Bacteriophages as therapeutic & disinfectant agents to tackle multidrug-resistant Acinetobacter baumannii

Background & objectives: Multidrug-resistant (MDR) Acinetobacter baumannii is a serious threat for human health worldwide. The studies on agents targeting A. baumannii are imperative due to identified A. baumannii co-infections in COVID-19. Bacteriophages are promising antibacterial agents against drug-resistant bacteria. This study intended to isolate bacteriophages against MDR A. baumannii from the water of river Ganga, to be used potentially as therapeutic and disinfectant particles. Methods: Acinetobacter phages were isolated from the Ganga water collected from Kanpur and further tested on 50 MDR A. baumannii isolates to determine host range. The phages were morphologically characterized by transmission electron microscopy. The disinfectant property of the isolated phages was tested by spraying of bacteriophage cocktail on MDR A. baumannii contaminated plastic surface, analyzed by colony-forming unit (CFU) and bioluminescence assay (adenosine triphosphate monitoring). Results: A total of seven bacteriophages were isolated against MDR A. baumannii. The bacteriophages lysed three MDR A. baumannii isolates out of 50 tested, showing narrow host range. Electron microscopy revealed hexagonal heads and long tails of bacteriophages, belonging to order Caudovirales. The bacteriophage cocktail reduced the MDR A. baumannii load efficiently on plastic surface, evidenced by reduction in CFUs and bioluminescence. Interpretation & conclusions: The findings of this study suggest that the isolated bacteriophages are potential lytic agents for MDR A. baumannii clinical isolates, and may be used as potential therapeutic agents as well as disinfectant to combat MDR A. baumannii with due consideration to phage host specificity, with further characterization.n

On-Site Assessment of a Cryogenic Disinfectant for the Alpine Environment and Outer Packaging of Frozen Items / 生物医学与环境科学（英文）

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

In vitro evaluation for estrogenic mechanisms of the disinfectant benzalkonium chloride as an emerging contaminant

This study aimed to evaluate in vitro the possible mechanisms underlying the estrogenic potential of benzalkonium chloride (BAC) as a disinfectant emerging contaminant. Effects of BAC at the environmentally-relevant concentrations on estrogen synthesis and estrogen receptor (ER) signaling were assessed using the H295R steroidogenesis assay and the MCF-7 proliferation assay, respectively. Results showed that exposure to BAC at concentrations of 1.0-1.5 mg/L for 48 h significantly increased estradiol production of H295R cells in a concentration-dependent manner. Transcription of steroidogenic genes 3β‐HSD2, 17β‐HSD1, 17β‐HSD4, and CYP19A were significantly enhanced by BAC. In ER-positive MCF-7 cells, exposure to 0.5-1.5 mg/L BAC for 48 h significantly promoted cell proliferation and increased the expressions of ERα and G-protein coupled estrogen receptor 1. Flow cytometry analysis showed that 0.5-1.5 mg/L BAC significantly decreased the percentage of cells in G0/G1 phase, increased the percentage in S phase, and BAC at concentrations of 1.0 and 1.5 mg/L increased the G2/M phase cells. Findings of the study suggested that BAC at environmentally-relevant concentrations might act as a xenoestrogen through its inhibitory effect on steroidogenesis and ER-mediated mechanism.

Rabies virus viability in vitro / 中华微生物学和免疫学杂志

Objective:To investigate the in vitro viability of rabies virus in tissues and body fluid samples. Methods:The viability of rabies virus in tissues and suspensions was analyzed by virus titer determination method, direct immunofluorescence, RT-PCR and laboratory techniques for virus isolation.Results:With the increase of temperature, the viability of rabies virus in brain tissues and suspensions decreased gradually. Rabies virus lost infectivity after 30 min at 56℃, but remained viable in tissues for 7 d at 37℃. The virus showed no viability after 1 h at pH9.6. The rabies virus in suspensions could be completely inactivated after the stimulation with ethanol at a final concentration above 30%, sodium hypochlorite above 500 mg/L or benzalkonium bromide above 100 mg/L for 3 min. It was found that 80% acetone had the strongest inactivation effect on rabies virus in tissues, and no virus could be isolated after soaking for 4 h.Conclusions:Rabies virus was not tolerant to high temperature and relatively stable in the environment with pH6.8-7.4. Common disinfectants could kill the virus. This study provided detailed data about the viability of rabies virus in vitro, which would be conducive to the prevention and control of rabies.

