucose plus BHB had significantly higher levels of IL-1ß, IL-6, and TNF-α (p < 0.05) and higher activity of the GPR109A/NF-κB signaling pathway. A pretreatment of either pertussis toxin (PTX, inhibitor of GPR109A) or pyrrolidinedithiocarbamic (PDTC, inhibitor of NF-κB p65) was effective in preventing the elevated secretion of pro-inflammatory cytokines induced by low glucose plus BHB (p < 0.05). These results indicated that the low glucose plus BHB condition would induce an enhanced pro-inflammatory response through the activation of the GPR109A/NF-κB signaling pathway in primary yak AMs, which is probably the reason why yaks experience a higher rate of respiratory diseases and mortality. This study will offer new insight into the prevention and treatment of bovine respiratory diseases.

RAGE-TLR4 Crosstalk Is the Key Mechanism by Which High Glucose Enhances the Lipopolysaccharide-Induced Inflammatory Response in Primary Bovine Alveolar Macrophages.

The receptor of advanced glycation end products (RAGE) and Toll-like receptor 4 (TLR4) are important receptors for inflammatory responses induced by high glucose (HG) and lipopolysaccharide (LPS) and show crosstalk phenomena in inflammatory responses. However, it is unknown whether RAGE and TLR4 can influence each other's expression through a crosstalk mechanism and whether the RAGE-TLR4 crosstalk related to the molecular mechanism of HG enhances the LPS-induced inflammatory response. In this study, the implications of LPS with multiple concentrations (0, 1, 5, and 10 µg/mL) at various treatment times (0, 3, 6, 12, and 24 h) in primary bovine alveolar macrophages (BAMs) were explored. The results showed that a 5 µg/mL LPS treatment at 12 h had the most significant increment on the pro-inflammatory cytokine interleukin 1ß (IL-1ß), IL-6, and tumor necrosis factor (TNF)-α levels in BAMs (p < 0.05) and that the levels of TLR4, RAGE, MyD88, and NF-κB p65 mRNA and protein expression were upregulated (p < 0.05). Then, the effect of LPS (5 µg/mL) and HG (25.5 mM) co-treatment in BAMs was explored. The results further showed that HG significantly enhanced the release of IL-1ß, IL-6, and TNF-α caused by LPS in the supernatant (p < 0.01) and significantly increased the levels of RAGE, TLR4, MyD88, and NF-κB p65 mRNA and protein expression (p < 0.01). Pretreatment with FPS-ZM1 and TAK-242, the inhibitors of RAGE and TLR4, significantly alleviated the HG + LPS-induced increment of RAGE, TLR4, MyD88, and NF-κB p65 mRNA and protein expression in the presence of HG and LPS (p < 0.01). This study showed that RAGE and TLR4 affect each other's expression through crosstalk during the combined usage of HG and LPS and synergistically activate the MyD88/NF-κB signaling pathway to promote the release of pro-inflammatory cytokines in BAMs.

Beta-Hydroxybutyrate: A Dual Function Molecular and Immunological Barrier Function Regulator.

Ketone bodies are crucial intermediate metabolites widely associated with treating metabolic diseases. Accumulating evidence suggests that ketone bodies may act as immunoregulators in humans and animals to attenuate pathological inflammation through multiple strategies. Although the clues are scattered and untrimmed, the elevation of these ketone bodies in the circulation system and tissues induced by ketogenic diets was reported to affect the immunological barriers, an important part of innate immunity. Therefore, beta-hydroxybutyrate, a key ketone body, might also play a vital role in regulating the barrier immune systems. In this review, we retrospected the endogenous ketogenesis in animals and the dual roles of ketone bodies as energy carriers and signal molecules focusing on beta-hydroxybutyrate. In addition, the research regarding the effects of beta-hydroxybutyrate on the function of the immunological barrier, mainly on the microbiota, chemical, and physical barriers of the mucosa, were outlined and discussed. As an inducible endogenous metabolic small molecule, beta-hydroxybutyrate deserves delicate investigations focusing on its immunometabolic efficacy. Comprehending the connection between ketone bodies and the barrier immunological function and its underlining mechanisms may help exploit individualised approaches to treat various mucosa or skin-related diseases.

Process of Glucose Increases Rather Than Constant High Glucose Was the Main Cause of Abnormal Glucose Induced Glomerulus Epithelial Cells Inflammatory Response.

