Benzalkonium Bromide Research Articles

Prevalence of the novel recombinant LSDV in east and Southeast Asia: Inducing skin and testicular damage in golden hamsters

In June 2020, Lumpy Skin Disease Virus (LSDV) was first discovered in Guangdong, China. Whole-genome sequencing and evolutionary analysis indicate that this strain represents a novel recombinant vaccine strain. Our investigation has identified regions affected by LSD outbreaks prior to 2024, revealing widespread prevalence of LSDV across East Asia and Southeast Asia. Subsequent analysis of the physical and chemical characteristics of the strain revealed LSDV's resilience to high temperatures, varying pH levels, humidity, UV radiation, and light exposure. Among the tested disinfectants, potassium persulfate, glutaraldehyde, and benzalkonium bromide have demonstrated the most potent virucidal efficacy against LSDV while maintaining high safety profiles. Utilizing the Syrian hamster model, infection with this strain has resulted in the formation of skin nodules and testicular damage, providing valuable insights into the pathogenesis of LSDV. In conclusion, the comprehensive experimental data presented herein serve as a cornerstone for advancing biosafety protocols, facilitating effective prevention and control strategies, and fostering the development of small animal model for LSDV.

Hypervirulent Klebsiella pneumoniae with a hypermucoviscosity phenotype challenges strategies of water disinfection for its capsular polysaccharides

Due to the strong pathogenicity of hypervirulent Klebsiella pneumoniae (hvKP), its performance against disinfectants in water should be understood to protect public health and ecological environment. Unfortunately, the disinfectant tolerance of hvKP with a hypermucoviscosity (HMV) phenotype is a critical underexplored area. Here, the tolerance of K. pneumoniae isolates to common disinfectants was evaluated, and its underlying mechanisms were clarified. Results showed that hvKP strains with HMV exhibited remarkable tolerance to triclosan (TCS), sodium hypochlorite (NaClO), and benzalkonium bromide (BB), surpassing that of low-virulent K. pneumoniae (lvKP) and Escherichia coli, which is the microbial indicator of drinking water quality. Ct value of NaClO reached 4.41 mg/L·min to kill 4-log hvKP, while the values were 2.52 and 2.28 mg/L·min to achieve 4-log killing of lvKP and E. coli, respectively. The curing of the virulence plasmid from hvKP strain K2044 revealed that capsular polysaccharide (CPS) synthesis, driven by the virulence plasmids, helped mitigate cell membrane injury and bacterial inactivation under NaClO stress; consequently, it provided a protective advantage to hvKP. Enhancing the antioxidative stress system to reduce ROS production and mitigate oxidative stress caused by NaClO further improved the disinfectant resistance of hvKP strains with HMV. This study emphasized that hvKP strains with HMV posed a considerable challenge to disinfection procedure of water treatment. It also revealed that an improved dosage of NaClO ensures bacteria killing, indicating the optimization of the design of water treatment processes involving disinfection strategies and technical parameters should be considered.

Stress responses and Physiological Changes of Salmonella enterica Serovar Enteritidis on Short-Term and Long-Term Benzalkonium Bromide Adaptation.

Salmonella enterica is a common foodborne pathogen that poses significant safety risks across the world. And benzalkonium bromide (BK) is widely used as a disinfectant to sterilize the food processing equipment. It has been reported that sub-lethal concentration of disinfectants induced not only the homologous resistance but also cross-resistances. This work analyzed the induced resistances of Salmonella Enteritidis by short-term adaptation (STA) and long-term adaptation (LTA) to BK. We have demonstrated that inefficient sterilization exposes Salmonella Enteritidis to sub-lethal concentrations of BK, and adapts bacteria to a higher minimum inhibitory concentration and minimum bactericidal concentration. In addition, STA, but not LTA, to BK induced heterogeneous resistance to sodium hypochlorite, and cross-resistance to freezing, desiccation, and heating, which may be caused by the membrane composition change of Salmonella Enteritidis. This work could be useful to the optimization of cleaning protocol.

