Biofilm reduction potential of 0.02% polyhexanide irrigation solution in several types of urethral catheters.

BACKGROUND: Long-term use of urethral catheters is associated with high risk of urinary tract infection (UTI) and blockage. Microbial biofilms are a common cause of catheter blockage, reducing their lifetime and significantly increasing morbidity of UTIs. A 0.02% polyhexanide irrigation solution developed for routine mechanical rinsing shows potential for bacterial decolonization of urethral catheters and has the potential to reduce or prevent biofilm formation. METHODS: Using an in vitro assay with standard market-leading types of catheters artificially contaminated with clinically relevant bacteria, assays were carried out to evaluate the biofilm reduction and prevention potential of a 0.02% polyhexanide solution versus no intervention (standard approach) and irrigation with saline solution (NaCl 0.9%). The efficiency of decolonization was measured through microbial plate count and membrane filtration. RESULTS: Irrigation using a 0.02% polyhexanide solution is suitable for the decolonization of a variety of transurethral catheters. The effect observed is significant compared to irrigation with 0.9% saline solution (p = 0.002) or no treatment (p = 0.011). No significant difference was found between irrigation with 0.9% saline solution and no treatment (p = 0.74). CONCLUSIONS: A 0.02% polyhexanide solution is able to reduce bacterial biofilm from catheters artificially contaminated with clinically relevant bacteria in vitro. The data shows a reduction of the viability of thick bacterial biofilms in a variety of commercially available urinary catheters made from silicone, latex-free silicone, hydrogel-coated silicone and PVC. Further research is required to evaluate the long-term tolerability and efficacy of polyhexanide in clinical practice.

Reduction of Postoperative Wound Infections by Antiseptica (RECIPE)?: A Randomized Controlled Trial.

OBJECTIVE: To evaluate whether intraoperative subcutaneous wound irrigation with 0.04% polyhexanide can reduce surgical site infection (SSI) in elective laparotomies compared to saline. BACKGROUND: SSI is a common complication after gastrointestinal surgery. To date, there is a lack of evidence whether subcutaneous wound irrigation is beneficial in terms of reduction of SSI. METHODS: The RECIPE trial was an investigator initiated single-center, single-blind prospective, randomized controlled trial with 2 parallel treatment groups, comparing wound irrigation with 0.9% saline to antiseptic 0.04% polyhexanide solution in elective laparotomies. Primary endpoint was the rate of SSI within 30 days postoperatively according to Centers for Disease Control and Prevention criteria. RESULTS: Between February 02, 2015, and May 23, 2018, 456 patients were randomly assigned to saline (n = 228) or polyhexanide (n = 228). Final cohort for analysis comprised 393 patients (202 in the saline and 191 in the polyhexanide group). Overall rate of SSI was 28.2%, n = 111. Simple analysis with cross tabulation revealed that significantly fewer SSIs occurred in the polyhexanide group: n = 70 (34.7%) versus n = 41 (21.5%); P = 0.004. In a multiple logistic regression model the factor wound irrigation with polyhexanide [odds ratio (OR) 0.44; 95% confidence interval (CI) 0.27-0.72; P = 0.001) was associated with risk reduction of SSI. Preoperative anemia (OR 2.08; 95% CI 1.27-3.40; P = 0.004) and more than 5 prior abdominal operations compared to none (OR 8.51; 95% CI 2.57-28.21; P < 0.001) were associated with SSI. CONCLUSIONS: Intraoperative subcutaneous wound irrigation with antiseptic 0.04% polyhexanide solution is effective in reducing SSI after elective laparotomies.

Short- and Long-Term Transcriptomic Responses of Escherichia coli to Biocides: a Systems Analysis.

