Quaternary Ammonium Disinfectants Research Articles

Impact of routine use of a spray formulation of bleach on Clostridium difficile spore contamination in non-C difficile infection rooms

The frequency of recovery of Clostridium difficile spores from surfaces after postdischarge cleaning of non-C difficile infection rooms was significantly reduced from 24%-5% after a commercial spray formulation of bleach was substituted for a quaternary ammonium disinfectant. These results suggest that routine use of a sporicidal disinfectant in all postdischarge rooms could potentially be beneficial in reducing the risk for C difficile transmission from contaminated surfaces.

Antimicrobial quaternary ammonium organosilane cross-linked nanofibrous collagen scaffolds for tissue engineering.

IntroductionIn search for cross-linkers with multifunctional characteristics, the present work investigated the utility of quaternary ammonium organosilane (QOS) as a potential cross-linker for electrospun collagen nanofibers. We hypothesized that the quaternary ammonium ions improve the electrospinnability by reducing the surface tension and confer antimicrobial properties, while the formation of siloxane after alkaline hydrolysis could cross-link collagen and stimulate cell proliferation.Materials and methodsQOS collagen nanofibers were electrospun by incorporating various concentrations of QOS (0.1%–10% w/w) and were cross-linked in situ after exposure to ammonium carbonate. The QOS cross-linked scaffolds were characterized and their biological properties were evaluated in terms of their biocompatibility, cellular adhesion and metabolic activity for primary human dermal fibroblasts and human fetal osteoblasts.Results and discussionThe study revealed that 1) QOS cross-linking increased the flexibility of otherwise rigid collagen nanofibers and improved the thermal stability; 2) QOS cross-linked mats displayed potent antibacterial activity and 3) the biocompatibility of the composite mats depended on the amount of QOS present in dope solution – at low QOS concentrations (0.1% w/w), the mats promoted mammalian cell proliferation and growth, whereas at higher QOS concentrations, cytotoxic effect was observed.ConclusionThis study demonstrates that QOS cross-linked mats possess anti-infective properties and confer niches for cellular growth and proliferation, thus offering a useful approach, which is important for hard and soft tissue engineering and regenerative medicine.

Effectiveness of targeted enhanced terminal room disinfection on hospital-wide acquisition and infection with multidrug-resistant organisms and Clostridium difficile: a secondary analysis of a multicentre cluster randomised controlled trial with crossover design (BETR Disinfection)

The hospital environment is a source of pathogen transmission. The effect of enhanced disinfection strategies on the hospital-wide incidence of infection has not been investigated in a multicentre, randomised controlled trial. We aimed to assess the effectiveness of four disinfection strategies on hospital-wide incidence of multidrug-resistant organisms and Clostridium difficile in the Benefits of Enhanced Terminal Room (BETR) Disinfection study. We did a prespecified secondary analysis of the results from the BETR Disinfection study, a pragmatic, multicentre, crossover cluster-randomised trial that assessed four different strategies for terminal room disinfection in nine hospitals in the southeastern USA. Rooms from which a patient with a specific infection or colonisation (due to the target organisms C difficile, meticillin-resistant Staphylococcus aureus, vancomycin-resistant enterococci (VRE), or multidrug-resistant Acinetobacter spp) was discharged were terminally disinfected with one of four strategies: standard disinfection (quaternary ammonium disinfectant, except for C difficile, for which 10% hypochlorite [bleach] was used; reference); standard disinfection and disinfecting ultraviolet light (UV-C), except for C difficile, for which bleach and UV-C was used (UV strategy); 10% hypochlorite (bleach strategy); and bleach and UV-C (bleach and UV strategy). We randomly assigned the sequence of strategies for each hospital (1:1:1:1), and each strategy was used for 7 months, including a 1-month wash-in period and 6 months of data collection. The prespecified secondary outcomes were hospital-wide, hospital-acquired incidence of all target organisms (calculated as number of patients with hospital-acquired infection with a target organism per 10 000 patient days), and hospital-wide, hospital-acquired incidence of each target organism separately. BETR Disinfection is registered with ClinicalTrials.gov, number NCT01579370. Between April, 2012, and July, 2014, there were 271 740 unique patients with 375 918 admissions. 314 610 admissions met all inclusion criteria (n=73 071 in the reference study period, n=81 621 in the UV study period, n=78 760 in the bleach study period, and n=81 158 in the bleach and UV study period). 2681 incidenct cases of hospital-acquired infection or colonisation occurred during the study. There was no significant difference in the hospital-wide risk of target organism acquisition between standard disinfection and the three enhanced terminal disinfection strategies for all target multidrug-resistant organisms (UV study period relative risk [RR] 0·89, 95% CI 0·79-1·00; p=0·052; bleach study period 0·92, 0·79-1·08; p=0·32; bleach and UV study period 0·99, 0·89-1·11; p=0·89). The decrease in risk in the UV study period was driven by decreases in risk of acquisition of C difficile (RR 0·89, 95% CI 0·80-0·99; p=0·031) and VRE (0·56, 0·31-0·996; p=0·048). Enhanced terminal room disinfection with UV in a targeted subset of high-risk rooms led to a decrease in hospital-wide incidence of C difficile and VRE. Enhanced disinfection overcomes limitations of standard disinfection strategies and is a potential strategy to reduce the risk of acquisition of multidrug-resistant organisms and C difficile. US Centers for Disease Control and Prevention.