Variations in growth, photosynthesis, oxidative stress and microcystin production in Microcystis aeruginosa caused by acute exposure to Benzalkonium Chloride and Benzalkonium Bromide

Due to the COVID-19 pandemic, the use of quaternary ammonium salts (QACs) and their release into the aquatic environment increased dramatically. The ecological risks of QACs still need to be explored. Two extensively used QACs, Benzalkonium Chloride (BAC) and Benzalkonium Bromine (BAB), were selected to explore their acute toxic effects on a common bloom-forming cyanobacterium M. aeruginosa. Both QACs had the same 96 h-EC50 concentration on M. aeruginosa, which was 0.97 mg L-1. Nevertheless, BAC was able to inhibit the growth of M. aeruginosa at real environmental concentrations. Under the EC50 concentration, the inhibition of photosynthesis was more intense induced by BAC than BAB. The ROS levels under BAC and BAB stress were 5.88 and 4.31 times of the control, demonstrating that the oxidative stress caused by BAC was stronger. Notably, the increase of antioxidant substances such as SOD, CAT and GSH and the significant upregulation of genes such as sod2 proved that oxidation defense mechanisms were activated in response to the stressors. Both QACs significantly promoted the synthesis and release of microcystin-LR but the mechanism was different. The effects of QACs on microbial and algal communities and on microcystins synthesis should be paid special attention in future environmental management work.

Effect of different disinfectants on preventing asymptomatic bacteriuria and catheter-related urinary tract infection: a network meta-analysis

ObjectiveTo analyze the effect of different types of disinfectants for perineum and urethral meatus cleaning in preventing catheter-associated asymptomatic bacteriuria and catheter-associated urinary tract infection (CAUTI).MethodsChinese and English databases were searched to collect randomized controlled trials (RCTs) of different disinfectants for perineum and urethral meatus cleaning to prevent CAUTI, and the positive rates of urine culture with different cleaning methods were contrasted by network meta-analysis.ResultsA total of 18 RCTs were included in this study to analyze the effect of 10 disinfectants in preventing CAUTI. The disinfectants were 0.1% chlorhexidine (CHG), 0.5% CHG, 2% CHG, 0.1% benzalkonium bromide (DBDAB), 0.05% iodophor, 0.5% iodophor, acidic oxidizing potential water (EOW), normal saline (NS), Shehuang lotion, and sterile water. Meta-analysis showed that the positive rates of urine culture in the 0.5% CHG cluster, EOW cluster, 0.5% iodophor cluster, and Shehuang lotion cluster were remarkably lower than that in the 0.1% DBDAB cluster (P < 0.05). The positive rate of urine culture in the 0.5% CHG cluster was remarkably lower than that in the 0.05% iodophor cluster (P < 0.05), whereas the positive rates of urine culture in the 0.5% CHG cluster, 0.5% iodophor cluster, Shehuang lotion cluster, and EOW were remarkably lower than that in the normal saline cluster (P < 0.05). The positive rate of urine culture in the 0.5% CHG cluster and EOW cluster were remarkably lower than those in the sterile water cluster (P < 0.05). The results of the area under the cumulative ranking probability plot (SUCRA) analysis showed that the probability ranking of the preventive effect of different disinfectants was as follows: 0.5% CHG > Shehuang lotion > EOW > 0.5% Iodophor > 2% CHG > 0.1% CHG > 0.05% Iodophor > Sterile Water > 0.1% DBDAB > Saline. Conclusion0.5% CHG, Shehuang lotion, EOW, and 0.5% iodophor can be used to clean the perineum and urethral meatus in patients with indwelling catheters.Systematic review registrationChinese Clinical Trial Registry (ChiCTR), identifier ChiCTR2100052260.

