Robbing Peter to Pay Paul: Chlorhexidine gluconate demonstrates short-term efficacy and long-term cytotoxicity.

Wound cleansing agents are routine in wound care and preoperative preparation. Antiseptic activity intends to prevent contaminating microbes from establishing an infection while also raising concerns of cytotoxicity and delayed wound healing. We evaluated the cytotoxicity of five clinically used wound cleaning agents (saline, povidone iodine, Dove® and Dial® soaps, and chlorhexidine gluconate [CHG]) using both an ex vivo and in vivo human skin xenograft mouse model, in contrast to classical in vitro models that lack the structural and compositional heterogeneity of human skin. We further established an ex vivo wound contamination model inoculated with ~100 cells of Pseudomonas aeruginosa or Staphylococcus aureus to evaluate antimicrobial efficacy. Scanning electron microscopy and confocal microscopy were used to evaluate phenotypic and spatial characteristics of bacterial cells in wound tissue. CHG significantly reduced metabolic activity of the skin explants, while all treatments except saline affected local cellular viability. CHG cytotoxicity persisted and progressed over 14 days, impairing wound healing in vivo. Within the contamination model, CHG treatment resulted in a significant reduction of P. aeruginosa wound surface counts at 24 h post-treatment. However, this effect was transient and serial application of CHG had no effect on both P. aeruginosa or S. aureus microbial growth. Microscopy revealed that viable cells of P. aeruginosa reside deep within wound tissue post-CHG application, likely serving as a reservoir to re-populate the tissue to a high bioburden. We reveal concerning cytotoxicity and limited antimicrobial activity of CHG in human skin using clinically relevant models, with the ability to resolve spatial localization and temporal dynamics of tissue viability and microbial growth.

Efficacy of commercial mouth-rinses on SARS-CoV-2 viral load in saliva: randomized control trial in Singapore.

PURPOSE: One of the key approaches to minimize the risk of COVID-19 transmission would be to reduce the titres of SARS-CoV-2 in the saliva of infected COVID-19 patients. This is particularly important in high-risk procedures like dental treatment. The present randomized control trial evaluated the efficacy of three commercial mouth-rinse viz. povidone-iodine (PI), chlorhexidine gluconate (CHX) and cetylpyridinium chloride (CPC), in reducing the salivary SARS-CoV-2 viral load in COVID-19 patients compared with water. METHODS: A total of 36 SARS-CoV-2-positive patients were recruited, of which 16 patients were randomly assigned to four groups-PI group (n = 4), CHX group (n = 6), CPC group (n = 4) and water as control group (n = 2). Saliva samples were collected from all patients at baseline and at 5 min, 3 h and 6 h post-application of mouth-rinses/water. The samples were subjected to SARS-CoV-2 RT-PCR analysis. RESULTS: Comparison of salivary Ct values of patients within each group of PI, CHX, CPC and water at 5 min, 3 h and 6 h time points did not show any significant differences. However, when the Ct value fold change of each of the mouth-rinse group patients were compared with the fold change of water group patients at the respective time points, a significant increase was observed in the CPC group patients at 5 min and 6 h and in the PI group patients at 6 h. CONCLUSION: The effect of decreasing salivary load with CPC and PI mouth-rinsing was observed to be sustained at 6 h time point. Within the limitation of the current study, as number of the samples analyzed, the use of CPC and PI formulated that commercial mouth-rinses may be useful as a pre-procedural rinse to help reduce the transmission of COVID-19. ISRCTN (ISRCTN95933274), 09/09/20, retrospectively registered.

Povidone-iodine as a corrosion inhibitor towards a low modulus beta Ti-45Nb implant alloy in a simulated body fluid.

Povidone-iodine and various bactericidal agents used in dental procedures may affect the corrosion response of an implant/prosthesis in the oral environment. The effect of various concentrations of povidone-iodine (PI) on the corrosion behavior of a low modulus beta titanium alloy, Ti-45Nb, has been investigated in normal saline solution. The open circuit potential, electrochemical impedance spectroscopy and potentiodynamic polarization measurements have been used to assess the electrochemical response of the alloy surface on PI addition so as to effectively predict the prosthetic treatment outcome. As the concentration of PI is increased, the corrosion rate decreases, suggested by decreased R(p) values. Povidone-iodine acts as an anodic inhibitor by adsorbing on the anodic sites of the alloy. Addition of PI to a simulated body fluid such as normal saline leads to a decrease in corrosion rate of Ti-45Nb alloy.