Effect of cavity disinfection protocols on microtensile bond strength of universal adhesive to dentin / Efecto de los protocolos de desinfección de cavidades en la fuerza de adhesión microtensil del adhesivo universal a la dentina

Abstract The purpose of this study was to compare the effect of different disinfection protocols of dentin on bond strength of an MDP-containing universal adhesive. Twelve extracted mandibular third molars were separated horizontally at the mid-coronal of crown to get smooth and sound dentin surfaces using low-speed diamond saw. The teeth were randomly fallen into four groups: chlorhexidine (CHX), ozone, Er,Cr:YSGG laser irradiation (LASER) and no treatment (control). After cavity disinfection application, a universal adhesive (G-Premio Bond) was applied to the surface of dentin according to self-etch mode as instructed by the manufacturer. After incremental built-up of composite resin (Charisma Smart), the specimens were immersed in distilled water at 37°C for 24h. Dentin/composite beams with 1 mm² cross sectional area were produced and micro-tensile bond strength (µTBS) was applied on these beams (n=20). Failure mods were determined under a stereomicroscope at ×40. The resin penetration of samples stained with Rhodamine B fluorochrome dye was examined with a confocal laser scanning microscope. Statistical analysis was performed with SPSS-22. Test results were analyzed using One-way Anova and Tukey HSD Post-Hoc tests (p0.5). All applications of cavity disinfection procedures decreased the µTBS of the resin-dentin interface.

Resumen El propósito de este estudio fue comparar el efecto de diferentes protocolos de desinfección de la dentina sobre la fuerza de unión de un adhesivo universal que contiene MDP. Doce terceros molares mandibulares extraídos se quebraron horizontalmente en la mitad de la corona para obtener superficies de dentina lisas y sólidas utilizando una sierra de diamante de baja velocidad. Los dientes se dividieron aleatoriamente en cuatro grupos: clorhexidina (CHX), ozono, irradiación con láser Er,Cr:YSGG (LASER) y ningún tratamiento (control). Después de la aplicación de la desinfección de la cavidad, se aplicó un adhesivo universal (G-Premio Bond) a la superficie de la dentina según el modo de autograbado indicado por el fabricante. Después de la obturación con resina compuesta (Charisma Smart), las muestras se sumergieron en agua destilada a 37°C durante 24h. Se produjeron porciones de dentina/resina con un área de sección transversal de 1 mm² y se aplicó una fuerza de adhesión microtensile (µTBS) (n=20). Los modos de falla se determinaron bajo un microscopio estereoscópico a ×40. La penetración de la resina de las muestras teñidas con colorante fluorocromo rodamina B se examinó con un microscopio de barrido láser confocal. El análisis estadístico se realizó con SPSS-22. Los resultados de las pruebas se analizaron utilizando las pruebas post-hoc Anova unidireccional y Tukey HSD (p0.5). Todas las aplicaciones de procedimientos de desinfección de cavidades redujeron el µTBS de la interfaz resina-dentina.

Advances on toxicity of polyhexamethyl guanidine / 环境与职业医学

Polyhexamethyl guanidine (PHMG) is a widely used guanidine disinfectant. Since a lung injury incident induced by humidifier disinfectant (PHMG was identified as a main component) was reported in Korea, its inhalation toxicity has attracted the attention of researchers. At present, there are few domestic studies on inhalation toxicity of PHMG. In this paper, based on the domestic and foreign studies of PHMG, the toxicities of PHMG, including inhalation toxicity and associated toxic mechanism, and other potential toxicities, such as liver toxicities, cardiovascular toxicity, immunotoxicity, and reproductive and developmental toxicity, were systematically introduced, revealing that the effects of use of PHMG in a non-standard manner on the body and its possible mechanisms, which could provide reference for the use of PHMG properly and to lay a theoretical foundation and provide a scientific basis for follow-up study.