Abnormal glycemia is frequently along with nephritis, whose pathogenesis is unexplicit. Here, we investigated the effects of abnormal glucose on the renal glomerulus epithelial cells by stimulating immortalized bovine renal glomerulus epithelial (MDBK) cells with five different levels of glucose, including low glucose (2.5 mM for 48 h, LG), normal glucose (5 mM for 48 h, NG), high glucose (25 mM for 48 h, HG), increasing glucose (24 h of 2.5 mM glucose followed by 24 h of 25 mM, IG), and reducing glucose (24 h of 25 mM glucose followed by 24 h of 2.5 mM, RG). The results showed that LG and RG treatments had nonsignificant effects (p > 0.05) on the viability of MDBK cells. HG treatment decreased the viabilities of cells (p < 0.01) without triggering an apparent inflammatory response by activating the nox4/ROS/p53/caspase-3-mediated apoptosis pathway. IG treatment decreased the viabilities of cells significantly (p < 0.01) with high levels of pro-inflammatory cytokines IL-1ß and IL-18 in the supernatant (p < 0.05) by triggering the txnip/nlrp3/gsdmd-mediated pyroptosis pathway. These results indicated that the process of glucose increase rather than the constant high glucose was the main cause of abnormal glucose-induced MDBK cell inflammatory death, prompting that the process of glycemia increases might be mainly responsible for the nephritis in diabetic nephropathy, underlining the importance of glycemic control in diabetes patients.

Metagenomics Reveals That Proper Placement After Long-Distance Transportation Significantly Affects Calf Nasopharyngeal Microbiota and Is Critical for the Prevention of Respiratory Diseases.

Transportation is an inevitable phase for the cattle industry, and its effect on the respiratory system of transported cattle remains controversial. To reveal cattle's nasopharyngeal microbiota dynamics, we tracked a batch of beef calves purchased from an auction market, transported to a farm by vehicle within 3 days, and adaptively fed for 7 days. Before and after the transport and after the placement, a total of 18 nasopharyngeal mucosal samples were collected, and microbial profiles were obtained using a metagenomic shotgun sequencing approach. The diversity, composition, structure, and function of the microbiota were collected at each time point, and their difference was analyzed. The results showed that, before the transportation, there were a great abundance of potential bovine respiratory disease (BRD)-related pathogens, and the transportation did not significantly change their abundance. After the transportation, 7 days of placement significantly decreased the risk of BRD by decreasing the abundance of potential BRD-related pathogens even if the diversity was decreased. We also discussed the controversial results of transportation's effect in previous works and the decrease in diversity induced by placement. Our work provided more accurate information about the effect of transportation and the followed placement on the calf nasopharyngeal microbial community, indicated the importance of adaptive placement after long-distance transport, and is helpful to prevent BRD induced by transportation stress.

Metagenomics Reveals That Intravenous Injection of Beta-Hydroxybutyric Acid (BHBA) Disturbs the Nasopharynx Microflora and Increases the Risk of Respiratory Diseases.

It is widely accepted that maintenance of microbial diversity is essential for the health of the respiratory tract; however, there are limited reports on the correlation between starvation and respiratory tract microbial diversity. In the present study, saline/ß-hydroxybutyric acid (BHBA) intravenous injection after dietary restriction was used to imitate different degrees of starvation. A total of 13 healthy male yaks were imposed to different dietary restrictions and intravenous injections, and their nasopharyngeal microbiota profiles were obtained by metagenomic shotgun sequencing. In healthy yaks, the main dominant phyla were Proteobacteria (33.0%), Firmicutes (22.6%), Bacteroidetes (17.2%), and Actinobacteria (13.2%); the most dominated species was Clostridium botulinum (10.8%). It was found that 9 days of dietary restriction and 2 days of BHBA injection (imitating severe starvation) significantly decreased the microbial diversity and disturbed its structure and functional composition, which increased the risk of respiratory diseases. This study also implied that oral bacteria played an important role in maintaining nasopharynx microbial homeostasis. In this study, the correlation between starvation and nasopharynx microbial diversity and its potential mechanism was investigated for the first time, providing new ideas for the prevention of respiratory diseases.

Disinfection efficiency of positive pressure respiratory protective hood using fumigation sterilization cabinet.