Antibacterial activity of amoxicillin in vitro and its oral bioavailability in broiler chickens under the influence of 3 water sanitizers.

The interaction of 3 water sanitizers (sodium hypochlorite, iodine-polyvinylpyrrolidone, and citrate) utilized in poultry production on antibacterial activity and bioavailability of amoxicillin trihydrate (AMX) were studied. Sanitizers were mixed with AMX in prepared water, the resulting substances were regarded as amoxicillin-sanitizer products (ASP). First, the in vitro antibacterial activity of each ASP was compared to that of AMX. Then, pharmacokinetics (PK) of ASP and AMX diluted in prepared water, were carried out in broiler-chickens. Amoxicillin or ASP (20 mg/kg) from different concentrations of sanitizers was directly placed into the chicken's crop and blood samples were taken. Basic PK parameters were obtained. Serum activity/concentrations of AMX were assessed by agar diffusion and corroborated with high performance liquid chromatography. Results show that ASP of AMX/sodium hypochlorite decrease both, the antimicrobial activity of in vitro AMX and its relative bioavailability (Fr) assessed with the maximum serum concentration (Cmax), the area under the concentration-time curve, and the mean residence time (MRT) (3.80 µg/mL, 2.70 µg/mL·h, and 0.59 h, respectively), compared to the AMX administered alone (12.54 µg/mL, 44.02 µg/mL·h, and MRT 2.78 h). ASP from amoxicillin/ionophore, reduced the Cmax (10.62 µg/mL), Fr (94.67%), and MRT (2.07 h), at the highest tested concentrations. In contrast, the 2 highest concentrations of the citrate sanitizer increased the Cmax (15.07 and 15.47 µg/mL), Fr (119 and 132%), and MRT (3.32 and 4.06 h) and their in vitro antimicrobial activity. Interactions between the tested water sanitizers and AMX modify the Cmax, Fr, MRT of the latter, altering the PK/pharmacodymanic ratios for a time-dependent antibiotic. Results also reveal that the use of amoxicillin trihydrate administered through the drinking water does not meet the required PK/pharmacodymanic ratios. Thus, it is here postulated that this antibiotic should be administered at least twice a day and that its interaction with water sanitizers should be considered.

Comparison of free and bound iodine and iodide species as a function of the dilution of three commercial povidone-iodine formulations and their microbicidal activity.

Equilibrium dialysis on povidone-iodine-solutions (Braunol, standardized Betadine and non-standardized iso-Betadine reveal that the amount of available iodine, free iodine, iodide and triiodide varies significantly both in the undiluted and diluted forms. These differences are reflected in the different bactericidal activity against Staphyloccus aureus as determined by the standard quantitative in vitro suspension test. The amount of available iodine is not an appropriate measure for an assessment of the microbicidal activity. For this, the free iodine has to be determined by means of equilibrium dialysis. The free iodine concentration in the Braunol concentrate was found to be 22 mg/L, in the standardized Betadine 9.7 mg/L and in the non-standardized Betadine concentrate only 2.1mg/L. Because of the atypical behaviour of iodophores and the increase of free iodine at dilution and because of a bactericidal level of free iodine of 5mg/L, Braunol and standardized Betadine can be employed as disinfectant as such, iso-Betadine has to be diluted before use. Summarizing all results, it can be stated that Braunol is superior to standardized Betadine and unstandardized iso-Betadine both as to the release of free iodine in the undiluted and in the diluted forms as in the killing rate of S. aureus.

Comparison of free iodine as a function of the dilution of two commercial povidone-iodine formulations.

Binding studies by means of equilibrium dialysis on two different Povidone-lodine-solutions reveal that the amount of available iodine and free iodine is very different as such and after dilution. The free iodine concentration in the Braunol concentrate was found to be ca. 22 mg/L and in the iso-Betadine concentrate only ca. 2.1 mg/L, despite the total amount of available iodine in iso-Betadine being higher than that of Braunol. As the bactericidal level of free iodine is characterised by concentrations >5 ppm, Braunol can be employed as a disinfectant as such, iso-Betadine has to be diluted before use. In both concentrates more than 99% of available iodine is present as reservoir for free iodine. Concerning the results as a function of dilution, it was demonstrated that, for both solutions, free iodine reaches a maximum after a 50-fold dilution (ca. 31 mg/L and ca. 51 mg/L for iso-Betadine and Braunol respectively). After dilution, a more constant level of free iodine was observed in the Braunol than in the iso-Betadine solution, and this is attributed to the present molar ratio of I(2)/I- and the addition of iodate in the former. The pH for both solutions approximates that of the skin, as such and after dilution. In summary, it can be stated that Braunol is superior to iso-Betadine as to the release of free iodine in both the undiluted as well as in the diluted form.