Preparation of biodegradable polypropylene carbonate-polylactic acid core yarn by electrospinning and its antibacterial finishing

With the improvement of living standards, people’s awareness of health and environmental protection continues to strengthen. The production of textiles with antibacterial functions is one of the effective ways to protect people from or reduce bacterial invasion. Therefore, textiles with antibacterial functions are increasingly favored by people. At the same time, due to the impact of global warming, people are committed to reducing carbon emissions in all aspects of life. The biodegradable material polypropylidene carbonate (PPC) that can consume carbon dioxide (CO2) in the production process fully conforms to people’s environmental protection concept. However, polypropylidene carbonate itself has poor thermal stability and narrow application range. Polypropylidene carbonate thermoplastic polyurethane (PPC-TPU) is obtained by chain extension modification, which can broaden the application range of polypropylidene carbonate. To develop a yarn with excellent antibacterial and mechanical properties, which can be woven into fabrics for medical applications while taking into account environmental protection and degradability, the antibacterial yarn in this article was prepared by electrospinning using PPC-TPU and polylactic acid (PLA) yarn as raw materials. The preparation process was optimized by adjusting the supply speed, winding collection speed and horn barrel speed, and the optimal concentration of antimicrobial agent was explored by adding different concentrations of benzalkonium bromide antimicrobial. Through the characterization of the properties of the materials, we believe that PPC-PLA yarn with the addition of 5% benzalkonium bromide has broad development prospects in the medical field due to its excellent mechanical and antibacterial properties.

Characterization of Staphylococcus aureus and methicillin‐resistant S. aureus from yak

AbstractStaphylococcus aureus, particularly methicillin‐resistant S. aureus (MRSA), is an important zoonotic pathogen which not only causes significant economic loss in livestock production but also emerges as a potential threat to public health. Compared with bovines, the information on the colonization of S. aureus and MRSA in yaks, the only bovine species providing meat and other necessities for Tibetans living at high altitude, is very limited. Therefore, in the current study, S. aureus and MRSA prevalence, virulence genes, and antibiotic and antiseptic resistance properties in yaks from 18 counties of Ganzi Prefecture, Sichuan province, China were investigated. The results revealed that the overall prevalence of S. aureus during yak breeding was 7.10% among 1281 samples (91/1281), containing 9.44% from nasal (62/657) and 4.65% from anus (29/624). Nearly all of the S. aureus isolates carried at least one staphylococcal enterotoxin (SE) gene and the predominant enterotoxin gene was selx (51.65%). In addition, virulence genes (hlα, hlβ, pvl, and tsst‐1), antiseptic resistance genes (qacA/B, qacC, and qacG), and heavy metal resistance genes (copA, arsB, cadD, and arsA) were also found. Furthermore, 24 MRSA strains were identified. SCCmec, spa, and multilocus sequence typing typing revealed that the predominant types of MRSA were ST59‐IVa‐t437 and ST59‐III‐t437. It was noteworthy that all these methicillin‐resistant strains were resistant to two or more antibiotics and possessed virulence genes. The minimal inhibitory concentration (MIC) values of antiseptic peroxyacetic acid, sodium hypochlorite, and benzalkonium bromide against these MRSA strains were measured and the MIC values of benzalkonium bromide (1.22–9.77 μg/mL) were relatively low. Furthermore, the challenge with 1/4 MIC of oxacillin sodium or ofloxacin or benzalkonium bromide for 216 h increased the resistance of the MRSA strain YB786 to these antibiotics but decreased the MIC value of benzalkonium bromide. The results provide an indication of the health risks associated with these S. aureus strains, especially methicillin‐resistant strains from yaks and new approaches are needed to treat these strains.

Effect and mechanism of benzalkonium bromide on short chain fatty acid production from anaerobic sludge fermentation process

Quaternary ammonium compounds (QACs) was frequently detected in wastewater treatment plants and leads to potential toxicity to the related biological processes. In this study, the effect of benzalkonium bromide (BK) on anaerobic sludge fermentation process for short chain fatty acid (SCFAs) production was investigated. Batch experiments indicated that BK exposure significantly enhanced the SCFAs production from anaerobic fermentation sludge and the maximum concentration of total SCFAs increased from 474.40 ± 12.35 mg/L to 916.42 ± 20.35 mg/L with BK increasing from 0 to 8.69 mg/g VSS. Mechanism exploration exhibited that the presence of BK enhanced much more bioavailable organic matters release, little affected on hydrolysis, acidification, but seriously inhibited methanogenesis. Microbial community investigation revealed that BK exposure importantly enhanced the relative abundances of hydrolytic-acidifying bacteria and also improved the metabolic pathways and functional genes for sludge lysis. This work further supplement the information for environmental toxicity of emerging pollutants.