Concerns have been raised about both the disinfection and the reusability of respiratory protective equipment following a disinfection process. Currently, there is little data available on the effects of disinfection and decontamination on positive pressure respiratory protective hoods (PPRPH). In this study, we evaluated the effect of vaporized hydrogen peroxide (VHP) on the disinfection of PPRPH to determine applicability of this method for disinfection of protective equipment, especially protective equipment with an electric supply system. A hydrogen peroxide-based fumigation sterilization cabinet was developed particularly for disinfection of protective equipment, and the disinfection experiments were conducted using four PPRPHs hung in the fumigation chamber. The pathogenic microorganism Geobacillus stearothermophilus ATCC 7953 was used as a biological indicator in this study and the relationship between air flow (the amount of VHP) and disinfection was investigated. Both function and the material physical properties of the PPRPH were assessed following the disinfection procedure. No surviving Geobacillus stearothermophilus ATCC 7953, both inside and outside of these disinfected PPRPHs, could be observed after a 60 min treatment with an air flow of 10.5-12.3 m3/h. Both function and material physical properties of these PPRPHs met the working requirements after disinfection. This study indicates that air flow in the fumigation chamber directly influences the concentration of VHP. The protective equipment fumigation sterilization cabinet developed in this paper achieves the complete sterilization of the PPRPHs when the air flow is at 10.5-12.3 m3/h, and provides a potential solution for the disinfection of various kind of protective equipment.

Development of a negative pressure hood for isolation and transportation of individual patient with respiratory infectious disease.

The frequent and sudden occurrence of both known and unknown infectious diseases can cause global social panic. If the source of infection can be effectively controlled in the early stages of an outbreak, the spread of infectious diseases can be prevented. In view of this situation, this study developed for infectious or suspected infectious patients a negative pressure isolation hood which effectively achieves direct individual isolation during the early stages of disease outbreak, and facilitates long-distance transport. The hood body is made of flexible transparent polyvinyl chloride (PVC) material, and the combination of the hood material is airtight. The unique inflatable column support structure and the design of the inflatable neck sleeve effectively ensure both stiffness and air tightness of the hood body. The electrical exhaust system maintains a stable negative pressure environment inside the hood, and polluted air inside the hood can be purified by a high efficiency filter. Test results showed that the internal noise of the hood was 68 ± 1 dB (A), the air exhaust volume of the electric exhaust system was not <200 L/min, and the filtration efficiency of the filter to 0.3 µm particles was >99.99%, indicating that the hood achieved effective isolation protection for patients with respiration infectious diseases.

Establishment of the key Technical Indicators of Positive Pressure Biological Protective Clothing.

OBJECTIVE: Trying to establish the key technical indicators related to positive pressure biological protective clothing (PPBPC), providing technical support for the establishment of PPBPC standards in the future. METHOD: We examined the protection standard systems established by the major standards organizations in China and other developed countries. We also analyzed the technical indicators of the gas-tight chemical protective clothing and ventilated protective clothing against particulate radioactive contamination which closely related to PPBPC. And tested the performance of a set of imported dual-purpose PPBPC to verify the fit of its technical indicators with the standards. We aimed to identify the status of China's standards in the area of personnel protection and put forward feasible suggestions for the production of PPBPC in China. RESULTS: Developed countries in Europe and North America have a complete system of standard protective clothing. China should also strengthen the construction of standard protective clothing, especially PPBPC. CONCLUSION: With the improvements in infectious disease prevention and control on a global scale, the demand for PPBPC continues to increase and consideration should be given to the establishment of standards for this.

Metabolome analysis of effect of aspirin on Drosophila lifespan extension.

Effective approaches for drug development involve the repurposing of existing drugs which are already approved by the FDA. Aspirin has been shown to have many health benefits since its discovery as a nonsteroidal anti-inflammatory drug (NSAID) to treat pain and inflammation. Recent experiments demonstrated the longevity effects of aspirin in Drosophila, but its mechanism remains to be explored. In order to elucidate the effects of drug on metabolism, we carried out the metabolic analysis of aspirin-treated flies. The results identified 404 active metabolites in addition to the extended lifespan and improved healthspan in fly. There were 28 metabolites having significant changes between aspirin-treated group and the control group, out of which 22 compounds were found to have detailed information. These compounds are reported to have important functions in energy metabolism, amino sugar metabolism, and urea metabolism, indicating that aspirin might be playing positive roles in the fly's lifespan and healthspan improvement. Because of the conservation of major longevity pathways and mechanisms in different species, the health benefits of aspirin administration could be extended to other animals and humans as well.

A pilot study on using chlorine dioxide gas for disinfection of gastrointestinal endoscopes.