Intraocular Pharmacokinetics of Povidone-Iodine and Its Effects on Experimental Staphylococcus epidermidis Endophthalmitis.

PURPOSE: The purpose of this study was to investigate the pharmacokinetics and safety of intravitreal povidone-iodine (PVI) and its efficacy against experimental Staphylococcus epidermidis endophthalmitis. METHODS: In phase I, forty New Zealand white rabbits were divided into groups I and II and received intravitreal 0.1% and 0.3% PVI, respectively. Electroretinography (ERG) and histologic examinations were conducted at baseline, 6, and 12 hours. Half-life was determined using high-performance liquid chromatography. In phase II, after the induction of S. epidermidis endophthalmitis, 0.1% and 0.3% PVI were injected intravitreally once in groups A and B and three times every second day in groups C and D (n = 10 in each group). Electroretinographs, histologic examinations, and vitreous cultures were conducted on day 14. RESULTS: Electroretinography and histologic examinations did not reveal any notable retinal damage in phase I in either group. Half-lives were 3.27 and 3.58 hours in groups I and II, respectively. In phase II, all groups demonstrated marked improvement, compared to controls. Bacterial growth was found in four eyes in group A (20, 60, 60, and 70 colony forming units [CFU]) and in three eyes in group B (20, 40, and 60 CFU) but not in those belonging to groups C and D at day 14. Retinal damage with lymphocyte infiltration in the inner retinal layers was more common in groups A and B than in groups C and D. CONCLUSIONS: Half-life of PVI was approximately 3 hours in the vitreous. Repeated injection of intraocular PVI, even at low concentrations, is most likely to be effective for the treatment of bacterial endophthalmitis.

The uptake and release of molecular iodine by the skin: chemical and bactericidal evidence of residual effects caused by povidone-iodine preparations.

The residual effect of iodine-based disinfectants is caused by a dynamic back-diffusion which is the reverse of the absorption occurring during application. A very sensitive photometric method was used to measure the iodine flux of the back-diffusion after treating the skin with povidone-iodine preparations and Lugol's solution. After removal of the preparation the intensity of the iodine flux decreases with time and correlates with the amount of iodine being resorbed. The latter depends on the concentration of free molecular iodine of the preparation, the contact time and the thickness of the horny layer of the treated skin. With Lugol's solution (approximately 170 ppm free molecular iodine) iodine flux could be observed 12-24 h after an application of 20-60s, while with low-level povidone-iodine preparations (0.5-20 ppm free iodine) the measurable flux lasted only 0.5-1 h after an application time of 3 min. The bactericidal activity of the back-diffusing iodine from skin previously treated with a commercial povidone-iodine preparation was assayed by using an inoculation with Micrococcus luteus. This showed a logarithmic reduction of 0.4 in bacterial concentration. Since the skin was washed with soap for 1 min after application this bactericidal action reflected the residual effect of the back-diffusing iodine.

Catheter port cleansing techniques and the entry of povidone-iodine into the epidural space.

PURPOSE/OBJECTIVES: To determine whether three epidural catheter port cleansing techniques used to apply a povidone-iodine solution differed with respect to the introduction of this solution through the epidural catheter. DESIGN: Experimental. SETTING: Laboratory. SAMPLE: Five DuPen (Davol, Cranston, RI) epidural catheters. METHODS: Five DuPen epidural catheters each were cleansed twice with (a) a commercially available 10% povidone-iodine swabstick, (b) a commercially available pledget impregnated with 10% povidone-iodine, and (c) a gauze pad saturated with 10% povidone-iodine. The order of cleansing was randomized. Each solution was used to clean the port for 30 seconds, and the port was allowed to dry for 30 seconds, similar to the technique used in the clinical setting. After cleaning the catheter port, water was injected through the catheter, and the solution from the tip of the catheter was analyzed using absorbance spectrophotometry. MAIN RESEARCH VARIABLES: Cleansing techniques, presence of povidone-iodine in catheter. FINDINGS: A statistically significant difference existed between the three cleansing techniques, with the pledget yielding the lowest values of povidone-iodine contamination of the epidural catheter (Freidman test, p = 0.02). CONCLUSIONS: Use of pledgets allowed the least amount of povidone-iodine to enter the epidural catheter as compared with the swabsticks or gauze pads. IMPLICATIONS FOR NURSING PRACTICE: Commercially available pledgets used to cleanse catheter injection ports may limit the introduction of 10% povidone-iodine into the epidural or intrathecal space.

