Aggravation of asthmatic inflammation by chlorine exposure via innate lymphoid cells and CD11cintermediate macrophages.

BACKGROUND: Chlorine is widely used in daily life as disinfectant. However, chronic exposure to chlorine products aggravates allergic TH 2 inflammation and airway hyperresponsiveness (AHR). Innate lymphoid cells (ILCs) in airways contribute to the inception of asthma in association with virus infection, pollution, and excess of nutrient, but it is not known whether chronic chlorine exposure can activate innate immune cells. The aim of this study was to evaluate the impact of chlorine inhalation on the innate immunity such as ILCs and macrophages in relation with the development of asthma by using murine ovalbumin (OVA) sensitization/challenge model. METHODS: Six-week-old female BALB/c mice were sensitized and challenged with OVA in the presence and absence of chronic low-dose chlorine exposure by inhalation of naturally vaporized gas of 5% sodium hypochlorite solution. AHR, airway inflammatory cells, from BALF and the population of ILCs and macrophages in the lung were evaluated. RESULTS: The mice exposed to chlorine with OVA (Cl + OVA group) showed enhanced AHR and eosinophilic inflammation compared to OVA-treated mice (OVA group). The population of TH 2 cells, ILC2s, and ILC3s increased in Cl + OVA group compared with OVA group. CD11cint macrophages also remarkably increased in Cl + OVA group compared with OVA group. The deletion of macrophages by clodronate resulted in reduction of ILC2s and ILC3s population which was restored by adoptive transfer of CD11cint macrophages. CONCLUSIONS: Chronic chlorine inhalation contributes to the exacerbation of airway inflammation in asthmatic airway by mobilizing pro-inflammatory macrophage into the lung as well as stimulating group 2 and 3 ILCs.

Differences in Viral Disinfection Mechanisms as Revealed by Quantitative Transfection of Echovirus 11 Genomes.

Virus inactivation mechanisms can be elucidated by methods that measure the loss of specific virus functionality (e.g., host attachment, genome internalization, and genome replication). Genome functionality is frequently assessed by PCR-based methods, which are indirect and potentially inaccurate; genome damage that affects detection by high-fidelity PCR enzymes may not adversely affect the ability of actual cellular enzymes to produce functional virus. Therefore, we developed here a transfection-based assay to quantitatively determine viral genome functionality by inserting viral RNA into host cells directly to measure their ability to produce new functional viruses from damaged viral genomes. Echovirus 11 was treated with ozone, free chlorine (FC), UV light at 254 nm (UV254), or heat, and then the reductions in genome functionality and infectivity were compared. Ozone reduced genome functionality proportionally to infectivity, indicating that genome damage is the main mechanism of virus inactivation. In contrast, FC caused little or no loss of genome functionality compared to infectivity, indicating a larger role for protein damage. For UV254, genome functionality loss accounted for approximately 60% of virus inactivation, with the remainder presumably due to protein damage. Heat treatment resulted in no reduction in genome functionality, in agreement with the understanding that heat inactivation results from capsid damage. Our results indicate that there is a fundamental difference between genome integrity reductions measured by PCR enzymes in previous studies and actual genome functionality (whether the genome can produce virus) after disinfection. Compared to PCR, quantitative transfection assays provide a more realistic picture of actual viral genome functionality and overall inactivation mechanisms during disinfection.IMPORTANCE This study provides a new tool for assessing virus inactivation mechanisms by directly measuring a viral genome's ability to produce new viruses after disinfection. In addition, we identify a potential pitfall of PCR for determining virus genome damage, which does not reflect whether a genome is truly functional. The results presented here using quantitative transfection corroborate previously suggested virus inactivation mechanisms for some virus inactivation methods (heat) while bringing additional insights for others (ozone, FC, and UV254). The developed transfection method provides a more mechanistic approach for the assessment of actual virus inactivation by common water disinfectants.