Effect of heating skin disinfectant for premature infants during peripheral central venous catheterization / 中国新生儿科杂志

Objective:To study the effect of heating skin disinfectant during peripherally inserted central catheter (PICC) in preterm infants.Methods:Premature infants were retrospectively analyzed who received PICC catheterization during hospitalization in the Department of Neonatology of the Affiliated Hospital of Southwest Medical University from April 2020 to March 2021. They were divided into the control and heating groups according to different disinfection methods in two different periods. The skin of premature infants in the heating group was disinfected with disinfectant at 37℃, and the control group was disinfected with room temperature disinfectant. The rate of successful primary catheterization, operation duration, and catheter-associated infection were compared between the two groups.Results:The rate of successful primary catheterization in the heating group was higher than that of the control group [80.2% (65/81) vs. 66.7% (56/84)], and the operation time was shorter than that of the control group [(45.0±9.0) min vs. (48.4±11.9) min] ( P<0.05). There was no statistical difference in catheter keeping time, unplanned extubation rate, the rate of positive catheter tip cultures, and the blood cultures. Conclusions:During PICC puncture in premature infants, heating skin disinfectant can increase the success rate of one-time PICC catheterization, reduce the operation duration, and not increase the risk of catheter-associated infection.

Comparison of two types of disinfectants on the disinfection of the fixed end of the table suction pipe in the oral comprehensive treatment table / 口腔疾病防治

Objective@#To compare the disinfection effects of 500 mg/L chlorine-containing disinfectant and 3% hydrogen peroxide disinfectant applied to the threaded plastic hose at the fixed end of the saliva suction pipe of the oral comprehensive treatment table after diagnosis and treatment of patients in stomatology to provide a basis for clinical cleaning and disinfection.@* Methods @#The fixed ends of saliva suction pipes of 12 comprehensive treatment tables in the dental pulp department and maxillofacial surgery were selected as the research objects. The absorption was randomly divided into two groups and a control group: experimental group 1 with 500 mg/L chlorine disinfectants and experiment 2 group with 3% hydrogen peroxide disinfectant rinse disinfection and the control group with 0.9% sterile saline flushing pipe once a week for four weeks. Before and after washing and disinfection, samples from the inner wall of the threaded plastic hose interface were collected for bacterial culture and colony count, and colony counts within and between groups were compared before and after disinfection. Statistical analysis was conducted using SPSS 24.0 software.@*Results@#The baseline number of bacterial colonies in the first three groups was balanced, with no statistically significant difference (χ2 = 0.538, P = 0.764). The number of bacterial colonies after washing and disinfection was lower than that before washing and disinfection. The difference between 500 mg/L chlorine-containing disinfectant and 3% hydrogen peroxide disinfectant before and after disinfection was highly significant (Z = -4.801, P<0.001; Z = -4.429, P<0.001). There was no significant difference between the disinfection effect of 500 mg/L chlorine-containing disinfectant and 3% hydrogen peroxide disinfectant, but they were both better than the control group (χ2 = 18.070, P<0.001).@*Conclusion@#Disinfecting the saliva suction pipe with disinfectant between diagnosis and treatment can effectively reduce the bacterial contamination at the fixed end threaded plastic hose interface of the saliva suction pipe. The disinfection method is simple and convenient, and it is worth applying in the oral clinic.