OBJECTIVES: This pilot study of employing chlorine dioxide (CD) gas to disinfect gastrointestinal endoscopes was conducted to meet the expectations of many endoscopy units in China for a high-efficiency and low-cost disinfectant. METHODS: An experimental prototype with an active circulation mode was designed to use CD gas to disinfect gastrointestinal endoscopes. One type of testing device composed of polytetrafluoroethylene (PTFE) tubes (2 m long, inner diameter 1 mm) and bacterial carrier containers was used to simulate the channel of the endoscope. PTFE bacterial carriers inoculated with Bacillus atrophaeus with or without organic burden were used to evaluate the sporicidal activity of CD gas. Factors including exposure dosage, relative humidity (RH), and flow rate (FR) influencing the disinfection effect of CD gas were investigated. Moreover, an autoptic disinfecting test on eight real gastrointestinal endoscopes after clinical use was performed using the experimental prototype. RESULTS: RH, exposure dosage, organic burden, and the FR through the channel significantly (P<0.05) affected the disinfection efficacy of CD gas for a long and narrow lumen. The log reduction increased as FR decreased. Treatment with 4 mg/L CD gas for 30 min at 0.8 L/min FR and 75% RH, resulted in complete inactivation of spores. Furthermore, all eight endoscopes with a maximum colony-forming unit of 915 were completely disinfected. The cost was only 3 CNY (0.46 USD) for each endoscope. CONCLUSIONS: The methods and results reported in this study could provide a basis for further studies on using CD gas for the disinfection of endoscopes.

Kinetics of Inactivation of Bacillus subtilis subsp. niger Spores and Staphylococcus albus on Paper by Chlorine Dioxide Gas in an Enclosed Space.

UNLABELLED: Bacillus subtilis subsp. niger spore and Staphylococcus albus are typical biological indicators for the inactivation of airborne pathogens. The present study characterized and compared the behaviors of B. subtilis subsp. niger spores and S. albus in regard to inactivation by chlorine dioxide (ClO2) gas under different gas concentrations and relative humidity (RH) conditions. The inactivation kinetics under different ClO2 gas concentrations (1 to 5 mg/liter) were determined by first-order and Weibull models. A new model (the Weibull-H model) was established to reveal the inactivation tendency and kinetics for ClO2 gas under different RH conditions (30 to 90%). The results showed that both the gas concentration and RH were significantly (P < 0.05) and positively correlated with the inactivation of the two chosen indicators. There was a rapid improvement in the inactivation efficiency under high RH (>70%). Compared with the first-order model, the Weibull and Weibull-H models demonstrated a better fit for the experimental data, indicating nonlinear inactivation behaviors of the vegetative bacteria and spores following exposure to ClO2 gas. The times to achieve a six-log reduction of B. subtilis subsp. niger spore and S. albus were calculated based on the established models. Clarifying the kinetics of inactivation of B. subtilis subsp. niger spores and S. albus by ClO2 gas will allow the development of ClO2 gas treatments that provide an effective disinfection method. IMPORTANCE: Chlorine dioxide (ClO2) gas is a novel and effective fumigation agent with strong oxidization ability and a broad biocidal spectrum. The antimicrobial efficacy of ClO2 gas has been evaluated in many previous studies. However, there are presently no published models that can be used to describe the kinetics of inactivation of airborne pathogens by ClO2 gas under different gas concentrations and RH conditions. The first-order and Weibull (Weibull-H) models established in this study can characterize and compare the behaviors of Bacillus subtilis subsp. niger spores and Staphylococcus albus in regard to inactivation by ClO2 gas, determine the kinetics of inactivation of two chosen strains under different conditions of gas concentration and RH, and provide the calculated time to achieve a six-log reduction. These results will be useful to determine effective conditions for ClO2 gas to inactivate airborne pathogens in contaminated air and other environments and thus prevent outbreaks of airborne illness.

Response surface modeling for the inactivation of Bacillus subtilis subsp. niger spores by chlorine dioxide gas in an enclosed space.

UNLABELLED: Bacillus subtilis subsp. niger spores are a commonly used biological indicator to evaluate the disinfection of an enclosed space. In the present study, chlorine dioxide (ClO2) gas was applied to inactivate B. subtilis subsp. niger spores in an enclosed space. The effects of the ClO2 gas concentration (1-3 mg/l), relative humidity (RH, 30-70%) and exposure time (30-90 min) were investigated using a response surface methodology (RSM). A three-factor Box-Behnken experimental design was used. The obtained data were adequately fitted to a second-order polynomial model with an R2adj of 0.992. The ClO2 gas concentration, RH and exposure time all significantly (P<0.05) and positively correlated with the inactivation of B. subtilis subsp. niger spores. The interaction between the ClO2 gas concentration and RH as well as that between the exposure time and RH indicated significant and synergistic effects (P<0.05). The predictive model was validated by additional eight experiments and proven to be with good accuracy. Overall, this model established by the RSM could show the trend of the inactivation of spores, indicate the interactions between important factors, and provide a reference to determine effective conditions for the disinfection in different enclosed spaces by ClO2 gas. IMPLICATIONS: The inactivation of indoor biological contaminants plays an important role in preventing the transmission of pathogens and ensuring human safety. The predictive model using response surface methodology indicates the influence and interaction of the main factors on the inactivation of Bacillus subtilis subsp. niger spores by ClO2 gas, and can predict a ClO2 gas treatment condition to achieve an effective sterilization of enclosed spaces. The results in this paper will provide a reference for the application of ClO2 gas treatments for indoor disinfection.