Fixed-Dose Combination Antibiotics Interacting with a Quaternary Ammonium Disinfectant: Insights from Spectral and Chromatographic Measurements

Core–shell architecture of surfactant micelles can act to shield active drug molecules from the adverse environmental conditions and enhance their bioavailability. In the present study the molecular interactions of a fixed dose combination (FDC) containing ofloxacin (OFX) and ornidazole (ORN), with cetyltrimethylammonium bromide (CTAB, a quaternary ammonium surfactant) were investigated under normal physiological pH (pH 7.4 ± 0.1). The impact of the cationic micelle on the spectral and physiochemical properties of the FDC components OFX and ORN was systematically examined by electronic spectroscopy. Micellar liquid chromatography and differential spectral methods were used to optimize analysis of the magnitude of binding constants and related Gibbs energies. The results suggest the potential solubilization of drugs in the external part of the micelles, which may prove to be more helpful for their controlled release. These outcomes have been verified by the binding capacities of drug–CTAB combinational system that may be helpful to customize the uptake of drug molecules in cells.

PDMS tri-block copolymers bearing quaternary ammonium salts for epidermal antimicrobial agents: Synthesis, surface adsorption and non-skin-penetration

Quaternary ammonium salts are widely used as epidermal and topical antimicrobial agents in medical treatments due to their broad activity, excellent performance and ready availability. However, their epidermal application has revealed many noticeable disadvantages, including short-term functionality, environmental toxicity, rapid antimicrobial resistance and skin penetration. Here, a series of tri-block copolymers grafted with dimethylaminopropyl benzyl chloride and based on a polydimethylsiloxane (PDMS) backbone, referred to as PDMS-b-(PDMS-g-BC)-g-PDMS, were prepared with well-controlled chain length and cationic grafting content. The quaternary ammonium salt-containing polymers were effective antimicrobial agents against epidermal pathogenic microbes, such as E. coli, S. albus and C. albicans. By incorporating hydrophilic and antimicrobial quaternary ammonium salt groups into the hydrophobic PDMS backbones, the amphiphilic tri-block copolymers were water-soluble but capable of assembling onto different surfaces, driven by electrostatic attraction or hydrophobic repulsion, which yielded long-term functionality on the surface. Moreover, the enlarged molecular size prevented penetration though full-thickness rat skins. These findings suggest a promising application of polymeric quaternary ammonium salts with hydrophobic moieties as epidermal antimicrobial agents.