The mechanisms of the bacterial response to biocides are poorly understood, despite their broad application. To identify the genetic basis and pathways implicated in the biocide stress response, we exposed Escherichia coli populations to 10 ubiquitous biocides. By comparing the transcriptional responses between a short-term exposure (30 min) and a long-term exposure (8 to 12 h) to biocide stress, we established the common gene and pathway clusters that are implicated in general and biocide-specific stress responses. Our analysis revealed a temporal choreography, starting from the upregulation of chaperones to the subsequent repression of motility and chemotaxis pathways and the induction of an anaerobic pool of enzymes and biofilm regulators. A systematic analysis of the transcriptional data identified a zur-regulated gene cluster to be highly active in the stress response against sodium hypochlorite and peracetic acid, presenting a link between the biocide stress response and zinc homeostasis. Susceptibility assays with knockout mutants further validated our findings and provide clear targets for downstream investigation of the implicated mechanisms of action.IMPORTANCE Antiseptics and disinfectant products are of great importance to control and eliminate pathogens, especially in settings such as hospitals and the food industry. Such products are widely distributed and frequently poorly regulated. Occasional outbreaks have been associated with microbes resistant to such compounds, and researchers have indicated potential cross-resistance with antibiotics. Despite that, there are many gaps in knowledge about the bacterial stress response and the mechanisms of microbial resistance to antiseptics and disinfectants. We investigated the stress response of the bacterium Escherichia coli to 10 common disinfectant and antiseptic chemicals to shed light on the potential mechanisms of tolerance to such compounds.

Differential Cytotoxicity of Haloaromatic Disinfection Byproducts and Lead Co-exposures against Human Intestinal and Neuronal Cells.

Disinfecting drinking water with chlorine inadvertently generates disinfection byproducts (DBPs) which can cause potential adverse health effects to humans. Haloaromatic DBPs are a group of emerging DBPs recently identified, suspected to be substantially more toxic than haloaliphatic DBPs but have not been extensively studied. Simultaneously, service pipelines made of lead materials are widely used in water distribution systems and become a source of dissolved lead (Pb) in tap water. In this study, we investigated the cytotoxicity of nine haloaromatic DBPs and lead ion (Pb2+), both separately as well as in combination, to human epithelial colorectal adenocarcinoma (Caco-2) and neuroblastoma (SH-SY5Y) cells. Results show that the cytotoxicity of the DBPs against Caco-2 cells followed the descending rank order of 2,4,6-triiodophenol ≅ 2,5-dibromohydroquinone > 2,4,6-tribromophenol > 3,5-dibromo-4-hydroxybenzaldehyde ≅ 2,4,6-trichlorophenol > 4-chlorophenol ≅ 3,5-dibromo-4-hydroxybenzoic acid > 2,6-dichlorophenol >5-chlorosalicylic acid, and the cytotoxicity of the DBPs against SH-SY5Y cells followed a similar rank order, 2,4,6-triiodophenol ≅ 2,5-dibromohydroquinone > 2,4,6-tribromophenol > 3,5-dibromo-4-hydroxybenzaldehyde ≅ 2,4,6-trichlorophenol > 4-chlorophenol > 3,5-dibromo-4-hydroxybenzoic acid > 2,6-dichlorophenol ≅ 5-chlorosalicylic acid. Lead in water did not change the toxicity of 3,5-dibromo-4-hydroxybenzoic acid (to either cell-type) or the toxicity of 4-chlorophenol (to the neuronal cell-type); but Pb2+ exhibited different degrees of synergistic effects with other tested DBPs. The synergism resulted in different rank orders of cytotoxicity against both intestinal and neuronal cells. These data indicate that future prioritization and regulation of emerging haloaromatic DBPs in drinking water should be considered in terms of their own toxicity and combinatorial effects with lead in water.

Consequences of chemical impact of disinfectants: safe preventive measures against COVID-19.

Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has created a significant threat to global health. It originated in Wuhan, China and caused a total of 83,483 confirmed cases and 4634 deaths until June 2020. This novel virus spread primarily through respiratory droplets and close contact. The person-to-person transmission by direct transmittance through cough, sneeze, droplet inhalation, and contact spreading from dry surfaces contaminated with secretions of nose, mouth, and eyes of an infected person has been proven about SARS-CoV-2 transmission. As disease progressed, a series of complications tends to develop, especially in critically ill and immunocompromised patients. Pathological studies showed representative features of acute respiratory distress syndrome (ARDS) and implications on multiple organs as well. However, no specific antiviral drugs or vaccines are immediately available for the treatment of this lethal disease. The efficacy of some promising antivirals needs to be investigated by ongoing clinical trials. In current circumstances, supportive care, precautions, and social distancing are the only preventive options to ameliorate COVID-19. To disinfect the environment, mainly chemical disinfectants are being used robustly. However, due to panic state, fright, and unawareness, people are using it violently, which can have an adverse effect on human health and environment. This review discusses about the potential harmful effect of disinfectants, if used inappropriately. Here, we will also discuss safe preventive options as an alternative to robust use of disinfection methods to fight against COVID-19.