Covalent immobilization of benzalkonium bromide on polyethylene by hyperthermal-hydrogen induced-crosslinking

Covalent immobilization in functional surface modification is a prerequisite for durability and functional-integrity in many applications. This work devises an innovative surface treatment using the hyperthermal-hydrogen induced-crosslinking technique to prepare a long-lasting antibacterial film in which chemical bonds are established between the antibacterial benzalkonium bromide (BB) molecule and polyethylene macromolecule (PE). Briefly, PE film is firstly pretreated by UV-Ozone (UVO) to raise the surface energy of PE for driving adsorption of BB. Then hyperthermal hydrogen bombardment is used to cleave C-H bonds at the interface of PE-BB for accomplishing colvalent immobilization of BB. The chemical structure, morphology, thermal properties, barrier and antimicrobial properties of the resultant BB-grafted-PE (PE-g-BB) films are examined to verify covalent immobilization. Even after 60 min accelerated labilization test by ultrasound intervention, the modified film maintained excellent microorganism inhibition and antibacterial activity against E. coli and S. aureus with respective R values of 1.6 and 3.0.

Antidepressant exposure as a source of disinfectant resistance in waterborne bacteria

The emergence of disinfectant-resistant pathogens in water is a major threat to public health. However, whether human-consumed pharmaceuticals can induce bacterial resistance to disinfectants remains unclear. Herein, Escherichia coli was exposed to 12 antidepressants, and susceptibility of antidepressant-induced chloramphenicol (CHL)-resistant mutants to disinfectants was tested. Whole genome sequencing, global transcriptomic sequencing, and real-time quantitative polymerase chain reaction were used to elucidate the underlying mechanisms. We observed that duloxetine, fluoxetine, amitriptyline, and sertraline significantly increased the mutation frequency of E. coli against CHL by 15- to 2948-fold. The resultant mutants increased the average MIC50 of sodium hypochlorite, benzalkonium bromide, and triclosan roughly 2- to 8-fold. Consistently, marRAB and acrAB-tolC genes, together with ABC transporter genes (e.g., yddA, yadG, yojI, and mdlA), were triggered to increase the efflux of disinfectants out of the cell, while ompF was inhibited, reducing disinfectant penetration into the cell. Additionally, the occurrence of DNA mutations in marR and acrR in the mutants was observed, potentially resulting in increased synthesis of the AcrAB-TolC pump. This study indicates that pharmaceutical exposure may create disinfectant-resistant bacteria, which may then be released into water systems, providing novel insights into the potential source of water-borne disinfectant-resistant pathogens.

Synergistic Antibacterial Activity of Benzalkonium Bromide and Cu-Bearing Duplex Stainless Steel against Pseudomonas aeruginosa

The bactericide benzalkonium bromide is widely used to kill Pseudomonas aeruginosa, which causes microbiologically influenced corrosion (MIC). However, the extensive use of benzalkonium bromide will enhance bacterial drug resistance and cause environmental pollution. In this study, benzalkonium bromide combined with Cu-bearing 2205 duplex stainless steel (2205-Cu DSS) was used to kill Pseudomonas aeruginosa; the germicidal rate of the combination of benzalkonium bromide and 2205-Cu DSS was 24.2% higher than that of using benzalkonium bromide alone, after five days. The antibacterial efficacy was evaluated using an antibacterial test and biofilm observation. The results showed that, in the presence of P. aeruginosa, the combination of 23.44 ppm benzalkonium bromide and 2205-Cu DSS showed the best antibacterial efficacy.

Disinfectants facilitate the transformation of exogenous antibiotic resistance genes via multiple pathways