Index cluster analysis of drug resistance-related genes in multidrug-resistant shigella flexneri

Objective To investigate the antimicrobial characteristics of shigella flexneri and to analyze the correlation between acquired resistance genes and mobile genetic elements. Methods 139 strains of shigella flexneri collected from each district of Centers for Disease Control and Prevention in Shanghai from 2010 to 2014 were recovered. The K-B method was used to determine the susceptibility of the strains to 13 antibiotics. And then 17 kinds of acquired resistance genes to β-lactams, sulfonamides, aminoglycosides and 7 kinds of genetic markers of mobile genetic elements were analyzed by PCR. Index cluster analysis was performed to explore the correlation between them. Results Among 139 strains of Shigella flexneri, 3 kinds of genetic markers of mobile genetic elements, ISEcp1, intI1 and trbC, 3 kinds of acquired β-lactam-resistance genes, CTX-M, OXA and TEM, 2 kinds of acquired aminoglycoside-resistance genes, ant(3)-I and aac(6′)-Ib, 1 kind of overlapping gene of quaternary ammonium disinfectant and sulfonamides, qacEΔ1-sull and 1 kind of sulfamethoxazole/trimethoprim-resistant gene, dfrA1 were detected. The resistence genes, OXA, ant(3)-I and drfA1 were highly related with each other, which were mediated by Class 1 integron. TEM, qacEΔl-sull and aac(6′)-Ib were highly related with each other, which were mediated by trbC. Conclusion Acquired multidrug resistance gene transfer mediated by a variety of mobile genetic elements may have largely contributed to the spreading of resistant strains of Shigella.(Chin J Lab Med, 2017, 40: 970-974) Key words: Shigella; Mobile genetic element; Index cluster analysis

Spectral and chromatographic characterization of fixed dose combination norfloxacin and metronidazole interacting with cetyltrimethylammonium bromide

Surfactant molecular self-assemblies solubilize and shelter the drugs from adverse conditions. As membrane mimetic they serve as a powerful tool to understand the consequences of drug membrane interactions. In this study the interaction modulation of fixed dose combination (FDC) having norfloxacin (NOR) and metronidazole (MET) with quaternary ammonium disinfectant (cetyltrimethylammonium bromide) has been described at physiological condition (pH7.4). The spectral and physiochemical characteristic of NOR and MET interacting with cationic micelles were investigated by electronic spectroscopy as function of cetyltrimethylammonium bromide (CTAB) concentration from pre-micellar to post-micellar region. Magnitudes of binding constant and related Gibbs free energies were optimized using differential absorption spectrometry and micellar liquid chromatography (MLC). The results indicate potential solubilization of drugs in the peripheral region of micelles that may be helpful to their control release. The values of the binding capacities of drug-micelle system have verified these results.

Cleaning and Disinfection of Biofilms Composed of Listeria monocytogenes and Background Microbiota from Meat Processing Surfaces.

Surfaces of food processing premises are exposed to regular cleaning and disinfection (C&D) regimes, using biocides that are highly effective against bacteria growing as planktonic cells. However, bacteria growing in surface-associated communities (biofilms) are typically more tolerant toward C&D than their individual free-cell counterparts, and survival of pathogens such as Listeria monocytogenes may be affected by interspecies interactions within biofilms. In this study, Pseudomonas and Acinetobacter were the most frequently isolated genera surviving on conveyor belts subjected to C&D in meat processing plants. In the laboratory, Pseudomonas, Acinetobacter, and L. monocytogenes dominated the community, both in suspensions and in biofilms formed on conveyor belts, when cultures were inoculated with eleven-genus cocktails of representative bacterial strains from the identified background flora. When biofilms were exposed to daily C&D cycles mimicking treatments used in food industry, the levels of Acinetobacter and Pseudomonas mandelii diminished, and biofilms were instead dominated by Pseudomonas putida (65 to 76%), Pseudomonas fluorescens (11 to 15%) and L. monocytogenes (3 to 11%). The dominance of certain species after daily C&D correlated with high planktonic growth rates at 12°C and tolerance to C&D. In single-species biofilms, L. monocytogenes developed higher tolerance to C&D over time, for both the peracetic acid and quaternary ammonium disinfectants, indicating that a broad-spectrum mechanism was involved. Survival after C&D appeared to be a common property of L. monocytogenes strains, as persistent and sporadic subtypes showed equal survival rates in complex biofilms. Biofilms established preferentially in surface irregularities of conveyor belts, potentially constituting harborage sites for persistent contamination.IMPORTANCE In the food industry, efficient production hygiene is a key measure to avoid the accumulation of spoilage bacteria and eliminate pathogens. However, the persistence of bacteria is an enduring problem in food processing environments. This study demonstrated that environmental bacteria can survive foam cleaning and disinfection (C&D) at concentrations used in the industrial environment. The phenomenon was replicated in laboratory experiments. Important characteristics of persisting bacteria were a high growth rate at low temperature, a tolerance to the cleaning agent, and the ability to form biofilms. This study also supports other recent research suggesting that strain-to-strain variation cannot explain why certain subtypes of Listeria monocytogenes persist in food processing environments while others are found only sporadically. The present investigation highlights the failure of regular C&D and a need for research on improved agents that efficiently detach the biofilm matrix.

