Antimicrobial Efficacy of the Silver Wound Dressing Biatain Ag in a Disc Carrier Test Simulating Wound Secretion

Aim: The efficacy of antimicrobial compounds included in wound dressings has been determined using the quantitative suspension test according to EN 13727 before. However, as suspension tests are not an accurate reflection of the conditions under which wound antiseptics are used, it was investigated if a disc carrier test would yield results simulating practical conditions on wound surfaces. A silver-leaching foam wound dressing was used for evaluation of the disc carrier test method. Method: The disc carriers consisted of circular stainless-steel discs measuring 2 cm in diameter and 1.5 mm in thickness, complying with the requirements of EN 10088-2. Carriers were contaminated with Staphylococcus aureus, methicillin-resistant S. aureus or Pseudomonas aeruginosa, respectively, together with an artificial wound secretion and left to dry at room temperature for 30 min. The wound dressings being tested were placed on the discs for the length of the exposure time, and after neutralization by thioglycolate in phosphate-buffered saline the number of surviving test organisms was then counted. The logarithmic reduction factor was calculated from the difference between the initial inoculum and the number of recovered test organisms. Results: The disc carrier test allowed determination of an antimicrobial efficacy in a realistic setting. It also imposed more stringent requirements on efficacy over time than the quantitative suspension test. The silver foam wound dressing showed a time-dependent antimicrobial efficacy. After 24-hour application time, the reduction factors against S. aureus, P. aeruginosa and the methicillin-resistant S. aureus were 1.9 ± 0.15, 2.1 ± 0.14 and 3.1 ± 0.18, respectively. Conclusion: The disc carrier test was a useful method for testing the antimicrobial efficacy of a foam silver dressing. The antimicrobial dressing exhibited an antimicrobial effect after 3 h and achieved a reduction >2 log against the tested bacterial strains in the presence of a simulated wound secretion after 24 h

Clinical Use of the Antiseptic Polihexanide for Genital Tract Infections

Background: In clinical practice, treatment of genital tract infections is based on administration of either antibiotics or antiseptics. While antibiotics may be applied systemically or topically, antiseptics may be applied only topically. In case of bacterial vaginosis (BV), antibiotic therapy may often be limited and side effects due to systemic administration may develop. Polihexanide (PHMB) is a promising option for the topical treatment of genital tract infections, in particular BV and vaginitis. Method: A systematic search for publications on the use of PHMB for the treatment of genital infections in two electronic databases was performed. Titles, abstracts and citations were imported into a reference database. Duplicates were removed and two reviewers assessed each identified publication separately. Results: Among a total of 204 references, 3 prospective randomized trials were identified. Two trials treated BV infections with PHMB in comparison to clindamycin as antibiotic standard therapy with no significant differences either in safety or in efficacy. The third controlled trial investigated the clinical efficacy of PHMB compared to placebo in the treatment of human papilloma virus. Patients treated with PHMB daily for up to 16-weeks showed significantly higher (52%) clearance of genital warts as compared to patients treated with placebo (4%). Conclusion: PHMB may be a clinically effective alternative for the treatment of BV and human papilloma virus. Although PHMB-based antiseptics are available since the late 90s, controlled trials to investigate its clinical potential for antiseptic treatment are scant. Clinical use of antiseptics for the treatment of infectious diseases should be explored and supported further

Efficacy of Different Carrier Gases for Barrier Discharge Plasma Generation Compared to Chlorhexidine on the Survival of Pseudomonas aeruginosa Embedded in Biofilm in vitro