The prevalence and spread of multidrug-resistant (MDR) bacteria pose a global challenge to public health. Natural transformation is one of the essential ways for horizontal transfer of antibiotic resistance genes (ARGs). Although disinfectants are frequently used during COVID-19, little is known about whether these disinfectants are associated with the transformation of plasmid-borne ARGs. In our study, we assessed the effect of some disinfectants on bacterial transformation using resistance plasmids as extracellular DNA and E. coli DH5α as the recipient bacteria. The results showed that these disinfectants at environmentally relevant concentrations, including benzalkonium bromide (BB), benzalkonium chloride (BC) and polyhexamethylene guanidine hydrochloride (PHMG), significantly enhanced the transformation of plasmid-encoded ARGs. Furthermore, we investigated the mechanisms underlying the promotive effect of disinfectants on transformation. We revealed that the addition of disinfectants significantly increased the membrane permeability and promoted membrane-related genes expression. Moreover, disinfectants led to the boosted bacterial respiration, ATP production and flagellum motility, as well as increased expression of bacterial secretion system-related genes. Together, our findings shed insights into the spread of ARGs through bacterial transformation and indicate potential risks associated with the widespread use of disinfectants.

In vitro and in vivo Evaluation of the Bioactive Nanofibers-Encapsulated Benzalkonium Bromide for Accelerating Wound Repair with MRSA Skin Infection.

PurposeDeveloping the ideal drug or dressing is a serious challenge to controlling the occurrence of antibacterial infection during wound healing. Thus, it is important to prepare novel nanofibers for a wound dressing that can control bacterial infections. In our study, the novel self-assembled nanofibers of benzalkonium bromide with bioactive peptide materials of IKVAV and RGD were designed and fabricated.MethodsDifferent drug concentration effects of encapsulation efficacy, swelling ratio and strength were determined. Its release profile in simulated wound fluid and its cytotoxicity were studied in vitro. Importantly, the antibacterial efficacy, inhibition of biofilm formation effect and wound healing against MRSA infections in vitro and in vivo were performed after observing the tissue toxicity in vivo.ResultsIt was found that the optimized drug load (0.8%) was affected by the encapsulation efficacy, swelling ratio, and strength. In addition, the novel nanofibers with average diameter (222.0 nm) and stabile zeta potential (−11.2 mV) have good morphology and characteristics. It has a delayed released profile in the simulated wound fluid and good biocompatibility with L929 cells and most tissues. Importantly, the nanofibers were shown to improve antibacterial efficacy, inhibit biofilm formation, and lead to accelerated wound healing following infection with methicillin-resistant Staphylococcus aureus.ConclusionThese data suggest that novel nanofibers could effectively shorten the wound-healing time by inhibiting biofilm formation, which make it promising candidates for treatment of MRSA-induced wound infections.

Antimicrobial and anticancer potential of novel polyaspartate derivatives synthesized via quaternary ammonium grafting

AbstractThree novel polyaspartate derivatives with antibacterial properties and low hemolytic effects are synthesized by the reaction of sodium polyaspartate (PAspNa) with different quaternary ammonium salts with a carboxylic end‐group, subsequently these are tested in vitro against different cancer and normal cell lines. 1‐(carboxypentyl) pyridinium bromide, 1‐(carboxypentyl) benzalkonium bromide, and 1‐(carboxypentyl) quinolinium bromide are synthesized from a quaternization reaction between 6‐bromohexanoic acid and the respective tertiary amines (pyridine, N,N‐dimethylbenzylamine, and quinoline). Then, these ammonium salts are chemically grafted along the sodium polyaspartate macromolecular chains through an acid–base reaction. Three different polyaspartate derivatives are obtained and their chemical structures analyzed and confirmed by FT‐IR and 1H NMR, the corresponding thermal stability is analyzed by thermogravimetric analysis. The antibacterial efficiency of these PAspNa derivatives against Escherichia coli is determined by measuring the minimum inhibitory concentration and the minimum bactericidal concentration. Hemolysis assays are performed on isolated human erythrocytes and finally the cell proliferation is studied by 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT) analysis. All the PAspNa derivatives show antibacterial activities, low hemolytic effects, and antiproliferative effect in some concentrations evaluated in murine fibroblast (3T3), and cancer cell lines of cervix (HeLa), breast (4T1), and liver (HepG2) cells lines.

Disinfection Strategies for Carbapenem-Resistant Klebsiella pneumoniae in a Healthcare Facility.