Ambient and Dosed Exposure to Quaternary Ammonium Disinfectants Causes Neural Tube Defects in Rodents.

BackgroundQuaternary ammonium compounds are a large class of chemicals used for their antimicrobial and antistatic properties. Two common quaternary ammonium compounds, alkyldimethylbenzyl ammonium chloride (ADBAC) and didecyldimethyl ammonium chloride (DDAC), are combined in common cleaners and disinfectants. Introduction of a cleaner containing ADBAC+DDAC in the vivarium caused neural tube defects (NTDs) in mice and rats.MethodsTo further evaluate this finding, male and female mice were dosed in the feed at 60 or 120 mg/kg/day, or by oral gavage at 7.5, 15, or 30 mg/kg ADBAC+DDAC. Mice also received ambient exposure to ADBAC+DDAC from the disinfectant used in the mouse room. Embryos were evaluated on gestational day 10 for NTDs, and fetuses were evaluated on gestational day 18 for gross and skeletal malformations.ResultsWe found increased NTDs with exposure to ADBAC+DDAC in both rats and mice. The NTDs persisted for two generations after cessation of exposure. Notably, male exposure alone was sufficient to cause NTDs. Equally significant, ambient exposure from disinfectant use in the vivarium, influenced the levels of NTDs to a greater extent than oral dosing. No gross or significant axial skeletal malformations were observed in late gestation fetuses. Placental abnormalities and late gestation fetal deaths were increased at 120 mg/kg/day, which might explain the lack of malformations observed in late gestation fetuses.ConclusionThese results demonstrate that ADBAC+DDAC in combination are teratogenic to rodents. Given the increased use of these disinfectants, further evaluation of their safety in humans and their contribution to health and disease is essential.

Efficacy of three disinfectants against Senecavirus A on five surfaces and at two temperatures

Objectives: To evaluate the virucidal efficacy of three commercial disinfectants against Senecavirus A (SVA) on five different surfaces at ~25°C and 4°C. Materials and methods: Household bleach, a phenolic disinfectant, and a quaternary ammonium-aldehyde disinfectant were tested at manufacturer’s recommended concentrations against a contemporary strain of SVA on aluminum, stainless steel, rubber, cement, and plastic surfaces at ~25°C and 4°C. Virus propagation and titration were performed on swine testicular cells. Viral titers were calculated before and after exposure to the disinfectant being tested. Results: At ~25°C, household bleach at 1:20 dilution inactivated ≥ 99.99% of the virus within 10 to 15 minutes on aluminum, rubber, and plastic. On stainless steel and cured cement, it inactivated 99.97% and 99.98% of the virus, respectively. At 4°C, bleach inactivated ≥ 99.99% of the virus within 5 to15 minutes on all surfaces except rubber; on rubber, inactivation was 99.91% after 15 minutes. The phenolic disinfectant at the manufacturer’s recommended concentration inactivated only ≤ 82.41% of the virus at either temperature and on any surface, even after a 60-minute contact time. Results for the quaternary ammonium disinfectant were intermediate: 78.12% to 99.81% of the virus was inactivated within 60 minutes at both temperatures and on all surfaces. To detect differences between disinfectants, paired Wilcoxon tests were performed. At 10- and 15-minute time points, efficacies of the three disinfectants differed significantly. Implications: Significant variation exists in the antiviral efficacies of different disinfectants. Hence, they should be tested against various pathogens before use in the field.