Investigation on an incident of occupational contact dermatitis in a farm / 预防医学

Objective@#To investigate the cause of an incident of occupational contact dermatitis in a farm in Tianjin Prefecture, so as to provide insights into occupational safety.@*Methods@#The disinfection process, use of disinfectants and individual protective measures in this farm were collected, and a field epidemiological investigation was conducted to collect the demographic characteristics, history of occupational contact, clinical symptoms, diagnosis and treatment data, and onset of disease among individuals with the same type of job. The cause of this incident was analyzed.@*Results@#There were ten interns exposed to potassium hydrogen sulfate compounds simultaneously in this farm, and then, nine interns developed skin flushing across the body, and swelling and itching of the skin. Among these ten interns, five individuals were admitted to hospitals because of severe symptoms and were then clinically diagnosed as systemic contact dermatitis. All five individuals were cured following treatments. Epidemiological survey showed that all cases had a definite history of occupational contact with potassium hydrogen sulfate compounds but without use of any protective agents. In addition, there were thirty-five individuals with the same type of job in this farm that developed similar symptoms when they joined in the disinfection for the first time, and these individuals were self-cured following cessation to contact; however, recurrence of symptoms was found following contacts again.@*Conclusion@#This is a cluster of occupational contact dermatitis caused by exposure to potassium hydrogen sulfate compound.

Antimicrobial and disinfectant resistance of Salmonella Heidelberg from Brazilian flocks did not increase for ten years (2006-2016) / A resistência a desinfetantes e a antimicrobianos não aumentou em um período de 10 anos (2006 a 2016) em Salmonella Heidelberg isoladas de granjas avícolas brasileiras

Salmonella is a major cause of foodborne illness worldwide, and poultry and its derived products are the most common food products associated with salmonellosis outbreaks. Some countries, including Brazil, have experienced an increased prevalence of Salmonella Heidelberg among their poultry flocks. Some isolates have also presented high resistance to antimicrobial agents and persist in the poultry farm environment. This study aimed to compare the susceptibility of S. Heidelberg strains isolated in 2006 with those isolated in 2016 against disinfectants and antimicrobial agents. The results showed that all the strains were highly susceptible to sodium hypochlorite, regardless of the conditions and year of isolation. Resistance to benzalkonium chloride varied according to the conditions applied, but not to the year of isolation. Increased antimicrobial resistance from 2006-2016 was observed only for tetracycline. The results suggest that the antimicrobial and disinfectant resistance of S. Heidelberg did not increase for ten years (2006-2016). However, further analysis should include a larger number of S. Heidelberg isolates from poultry origin and additional antimicrobial agents for more precise conclusions about the increasing in antimicrobial resistance in the last years.(AU)

Salmonella é uma das principais causas das doenças transmitidas por alimento em todo o mundo, e a carne de frango e produtos derivados são os principais alimentos associados com surtos de salmonelose em humanos. Alguns países, incluindo o Brasil, têm observado um aumento da ocorrência de Salmonella Heidelberg nas suas granjas avícolas. Além disto, alguns isolados têm apresentado alta resistência aos antimicrobianos e têm persistido no ambiente de produção avícola. Neste contexto, o objetivo deste estudo foi comparar a susceptibilidade de cepas de S. Heidelberg isoladas em 2006 com aquelas isoladas em 2016 contra desinfetantes e agentes antimicrobianos. Os resultados demonstraram que as cepas foram altamente resistentes a hipoclorito de sódio, independentemente das condições e do ano de isolamento. A resistência ao cloreto de benzalcônio variou de acordo com as condições testadas, mas não com o ano de isolamento. Um aumento da resistência aos antimicrobianos de 2006 a 2016 foi observado apenas para tetraciclina. Os resultados sugerem que a resistência aos desinfetantes e aos antimicrobianos não aumentou em um período de dez anos (2006-2016). Entretanto, novas análises devem incluir um número maior de cepas de S. Heidelberg isoladas de fontes avícolas e outros agentes antimicrobianos para uma conclusão mais precisa sobre o aumento da resistência antimicrobiana nos últimos anos.(AU)

Antimicrobial and disinfectant resistance of Salmonella Heidelberg from Brazilian flocks did not increase for ten years (2006-2016)

