A prototype for on-site generation of chlorinated disinfectant for use in rural aqueducts

Sodium hypochlorite has significant potential as a sanitation solution in hard-to-reach areas.Few studies have investigated the optimal electrolysis parameters for its production with volumes greater than 1o L.This study evaluated sodium hypochlorite production through electrolysis in a 22-L prototype and identified the optimal operating parameters.Tests were performed using graphite electrodes with areas of 68.4 cm²at the laboratory scale and 1865.0 cm?at the prototype scale.A design for experiments with different operating times,chloride concentrations,and electric current intensities was developed.The optimal operating time,sodium chloride concentration,and current intensity at the laboratory scale were 120 min,150 g of chloride per liter,and 3 A,respectively,leading to the production of 5.02 g/L of the disinfectant with an energy efficiency of 12.21 mg of Cl2 per kilojoule.At the prototype scale,the maximum sodium hypochlorite concentration of 3.99 g of chloride per liter was achieved with an operating time of 120 min,a sodium chloride concentration of 100 g of chloride per liter,and a current intensity of 70 A,reaching an energy efficiency of 42.56 mg of Cl2 per kilojoule.In addition,this study evaluated the influences of the chloride concentration,current intensity,and operating time on the production of sodium hypochlorite at the two scales,and formulated the equations showing the trends of sodium hypochlorite production and energy efficiency in the electrochemical systems.The 22-L prototype model for production of this oxidizing substance is promising for disinfection of large volumes of water in areas that are difficult to access.

On-Site Assessment of a Cryogenic Disinfectant for the Alpine Environment and Outer Packaging of Frozen Items

Objective To study the effectiveness and feasibility of cryogenic disinfectants in different cold scenarios and analyze the key points of on-site cryogenic disinfection.Methods Qingdao and Suifenhe were selected as application sites for the manual or mechanical spraying of cryogenic disinfectants.The same amount of disinfectant(3,000 mg/L)was applied on cold chain food packaging,cold chain containers,transport vehicles,alpine environments,and article surfaces.The killing log value of the cryogenic disinfectant against the indicator microorganisms(Staphylococcus aureus and Escherichia coli)was used to evaluate the on-site disinfection effect.Results When using 3,000 mg/L with an action time of 10 min on the ground in alpine regions,the surface of frozen items,cold-chain containers,and cold chain food packaging in supermarkets,all external surfaces were successfully disinfected,with a pass rate of 100%.The disinfection pass rates for cold chain food packaging and cold chain transport vehicles of centralized supervised warehouses and food processing enterprises were 12.5%(15/120),81.67%(49/60),and 93.33%(14/15),respectively;yet,the surfaces were not fully sprayed.Conclusion Cryogenic disinfectants are effective in disinfecting alpine environments and the outer packaging of frozen items.The application of cryogenic disinfectants should be regulated to ensure that they cover all surfaces of the disinfected object,thus ensuring effective cryogenic disinfection.

Corrosion Behaviors of Disinfectants on Dental Unit Waterlines

To investigate the corrosion behaviors and antibacterial effects of sodium hypochlorite(NaClO)and hydrogen peroxide silver ion(HPSI)disinfectants with different concentrations against dental unit waterlines and provide guidance and reference for the use of chemical disinfectants,polyurethane tubes were immersed in ultrapure water(control group),0.1%NaClO,0.5%NaClO,1.0%NaClO,2.5%HPSI,5.0%HPSI,and 10%HPSI solutions for 6,12,and 18 weeks.Contact angles and Fourier transform infrared spectra were detected.Surface morphologies were observed using scanning electron microscopy and antibacterial activity was evaluated using Gram-positive Staphylococcus aureus(S.aureus).The results showed that sodium hypochlorite and hydrogen peroxide silver ion disinfectants presented good antibacterial activity against S.aureus.However,sodium hypochlorite could cause serious damage to the water pipes where corrosion pits and cracks were observed,and increasing the concentration of sodium hypochlorite could accelerate the corrosion process.Hydrogen peroxide silver ion disinfectants had no obvious damage to the water pipes.Therefore,hydrogen peroxide silver ion disinfectants are recommended to use for controlling bacterial infection in dental unit waterlines which can reduce the damage to the water pipes.