The Development of Next-Generation Pyridinium-Based multiQAC Antiseptics.

A series of 18 bis- and tris-pyridinium amphiphiles were prepared and tested for both antimicrobial activity and lytic capability, in comparison with the commercially available pyridinium antiseptic cetylpyridinium chloride (CPC). Assessments were made against Gram-positive and Gram-negative bacteria, including two methicillin-resistant Staphylococcus aureus (MRSA) strains. While 2Pyr-11,11 was identified as one of the most potent antimicrobial quaternary ammonium compounds (QACs) reported to date, boasting nanomolar inhibition against five of six bacteria tested, no significant improvement in bioactivity of tris-pyridinium amphiphiles over their bis-pyridinium counterparts was observed. However, the multicationic QACs (multiQACs) presented herein did display significant advantages over the monocationic CPC; while similar red blood cell lysis was observed, superior activity against both Gram-negative bacteria and resistant S. aureus strains led to the discovery of four pyridinium-based multiQACs with advantageous therapeutic indices.

Enhanced terminal room disinfection and acquisition and infection caused by multidrug-resistant organisms and Clostridium difficile (the Benefits of Enhanced Terminal Room Disinfection study): a cluster-randomised, multicentre, crossover study

Patients admitted to hospital can acquire multidrug-resistant organisms and Clostridium difficile from inadequately disinfected environmental surfaces. We determined the effect of three enhanced strategies for terminal room disinfection (disinfection of a room between occupying patients) on acquisition and infection due to meticillin-resistant Staphylococcus aureus, vancomycin-resistant enterococci, C difficile, and multidrug-resistant Acinetobacter. We did a pragmatic, cluster-randomised, crossover trial at nine hospitals in the southeastern USA. Rooms from which a patient with infection or colonisation with a target organism was discharged were terminally disinfected with one of four strategies: reference (quaternary ammonium disinfectant except for C difficile, for which bleach was used); UV (quaternary ammonium disinfectant and disinfecting ultraviolet [UV-C] light except for C difficile, for which bleach and UV-C were used); bleach; and bleach and UV-C. The next patient admitted to the targeted room was considered exposed. Every strategy was used at each hospital in four consecutive 7-month periods. We randomly assigned the sequence of strategies for each hospital (1:1:1:1). The primary outcomes were the incidence of infection or colonisation with all target organisms among exposed patients and the incidence of C difficile infection among exposed patients in the intention-to-treat population. This trial is registered with ClinicalTrials.gov, NCT01579370. 31 226 patients were exposed; 21 395 (69%) met all inclusion criteria, including 4916 in the reference group, 5178 in the UV group, 5438 in the bleach group, and 5863 in the bleach and UV group. 115 patients had the primary outcome during 22 426 exposure days in the reference group (51·3 per 10 000 exposure days). The incidence of target organisms among exposed patients was significantly lower after adding UV to standard cleaning strategies (n=76; 33·9 cases per 10 000 exposure days; relative risk [RR] 0·70, 95% CI 0·50-0·98; p=0·036). The primary outcome was not statistically lower with bleach (n=101; 41·6 cases per 10 000 exposure days; RR 0·85, 95% CI 0·69-1·04; p=0·116), or bleach and UV (n=131; 45·6 cases per 10 000 exposure days; RR 0·91, 95% CI 0·76-1·09; p=0·303) among exposed patients. Similarly, the incidence of C difficile infection among exposed patients was not changed after adding UV to cleaning with bleach (n=38 vs 36; 30·4 cases vs 31·6 cases per 10 000 exposure days; RR 1·0, 95% CI 0·57-1·75; p=0·997). A contaminated health-care environment is an important source for acquisition of pathogens; enhanced terminal room disinfection decreases this risk. US Centers for Disease Control and Prevention.