ABSTRACT: Salmonella is a major cause of foodborne illness worldwide, and poultry and its derived products are the most common food products associated with salmonellosis outbreaks. Some countries, including Brazil, have experienced an increased prevalence of Salmonella Heidelberg among their poultry flocks. Some isolates have also presented high resistance to antimicrobial agents and persist in the poultry farm environment. This study aimed to compare the susceptibility of S. Heidelberg strains isolated in 2006 with those isolated in 2016 against disinfectants and antimicrobial agents. The results showed that all the strains were highly susceptible to sodium hypochlorite, regardless of the conditions and year of isolation. Resistance to benzalkonium chloride varied according to the conditions applied, but not to the year of isolation. Increased antimicrobial resistance from 2006-2016 was observed only for tetracycline. The results suggest that the antimicrobial and disinfectant resistance of S. Heidelberg did not increase for ten years (2006-2016). However, further analysis should include a larger number of S. Heidelberg isolates from poultry origin and additional antimicrobial agents for more precise conclusions about the increasing in antimicrobial resistance in the last years.

RESUMO: Salmonella é uma das principais causas das doenças transmitidas por alimento em todo o mundo, e a carne de frango e produtos derivados são os principais alimentos associados com surtos de salmonelose em humanos. Alguns países, incluindo o Brasil, têm observado um aumento da ocorrência de Salmonella Heidelberg nas suas granjas avícolas. Além disto, alguns isolados têm apresentado alta resistência aos antimicrobianos e têm persistido no ambiente de produção avícola. Neste contexto, o objetivo deste estudo foi comparar a susceptibilidade de cepas de S. Heidelberg isoladas em 2006 com aquelas isoladas em 2016 contra desinfetantes e agentes antimicrobianos. Os resultados demonstraram que as cepas foram altamente resistentes a hipoclorito de sódio, independentemente das condições e do ano de isolamento. A resistência ao cloreto de benzalcônio variou de acordo com as condições testadas, mas não com o ano de isolamento. Um aumento da resistência aos antimicrobianos de 2006 a 2016 foi observado apenas para tetraciclina. Os resultados sugerem que a resistência aos desinfetantes e aos antimicrobianos não aumentou em um período de dez anos (2006-2016). Entretanto, novas análises devem incluir um número maior de cepas de S. Heidelberg isoladas de fontes avícolas e outros agentes antimicrobianos para uma conclusão mais precisa sobre o aumento da resistência antimicrobiana nos últimos anos.

In vitro efficacy of iodine in the pre and post dipping against coagulase negative Staphylococcus isolated in milk of cows with subclinical mastitis / Eficácia in vitro do iodo no pré e pós dipping frente a Staphylococcus coagulase negativa isolados em leite de vacas com mastite subclínica

ABSTRACT: The efficiency of the disinfectants used in the milking management is fundamental to the success in the dairy activity, being a critical point to the control of mastitis. The objective was to evaluate the in vitro efficacy of iodine used in pre and post-dipping against coagulase negative Staphylococcus (CNS). Thus, 53 CNS isolates were studied for the action of the 1.0% disinfectant and their serial dilutions of 0.5%, 0.375% and 0.25%, in addition to two commercial presentations of iodine in concentrations of 0.5% and 0.25%. The rate of CNS inhibition achieved by iodine at 0.375%, 0.5% and 1.0% for 60 seconds, was 60.4%. In 30 seconds, iodine at 0.5% and 1.0% showed a microbial inhibition rate of 52.8% and 56.6%, respectively. The other protocols tested were less efficient. It is concluded that the greatest in vitro disinfectant activity for CNS was demonstrated by iodine at 0.375%, 0.5% and 1.0%, for 60 seconds. Microbial susceptibility tests should be carried out periodically, as well as health education practices and corrective training on the property, in order to ensure udder health and mastitis control.