Studies of non-metallic organic disinfectants on inactivation of avian influenza viruses

Six different kinds of non-metallic or organic disinfectants were obtained in this research study including “Neutral Electrolyzed Water”, “M22” organic disinfectant solution, Superoxy Food Wash disinfectant, Hydrogen Peroxide, Clorox Germicidal Bleach and Clidox-S. The effectiveness of these disinfectants was studied against various subtypes of avian influenza virus (AIV). The virus-disinfectant mixtures were prepared in serial dilutions of each disinfectant with a constant virus titer and incubated at ambient temperature in different time intervals for virus inactivation. The virus inactivation results were determined by virus recovery in embryonating chicken eggs. Among the six different kinds of nonmetallic disinfectants obtained for this research project, Neutral Electrolyzed Water, “M22” solution, Clorox Germicidal Bleach and Clidox-S were effectively inactivated AIV with appropriate working dilutions and reaction times. Superoxy Food Wash disinfectant and Hydrogen Peroxide were found having limited effect on virus inactivation with extended exposure times of more than 2 hours. These research findings provide scientific data to poultry industry with guidelines to select and use non-metallic organic disinfectants for poultry flock sanitation and disinfection to effectively prevent and control of avian influenza outbreaks.

Comparative Analysis of the Therapeutic Effect of Disinfectant and Non-disinfectant on the Separation of the Labia Minora in Infants

Objective:To compare the effects of the use and non-use of a disinfectant on the outcomes of separation of the labia minora in infants.Methods:The patients were randomly divided into an experimental group with 24 cases and a control group with 25 cases.In the control group,1%iodophor was used to clean and disinfect the large and small labia and the surrounding skin,while normal saline was used in the experimental group.Other procedures such as the surgery and nursing method were the same in both groups.Results:There were no symptoms of urinary tract infection such as redness of the vulva,swelling,pain,and abnormal urination in the test group and control group after three days of follow-up,and no recurrence was seen at one month of follow-up.There was no statistically significant difference between the two groups(P>0.05).Conclusion:Use or non-use of a disinfectant to clean the urethral opening before separation of the labia minora has no significant effect on the outcomes,and does not cause postoperative urinary tract infection symptoms.Moreover,non-use of a disinfectant can prevent local irritation and reduce the economic burden on the patients.

Preparation and Evaluation of Novel Solid Chlorine Dioxide-based Disinfectant Powder in Single-pack

Objective To prepare and evaluate novel chlorine dioxide-based disinfectant powder in single-pack that is more convenient for use and transportation. Methods Orthogonal experiment was performed to determine the recipe of the disinfectant powder. Stability test, suspension quantitative bactericidal test, simulation field triM, and animal toxicity test were carded out to observe its bactericidal and toxicological effects. Results The orthogonal experiment showed that the type of water solution had no effect on the disinfectant powder and the best ratio of sodium chlorite to solid acid was 1：3. Ten grams of the disinfectant powder was fully dissolved in 20 mL water for 2 min, and diluted to 500 mL in water. After 5-10 min, the concentration of chlorine dioxide （CIO2） solution was 266 mg/L to 276 mg/L. After stored at 54℃ for 14 d, the average concentration of CIO2 was decreased by 5.03%. Suspension quantitative bactericidal test showed that the average killing logarithm （KL） value for both Staphylococcus aureus and Escherichia coli in 100 mg/L CIO2 solution for 2 min was over 5.00. In simulation field triM, the average descending KL value for Escherichia coli in the solution containing 100 mg/L CIO2 for 5 min was over 3.00. The mouse acute LD50 in the solution 5 times exceeded 5000 mg/kg. The disinfectant powder was not toxic and irritative to rabbit skin and had no mutagenic effect on mouse marrow polychromatic erythrocytes （PCE）. Conclusion The stability and bactericidal efficacy of solid chlorine dioxide-based disinfectant powder in single-pack are good. The solution containing 100 mg/L CIO2 can kill vegetative forms of bacteria. The concentration of CIO2 on the disinfecting surface of objects is 100 mg/L. The disinfectant powder is not toxic and irritative.