Disinfectant resistance is evolving into a serious problem due to the long-term and extensive use of disinfectants, which brings great challenges to hospital infection control. As a notorious multidrug-resistant bacterium, carbapenem-resistant Klebsiella pneumoniae (CRKP) is one of the most common and difficult pathogens of nosocomial infection. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) tests of seven kinds of disinfectants (0.1% benzalkonium bromide, 4% aqueous chlorhexidine, 75% alcohol, entoiodine II, 2% glutaraldehyde, 2000 mg/L chlorine-containing disinfectants, and 3% hydrogen peroxide) were detected by the broth dilution method. Three efflux pump genes (oqxA, oqxB, and qacE∆1-sul1) were detected by PCR. The mean MIC value of aqueous chlorhexidine from the intensive care unit (ICU) (0.0034%) was significantly higher than that from non-ICUs (0.0019%) (p < 0.05). The positive rates of three efflux pump genes oqxA, oqxB and qacE∆1-sul1 were 60.9% (39/64), 17.2% (11/64) and 71.9% (46/64) in the detected CRKP isolates, respectively. This study discovered that CRKP strains demonstrated extensive resistance to clinical disinfectants and suggest that it is necessary to perform corresponding increases in the concentration of aqueous chlorhexidine and chlorine-containing disinfectants on the basis of current standards in the healthcare industry.

Slightly acidic electrolyzed water as an alternative disinfection technique for hatching eggs

Conventional chemical disinfectants used for egg disinfection could result in toxic residue and endanger hatchability, chick quality, and pullet growth performance. Slightly acidic electrolyzed water (SAEW) is known as a novel disinfectant for egg sterilization due to its high efficiency and no residue. In this study, a comprehensive assessment of slightly acidic electrolyzed water and benzalkonium bromide solution (BBS) used in the disinfection channel was conducted to assess the microbial count, eggshell quality, and hatchability concomitantly. The results show that the sterilization efficiency of SAEW increased with an increase in available chlorine concentration (ACC), spraying volume, and sterilization duration. SAEW with an ACC of 150 mg/L and 10,000 mg/L benzalkonium bromide solution had the same sterilization rates of approximately 86.2% at a spraying volume of 0.5 mL/egg and sterilization duration of 180 s. Neither had significant effect on eggshell strength or thickness. The eggshell cuticle quality in the benzalkonium bromide group was significantly higher than the control group (no disinfection) and the 150 mg/L SAEW group. The embryo weight, relative embryo weight, hatchability, and embryonic mortality in the SAEW group had no significant differences of those in the benzalkonium bromide group. SAEW should be more popular because of its simple preparation, low cost, and no residue. Our results indicate SAEW is an alternative disinfectant for the sterilization of hatching eggs instead of conventional chemical disinfectants, such as benzalkonium bromide, and give a recommendation is using SAEW as a disinfectant with 150 mg/L ACC, 0.5 mL/egg spray volume, and disinfection for 180 s in the novel disinfection channel.

A microfluidic system for viability determination of microalgae upon disinfectant treatment under continuous flow

The extensive use of quaternary ammonium compounds (QACs) has raised concerns regarding their environmental fate and potential risks to the ecosystem. As sensitive pollution indicators, green microalgae could readily monitor the aquatic toxicity of QACs as reflective of the changes in cell viability. Recent microfluidic-based systems have been designed for environmental biomonitoring and ecotoxicity studies while overall information of cell viability cannot be directly visualized under flowing conditions. In the present study, we developed a multifunctional microfluidic platform with the integration of analytical techniques including laser speckle contrast imaging and fluorescence spectroscopy for monitoring algal activity in response to QAC treatment. The biocidal efficiency of a representative QAC benzalkonium bromide (BAB) on a typical aquatic algae Chlorella vulgaris was determined by collecting the bio-speckles and chlorophyll autofluorescence in real-time, where dose-dependent and time-dependent decrease of algal growth was found with the increase of BAB concentration and interaction time. The integrated system was capable of rapid detection of the aquatic toxicity of QACs along with macroscopical visualization of algal activities under flowing conditions in time-course, which could be extended to future implementation for broad ecotoxicity analysis of versatile environmental samples.