Structure and activity of thermophilic methanogenic microbial communities exposed to quaternary ammonium sanitizer

Food processing facilities often use antimicrobial quaternary ammonium compound (QAC) sanitizers to maintain cleanliness. These QACs can end up in wastewaters used as feedstock for anaerobic digestion. The aim of this study was to measure the effect of QAC contamination on biogas production and structure of microbial communities in thermophilic digester sludge. Methane production and biogas quality data were analyzed in batch anaerobic digesters containing QAC at 0, 15, 50, 100 and 150mg/L. Increasing sanitizer concentration in the bioreactors negatively impacted methane production rate and biogas quality. Microbial community composition data was obtained through 16S rRNA gene sequencing from the QAC-contaminated sludges. Sequencing data showed no significant restructuring of the bacterial communities. However, significant restructuring was observed within the archaeal communities as QAC concentration increased. Further studies to confirm these effects on a larger scale and with a longer retention time are necessary.

A Quaternary Ammonium Disinfectant Containing Germinants Reduces Clostridium difficile Spores on Surfaces by Inducing Susceptibility to Environmental Stressors.

Exposing Clostridium difficile spores to germinants in a quaternary ammonium matrix was an effective method to reduce environmental contamination by sensitizing the spores, leaving them susceptible to ambient conditions and enhancing killing by acid, high-intensity visible light, and radiation.

Anti-herpesviral effects of a novel broad range anti-microbial quaternary ammonium silane, K21

We have created a novel quaternary ammonium silane, K21 through sol-gel chemistry, using an ethoxylated version of an organosilane quaternary ammonium compound and TetraEthyl Ortho Silicate (TEOS) as precursors. Previous studies using the precursor molecule quaternary ammonium compounds (QACs) and a methacryloxy version of K21, primarily designed for use in dental healthcare, have shown inhibited growth properties against several types of gram-positive and gram-negative bacteria including Escherichia coli, Streptococcus mutans, Actinomyces naeslundii and Candida albicans etc. Here we tested the effect of K21 on HSV-1, HHV-6A and HHV-7 in in vitro cell culture infection models. Our results show growth inhibitory effect of K21 on HSV-1, HHV-6A and HHV-7 infection.

Potential Impact of the Resistance to Quaternary Ammonium Disinfectants on the Persistence of Listeria monocytogenes in Food Processing Environments.

The persistence of certain strains of Listeria monocytogenes, even after the food processing environment has been cleaned and disinfected, suggests that this may be related to phenomena that reduce the concentration of the disinfectants to subinhibitory levels. This includes (i) the existence of environmental niches or reservoirs that are difficult for disinfectants to reach, (ii) microorganisms that form biofilms and create microenvironments in which adequate concentrations of disinfectants cannot be attained, and (iii) the acquisition of resistance mechanisms in L. monocytogenes, including those that lead to a reduction in the intracellular concentration of the disinfectants. The only available data with regard to the resistance of L. monocytogenes to disinfectants applied in food production environments refer to genotypic resistance to quaternary ammonium compounds (QACs). Although there are several well-characterized efflux pumps that confer resistance to QACs, it is a low-level resistance that does not generate resistance to QACs at the concentrations applied in the food industry. However, dilution in the environment and biodegradation result in QAC concentration gradients. As a result, the microorganisms are frequently exposed to subinhibitory concentrations of QACs. Therefore, the low-level resistance to QACs in L. monocytogenes may contribute to its environmental adaptation and persistence. In fact, in certain cases, the relationship between low-level resistance and the environmental persistence of L. monocytogenes in different food production chains has been previously established. The resistant strains would have survival advantages in these environments over sensitive strains, such as the ability to form biofilms in the presence of increased biocide concentrations.

Quaternary Ammonium Disinfectant Issues Encountered in an Environmental Services Department.

We identified several factors affecting the use of quaternary ammonium-based (Quat) disinfectant in our facility. Microfiber wipers, cotton towels, and 1 of 2 types of disposable wipes soaked in a Quat disinfectant revealed significant binding of the disinfectant. Concentrations of Quat delivered by automated disinfectant dispensers varied widely.

Formulation and characterization of antimicrobial quaternary ammonium dendrimer in poly(methyl methcarylate) bone cement.