Drug residues in milk after intrauterine injection of oxytetracycline, lincomycin-spectinomycin, and povidone-iodine in cows with metritis.

A study was conducted to document the maximum retention times of antimicrobial residues in milk after their use in intrauterine treatment of metritis in lactating cows and to evaluate several risk factors hypothesized to influence the retention time of these drugs. Oxytetracycline (3 g), lincomycin-spectinomycin (2 g of one-third lincomycin and two-thirds spectinomycin), or povidone-iodine (6 g) were given to cows with metritis by intrauterine route. The Bacillus stearothermophilus var calidolactis disk assay was performed on each milk sample. Of the 61 cows treated with oxytetracycline, 30 had residues in their postinjection milk for variable periods (range, 12.5 to 44.0 hours; mean, 26.6 +/- 10.3). Of the 47 cows treated with lincomycin-spectinomycin, 17 had residues in their postinjection milk for various periods (range, 14.5 to 24 hours; mean, 19.5 +/- 8.9). Povidone-iodine was not detected in milk. Because a high number of cows (n = 61) were treated with oxytetracycline, only data from these cows were used in testing the influence of 3 factors (severity of metritis, time after parturition when cows with metritis were treated, and parity) on maximum retention of the drug in milk. Severity of metritis did not have a significant influence (P greater than or equal to 0.1) on the maximum retention time of the drug. The retention time decreased linearly with the increase of time after parturition when the cow with metritis was treated. First lactation cows had a significantly (P less than or equal to 0.01) shorter retention time than did older cows.

A povidone-iodine medicated dressing.

The iodine content of a tulle gras-type dressing medicated with povidone-iodine (Poviderm) has been measured and its potential efficacy in wound care explored by means of laboratory models. Simple tests demonstrated the ready diffusibility and antibacterial activity of povidone-iodine. Wound models clearly showed that the limiting factor for useful dressing life is extent of exudation. It seems likely that this dressing would provide good topical antibacterial prophylaxis and may reduce the bacterial burden of colonised wounds. The dressing should help contain wound bacteria and thus assist infection control.

Kinetic catalytic determination of trace levels of iodide based on the oxidation of basic dyes with hydrogen peroxide monitored potentiometrically using simple PVC electrodes.

Four sensitive catalytic potentiometric methods have been developed for trace levels determination of iodide based on its catalytic effects on the oxidation of four dyes: viz. variamine blue (VB), rhodamine B (RB), methylene blue (MB) and malachite green (MG), with H(2)O(2) in H(3)PO(4) medium at 25±0.5°C. The catalyzed reaction rates were estimated potentiometrically by monitoring the potential of the corresponding dye-PVC ion selective electrodes. To select the optimized reaction conditions offering the highest sensitivity of the method, parallel studies were carried out on each dye catalyzed reaction including: the effect of reactant concentration, reaction medium and temperature. The working calibration curves were linear over the concentration range from 0.32 to 2.54 mg L(-1) iodide for VB method and from 3.2 to 12.7 mg L(-1) for other ones. The tolerance limits of more than 20 interfering species were listed indicating the high selectivity of the method. Trace iodide in edible salt and pharmaceutical samples was determined without the need for separation or preconcentration procedures.

Spectrophotometric determination of iodine species in table salt and pharmaceutical preparations.

A sensitive spectrophotometric method for the determination of iodine species like iodide, iodine, iodate and periodate is described. The method involves the oxidation of iodide to ICl(2)(-) in the presence of iodate and chloride in acidic medium. The formed ICl(2)(-) bleaches the dye methyl red. The decrease in the intensity of the colour of the dye is measured at 520 nm. Beer's law is obeyed in the concentration range 0-3.5 microg of iodide in an overall volume of 10 ml. The molar absorptivity of the colour system is 1.73 x 10(5) l mol(-1) cm(-1) with a correlation coefficient of -0.9997. The relative standard deviation is 3.6% (n=10) at 2 microg of iodide. The developed method can be applied to samples containing iodine, iodate and periodate by prereduction to iodide using Zn/H(+) or NH(2)NH(2)/H(+). The effect of interfering ions on the determination is described. The proposed method has been successfully applied for the determination of iodide and iodate in salt samples and iodine in pharmaceutical preparations.