Enhanced Disinfection Effect of a Compound Disinfectant against Bovine Herpes Virus Type 1 at Low Temperature

A compound disinfectant, which consisted of didecyldimethylammonium chloride (DDAC), ortho-dichlorobenzene (1,2-dichlorobenzene, ODB), and chlorocresol (4-chloro-3-methylphenol, CC), and its component chemicals were individually tested for effectiveness against bovine herpes virus type 1 (BHV-1). DDAC, DDAC+ODB, DDAC+CC, and DDAC+ODB+CC showed effectiveness against BHV-1 at room temperature. However, ODB, CC, and ODB+CC showed no virucidal effects. The effects of all disinfectants tested were decreased at low temperature. DDAC showed disinfectant effects at a dilution of 1/800 and DDAC+ODB, DDAC+CC, and DDAC+ODB+CC at dilutions of 1/800 and 1/1600 at low temperature in the presence of 2% fetal bovine serum (FBS) but ODB, CC, and ODB+CC showed no virucidal effects. At low temperature and in the presence of 10% FBS, DDAC, DDAC+ODB, and DDAC+CC showed disinfectant effects at dilutions of 1/800, whereas ODB, CC, and ODB+CC showed no virucidal effects. DDAC+ ODB+CC was more effective (at 1/800 and 1/1600) than the other disinfectants under these conditions. In conclusion, a combination of three disinfectant components (DDAC+ODB+CC), enhanced the disinfectant effects at low temperature and in organic matter contamination.

Flashlight contamination and effectiveness of two disinfectants in a stomatology hospital

Aim: This study aims to assess the infection risks of flashlight contamination in a stomatology hospital and compare the disinfection effectiveness of alcohol (75%) and disinfecting wipes.Background: The flashlight is a basic non-critical medical device in oral and maxillofacial surgery wards. Wounds are mostly found in oral cavities;therefore, reusable flashlights may be a potential source of nosocomial infections (NIs). However, the microbial flora present in flashlights used in hospitals has not yet been explored. Methods: This study investigated the microbial contamination of 41 flashlights used in a stomatology hospital in Guangzhou in March 2016. Results: Results indicated that 75.6%(31/41) of the flashlights had microbial contamination. Gram-positive bacteria accounted for 72.7%(24/33)of the microbial groups contaminating the flashlights, and Gram-negative bacteria (21.2%, 7/33), and fungi (6.1%, 2/33) constituted the remaining contaminants. The predominantly isolated species was Staphyloccus (66.7%, 22/33), especially Staphylococcus aureus (24.2%, 8/33). Approximately 77.3%(17/22) of the types of bacteria detected in the hands were same as those in the corresponding flashlights. Both the bacterial overstandard and S. aureus detection rates of doctors' flashlights were higher than those of nurses' flashlights (16/17 vs. 14/23, 7/17 vs. 1/23, respectively) (P < 0.05). Moreover, both disinfectants performed excellently, and their eligibility rates were not significantly different (17/17 vs. 14/14) (P>0.05). Conclusion: Flashlights are potential causes of NIs. Disinfecting flashlights could be an effective and practical infection control method.

Chlorine poisoning caused by improper mixing of household disinfectants during the COVID-19 pandemic:Case series

BACKGROUND Misuse of disinfectants during the coronavirus disease 2019 pandemic has led to several poisoning incidents.However,there are few clinical case reports on poisoning caused by improper mixing of household disinfectants.AIM To summarize the clinical characteristics and treatment effects of chlorine poisoning caused by improper mixing of hypochlorite bleach with acidic cleaning agents.METHODS We retrospectively analyzed baseline and clinical data,clinical symptoms,and treatment methods of seven patients with chlorine poisoning who were admitted to the National Army Poisoning Treatment Center.RESULTS Among the seven patients,the average poisoning time(exposure to admission)was 57 h(4-240 h).All patients were involved in cleaning bathrooms.Chest computed tomography scans revealed bilateral lung effusions or inflammatory changes in five patients.The partial pressure of oxygen decreased in six patients,and respiratory failure occurred in one.Five patients had different degrees of increase in white blood cell count.Humidified oxygen therapy,non-invasive mechanical ventilation,anti-inflammatory corticosteroids,antioxidants,and antibiotics were administered for treatment.The average length of hospital stay was 7 d(4-9 d).All seven patients recovered and were discharged.CONCLUSION Improper mixing of household disinfectants may cause damage to the respiratory system due to chlorine poisoning.Corticosteroids may improve lung exudation in severe cases,and symptomatic supportive treatment should be performed early.