Slightly acidic electrolyzed water disrupts biofilms and effectively disinfects Pseudomonas aeruginosa.

INTRODUCTION: Biofilm formation is an important issue in the healthcare industry, but conventional disinfectants are not effective for biofilms formed in the hospital environment and on medical instruments. In this study, aim at determine the effectiveness of slightly acidic electrolyzed water (SAEW) on biofilm removal and the disinfection of biofilm-forming Pseudomonas aeruginosa. METHODS: Mucoid and non-mucoid strains were used for biofilm formation. Biofilms were incubated with SAEW and the reduction in biofilm volume was determined based on the optical density. Furthermore, to investigate the mechanism underlying the effects of SAEW, a biofilm was produced with alginate and structural changes in response to incubation with SAEW were observed by fluorescence microscopy. The minimum bactericidal chlorine concentration of SAEW for P. aeruginosa cells was evaluated. RESULTS: The amounts of alginate and biofilm decreased by 99.9% and 56.8% immersed by 30 ppm of SAEW at 25 °C for 10 min. The effectiveness of SAEW increased as the temperature increased, and the biofilm volume was reduced by 85.4% at 45 °C. Furthermore, 30 ppm SAEW completely disinfected P. aeruginosa in the biofilm, even for immersion at 15 °C for 5 min. CONCLUSION: Our results suggest that SAEW, a low-cost and safe chlorine disinfectant, is a useful disinfectant for biofilm-forming bacteria.

Acute respiratory changes and pulmonary inflammation involving a pathway of TGF-ß1 induction in a rat model of chlorine-induced lung injury.

We investigated acute and delayed respiratory changes after inhalation exposure to chlorine (Cl2) with the aim to understand the pathogenesis of the long-term sequelae of Cl2-induced lung-injury. In a rat model of nose-only exposure we analyzed changes in airway hyperresponsiveness (AHR), inflammatory responses in airways, expression of pro-inflammatory markers and development of lung fibrosis during a time-course from 5h up to 90days after a single inhalation of Cl2. A single dose of dexamethasone (10mg/kg) was administered 1h following Cl2-exposure. A 15-min inhalation of 200ppm Cl2 was non-lethal in Sprague-Dawley rats. At 24h post exposure, Cl2-exposed rats displayed elevated numbers of leukocytes with an increase of neutrophils and eosinophils in bronchoalveolar lavage (BAL) and edema was shown both in lung tissue and the heart. At 24h, the inflammasome-associated cytokines IL-1ß and IL-18 were detected in BAL. Concomitant with the acute inflammation a significant AHR was detected. At the later time-points, a delayed inflammatory response was observed together with signs of lung fibrosis as indicated by increased pulmonary macrophages, elevated TGF-ß expression in BAL and collagen deposition around airways. Dexamethasone reduced the numbers of neutrophils in BAL at 24h but did not influence the AHR. Inhalation of Cl2 in rats leads to acute respiratory and cardiac changes as well as pulmonary inflammation involving induction of TGF-ß1. The acute inflammatory response was followed by sustained macrophage response and lack of tissue repair. It was also found that pathways apart from the acute inflammatory response contribute to the Cl2-induced respiratory dysfunction.

[The multifunctional therapy of various forms of irritable bowel syndrome]. / Mnogofunktsional'naya terapiya pri razlichnykh formakh sindroma razdrazhennogo kishechnika.