Molecular Profiling on Surface-Disinfected Tomato Seeds Reveals High Diversity of Cultivation-Recalcitrant Endophytic Bacteria with Low Shares of Spore-Forming Firmicutes.

Seeds are known to harbor diverse microorganisms offering protective effects on them with the prospects of quick root colonization at germination, selective recruitment as endophytes, and possible vertical transmission. The study was undertaken to assess the gross seed-internal bacterial community in tomato and to confirm if spore-forming Firmicutes constituted major seed endophytes adopting cultivation versus molecular approach on surface-sterilized seeds. Testing the initial seed wash solutions of "Arka Vikas" and "Arka Abha" cultivars showed > 1000 bacterial cfu per dry seed, largely Bacillus spp. Tissue homogenates from surface-disinfected seeds did not show any cultivable bacteria on enriched media for 1-2 weeks, while 16S rRNA V3-V4 taxonomic profiling revealed a huge bacterial diversity (10-16 phyla per cultivar). Proteobacteria formed the dominant phylum (65.7-69.6% OTUs) followed by Firmicutes, Actinobacteria, Bacteroidetes, and a notable share of Euryarchaeota (1.1-3.1%). Five more phyla appeared common to both cultivars in minor shares (Acidobacteria, Planctomycetes, Chloroflexi, Spirochaetes, Verrucomicrobia) with the ten phyla together constituting 99.6-99.9% OTUs. Class level and family level, the cultivars displayed elevated bacterial diversity, but similar taxonomic profiles. Arka Vikas and Arka Abha showed 114 and 107 genera, respectively, with 63 common genera constituting 96-97% OTUs. Psychrobacter formed the dominant genus. Bacillus and related genera constituted only negligible OTU share (0.16-0.28%). KEGG functional analysis showed metabolism as the major bacterial community role. One-month-old in vitro seedlings showed the activation of some originally uncultivable bacteria uninfluenced by the OTU share. The study reveals a high diversity of cultivation-recalcitrant endophytic bacteria prevailing in tomato seeds with possible vertical transmission and significant roles in plant biology.

Repeated disinfectant use in broiler houses and pig nursery units does not affect disinfectant and antibiotic susceptibility in Escherichia coli field isolates.

BACKGROUND: Disinfectants are frequently used in animal production to reduce or eliminate the load of infectious agents and parasites in buildings and equipment associated with the housing or transportation of animals. There are growing concerns that the use of disinfectants would select for resistance to antibiotics and disinfectants. The aim of this study was to determine the effect of repeated use of different disinfectants on the disinfectant and antibiotic susceptibility under practical conditions in a broiler and pig pilot farm. Therefore, the susceptibility of Escherichia coli (E. coli) to 14 antibiotics and 4 disinfectants was monitored over a one-year period. RESULTS: High (20-50%) to very high (> 50%) resistance levels for ampicillin, sulfamethoxazole, trimethoprim and tetracycline were observed in both animal production types. Disinfectant susceptibility did not change over time and did not depend on the used disinfection product. Compared to in-use concentrations of formaldehyde, benzalkoniumchloride and a peracetic acid - hydrogen peroxide formulation, all E. coli strains remained susceptible indicating that the use of disinfectants did not select for disinfectant resistance. Moreover, no association could be found between the use of disinfectants and antibiotic resistance. CONCLUSIONS: These findings suggest that repeated use of disinfectants in agricultural environments does not select for antibiotic resistance nor does it reduce disinfectant susceptibility.

Tolerability and safety of urotainer® polihexanide 0.02% in catheterized patients: a prospective cohort study.