RESUMO: A eficiência dos desinfetantes empregados no manejo de ordenha é fundamental no sucesso na atividade leiteira, sendo um ponto crítico ao controle da mastite. Objetivou-se avaliar a eficácia in vitro do iodo utilizado no pré e pós-dipping frente à Staphylococcus coagulase negativa (SCN). Foram estudados 53 isolados de SCN quanto à ação do desinfetante a 1,0% e suas diluições seriadas de 0,5%, 0,375% e 0,25%, além de duas apresentações comerciais nas concentrações de 0,5% e 0,25%. A taxa de inibição de SCN alcançada pelo iodo a 0,375%, 0,5% e 1,0% durante 60 segundos, foi de 60,4%. Em 30 segundos, o iodo a 0,5% e 1,0% apresentaram taxa de inibição microbiana de 52,8% e 56,6%, respectivamente. Os demais protocolos testados foram menos eficientes. Conclui-se que a maior atividade desinfetante in vitro para SCN foi demonstrada pelo iodo a 0,375%, 0,5% e 1,0%, durante 60 segundos. Testes de susceptibilidade microbiana devem ser realizados periodicamente, assim como práticas de educação em saúde e treinamentos corretivos na propriedade, visando garantir a saúde do úbere e o controle da mastite.

Scope of herbal disinfectants to fight against SARS-CoV2 virus

@#Globally, COVID-19 outbreak is a major social issue in the current trend. SARS-CoV2 is a novel coronavirus causing Severe Acute Respiratory Syndrome in human and it is spreading rapidly among human population. In order to prevent SARS-CoV2 infection and managing this corona disease, WHO formula based alcoholic hand sanitisers are being widely used as one of the primary preventive agent and the demand is increasing worldwide. Herbal extracts and/or their phytochemicals have been considered as natural sources for formulating herbal hand sanitizers as alternative to alcoholic products. In this correspondence, we have described about the probable mechanistic action of herbal bioactives to fight against COVID-19 virus. Understanding of mechanistic action of bioactives could be useful to formulate herbal hand sanitizers and the products have high demand in the global sanitizer market.

Are Dropped Bone Grafts Safe to be Re-used? - An Experimental Study Comparing Efficacy of Chlorhexidine, Povidone-Iodine and Alcohol

@#Introduction: A dilemma arises when a bone graft or fracture fragment is accidentally dropped on the operation theatre floor and becomes contaminated. This study aimed to determine the efficacy of simple and readily available antiseptic solutions in disinfecting contaminated bones. Materials and methods: This experimental study involved 225 bone specimens prepared from discarded bone fragments during a series of 45 knee and hip arthroplasty surgeries. The bone fragments were cut into five identical cubes and were randomly assigned to either control (positive or negative), or experimental groups (0.5% chlorhexidine, 10% povidone-iodine or 70% alcohol). The control negative was to determine pre-contamination culture. All bone specimens, except the control negative group were uniformly contaminated by dropping on the operation theatre floor. Subsequently, the dropped bone specimens except for the control positive group, were disinfected by immersing in a respective antiseptic solution for 10 minutes, before transported to the microbiology laboratory for incubation. Results: The incidence of a positive culture from a dropped bone fragment was 86.5%. From the 37 specimens sent for each group, the incidence of positive culture was 5.4% (2 specimens) after being disinfected using chlorhexidine, 67.6% (25 specimens) using povidone-iodine and 81.1% (30 specimens) using alcohol. Simple logistic regression analysis demonstrated that chlorhexidine was significantly effective in disinfecting contaminated bones (p-value <0.001, odd ratio 0.009). Povidone-iodine and alcohol were not statistically significant (p-value 0.059 and 0.53, respectively). Organisms identified were Bacillus species and coagulase negative Staphylococcus. No gram-negative bacteria were isolated. Conclusion: A total of 0.5% chlorhexidine is effective and superior in disinfecting contaminated bones.

Peligros en la utilización de cabinas de desinfección contra el SARS-CoV-2 / Hazards in the use of disinfection cabinets against SARS-CoV-2

La pandemia producida por el coronavirus SARS-CoV-2 está causando estragos sanitarios y económicos en todo el mundo, obligando a la reorientación de recursos para disminuir el contagio y superar los problemas económicos. En ese sentido se comenzaron a construir y emplear las cabinas de desinfección para eliminar el SARS-CoV-2 de forma externa, las cuales eran colocadas en las entradas de los hospitales para rociar con agentes desinfectantes a las personas que entraban y salían del lugar, a pesar de que los productos empleados están habilitados para ser utilizados sobre objetos y por un tiempo determinado, lo cual representaba un riesgo para la salud del usuario por lo que se requería de un estudio para establecer los peligros relacionados y desaconsejar su utilización.