Irritable bowel syndrome (IBS) is a pathological condition characterized by heterogeneous etiology, pathogenesis, and clinical symptoms. These characteristics dictate the necessity of prescribing multiple medications for the treatment of IBS. Such compulsory polypharmacy inadvertently enhances the risk of adverse reactions to the treatment, increases its cost, and impairs compliance on the part of the patients. The objective of the present study was to evaluate the effectiveness of the administration of the clorine-bromine brine with the use of sinusoidal modulated current electrophoresis (SMC-phoresis) for the treatment of different forms of IBS. THE PATIENTS AND METHODS: We examined and treated 80 patients with different forms of IBS. The patients were divided into two equal groups comprised of 40 patients each. The patients of the study group were treated with the use of SMС-phoresis of the bromine-chlorine brine based at the «Varzi-yatchi¼ spa and health resort (the Udmurt Republic) making use of the sparing or stimulating techniques depending on the type of IBS. Each therapeutic course consisted of 10-12 sessions. The patients in the group of comparison received the standard pharmaceutical treatment for IBS (myotropic anti-spasmodics and lactulose). The emphasis was laid on the evaluation of dynamics of the intestinal motor function in different variants of IBS with the use of the EGS-4M apparatus based on the GSRS questionnaire (Gastrointestinal Symptom Rating Scale). Special attention was given to the interpretation of the main gastrointestinal syndromes and the evaluation of the quality of life of the patients in the course of the treatment and after its completion. RESULTS: Тhe main symptoms of IBS after a course of SMC-phoresis with the natural brine were significantly less pronounced compared to those in the patients managed by means of standard pharmacotherapy. Positive dynamics in the clinical picture of the disease had beneficial influence on the quality of life of the patients which approached that of the healthy subjects in the group of comparison. The results of colonography suggested the presence of various types of disturbances of motor function of the intestines. SMC-phoresis of the natural chlorine-bromine brine had a positive influence on dyskinesia associated with diarrhea and constipation associated with IBS, while the effect of the standard pharmaceutical treatment was unidirectional and significantly inferior to it in terms of efficiency. CONCLUSION: The use of complementary therapy can provide a better clinical outcome of IBS and to a greater extent improve the quality of life of the patients presenting with various forms of this pathology.

Effects of combined UV and chlorine treatment on the formation of trichloronitromethane from amine precursors.

The objective of this study was to investigate the effects of combined low-pressure ultraviolet (LPUV) irradiation and free chlorination on the formation of trichloronitromethane (TCNM) byproduct from amine precursors, including a commonly used polyamine coagulant aid (poly(epichlorohydrin dimethylamine)) and simple alkylamines dimethylamine (DMA) and methylamine (MA). Results showed that TCNM formation can increase up to 15 fold by combined UV/chlorine under disinfection to advanced oxidation conditions. The enhancement effect is influenced by UV irradiance, chlorine dose, and water pH. Extended reaction time leads to the decay of TCNM by direct photolysis. The combined UV/chlorine conditions significantly promoted degradation of polyamine to generate intermediates, including DMA and MA, which are better TCNM precursors than polyamine, and also facilitated transformation of these amine precursors to TCNM. Under combined UV/chlorine, polyamine degradation was likely promoted by radical oxidation, photodecay of chlorinated polyamine, and chlorine oxidation/substitution. Promoted TCNM formation from primary amine MA was primarily due to radicals' involvement. Promoted TCNM formation from secondary amine DMA likely involved a combination of radical oxidation, photoenhanced chlorination reactions, and other unknown mechanisms. Insights obtained in this study are useful for reducing TCNM formation during water treatment when both UV and chlorine will be encountered.

Toxicity of chlorine to zebrafish embryos.

Surface disinfection of fertilized fish eggs is widely used in aquaculture to reduce extraovum pathogens that may be released from brood fish during spawning, and this is routinely used in zebrafish Danio rerio research laboratories. Most laboratories use approximately 25 to 50 ppm unbuffered chlorine solution for 5 to 10 min. Treatment of embryos with chlorine has significant germicidal effects for many Gram-negative bacteria, viruses, and trophozoite stages of protozoa, but is less effective against cyst or spore stages of protozoa and certain Mycobacterium spp. Therefore, we evaluated the toxicity of unbuffered and buffered chlorine solutions to embryos exposed at 6 or 24 h post-fertilization (hpf) to determine whether higher concentrations can be used for treating zebrafish embryos. Most of our experiments entailed using an outbred line (5D), with both mortality and malformations as endpoints. We found that 6 hpf embryos consistently were more resistant than 24 hpf embryos to the toxic effects of chlorine. Chlorine is more toxic and germicidal at lower pH, and chlorine causes elevated pH. Consistent with this, we found that unbuffered chlorine solutions (pH ca. 8-9) were less toxic at corresponding concentrations than solutions buffered to pH 7. Based on our findings here, we recommend treating 6 hpf embryos for 10 min and 24 hpf embryos for 5 min with unbuffered chlorine solution at 100 ppm.