BACKGROUND: In patients with indwelling bladder catheters for > 2 weeks, bacterial colonization is inevitable, leading to urinary tract infections or encrustations with subsequent catheter blockage. Currently, bladder irrigations are the most frequently used prophylactic means, but the best solution remains yet to be determined. In vitro studies demonstrate that polihexanide is a promising option for catheter irrigation, but no data about safety and tolerability exist. METHODS: In a prospective observational study in patients with indwelling bladder catheter for > 2 weeks, a 0.02% polihexanide solution was used to rinse the catheter on five consecutive days. Adverse events, tolerability and vital signs were assessed before, during, after and at the end of the treatment period. RESULTS: There was no serious adverse event in the study. A total of 28 adverse events (AEs) in 15 (46.88%) participants were experienced. Absolute changes in pain scores were not clinically relevant. No incidences of either flushing or sweating were found during instillation. Bladder spasms during instillation were reported in two cases during a single instillation. Mean pulse rates did not change by more than 3 beats per minute. Mean changes in body temperature did not exceed 0.12 °C. Clinically relevant changes in blood pressure were recorded for 3 patients. CONCLUSIONS: This is the first study to demonstrate that a 0.02% polihexanide solution can safely be used for catheter irrigation. TRIAL REGISTRATION: ClinicalTrials.gov ( NCT02157415 ), June 6th, 2014.

Evaluation of decontamination strategies for cyclophosphamide.

PURPOSE: The main objective was to determine the efficacy of various types of cleaning equipment and products after deliberate contamination with cyclophosphamide. The secondary objective was to test various cleaning scenarios using these equipment and products. METHODS: The study had two phases: testing of cleaning equipment (wipe : woven microfibers - Hygen®, two layers of non-woven microfibres and an inner layer of highly absorbent viscose fibres - MicronSolo®, two layers of non-woven microfibres and an inner layer of highly absorbent viscose fibres - MicroMix®, simili-tissu (low filament production) - Tork® and, mop : woven microfibers - Hygen®, microfibre and viscose - MicroOne®) and products (disinfectant : quaternary ammonium - DR100®, chlorine 0.1% - Zochlor® - Brutab® - PCS® NPH, sodium hypochlorite 2%, cleaner : detergent - Nu- Action 3®, cleaner and disinfectant: sodium hypochlorite 0.6% + detergent - Aliflex® and water) in phase 1 and testing of various cleaning procedures in phase 2. Specific areas of a room with a laminar flow hood (class II/type B2) were contaminated with 10 mcg of cyclophosphamide. Different types of surfaces were cleaned with various scenarios and the remaining cyclophosphamide was measured by the Institut national de santé publique du Québec. All tests were performed in triplicate. RESULTS: A total of 189 samples were obtained: 42 negative controls and positive controls, 54 during phase 1 and 93 during phase 2. All products were more than 96.5% effective. The 0.1% chlorines were the most effective products. Cleaning procedures with two or three products had average cleaning efficacies of 99.94-99.99%. Efficacy increased with the number of successive cleanings. When two products were used, the average cleaning efficacy varied between 99.78% and 99.98%, depending on the surface. CONCLUSION: All cleaning products tested reduced cyclophosphamide contamination by more than 96.58%. Cleaning efficacy increased with successive cleaning. No scenario was effective in removing 100% of traces. Additional studies with larger samples should be conducted to confirm these results.

Recontamination of Healthcare Surfaces by Repeated Wiping with Biocide-Loaded Wipes: "One Wipe, One Surface, One Direction, Dispose" as Best Practice in the Clinical Environment.

The wiping of high-touch healthcare surfaces made of metals, ceramics and plastics to remove bacteria is an accepted tool in combatting the transmission of healthcare-associated infections (HCAIs). In practice, surfaces may be repeatedly wiped using a single wipe, and the potential for recontamination may be affected by various factors. Accordingly, we studied how the surface to be wiped, the type of fibre in the wipe and how the presence of liquid biocide affected the degree of recontamination. Experiments were conducted using metal, ceramic and plastic healthcare surfaces, and two different wipe compositions (hygroscopic and hydrophilic), with and without liquid biocide. Despite initially high removal efficiencies of >70% during initial wiping, all healthcare surfaces were recontaminated with E. coli, S. aureus and E. faecalis when wiped more than once using the same wipe. Recontamination occurred regardless of the fibre composition of the wipe or the presence of a liquid biocide. The extent of recontamination by E. coli, S. aureus and E. faecalis bacteria also increased when metal healthcare surfaces possessed a higher microscale roughness (<1 µm), as determined by Atomic Force Microscopy (AFM). The high propensity for healthcare surfaces to be re-contaminated following initial wiping suggests that a "One wipe, One surface, One direction, Dispose" policy should be implemented and rigorously enforced.