Disinfectant for Urinary Infection Caused by <i>Escherichia coli</i>by Using Natural Oils

According to the WHO analysis, antibacterial treatment which is preferred for treating peptic ulcers and oral health problems are considered as a major improvement in the treatment but are responsible for several health problems that include vomiting, diarrhea and the increase in the bacterial resistance is a major concern. So, there is an urgent need for a good therapeutic alternative which is effective. Usage of essential oils to treat different ailments is found to be extremely effective with no side effects. Thus, essential oils are gaining importance in treatments due to their antibacterial, antifungal, antiprotozoal properties. Essential oils are also used as aroma therapeutic agents. They are complex mixture of low molecular weight compounds that include terpenoids, phenylpropanoids, oxygenated derivatives (aldehydes, ketones, alcohols, esters) which greatly differ in composition in different essential oils are the major components present. The bioactive properties and their medical potential are widely used in pharmaceutical industries. In this study, we use these essential oils to prepare a disinfectant and analyze the antimicrobial properties using the agar diffusion method. Our major concern in this study is to decrease the growth of Escherichia coli which causes urinary infection, by using disinfectant prepared using a mixture of essential oils of particular concentration.

Effect of Disinfectants on Elastic Modulus, Flexural Strength and Color Stability of Denture Base Resins

Objective: Infection control protocols dictate the disinfection of dentures. There are no products available which are designed for the specific use of disinfecting dentures. The objective of this study was to investigate the impact of chemical disinfectants on elastic modulus, flexural strength and color stability of denture base resins. Methods: 256 specimens from four acrylic denture base resins were manufactured. Two cold-curing denture base resins: PalaXpress (Heraeus Kulzer, Hanau, Germany), Futura Gen (Schuetz Dental, Ro&szlig;bach, Germany) and two heat-curing denture base resins: Paladon 65 (Heraeus Kulzer, Hanau, Germany), FuturAcryl 2000 (Schuetz Dental, Ro&szlig;bach, Germany) were used. Three chemical disinfecting agents were tested: Impresept, D050 Instru-Gen, Stammopur DR. Specimens were stored in distilled water and in chemical disinfecting agents. They were divided randomly into groups. E-Modulus and flexural strength were measured using the three-point bending test. Color changes (ΔE) were determined spectrophotometrically. Results: The disinfection agents showed no significant influence on the E-modulus compared to distilled water (Acrylic vs. distilled water from (Futura Gen) 2688.80 ± 230.78 vs. 2766.60 ± 91.22 MPa to (PalaXpress) 3004.20 ± 26.40 vs. 2851.00 ± 95.23 MPa). Flexural strength after storage in distilled water and disinfection did not differ significantly (Acrylic vs. distilled water from (Paladon65) 27.28 ± 1.30 vs. 28.42 ± 0.84 N/mm2, (p > 0.05) to (PalaXpress) 30.88 ± 0.25 vs. 29.68 ± 0.79 N/mm2, p < 0.001). Disinfection caused a significant color change with Impresept of Paladon 65 (p ≤ 0.001), FuturaAcryl 2000 with Stammopur DR and D 050 Instru-Gen (p ≤ 0.001). Conclusions: The investigated disinfection agents did not influence elastic modulus and flexural strength of denture base resins negatively. ΔE-values were in a range of 1 to 2. Thus, the detected color changes may be marginal. Clinical relevance: Single use disinfections are feasible for acrylic dentures regarding to elastic modulus and flexural strength.

Bioactive Compound from Streptomyces sp. KB1 TISTR2504 as Effective Disinfectant against Microorganisms

A host environment cleaning using disinfectants is the most effective way to prevent the pathogen’s transmission.This study compared the activity among of commercial liquid disinfectants[3%hydrogen peroxide(HP),and 70%ethyl alcohol(EA)]and bioactive-compounds(BCs)from Streptomyces sp.KB1 on indicating microorganisms:Bacillus subtilis ATCC 6633 as representative of spores;Staphylococcus aureus TISTR 517 and clinical methicillin-resistant S.aureus as representative of gram-positive bacteria,Escherichia coli TISTR 887,Pseudomonas aeruginosa TISTR 1467,and extended spectrum beta-lactamase(ESBL)-Klebsiella pneumoniae 342 as representative of gram-negative bacteria;Candida albicans TISTR 5779 as representative of yeast.Results showed that B.subtilis spores are resistant to 70%EA and BCs from strain KB1-which are biocidal to TISTR strains and clinical isolate MRSA,ESBL-in the free floating microorganism(suspension test).On the other hand,this resistance was not observed with 3%HP.Thus,3%HP showed more promise for disinfecting microorganisms than that 70%EA and BCs.However,BCs did show the antimicrobial activities equal as 70%EA.The results might be implied that the using of BCs from selected bacterial strain as effective disinfectant against microorganism,especially vegetative cell,is a sustainable application in nearly future,to reduce using the chemical substances and zero wastes.