Because of its antimicrobial properties, nonthermal plasma could serve as an alternative to chemical antisepsis in wound treatment. Therefore, this study investigated the inactivation of biofilm-embedded Pseudomonas aeruginosa SG81 by a surface barrier-discharged (SBD) plasma for 30, 60, 150 and 300 s. In order to optimize the efficacy of the plasma, different carrier gases (argon, argon admixed with 1% oxygen, and argon with increased humidity up to approx. 80%) were tested and compared against 0.1% chlorhexidine digluconate (CHG) exposure for 600 s. The antimicrobial efficacy was determined by calculating the difference between the numbers of colony-forming units (CFU) of treated and untreated biofilms. Living bacteria were distinguished from dead by fluorescent staining and confocal laser scanning microscopy. Both SBD plasmas and CHG showed significant antimicrobial effects compared to the untreated control. However, plasma treatment led to a higher antimicrobial reduction (argon plasma 4.9 log10 CFU/cm2, argon with admixed oxygen 3 log10 CFU/cm2, and with increased gas humidity 2.7 log10 CFU/cm2 after 300 s) compared to CHG. In conclusion, SBD plasma is suitable as an alternative to CHG for inactivation of Pseudomonas aeruginosa embedded in biofilm. Further development of SBD plasma sources and research on the role of carrier gases and humidity may allow their clinical application for wound management in the future

Pilot study on the microbial contamination of conventional vs. silver-impregnated uniforms worn by ambulance personnel during one week of emergency medical service

The antimicrobial impregnation of products used everyday, such as surfaces, textiles and clothing – including those used in hospitals – is increasing. In view of potential toxic and environmental risks for users and patients, a careful risk-benefit assessment must be conducted for each newly developed product impregnated or coated with antimicrobial agents, prior to marketing and manufacture

A study of low-energy transfer orbits to the Moon: towards an operational optimization technique

In the Earth-Moon system, low-energy orbits are transfer trajectories from the earth to a circumlunar orbit that require less propellant consumption when compared to the traditional methods. In this work we use a Monte Carlo approach to study a great number of such transfer orbits over a wide range of initial conditions. We make statistical and operational considerations on the resulting data, leading to the description of a reliable way of finding "optimal" mission orbits with the tools of multi-objective optimization

On Optimal Two-Impulse Earth-Moon Transfers in a Four-Body Model

In this paper two-impulse Earth-Moon transfers are treated in the restricted four-body problem with the Sun, the Earth, and the Moon as primaries. The problem is formulated with mathematical means and solved through direct transcription and multiple shooting strategy. Thousands of solutions are found, which make it possible to frame known cases as special points of a more general picture. Families of solutions are defined and characterized, and their features are discussed. The methodology described in this paper is useful to perform trade-off analyses, where many solutions have to be produced and assessed

International nosocomial infection control consortium (INICC) report, data summary of 36 countries, for 2004-2009

The results of a surveillance study conducted by the International Nosocomial Infection Control Consortium (INICC) from January 2004 through December 2009 in 422 intensive care units (ICUs) of 36 countries in Latin America, Asia, Africa, and Europe are reported. During the 6-year study period, using Centers for Disease Control and Prevention (CDC) National Healthcare Safety Network (NHSN; formerly the National Nosocomial Infection Surveillance system [NNIS]) definitions for device-associated health care-associated infections, we gathered prospective data from 313,008 patients hospitalized in the consortium's ICUs for an aggregate of 2,194,897 ICU bed-days. Despite the fact that the use of devices in the developing countries' ICUs was remarkably similar to that reported in US ICUs in the CDC's NHSN, rates of device-associated nosocomial infection were significantly higher in the ICUs of the INICC hospitals; the pooled rate of central line-associated bloodstream infection in the INICC ICUs of 6.8 per 1,000 central line-days was more than 3-fold higher than the 2.0 per 1,000 central line-days reported in comparable US ICUs. The overall rate of ventilator-associated pneumonia also was far higher (15.8 vs 3.3 per 1,000 ventilator-days), as was the rate of catheter-associated urinary tract infection (6.3 vs. 3.3 per 1,000 catheter-days). Notably, the frequencies of resistance of Pseudomonas aeruginosa isolates to imipenem (47.2% vs 23.0%), Klebsiella pneumoniae isolates to ceftazidime (76.3% vs 27.1%), Escherichia coli isolates to ceftazidime (66.7% vs 8.1%), Staphylococcus aureus isolates to methicillin (84.4% vs 56.8%), were also higher in the consortium's ICUs, and the crude unadjusted excess mortalities of device-related infections ranged from 7.3% (for catheter-associated urinary tract infection) to 15.2% (for ventilator-associated pneumonia). Copyright © 2012 by the Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved