Synthesis and Correlation of Aggregation and Antimicrobial Properties of Homochiral Quaternary Ammonium Bromides Derived from Camphoric Acid

A group of homochiral quaternary ammonium salts bearing hydrophobic camphoric acid-derived moiety was synthesized and characterized. The aggregation properties of the prepared compounds were evaluated by surface tension measurements, and the critical micelle concentration (CMC) was calculated. The novel quaternary ammonium bromides were tested as antimicrobial and antifungal agents, and their minimal inhibitory concentration (MIC) was evaluated and compared to clinically used benzalkonium bromide (BAB). Correlation of MIC with CMC reveals that monomers of prepared cationic surfactants, instead of micelles, are primarily responsible for antimicrobial activity.

Evaluation of the Viricidal Efficacy of Four Chemical Disinfectants against Emerged H7N9 Avian Influenza Virus in China

Background: Establishment of scientific disinfection measures in domestic poultry farms and live-poultry markets (LPMs) are critical to prevent the spread of H7N9 subtype avian influenza that outbreaks in poultry and infection in humans. The current study was aimed to evaluate the efficacy of four common disinfectants to inactivate H7N9 subtype avian influenza virus (AIV). Methods: According to the disinfection technical specification, the average inactivation logarithmic values of four disinfectants against the epidemic H7N9 subtype AIV, including deciquam solution, glutaral and benzalkonium bromide solution, sodium dichloroisocyanurate powder, and peroxyacetic acid solution, were systematically evaluated. Result: Our data showed that incubation of 0.005% (w/v) deciquam solution for 30 min contact time, or 0.05% (v/v) glutaral and benzalkonium bromide solution for 10 min, or 0.24 g/L sodium dichloroisocyanurate powder for 30 min, or 0.05% (v/v) peroxyacetic acid solution for 10 min, can completely inactivate H7N9 subtype AIV. These results suggested that glutaral and benzalkonium bromide solution as well as peroxyacetic acid solution at recommended concentrations can be effectively used to cut off the spread of H7N9 subtype AIV in poultry farms and LPMs, however, deciquam solution and sodium dichloroisocyanurate powder need to increase their working concentration.

Efficient Tissue Culture Protocol for Magnolia lucida (Magnoliaceae) and Confirmation of Genetic Stability of the Regenerated Plants

Magnolia lucida (Magnoliaceae) is classified as an endangered species by the International Union for Conservation of Nature. It has high commercial value owing to its attractive tree shape and flowers. We adopted an excellent genotype of M. lucida as the parent material and established a mini-cut orchard through grafting to provide trunk shoots explants over the long-term. Optimal sterilization was achieved using a combination of 75% ethanol for 30 s, one percent benzalkonium bromide for five minutes, and 0.1% mercuric chloride for five minutes. Modified Murashige and Skoog medium (ML) was the optimal medium for the growth of M. lucida. Addition of one mg/L of 6-benzyl adenine (BA) and 0.05 mg/L of α-naphthaleneacetic acid (NAA) to the medium increased the shoot induction rate to 95.56%, and the ML medium containing 0.4 mg/L BA and 0.04 mg/L NAA achieved the maximum multiplication rate (284.56%). Dark treatment for seven days, followed by continuous light treatment could better resolve the challenge of difficult rooting in M. lucida plants. Using random amplified polymorphic DNA and inter simple sequence repeat markers, we confirmed the genetic uniformity and stability of the regenerated plants. Our protocol should be helpful for the propagation and conservation of this endangered plant.

Benzalkonium Bromide Cationic Surfactant Removal from Wastewater Using Magnetite Nanomaterial

The cationic surfactants have various applications being found in personal care products, detergents, cleaning products, disinfectants, hair conditioners, etc. Cationic surfactants are presented in domestic or industrial wastewater, being very resistant pollutants to biodegradation during conventional wastewater treatment (WT) methods, which generated the need to develop new efficient alternative methods. One of the alternative to conventional WT methods involves the utilization of the adsorbent nanomaterials, which are highly efficient, easy to operate, environmental friendly and cost effective. In this study, it was investigated the adsorption process of a cationic surfactant, benzyldodecyldimethylammonium bromide (benzalkonium bromide) from wastewater on magnetite nanomaterial. The adsorption investigation of benzalkonium bromide was analyzed by TOC analysis and the maximum adsorption efficiency obtained was 91.4 %. The experimental data fitted very well with Langmuir model, the correlation coefficient (R2) being 0.9792.

Isolation and identification of a novel Staphylococcus from benzalkonium chloride solution

A bacterium was isolated from benzalkonium chloride solution (5%) stored in an uncovered bottle. The strain was identified as Staphylococcus aureas named SA-RBC through the test of its morphology, biochemical and physiological characterization. The isolated strain SA-RBC has important symbol of pathogenic Staphylococcus by producing coagulase, phosphatase and thermonuclease. Resistance of SA-RBC to disinfectants or antibiotics was tested. The results showed that the strain was highly resistant to benzalkonium chloride, benzalkonium bromide, glutaraldehyde and sodium hypochlorite, but susceptive to phenylic acid. SA-RBC was highly resistant to oxacillin, cefoperazone, cefoxitin, gentamicin, ciprofloxacin, and tetracycline. The tolerable growth concentration of SA-RBC on various surfactants was examined. The results indicated that the strain SA-RBC could grow in a higher concentration of cationic surfactants up to 5%, compared with the control strains (Escherichia coli ATCC 25922, S.epidermidis ATCC12228 and S.aureus ATCC 29213) which were unable to grow in 0.1% cationic surfactants. The strain SA-RBC could not utilize benzalkonium chloride as the sole source of carbon and/or nitrogen. The findings in this study suggested that Staphylococcus aureas might be an original contaminant in the quaternary ammonium disinfectant and has potential risk for public health.

Synthesis and antimicrobial properties of camphorsulfonic acid derived imidazolium salts

A group of homochiral imidazolium salts bearing hydrophobic camphor derived moiety and ester or amide functional group were synthesized and characterized. The novel imidazolium bromides were tested as antimicrobial and antifungal agents and their minimal inhibitory concentration (MIC) was evaluated and compared to clinically used benzalkonium bromide (BAB) and carbethopendecinium bromide. The MIC values of amide derivatives 2a and 2b were slightly smaller than those for BAB, indicating their good activity. None of the prepared salts was more effective than carbethopendecinium bromide. The biocidal efficacy of amide derivatives was much higher compared to the ester analogues.