Impact of the residues of detergents and disinfectants used in dairy farms on the results of inhibitor tests for raw milk

The aim of the study was to determine the impact of residues of detergents and disinfectants on the results of most commonly used inhibitor tests for raw milk. Microbiological test (Delvotest SP-NT) and three rapid tests (Charm 3 MRL BL/TET2, Charm ROSA MRL BL/TET and Penzym) were used in the study. Three concentrations (recommended by the manufacturer, 10 times lower and twice higher) of 36 detergents and disinfectants in raw milk were investigated. All methods did not detect concentrations of detergents and disinfectants of alkaline and acid origin 10 times lower than recommended by the manufacturer. 39% of the investigated substances of alkaline origin were detected by Delvotest SP-NT and Penzym;Charm tests showed non-typical results only. Delvotest SP-NT did not detect substances of acid origin;Penzym detected 50% of these substances, Charm tests showed only non-typical results. Delvotest SP-NT and Penzym appeared to be more sensitive to the substances used for teat hygiene and disinfection. The scope of rapid tests (receptor or enzymatic) does not cover the detection of detergent and disinfectant re- sidues in milk. However, according to the non-typical results of the test, it is possible to suspect the presence of these substances in milk. McNemar’s and Cochran’s Q tests were used for statistical analysis of the data.

Interpretations on Disinfectant Standards

Disinfectants have become necessities for fighting against the epidemic since the outbreak of the Covid-19.There are a great variety of disinfectants on the market.This paper describes the types,standards,scope of application and other points for attention of disinfectants to help readers deeply understand disinfectants and use disinfectants correctly in their daily life.

Testing the Efficiency of Acacia Bark (Galool-Asal) as Disinfectant for Polluted Waters

Acacia bark efficiency for disinfecting polluted water for the purpose of using it for drinking purposes was tested. Five polluted water samples were collected from different locations in Jordan, namely, King Abdullah Canal, an Agricultural pond in the Jordan Valley, Yajouz wells, Hazeir spring, and Wadi-Seer spring. Different volumes of the water samples were treated with 10 g of the shredded acacia bark (obtained from Somalia) for different retention times. The volumes used were 1 L, 2.5 L, and 5 L and the detention times were 2, 4, and 24 hours. The samples were tested for total coliform, E. coli, electrical conductivity, pH, total dissolved solids, turbidity and color before and after treatment with the acacia bark. Results revealed that the optimum conditions for disinfection were: 1 L polluted water treated with 10 g acacia bark for 24 hours. Log removals of about 2.5 for E. coli were obtained under these conditions. Higher removals could be achieved by using larger amounts of the acacia bark, but the chemical water quality regarding turbidity and color will not be suitable for drinking purposes and levels of tannic acids present in the acacia bark might reach toxic levels. Toxic levels will not be reached if 1 glass of water/kg body weight every 4 - 5 hours daily is consumed.

Viricidal activity of several disinfectants against African swine fever virus

Prevention of African swine fever,a disease caused by African swine fever virus(ASFV),requires maintenance of high biosecurity standards,which principally relies on disinfection.Finding the perfect disinfectant against ASFV is difficult because of the lack of relevant data.Therefore,we aimed to find the most effective disinfectant and to optimise its concentration as well as contact time to confirm the viricidal effect against ASFV in vitro.We evaluated the viricidal activity of three concentrations each of six common disinfectants against ASFV using immersion disinfection assay(IDA)and spray disinfection assay(SDA);the concentrations of these disinfectants at which complete viral inactivation occurred were almost same as the manufacturer-recommended concentrations,but the exposure times for viral inactivation are different.The following disinfectants(assay:concentration,exposure time)showed complete inactivation:iodine and acid mixed solution(IDA/SDA:0.5%,10 min);compound potassium peroxymonosulfate(IDA:0.25%,30 min;SDA:0.25%,60 min);citric acid(IDA:0.25%,60 min;SDA:0.5%,60 min);sodium dichloroisocyanurate(IDA:0.125%,60 min;SDA:0.25%,60 min);and glutaral ang deciquam(IDA/SDA:0.2%,60 min);and deciquam(IDA/SDA:0.5%,60 min).However,in the presence of organic material contamination,disinfectants did not show a marked inactivation effect.Therefore,disinfection procedures should be performed in two steps:thorough mechanical cleaning followed by application of disinfectant.In conclusion,all the tested disinfectants can inactivate ASFV;these can be used as alternative disinfectants to enhance biosecurity.

Experimental study on disinfection effect of different dose of rapid hand disinfectant

Purpose:To investigate the appropriate antiseptic handrubbing method.Methods:Seventy-four clinical nurses were randomly divided into two groups based on the number of disinfectant presses used,with group 1 using one-press and group 2 using twopresses.Sterilizing effects as a function of presses were compared and analyzed between the two groups.Results:Prior to hand disinfection,the hand sampling region resulted in 72 colony forming units for the 74 nurses.Following disinfection,only 2 colony forming units(p<0.001)were found.The analysis of drying time effects on the disinfection rate between the two groups showed a significant difference(p?0.049).Conclusion:In an effort to reduce the incidence of nosocomial infection,the medical personnel should sufficiently dry hands following handrubbing with disinfectant in a strict accordance with the six part washing technique for antiseptic handrubbing.

Vaccinia virus viability under different environmental conditions and different disinfectants treatment

Monkeypox(mpox)outbreak in 2022 has caused more than 91,000 cases,has spread to 115 countries,regions,and territories,and has thus attracted much attention.The stability of poxvirus particles in the environment is recognized as an important factor in determining their transmission.However,few studies have investigated the persistence of poxviruses on material surfaces under various environmental conditions,and their sensitivity to biocides.Here,we systematically measured the stability of vaccinia virus(VACV)under different environmental conditions and sensitivity to inactivation methods via plaque assay,quantitative real‐time polymerase chain reaction(qPCR),and Gaussia luciferase(G‐luciferase)reporter system.The results show that VACV is stable on the surface of stainless steel,glass,clothing,plastic,towel,A4 paper,and tissue and persists much longer at 4℃ and?20℃,but is effectively inactivated by ultraviolet(UV)irradiation,heat treatment,and chemical reagents.Our study raises the awareness of long persistence of poxviruses in the environment and provides a simple solution to inactivate poxviruses using common disinfectants,which is expected to help the control and prevention of mpox virus and future poxvirus outbreaks.

Toxicity of the disinfectant benzalkonium chloride(C_(14))towards cyanobacterium Microcystis results from its impact on the photosynthetic apparatus and cell metabolism

Quaternary ammonium compounds(QACs)are commonly used in a variety of consumer and commercial products,typically as a component of disinfectants.During the COVID-19 pandemic,QACs became one of the primary agents utilized to inactivate the SARS CoV-2 virus on surfaces.However,the ecotoxicological effects of QACs upon aquatic organisms have not been fully assessed.In this study,we examined the effects of a widely used QAC(benzalkonium chloride-C_(14),BAC-14)on two toxigenic Microcystis strains and one non-toxigenic freshwater Microcystis strain and carried out an analysis focused on primary,adaptive and compensatory stress responses at apical(growth and photosynthesis)and metabolic levels.This analysis revealed that the two toxic Microcystis strains were more tolerant than the non-toxic strain,with 96 hr-EC_(50)values of 0.70,0.76,and 0.38 mg/L BAC-14 for toxigenic M.aeruginosa FACHB-905,toxigenic M.aeruginosa FACHB-469,and non-toxigenic M.wesenbergii FACHB-908,respectively.The photosynthetic activities of the Microcystis,assessed via F_(v)/F_(m) values,were significantly suppressed under 0.4 mg/L BAC-14.Furthermore,this analysis revealed that BAC-14 altered 14,12,and 8 metabolic pathways in M.aeruginosa FACHB-905,M.aeruginosa FACHB-469,and M.wesenbergii FACHB-908,respectively.It is noteworthy that BAC-14 enhanced the level of extracellular microcystin production in the toxigenic Microcystis strains,although cell growth was not significantly affected.Collectively,these data show that BAC-14 disrupted the physiological and metabolic status of Microcystis cells and stimulated the production and release of microcystin,which could result in damage to aquatic systems.