The use of novel antimicrobial molecules in bone cement can improve efficiency of recuperation after arthroplasty or joint replacement surgeries, avoiding the risks associated with antibiotic resistant antimicrobial agents. Nanomaterials particularly dendrimers are particularly useful for making broad spectrum killing agents owing to their large surface areas and functionalities. Therefore, we have synthesized generation 1 quaternary ammonium dendrimer of tripropylene glycol diacrylate (TPGDA) using octyl iodide (OI) [TPGDA G1.0 (=) quaternary octyl iodide (QOI)] and capitalized on their capabilities of contact killing based mechanism. We formulated different TPGDA G1.0 (=) QOI antimicrobial agent loaded liquid component composed of methyl methacrylate monomer and N,N-dimethyl-p-toluidine coinitiator. Different polymethyl methacrylate (PMMA) based experimental bone cement formulations were made and dendrimer concentration was optimized. Mechanical strength and compressive modulus of modified bone cement decreased on increasing concentrations and 10% was optimized for further analysis. The mechanical strength of bone cement yield the similar trend in wet conditions bone cement immersed in artificially created stimulated body fluids. Ten percent TPGDA G1.0 (=) QOI in bone cement was sufficient to kill gram positive and negative bacteria and its property is retained even after a period of 30 days. Thus novel dendritic structures show promise for clinical antimicrobial activity while retaining mechanical properties of bone cements. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 521-530, 2017.

Quaternary ammonium disinfectants cause subfertility in mice by targeting both male and female reproductive processes.

Alkyl dimethyl benzyl ammonium chloride (ADBAC) and didecyl dimethyl ammonium chloride (DDAC) are common ingredients in household bathroom and kitchen cleaning sprays. ADBAC+DDAC cause reproductive toxicity in mice. The aim of the present study was to investigate gender-specific reproductive effects from ADBAC+DDAC. Female reproduction was assessed through ovulation, oocyte implantation, and estrus cycling. Male reproductive function was assessed by sperm concentration, motility, and viability. Numbers of corpora lutea were not different after 2 weeks, but decreased after 8 weeks of ADBAC+DDAC exposure. Dams exposed for 5 weeks to ADBAC+DDAC spent significantly less time in estrus. ADBAC+DDAC exposed males exhibited declines in both sperm concentration and motility, but not sperm viability. Subfertility in mice from ADBAC+DDAC exposure is, therefore, mediated through reproductive disturbances in both females and males. While the effect of ADBAC+DDAC exposure on human health is unclear, widespread exposure necessitates further consideration of their potential reproductive toxicity.

Evaluation of disinfection protocols to reduce virus transmission via livestock transport vehicles using model trailers and experimental conditions

Objective: To determine the efficacy of accelerated hydrogen peroxide disinfectant and combined glutaraldehyde and quaternary ammonium disinfectant after a high-pressure wash against porcine reproductive and respiratory syndrome virus (PRRSV) and transmissible gastroenteritis virus (TGEV) in experimental settings mimicking field conditions commonly experienced on livestock trailers. Materials and methods: Aluminum model livestock trailers (1:61) were contaminated with PRRSV- and TGEV-spiked feces. Each model trailer underwent a simple washing procedure and an assigned disinfectant application. Four environmental swabs were collected per trailer at five time points and tested by PRRSV quantitative polymerase chain reaction (qPCR) and TGEV polymerase chain reaction (PCR). Ten-week old pigs were inoculated orally and intramuscularly with supernatant from environmental samples taken from model trailers at two time points after disinfection. Fecal swabs and blood collected at 7 and 14 days post inoculation were tested by PRRSV qPCR and TGEV PCR to determine if the inoculum had contained live infectious virus. Results: All Positive Control pigs were positive by PRRSV qPCR at 7 and 14 days post inoculation and by PRRSV enzyme-linked immunosorbent assay (ELISA) at day 14. Pigs in the other treatment groups were negative by PRRSV qPCR and PRRSV ELISA at all time points. Results of TGEV testing were inconclusive because the Positive Control group failed to become infected. Implication: Under study conditions, a high-pressure wash with cold water plus application of an accelerated hydrogen peroxide or a combined glutaraldehyde and quaternary ammonium disinfectant is effective at inactivating PRRSV.