The MBEC™ Physiology & Genetics Assay recently became the first approved ASTM standardized biofilm disinfectant efficacy test method. This report summarizes the results of the standardization process using Pseudomonas aeruginosa biofilms. Initial ruggedness testing of the MBEC method suggests that the assay is rugged (i.e., insensitive) to small changes to the protocol with respect to 4 factors...

The effects of long-chain (C(12) to C(18)) quaternary ammonium compounds (QACs) on the density, heterotrophic activity, and biodegradation capabilities of heterotrophic bacteria were examined in situ in a lake ecosystem. Monoalkyl and dialkyl substituted QACs were tested over a range of concentrations (0.001 to 10 mg/liter) in both acute (3 h) and chronic (21 day) exposures. In general, none of...

When applied within a low-strength electric field (+/- 12 V/cm) with a low current density (+/- 2.1 mA/cm2), several industrial biocides exhibited enhanced killing action against Pseudomonas aeruginosa biofilms grown on stainless steel studs. Biocide concentrations lower than those necessary to kill planktonic cells of P. aeruginosa (1, 5, and 10 ppm of the active ingredients of kathon, glutara...

Electrostatic calculations based on the recently solved crystal structure of acetylcholinesterase (acetylcholine acetylhydrolase, EC 3.1.1.7) indicate that this enzyme has a strong electrostatic dipole. The dipole is aligned with the gorge leading to its active site, so that a positively charged substrate will be drawn to the active site by its electrostatic field. Within the gorge, aromatic si...

BACKGROUND The history of the investigation of standardized mycobactericidal activity of disinfectants and antiseptics is not very long. There is growing interest among the manufacturers of disinfectants in carrying out research on the antimicrobial activities in accordance with European standards (EN). This research could facilitate the introduction of high-quality disinfectants to the market....

This study investigated the ability of fifteen disinfectants to eliminate pig-associated Salmonella, specifically focusing on monophasic Salmonella Typhimurium (S. 4,5,12:i:-). The study included three m-cresol, one glutaraldehyde/ formaldehyde, four glutaraldehyde/quaternary ammonium compounds (QAC), two iodine, two peracetic acid and three potassium peroxomonosulphate-based commercial disinfe...

The resistance of bacterial biofilms to physical and chemical agents is attributed in the literature to various interconnected processes. The limitation of mass transfer alters the growth rate, and physiological changes in the bacteria in the film also appear. The present work describes an approach to determination of the mechanisms involved in the resistance of bacteria to quaternary ammonium ...

A total of 74 methicillin-resistant Staphylococcus aureus (MRSA) strains isolated from three government hospitals in 2002 and 2003 were examined concerning the distribution of qacA/B gene, which is the determinant of resistance to quaternary ammonium compounds largely employed in hospital disinfection. By polymerase chain reaction the qacA/B gene was found in 80% of the isolates, which is a sig...

BACKGROUND Health care-associated infections (HAIs) are a significant problem in hospitals, and environmental surfaces have been implicated as a source of HAIs in the hospital environment. Furthermore, Gram-negative and Gram-positive bacteria can persist on dry environmental surfaces for as long as several months. Poorly cleaned surfaces may serve as vehicles for microbes, which may then be tra...

BACKGROUND We were alerted to increased rates of Clostridium difficile-positive tests at all 3 hospitals in our health care system by MedMined Data Mining Surveillance Service, CareFusion (San Diego, CA). In response, an intervention of terminal room cleaning with dilute bleach was instituted to decrease the amount of C difficile environmental spore contamination from patients with C difficile ...