A dynamic system for delivering controlled bromine and chlorine vapor exposures to weanling swine skin.

CONTEXT: Assessing the hazards of accidental exposure to toxic industrial chemical (TIC) vapors and evaluating therapeutic compounds or treatment regimens require the development of appropriate animal models. OBJECTIVE: The objective of this project was to develop an exposure system for delivering controlled vapor concentrations of TICs to the skin of anesthetized weanling pigs. Injury levels targeted for study were superficial dermal (SD) and deep dermal (DD) skin lesions as defined histopathologically. MATERIALS AND METHODS: The exposure system was capable of simultaneously delivering chlorine or bromine vapor to four, 3-cm diameter exposure cups placed over skin between the axillary and inguinal areas of the ventral abdomen. Vapor concentrations were generated by mixing saturated bromine or chlorine vapor with either dried dilution air or nitrogen. RESULTS: Bromine exposure concentrations ranged from 6.5 × 10(-4) to 1.03 g/L, and exposure durations ranged from 1 to 45 min. A 7-min skin exposure to bromine vapors at 0.59 g/L was sufficient to produce SD injuries, while a 17-min exposure produced a DD injury. Chlorine exposure concentrations ranged from 1.0 to 2.9 g/L (saturated vapor concentration) for exposures ranging from 3 to 90 min. Saturated chlorine vapor challenges for up to 30 min did not induce significant dermal injuries, whereas saturated chlorine vapor with wetted material on the skin surface for 30-60 min induced SD injuries. DD chlorine injuries could not be induced with this system. CONCLUSION: The vapor exposure system described in this study provides a means for safely regulating, quantifying and delivering TIC vapors to the skin of weanling swine as a model to evaluate therapeutic treatments.

Clinical outcomes of WF10 adjunct to standard treatment of diabetic foot ulcers.

OBJECTIVE: To study clinical outcomes and safety of WF I 0 as an adjunct to standard treatment for diabetic foot ulcers (DFU) and to determine the optimal number of WF I 0 cycles that should be administered. METHOD: A prospective, open-label study of WF I 0 adjunct to standard treatment for severe DFU but salvageable foot was carried out between July 2009 and June 20 I 0. Patients were classified into three groups, according to common clinical presentations: neuropathic ulcer, ischaemic ulcer and severely infected ulcer. Ulcer assessments were monitored using the wound severity score (WSS; range 0-16).The clinical outcomes at 24 weeks were defined as 'good' (ulcer achieved endpoint [WSS=0-1 ]), 'fair'(improved from baseline [WSS=2-4]) and 'poor' (not improved or worsened [WSS > 4]). RESULTS: From a total of 129 patients, 21 ( 16%) presented with neuropathic ulcers, 49 (38%) with ischaemic ulcers and 59 (46%) with severely infected ulcers.AII neuropathic ulcers achieved either a good or fair outcome, with 81% achieving a good outcome, as did 49% and 81% of ischaemic and severely infected ulcers, respectively. Minor amputations were necessary for 14 patients (I I%), but no major amputation was required. Twenty seven patients (21 %) had transient reduction of haematocrit after WF I 0 therapy. One hundred and one patients (78 %) received only I cycle of WF I 0. CONCLUSION: WF I 0 as an adjunct to standard DFU treatment showed good clinical outcomes in the neuropathic ulcer group and the severely infected ulcer group. A side effect of WF I 0, transient reduction of haematocrit, was observed in 21% of patients. Most patients required only one cycle of WF I 0.