The pandemic produced by the SARS-CoV-2 coronavirus is causing health and economic havoc throughout the world, forcing the redirection of resources to reduce contagion and overcome economic problems. In this sense, they began to build and use disinfection cabins to eliminate SARS-CoV-2 externally, which were placed at the entrances of hospitals to spray disinfectants with disinfectants to people who entered and left the place, despite the fact that the products used are enabled to be used on objects and for a certain time, which represented a risk to the health of the user, so a study was required to establish the related dangers and advise against their use.

An In Vivo Study to Evaluate the Efficacy of Aloe-Vera and 0.2% Chlorhexidine Digluconate as Preprocedural Mouth Rinses for Disinfecting Alginate Impression

A total of thirty subjects was selected. For each individual subject, 3 impressions of maxillary arch were made using alginate. Impressions were divided into three categories. First impression (Group 1) was made without using any preprocedural mouth rinse. After the impression was made, a sterile cotton swab was wiped over the impression surface and sent for culture sensitivity test. This swab acted as the control group. The swab was then run over the Blood Agar culture medium. The incubation of culture-medium plates was done for 24 hrs. at 37 °C. From the culture plate, smear was taken to examine bacterial growth and the colony forming units were counted on the slide. 24 hours after initial impression, the second impression (Group 2) was made after making the subject rinse with aloe vera for 30 seconds. After 48 hours after Group 1, third impression (Group 3) of the same subject was made, making the subject rinse with 0.2% chlorhexidine digluconate solution for 30 seconds. Rest of the steps were same for both the impressions as the first impression.Data was recorded and analysis for difference in the bacterial count between Group 1, Group 2 and Group 3 was done using ANOVA with post-hoc Bonferroni test from SPSS version 18. ResultsThe result showed an overall significant difference in the mean CFU among the three groups. Post-hoc test showed that group 1 had significantly higher mean CFU (7.54) than group 2 (2.98) and 3 (1.82). The least bacterial count was seen in the samples in which chlorhexidine digluconate was used as a mouth rinse before making the impression. The mean percentage reduction in bacterial count was 60.33 in the group for which aloe vera was used and 75.81 in the chlorhexidine digluconate group. Conclusions0.2 % chlorhexidine digluconate when used as preprocedural mouth rinse for 30 seconds markedly reduces the bacterial growth of aerobic culture. Although Aloe vera does have an antibacterial effect when used as preprocedural mouth rinses when compared with 0.2 % chlorhexidine digluconate, it is a weaker disinfectant. The antibacterial activity of 0.2 % chlorhexidine digluconate is more effective than aloe vera (99.9 %) when used as preprocedural mouth rinse.

Comparative Evaluation of Disinfecting Alginate Using Aloe Vera and 0.2% Chlorhexidine Digluconate by Internal Disinfection Method - An In Vivo Study.