The Formation, Persistence, and Resistance to Disinfectant of the Erysipelothrix piscisicarius Biofilm.

Erysipelothrix piscisicarius is an emergent pathogen in fish aquaculture, particularly in the ornamental fish trade. Very little is known on the biology of this pathogen; however, the recurrence of infection and disease outbreaks after removing the fish from a system and disinfecting the tank suggest its environmental persistence. Moreover, biofilm lifestyle in E. piscisicarius has been suspected but not previously shown. The purpose of this study was to investigate the formation of biofilms on an abiotic surface in Erysipelothrix spp. We used hydroxyapatite-coated plastic pegs to demonstrate the attachment, growth, and persistence of E. piscisicarius on abiotic surfaces in both fresh and marine environments and to investigate the susceptibility of this pathogen to different disinfectants that are used in the aquaculture industry. E. piscisicarius formed biofilms that persisted significantly longer than planktonic cells did in both freshwater and saltwater over a period of 120 h (P = 0.004). The biofilms were also more resistant to disinfectants than the planktonic cells were. Hydrogen peroxide was the most effective disinfectant against E. piscisicarius, and it eradicated the biofilms and planktonic cells at the recommended concentrations. In contrast, Virkon and bleach were able to eradicate only the planktonic cells. This information should be taken into consideration when developing biosecurity protocols in aquaculture systems, aquariums, and private collections.

[Study on fibrosis changes in the lungs of mice caused by repeated inhalation of polyhexamethyleneguaidine disinfectant].

Objective: To explore the lung damage caused by repeated inhalation of polyhexamethyleneguanidine (PHMG) disinfectant aerosol and the corresponding toxicological characteristics. Methods: Thirty four-week-old mice of C57BL/6N strain were randomly divided into three groups, the control group, low-dose group, and high-dose group. Each group had 5 male mice and 5 female mice. Lab II-level purified water was used in the control group. The PHMG disinfectant aerosol was generated by using the ultrasonic atomization of the aqueous solution containing PHMG. The PHMG concentrations in the low-and high-dose groups were 0.1 mg/ml (0.01%) and 1 mg/ml (0.1%), respectively. The concentration of PHMG in the post-chemical exposure room was 1.03 mg/m(3) and 9.09 mg/m(3) according to the air sampler analysis. The experimental mice were exposed to the PHMG in dynamic respiratory exposure mode for 4 hours every day in 21 days. After 21-day exposure, bronchia alveolus lung fluids (BALFs) were used to evaluate the inflammatory cells in the lungs, and pathological evaluation, special staining and immunohistochemical methods were further performed to evaluate the key indicators of pulmonary fibrosis. Results: Compared to the control group, the body weight of mice in the high-dose group was significantly decreased (P<0.05), while that of mice in the low-dose group did not significantly differ (P>0.05). The number of inflammatory cells in BALFs of low-dose exposed mice was slightly reduced, and the lung tissue pathology began to show lung damage with early fibrosis symptoms (P<0.05). The pathological examination of mice in the high-dose group showed changes in pulmonary fibrosis. Immunohistochemical staining showed that pulmonary fibrosis marker, α-SMA, was significantly increased in low-dose group and high-dose group (P<0.05). Conclusion: The repeated inhalation of PHMG disinfectant could cause lung damage such as pulmonary fibrosis in mice. It could suggest that special warnings should be given to this common disinfectant and respiratory protection measures should be adopted during industrial production and daily use.

The Cost-effectiveness of Antimicrobial Lock Solutions for the Prevention of Central Line-Associated Bloodstream Infections.