Post-exposure antioxidant treatment in rats decreases airway hyperplasia and hyperreactivity due to chlorine inhalation.

We assessed the safety and efficacy of combined intravenous and aerosolized antioxidant administration to attenuate chlorine gas-induced airway alterations when administered after exposure. Adult male Sprague-Dawley rats were exposed to air or 400 parts per million (ppm) chlorine (a concentration likely to be encountered in the vicinity of industrial accidents) in environmental chambers for 30 minutes, and returned to room air, and they then received a single intravenous injection of ascorbic acid and deferoxamine or saline. At 1 hour and 15 hours after chlorine exposure, the rats were treated with aerosolized ascorbate and deferoxamine or vehicle. Lung antioxidant profiles, plasma ascorbate concentrations, airway morphology, and airway reactivity were evaluated at 24 hours and 7 days after chlorine exposure. At 24 hours after exposure, chlorine-exposed rats had significantly lower pulmonary ascorbate and reduced glutathione concentrations. Treatment with antioxidants restored depleted ascorbate in lungs and plasma. At 7 days after exposure, in chlorine-exposed, vehicle-treated rats, the thickness of the proximal airways was 60% greater than in control rats, with twice the amount of mucosubstances. Airway resistance in response to methacholine challenge was also significantly elevated. Combined treatment with intravenous and aerosolized antioxidants restored airway morphology, the amount of airway mucosubstances, and airway reactivity to control levels by 7 days after chlorine exposure. Our results demonstrate for the first time, to the best of our knowledge, that severe injury to major airways in rats exposed to chlorine, as characterized by epithelial hyperplasia, mucus accumulation, and airway hyperreactivity, can be reversed in a safe and efficacious manner by the post-exposure administration of ascorbate and deferoxamine.

Regulation of alveolar epithelial Na+ channels by ERK1/2 in chlorine-breathing mice.

The mechanisms by which the exposure of mice to Cl(2) decreases vectorial Na(+) transport and fluid clearance across their distal lung spaces have not been elucidated. We examined the biophysical, biochemical, and physiological changes of rodent lung epithelial Na(+) channels (ENaCs) after exposure to Cl(2), and identified the mechanisms involved. We measured amiloride-sensitive short-circuit currents (I(amil)) across isolated alveolar Type II (ATII) cell monolayers and ENaC single-channel properties by patching ATII and ATI cells in situ. α-ENaC, γ-ENaC, total and phosphorylated extracellular signal-related kinase (ERK)1/2, and advanced products of lipid peroxidation in ATII cells were measured by Western blot analysis. Concentrations of reactive intermediates were assessed by electron spin resonance (ESR). Amiloride-sensitive Na(+) channels with conductances of 4.5 and 18 pS were evident in ATI and ATII cells in situ of air-breathing mice. At 1 hour and 24 hours after exposure to Cl(2), the open probabilities of these two channels decreased. This effect was prevented by incubating lung slices with inhibitors of ERK1/2 or of proteasomes and lysosomes. The exposure of ATII cell monolayers to Cl(2) increased concentrations of reactive intermediates, leading to ERK1/2 phosphorylation and decreased I(amil) and α-ENaC concentrations at 1 hour and 24 hours after exposure. The administration of antioxidants to ATII cells before and after exposure to Cl(2) decreased concentrations of reactive intermediates and ERK1/2 activation, which mitigated the decrease in I(amil) and ENaC concentrations. The reactive intermediates formed during and after exposure to Cl(2) activated ERK1/2 in ATII cells in vitro and in vivo, leading to decreased ENaC concentrations and activity.

Microbial community dynamics of an urban drinking water distribution system subjected to phases of chloramination and chlorination treatments.