Aloe vera and chlorhexidine are traditionally used as disinfectants of irreversible hydrocolloids. Most popular among irreversible hydrocolloids is alginate which is most commonly used in dentistry. We wanted to compare and evaluate the efficacy of aloe vera and 0.2% chlorhexidine as an internal disinfectant.METHODSFor each subject three impressions of the upper arch were made using irreversible hydrocolloid impression material i.e. Alginate (Zelgan 2002). After the impression was made, a sterile cotton swab was used and wiped over the impression surface from the center of the palate and was sent for culture sensitivity test. This swab acted as the control group (Group 1). The swab was then placed in normal saline transport medium and was sent for culture sensitivity test to the Gyan Pathology Lab, Kanpur. The swab was then run over the Blood Agar culture media. Incubation of the culture medium plates was done at 37°C for 24 hrs. From the culture plate, smear was taken to examine bacterial growth on a slide, semi-quantitatively, under light microscope, and the colony forming units were then counted. 24 hours after initial impression, second impression (Group 2) was made by mixing alginate with 99.9% aloe vera. 48 hours after the first impression, the third impression (Group 3) of the same subject was made after mixing alginate with 0.2% chlorhexidine digluconate. Remaining procedural steps were similar for second and third impressions as the first impression. Bacterial count was recorded and analysed for variation between group 1, group 2 and group 3 using Repeated Measures ANOVA with post-hoc Bonferroni test from SPSS version 18.RESULTSThis study showed that using 99.9% concentration of Aloe Vera as an internal disinfectant to manipulate irreversible hydrocolloid impression material did show a reduction (65.96%) in growth of aerobic bacteria. However, the decrease was significantly less when compared with chlorhexidine.CONCLUSIONSAmongst the two disinfecting agents used in this study, 0.2% chlorhexidine digluconate has shown to be more effective disinfecting agent than Aloe Vera.

Hydroalcoholic Extract of Eugenia uniflora as Denture Disinfectant: Antimicrobial Activity and Effect on the Physical Properties of Polymethylmethacrylate

Abstract To the moment, there is no ideal substance for home-based denture disinfection. This study assessed in vitro the antimicrobial effect of the hydroalcoholic extract of Eugenia uniflora and the effect on the physical properties of denture polymethylmethacrylate (PMMA). Candida albicans, Staphylococcus aureus, and Klebsiella oxytoca were isolated from samples of saliva collected from denture wearers. The extracts were produced in three concentrations, according to the Brazilian Pharmacopeia. One hundred eighty-eight disc-shaped specimens of thermopolymerizable PMMA were prepared and randomly allocated to five treatment groups: sterile saline solution (0.85%; control); chlorhexidine digluconate (0.2%); and hydroalcoholic extract of E. uniflora (0.2%, 0.8%, and 1.16%). The specimens were disinfected for 8 hours/day for 30 days. Adherence of microorganisms to the surface, PMMA surface roughness, and color stability were assessed. Inferential statistics were performed with one- and two-way ANOVA/Tukey test, and Kruskal Wallis, Mann-Whitney U, and paired t-tests, at α=0.05. The extract of E. uniflora at 0.2% and 1.16% reduced the microbial load of K. oxytoca, while chlorhexidine digluconate significantly reduced microbial load of all microrganisms. Microbial adherence at day 10 was reduced by all experimental substances (p<0.001). Surface roughness was not affected by the disinfecting substances (p>0.05). Nevertheless, all experimental groups produced unacceptable color change at the end of the disinfection protocol (p<0.001). The non-adherent potential against microorganisms isolated from the oral cavity confirm the potential of use of the hydroalcoholic extract of E. uniflora as a denture disinfectant. Yet, unacceptable color changes may occur, regardless of extract concentration.

Progress in respiratory toxicity of polyhexamethyleneguaidine disinfectant and mechanism exploration / 中华预防医学杂志

Polyhexamethylene guanidine (PHMG) is a high molecular guanidine compound with a broad spectrum of antibacterial effects. Since the outbreak of the 'humidifier disinfectant-induced lung injury’ event in South Korea, the respiratory toxicity of PHMG had become a public concern. An epidemiological survey in Korea found that PHMG-containing disinfectants were an important risk factor for pulmonary fibrosis. Animal experiments also showed that the exposure to PHMG through the respiratory tract could cause irreversible fibrosis in the lungs. TGF-β signaling pathway, epithelial-mesenchymal transition and pulmonary inflammation might be the main pathways that could mediate PHMG-induced pulmonary fibrosis. This article provided an overview of the characteristics of population exposure to PHMG and research progress in the field of respiratory toxicology and recommendations for the rational and standard of using PHMG-related products in China.

Study on fibrosis changes in the lungs of mice caused by repeated inhalation of polyhexamethyleneguaidine disinfectant / 中华预防医学杂志

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/m3 and 9.09 mg/m3 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.