Background: Antimicrobial lock solutions are a low-cost strategy that can reduce the incidence of central line-associated bloodstream infection (CLABSI). The aim of this study was to evaluate the cost-effectiveness of antimicrobial locks for the prevention of CLABSI. Methods: We constructed a decision-analytic model comparing antimicrobial lock solutions to heparin locks for the prevention of CLABSI in 3 settings: hemodialysis, cancer treatment, and home parenteral nutrition. Cost-effectiveness was determined by calculating CLABSIs prevented and incremental cost-effectiveness ratios. Uncertainty was addressed by plotting cost-effectiveness planes and acceptability curves for various willingness-to-pay thresholds. Results: In probabilistic analysis, at a willingness to pay of $50000, antimicrobial lock solutions had a 96.24% chance of being cost-effective, compared with heparin locks in the hemodialysis setting, an 88.00% chance in the cancer treatment setting, and a 92.73% chance in the home parenteral nutrition setting. In base-case analysis, antimicrobial lock solutions resulted in savings of $68721.03 for the hemodialysis setting, $85061.41 for the cancer setting, and $78513.83 for the home parenteral nutrition setting per CLABSI episode prevented. Conclusions: In 3 distinct and clinically important settings (hemodialysis, cancer treatment, and home parenteral nutrition), antimicrobial lock solutions are an effective strategy for the prevention of CLABSI, and their use can result in significant healthcare savings.

Is selective decontamination (SDD/SOD) safe in the ICU context?

Multiple individual studies of selective digestive decontamination/selective oropharyngeal decontamination (SDD/SOD) among ICU patients appear to show potent infection prevention effects. Surprisingly, the event rates for multiple endpoints including ventilator-associated pneumonia, bacteraemia and candidaemia among concurrent control groups within SDD/SOD studies appear unusually high versus other rates in the literature. These paradoxical observations raise concern that the contextual effects of SDD/SOD, as postulated in the original SDD/SOD study, not only exist but also are strong. Until these effects are addressed within an optimally designed study, the safety of SDD/SOD within the 'whole of ICU' remains questionable.

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

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

The use of bacteriophage MS2 for the development and application of a virucide decontamination test method for porous and heavily soiled surfaces.

AIMS: (i) To develop an analytical method for recovery and quantification of bacteriophage MS2-as a surrogate for foot-and-mouth disease virus-from complex porous surfaces, with and without the presence of laboratory-developed agricultural grime; (ii) to evaluate, with a 4-log dynamic range, the virucidal activity of common biocides for their ability to decontaminate surfaces and hence remediate facilities, following a foreign animal disease contamination incident. METHODS AND RESULTS: An analytical method was developed and optimized for MS2 recovery from simulated agricultural surfaces. The addition of Dey-Engley neutralizing broth to an extraction buffer improved MS2 viability in liquid extracts, with optimal analytical holding times determined as <8 to ≤24 h, depending on matrix. The recovery of MS2 from surface materials decreased in the order: nonporous reference material >grimed porous materials >nongrimed porous materials. In disinfectant testing, two spray applications of pAB were effective against MS2 (≥4-log reduction) on all operational-scale materials. Two per cent citric acid had limited effectiveness, with a ≥4-log reduction observed on a selected subset of grimed concrete samples. CONCLUSIONS: Decontamination efficacy test results can be affected by surface characteristics, extraction buffer composition, analytical holding time and surface-specific organism survivability. Efficacy should be evaluated using a test method that reflects the environmental characteristics of the intended application. SIGNIFICANCE AND IMPACT OF THE STUDY: The results of this study demonstrate the importance of analytical method verification tests for disinfectant testing prior to application in complex environments.

Limited association between disinfectant use and either antibiotic or disinfectant susceptibility of Escherichia coli in both poultry and pig husbandry.