Hemocultivos... ¿Qué te han contado y qué haces? / Blood cultures... What they tell you and what you do

Objetivo: Objetivo principal: Conocer la variabilidad práctica de los enfermeros/as (DUE's) del Hospital General Nuestra Señora del Prado, sobre la técnica para la extracción de hemocultivo. Objetivos específicos: Determinar las condiciones de asepsia/ esterilidad de la técnica. Establecer la utilización (desinfección, orden de llenado, volumen, cambio de aguja) de los frascos de hemocultivos. Método: Estudio descriptivo transversal realizado en el Hospital General Nuestra Señora del Prado. Ha consistido en la entrega de un cuestionario para autocumplimentación a los profesionales de enfermería, donde se han incluido variantes tanto cuantitativas como cualitativas. Resultados: Se han recogido 52,9% encuestas de los 363 DUE's del centro hospitalario, con una experiencia profesional media de 12,9 años [DE±7,9]. El 57,8% cree que no es necesario técnica estéril para el procedimiento. 94,7% utiliza un único antiséptico. 78,6% afirman que en la extracción de acceso venoso central desecha los primeros 10cc que extrae. Conclusiones: Consideramos un alto índice de respuesta, ya que es superior al 40% para cuestionarios autocumplimentados. Hemos observado que la mayoría de DUE's utilizan técnica aséptica y en los protocolos estudiados no existe un consenso entre la utilización de técnica estéril y aséptica. Este estudio nos revela que la mayoría de los DUE's utilizan un único antiséptico, sin embargo la mayoría de los protocolos recomiendan la utilización primero de alcohol y luego povidona yodada para la desinfección de la piel (AU)

Aims: Main aim: To ascertain differences in nurses at the Hospital General Nuestra Señora del Prado, in blood extraction and blood culture techniques. Specific aims: To determine the asepsis/sterility conditions of the technique; to establish the use (disinfection, filling order, volume, needle change) of the blood culture vials. Method: Transversal descriptive study made at the Hospital General Nuestra Señora del Prado. A self-completion questionnaire including quantitative and qualitative variants was delivered to nursing professionals. Results: 52.9% of the questionnaires were collected from the 363 DUE's at the hospital. Mena working experience was 12.9 years [DE±7,9]. 57,8% believe sterile technique for the procedure was not necessary. 94.7% use a single antiseptic. 78.6% stated that they discard the first 10 cc extracted from the central vein. Conclusions: We consider that the response is high, with over 40% of the questionnaires being completed. We observed that most DUE's use aseptic techniques and in the protocols studied there was no consensus about the use of sterilization and septic techniques. The study reveals that the majority of the DUE's use a single antiseptic, even though most protocols recommend the use of alcohol, followed by povidone.iodine to disinfect the skin (AU)

Pharmaceutical and bacteriological study on povidone-iodine sugar ointment.

Povidone-iodine sugar ointment is an excellent preparation for the treatment of decubitus. It has been used as an intrahospital preparation made according to the formula each hospital decided on from experience. Although commercial products have also been developed and used, they are too expensive. The efficacy of a povidone-iodine sugar ointment formulation which can be prepared by a single method and which has the stability and antibacterial activity equal to commercially available products was evaluated. As the test drugs, one commercially available product (UP), and three preparations with different formulas (P-1, P-2 and P-3) were used. All of these test drugs were stored at 20 and 40 degrees C. Specimens were sampled immediately after storage and after 20, 60, 90, 120 and 150 days and examined pharmaceutically (measurement of pH value and determinations of available iodine and sucrose levels). For the determination of bacteriological effects, 5 standard strains of 5 genera and 5 strains of methicillin-resistant Staphylococcus aureus (MRSA) were used and the time required to kill the bacteria was determined. For UP and P-3, no changes were seen pharmaceutically after 150 days of storage at 20 and 40 degrees C. However, MRSA could not be killed within 30 min. P-1 and P-2 showed remarkable changes pharmaceutically after 60 days of storage at 40 degrees C and could not be used any more. It became possible to make a preparation of povidone-iodine sugar ointment which has a stability almost similar to that of UP. Moreover, such a preparation can be made at low cost. However, since the bactericidal activity against MRSA was not higher than those of other drugs, the future task is to improve the bactericidal activity.