Water utilities in parts of the U.S. control microbial regrowth in drinking water distribution systems (DWDS) by alternating postdisinfection methods between chlorination and chloramination. To examine how this strategy influences drinking water microbial communities, an urban DWDS (population ≅ 40,000) with groundwater as the source water was studied for approximately 2 years. Water samples were collected at five locations in the network at different seasons and analyzed for their chemical and physical characteristics and for their microbial community composition and structure by examining the 16S rRNA gene via terminal restriction fragment length polymorphism and DNA pyrosequencing technology. Nonmetric multidimension scaling and canonical correspondence analysis of microbial community profiles could explain >57% of the variation. Clustering of samples based on disinfection types (free chlorine versus combined chlorine) and sampling time was observed to correlate to the shifts in microbial communities. Sampling location and water age (<21.2 h) had no apparent effects on the microbial compositions of samples from most time points. Microbial community analysis revealed that among major core populations, Cyanobacteria, Methylobacteriaceae, Sphingomonadaceae, and Xanthomonadaceae were more abundant in chlorinated water, and Methylophilaceae, Methylococcaceae, and Pseudomonadaceae were more abundant in chloraminated water. No correlation was observed with minor populations that were detected frequently (<0.1% of total pyrosequences), which were likely present in source water and survived through the treatment process. Transient microbial populations including Flavobacteriaceae and Clostridiaceae were also observed. Overall, reversible shifts in microbial communities were especially pronounced with chloramination, suggesting stronger selection of microbial populations from chloramines than chlorine.

Addition of chlorine during water purification reduces iodine content of drinking water and contributes to iodine deficiency.

Drinking water is the major natural source of iodine in many European countries. In the present study, we examined possible sites of iodine loss during the usual water purification process.Water samples from 6 sites during the technological process were taken and analyzed for iodine content. Under laboratory circumstances, prepared iodine in water solution has been used as a model to test the effect of the presence of chlorine. Samples from the purification sites revealed that in the presence of chlorine there is a progressive loss of iodine from the water. In the chlorine concentrations employed in the purification process, 24-h chlorine exposure eliminated more than 50% of iodine when the initial iodine concentration was 250 µg/l or less. Iodine was completely eliminated if the starting concentration was 16 µg/l.We conclude that chlorine used during water purification may be a major contributor to iodine deficiency in European communities.

Control of biofouling by Cordylophora caspia in freshwater using one-off, pulsed and intermittent dosing of chlorine: laboratory evaluation.

Cordylophora caspia is a hydrozoan which causes biofouling in power plants and is an increasing problem in UK drinking water treatment works. Thermal control is not usually feasible without a ready source of hot water so laboratory experiments were conducted to assess whether using pulsed doses of chlorine is an alternative solution. C. caspia polyps disintegrated after a single 20 min dose (the length of one backwash cycle in water treatment work filter beds) of 2.5 ppm chlorine. Without further treatment colonies regenerated within 3 days, but repeated dosing with chlorine for 20 min each day inhibited this regeneration. The resistance of surviving colonies to chlorine increased over time, although colony size and polyp regeneration continued to fall. These results suggest pulsed treatment with chlorinated backwashes at 2 ppm could be used to control C. caspia biofouling in rapid gravity filters and this may have relevance to other settings where thermal control is not feasible.

Chlorine truck attack consequences and mitigation.

We develop and apply an integrated modeling system to estimate fatalities from intentional release of 17 tons of chlorine from a tank truck in a generic urban area. A public response model specifies locations and actions of the populace. A chemical source term model predicts initial characteristics of the chlorine vapor and aerosol cloud. An atmospheric dispersion model predicts cloud spreading and movement. A building air exchange model simulates movement of chlorine from outdoors into buildings at each location. A dose-response model translates chlorine exposures into predicted fatalities. Important parameters outside defender control include wind speed, atmospheric stability class, amount of chlorine released, and dose-response model parameters. Without fast and effective defense response, with 2.5 m/sec wind and stability class F, we estimate approximately 4,000 (half within ∼10 minutes) to 30,000 fatalities (half within ∼20 minutes), depending on dose-response model. Although we assume 7% of the population was outdoors, they represent 60-90% of fatalities. Changing weather conditions result in approximately 50-90% lower total fatalities. Measures such as sheltering in place, evacuation, and use of security barriers and cryogenic storage can reduce fatalities, sometimes by 50% or more, depending on response speed and other factors.