BACKGROUND: Farm disinfectants are widely used in primary production, but questions have been raised if their use can select for antimicrobial resistance. The present study examined the use of disinfectants in poultry and pig husbandry and its contribution to the antibiotic and disinfectant susceptibility of Escherichia coli (E. coli) strains obtained after cleaning and disinfection. On those field isolates antibiotic susceptibility was monitored and susceptibility to commonly used active components of farm disinfectants (i.e. glutaraldehyde, benzalkoniumchloride, formaldehyde, and a formulation of peracetic acid and hydrogen peroxide) was tested. RESULTS: This study showed a high resistance prevalence (> 50%) for ampicillin, sulfamethoxazole, trimethoprim and tetracycline for both production animal categories, while for ciprofloxacin only a high resistance prevalence was found in broiler houses. Disinfectant susceptibility results were homogenously distributed within a very small concentration range. Furthermore, all E. coli strains were susceptible to in-use concentrations of formaldehyde, benzalkoniumchloride and a formulation of peracetic acid and hydrogen peroxide, indicating that the practical use of disinfectants did not select for disinfectant resistance. Moreover, the results showed no indications for the selection of antibiotic resistant bacteria through the use of disinfectants in agricultural environments. CONCLUSION: Our study suggests that the proper use of disinfectants in agricultural environments does not promote antibiotic resistance nor reduce E. coli disinfectant susceptibility.

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

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

Cluster-Randomized Trial of Devices to Prevent Catheter-Related Bloodstream Infection.

Central venous catheters (CVCs) contribute disproportionately to bloodstream infection (BSI) and, by extension, to infection-related hospitalization, mortality, and health care costs in patients undergoing dialysis. Recent product advancements may reduce BSIs, but a sufficiently powered comparative-effectiveness study is needed to facilitate evidence-based patient care decisions. In a 13-month, prospective, cluster-randomized, open-label trial, we compared BSI rates in facilities using ClearGuard HD antimicrobial barrier caps (ClearGuard group) with those in facilities using Tego hemodialysis connectors plus Curos disinfecting caps (Tego+Curos group). Forty DaVita dialysis facilities in the United States were pair-matched by BSI rate, number of patients using CVCs, and geographic location, and then cluster randomized 1:1. We enrolled all adult patients undergoing dialysis with CVCs at these facilities, except those allergic to heparin or chlorhexidine. Overall, 1671 patients participated in the study, accruing >183,000 CVC-days. The study outcome was positive blood culture (PBC) rate as an indicator of BSI rate. We calculated results at the cluster level and adjusted for the facility cluster effect. During a 3-month run-in period immediately before study interventions, the groups had similar BSI rates (P=0.8). During the 13-month intervention period that immediately followed, the ClearGuard group had a BSI rate significantly lower than that of the Tego+Curos group (0.28 versus 0.75 PBCs per 1000 CVC-days, respectively; P=0.001). No device-related adverse events were reported. In conclusion, compared with Tego connectors plus Curos caps, ClearGuard HD antimicrobial barrier caps significantly lowered the rate of catheter-related BSIs in patients undergoing hemodialysis using CVCs, representing an important advancement in hemodialysis patient care.

Influencing factors on gelatin matrix for chlorhexidine delivery.

OBJECTIVE: The objective was to evaluate the influencing factors in the fabrication of gelatin matrix (gelatin chips) for drug delivery. The attributes affecting drug release characteristics of the gelatin products were examined. SIGNIFICANCE: Understanding the attributes that affect drug release from gelatin matrix could provide the knowledge base for the development, manufacturing, and performance evaluation of gelatin-based drug products for sustained drug delivery. METHODS: Chlorhexidine (CHX) was the model drug in the gelatin-product testing. The gelatin products were fabricated by two methods: a single-pot mixing of all the components and a two-step gelatin crosslinking followed by drug loading. Different gelatin types (Type A porcine and Type B bovine), glutaraldehyde (GTA) crosslinking conditions, glycerin concentration, and CHX concentration in drug loading and loading time were used to fabricate the products. The cumulative amounts of CHX release from the gelatin products were determined using in vitro release testing (IVRT). RESULTS: The attributes affecting CHX release from the gelatin products were gelatin type, GTA crosslinking, and CHX loading concentration. The fabrication methods (two-step method of gelatin crosslinking and drug loading by equilibration vs. direct mixing of the components) also affected CHX release. Other attributes such as glycerin and CHX loading time did not show significant effects on drug release under the conditions studied. In addition, the results in the two IVRT methods employed in this study were comparable. CONCLUSION: Gelatin products of qualitative (Q1) and quantitative (Q2) differences could lead to different drug release behaviors. Drug release was also affected by the ingredient mixing steps during gelatin chip fabrication.