Decontamination of Bacillus subtilis var. niger spores on selected surfaces by chlorine dioxide gas.

OBJECTIVE: Chlorine dioxide (CD) gas has been used as a fumigant in the disinfection of biosafety laboratories. In this study, some experiments were conducted to assess the inactivation of spores inoculated on six materials [stainless steel (SS), painted steel (PS), polyvinyl chlorid (PVC), polyurethane (PU), glass (GS), and cotton cloth (CC)] by CD gas. The main aims of the study were to determine the sporicidal efficacy of CD gas and the effect of prehumidification before decontamination on sporicidal efficacy. METHODS: Material coupons (1.2 cm diameter of SS, PS, and PU; 1.0 cm×1.0 cm for PVC, GS, and CC) were contaminated with 10 µl of Bacillus subtilis var. niger (ATCC 9372) spore suspension in mixed organic burden and then dried in a biosafety cabinet for 12 h. The spores were recovered by soaking the coupons in 5 ml of extraction liquid for 1 h and then vortexing the liquid for 1 min. RESULTS: The log reductions in spore numbers on inoculated test materials exposed to CD gas [0.080% (volume ratio, v/v) for 3 h] were in the range of from 1.80 to 6.64. Statistically significant differences were found in decontamination efficacies on test material coupons of SS, PS, PU, and CC between with and without a 1-h prehumidification treatment. With the extraction method, there were no statistically significant differences in the recovery ratios between the porous and non-porous materials. CONCLUSIONS: The results reported from this study could provide information for developing decontamination technology based on CD gas for targeting surface microbial contamination.

One-pot fabrication and antimicrobial properties of novel PET nonwoven fabrics.

Recently, with the ever-growing demand for healthy living, more and more research is focused on materials capable of killing harmful microorganisms around the world. It is believed that designing such protective materials for hygienic and biomedical applications can benefit people in professional areas and daily life. Thus, in this paper, one novel kind of antibacterial poly(ethylene terephthalate) (PET) nonwoven fabrics was conveniently one-pot prepared, with the combined immobilization of two biological antimicrobial agents, i.e. ε-polylysine and natamycin, by using the soft methacrylate nonwoven fabrics adhesives. Then, the antimicrobial activities of the functional fabrics were investigated by using the standard shaking-flask method, showing excellent antibacterial efficiency (AE) against both Escherichia coli (8099) and Staphylococcus aureus (ATCC 6538) (AE > 99.99%) compared with untreated PET nonwoven fabrics. The anti-bioaerosol tests also showed similar trends. Meantime, scanning electron microscopy analysis indicated that the bacteria on the antibacterial PET appeared to be partly bacteriolyzed and showed much less viability than those on the pristine ones. Moreover, the long residual biocidal action of such modified PET fabrics was also evaluated, and the antibacterial activity of antibacterial fibers was unaffected by the 3 month artificially accelerated aging.

New technique: Development of a large-scale isolation chamber system for the safe and humane care of medium-sized laboratory animals harboring infectious diseases.

The close phylogenetic relationship between humans and non-human primates makes non-human primates an irreplaceable model for the study of human infectious diseases. In this study, we describe the development of a large-scale automatic multi-functional isolation chamber for use with medium-sized laboratory animals carrying infectious diseases. The isolation chamber, including the transfer chain, disinfection chain, negative air pressure isolation system, animal welfare system, and the automated system, is designed to meet all biological safety standards. To create an internal chamber environment that is completely isolated from the exterior, variable frequency drive blowers are used in the air-intake and air-exhaust system, precisely controlling the filtered air flow and providing an air-barrier protection. A double door transfer port is used to transfer material between the interior of the isolation chamber and the outside. A peracetic acid sterilizer and its associated pipeline allow for complete disinfection of the isolation chamber. All of the isolation chamber parameters can be automatically controlled by a programmable computerized menu, allowing for work with different animals in different-sized cages depending on the research project. The large-scale multi-functional isolation chamber provides a useful and safe system for working with infectious medium-sized laboratory animals in high-level bio-safety laboratories.