Study on the Removal Effect of Salmonella Typhimurium Biofilm

Objective: This research focused on the effects of different disinfectants, preservatives and natural ingredients commonly used in the food industry on the biofilm of Salmonella typhimurium. Methods: By adding different kinds and concentrations of scavengers during the culture process, the influence on the formation of biofilm was determined. The mature biofilm was soaked with various selected scavengers to evaluate the clearance effect under different concentrations of each substance. The metabolic activity of bacteria cells in the biofilm was determined by methylthiazolyldiphenyl-tetrazolium bromide (MTT) assay. And the number of viable bacteria was calculated by dilution plate coating method. Results: The disinfectant ethanol (50%), hydrogen peroxide (1%), benzalkonium chloride (0.6%), benzalkonium bromide (0.6%), and natural components carvol, cinnamaldehyde and thyme essential oil (1.0 μL/mL) could effectively inhibit the formation of S. typhimurium CDC3 and S. typhimurium ST34. Disinfectants detergent, hydrogen peroxide, natural ingredients (carvol, cinnamaldehyde and thyme essential oil) showed certain advantages in the removal of mature biofilm. Among them, the most ideal removal efficiency was hydrogen peroxide, which could reach about 90%, the maximum removal rate of detergent could reach 80%, and the essential oils of carvacrol, cinnamaldehyde and thyme could reach about 70%; The disinfectant ethanol, benzalkonium chloride and benzalkonium bromide, as well as the natural components carvol, cinnamaldehyde and thyme essential oil could significantly reduce the cell metabolic activity and the number of viable bacteria in biofilm, the number of viable bacteria in the biofilm could be reduced by 2 to 3 lg values. Conclusions: In contrast with the removal of mature biofilm, the addition of scavenging agent or natural ingredients at the early stage of cultivation made up for a more efficient control of the biofilm.

Targeting Antibacterial Effect and Promoting of Skin Wound Healing After Infected with Methicillin-Resistant Staphylococcus aureus for the Novel Polyvinyl Alcohol Nanoparticles.

IntroductionTopical agents typically remain in the wound site for time duration that are too short to effectively eradicate MRSA tradition formation of BZK that can be maintained within the wound site for longer time periods, should be more effective.MethodsThe novel chitosan and poly (D,L-lactide-co-glycoside) nanoparticles loaded with benzalkonium bromide (BZK) were designed, for the promotion wound healing after MRSA infection. The physical characterization of these nanoparticles, as well as their antibacterial activity in vitro, release profile in simulated wound fluid, cell toxicity, anti-biofilm activity, and their ability to improve the skin wound healing in a mouse model were also studied.ResultsThese novel nanoparticles were found to have a significant antibacterial activity (p<0.01), both in vitro and in vivo test. The stronger anti-biofilm ability of the nanoparticles to inhibit the formation of bacterial biofilms, at a concentration of 3.33 μg/mL, and clear existing bacterial biofilms, at a concentration of 5 mg/mL, compared with its water solution. In addition, significant damage to bacterial cell walls also was found, providing insight into the mechanism of antibacterial activity.ConclusionTaken together, these results demonstrated the ability of BZK-loaded nanoparticles in the promotion of skin wound healing with MRSA infection. The current findings open a new avenue for nanomedicine development and future clinical applications in the treatment of wounds.

The inhibitory effects of disinfectants against Aeromonas salmonicida at low temperatures

Aeromonas salmonicida is a fish pathogen that has resulted in significant losses to the aquaculture industry worldwide. In the winter of 2018/2019, a serious outbreak of A. salmonicida infection of grass carp (Ctenopharyngodon idella) occurred in China. Since C. idella do not feed at low water temperatures, antibiotics cannot be delivered orally, thus the use of disinfectants is the only viable option to control the disease in the winter months. Therefore, the aim of this study was to elucidate the inhibitory effects of different disinfectants against A. salmonicida at various temperatures and pH values. The microdilution method was used to determine the minimum inhibitory concentration (MIC) of five disinfectants against A. salmonicida at different temperatures. The results showed that A. salmonicida was highly adaptable to temperatures ranging from 8 to 35 °C and pH values from 5 to 9. Moreover, based on the results, benzalkonium bromide (BB) had the strongest inhibitory effect at every temperature. Since A. salmonicida has strong environment adaptability, BB should be chosen to control the disease at low temperatures.