Efficacy of Negative-Pressure Wound Therapy with Tetrachlorodecaoxygen-Anion Complex Instillation Compared with Standard Negative-Pressure Wound Therapy for Accelerated Wound Healing: A Prospective, Randomized, Controlled Trial.

BACKGROUND: Negative-pressure wound therapy (NPWT) with instillation is a novel wound therapy. The optimal solution is still being investigated. Tetrachlorodecaoxygen-anion complex (TCDO) causes increased phagocytosis and oxygenation. The authors' objective was to investigate the efficacy of NPWT with TCDO instillation (NPWTi) and to compare the results with NPWT alone. METHODS: A randomized controlled trial was conducted. Inclusion criteria were wound size greater than 4 cm2 and depth greater than 10 mm. Exclusion criteria were malignancy, immunocompromise, and allergy to TCDO. Patients were randomized into NPWT and NPWTi groups. Outcome measurements consisted of wound surface area, depth, volume, tissue culture, and pathologic evaluation. RESULTS: A total of 24 patients in each group were enrolled. The percentages of wound surface area reduction of NPWTi and NPWT groups were 24.1 ± 6.8 and 28.2 ± 7.6 on day 12, and 19.0 ± 6.6 and 22.7 ± 7.8 on day 15, respectively (p < 0.05). The percentages of wound depth reduction were 16.4 ± 5.3 and 22.5 ± 10.5 on day 12, and 12.0 ± 6.7 and 14.1 ± 8.0 on day 15, respectively (p < 0.05). The percentages of wound volume reduction were 17.9 ± 4.6 and 21.6 ± 5.8 on day 12, and 14.7 ± 6.0 and 17.1 ± 6.6 on day 15, respectively (p < 0.05). No statistically significant difference in microbial reduction was found between the groups. Histopathologic examination showed that more angiogenesis was observed in the NPWTi group than in the NPWT group. CONCLUSIONS: NPWT with TCDO instillation statistically significantly accelerated wound healing, but it did not show significant microbial reduction. The authors' results suggest that TCDO instillation may be an adjunctive treatment in NPWT. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, II.

Acanthamoeba castellanii: cellular changes induced by chlorination.

Chlorination is a well-known disinfection method, used in water treatment to inactivate various microorganisms, it induces numerous cellular changes. Even though Acanthamoebae are frequently found in water, the cellular changes induced in Acanthamoebae have not been described in the literature. Acanthamoebae are pathogenic amoebae and may provide a reservoir for pathogenic bacteria such as Legionellapneumophila; it is consequently important to understand the response of this amoeba to chlorination, and our study was indeed aimed at examining cellular changes in Acanthamoebae following chlorination. Acanthamoeba trophozoites were treated at various chlorine concentrations (1-5mg/L). A 3-log reduction in Acanthamoebae population was achieved with 5mg/L of free chlorine. Confocal microscopy and flow cytometry experiments indicated that chlorination induced cell permeabilization, size reduction and likely intracellular thiol concentration. Our data show that among the non-cultivable cells some remained impermeabilized (negative staining with propidium iodide), thereby suggesting that these cells might remained viable. A similar state is described in other microorganisms as a VBNC (viable but not cultivable) state. Electron microscopy observations illustrate drastic morphological changes: the pseudopods disappeared and subcellular components, such as mitochondrion, were pronouncedly affected. In conclusion, depending on the concentration used, chlorination leads to many cellular effects on Acanthamoeba that could well arise in cell inactivation.