In vitro and in vivo evaluation of efficacy of citrate/methylene blue/parabens/IPA solution as a skin disinfectant.

OBJECTIVE: The objective of this study was to evaluate the bactericidal activity of a new antiseptic in an in vitro model using reference bacterial strains and on abdominal and inguinal skin of healthy human subjects. ZuraPrep (C/MB/P/IPA) contains citrate, methylene blue, parabens and isopropyl alcohol 70%. METHODS: In vitro and in vivo studies evaluate immediate and persistent activity of the tested solution using bovine rawhides inoculated with single strains of microorganisms and natural bacterial flora on skin of adult human subjects. Depending upon the anatomical site (abdominal or inguinal), several different configurations of test times were executed. Post-prep surface cultures were performed at 10 min and 6h after application of the test solution. RESULTS: Tested solution showed high efficiency in log reduction of viable microbes both in vitro and in vivo. Post-prep activity 10 min after application ranged from 2.5 to 3 log(10) reduction from baseline on abdominal sites and 3.5-4.5 on inguinal sites. Similar levels of reduction persisted 6h after application. CONCLUSION: The level of antisepsis provided by the tested solution is similar or greater than that obtained with other antiseptics currently in use, and further clinical testing of the new antiseptic is warranted.

Effect of a solution containing citrate/Methylene Blue/parabens on Staphylococcus aureus bacteria and biofilm, and comparison with various heparin solutions.

OBJECTIVES: Some antibiotic solutions increase bacterial resistance and may cause toxic side effects. Heparin, frequently used as an anticoagulant in catheter lock solutions, may cause bleeding and stimulate biofilm formation. The aim of this study was to investigate the effect of a new antibacterial/antithrombotic solution, citrate/Methylene Blue/parabens (C/MB/P), versus various heparin solutions on the viability and the structure of preformed mature biofilms of Staphylococcus aureus bacteria. The degree of eradication of both planktonic and sessile microorganisms was evaluated. METHODS: The changes in the structure of biofilms after exposure to C/MB/P and several concentrations of heparin were analysed by means of confocal laser scanning microscopy. COMSTAT image analysis was utilized to compare biofilm biomass, average and maximum height, surface coverage and roughness coefficient. Viability studies were performed on both biofilms and supernatant solutions. RESULTS: C/MB/P, in contrast to heparin solutions, significantly reduced biofilm biomass and thickness and reduced viability by 5 log when compared with saline treatment. No viable planktonic bacteria were detected and the few remaining biofilm cells appeared to be lysed. In contrast, most heparin solutions only reduced viability up to 1.0 log and failed to eradicate planktonic bacteria. CONCLUSIONS: C/MB/P has a rapid bactericidal effect on the preformed, mature biofilm of S. aureus. The structural changes of biofilms treated with C/MB/P, together with the observed log reduction of viable biofilm cells, confirmed the high potential of this solution to eliminate sessile bacteria. Furthermore, the tested solution entirely eliminated planktonic bacteria detached from the biofilm.

Microbial inactivation properties of a new antimicrobial/antithrombotic catheter lock solution (citrate/methylene blue/parabens).

BACKGROUND: Microbial infections are the most serious complications associated with indwelling central venous catheters. A catheter lock solution that is both antibacterial and antithrombotic is needed. The goal of this study was to determine whether a new catheter lock solution containing citrate, methylene blue and parabens has antimicrobial properties against planktonic bacteria and against sessile bacteria within a biofilm. These effects were compared to the antimicrobial properties of heparin at 2500 units/ml. METHODS: The tested solution (C/MB/P comprising 7% sodium citrate, 0.05% methylene blue and 0.165% parabens) and individual components were challenged against gram-positive and gram-negative organisms and fungi. Control solutions were heparin with preservatives. Studies included evaluation of eradication of planktonic bacteria and sessile organisms in a biofilm grown on polymeric and glass coupons. Biofilm samples were inspected by scanning electron microscopy, atomic force microscopy and vital stains. RESULTS: The C/MB/P solution, contrary to heparin, kills most tested planktonic microorganisms within 1 h of incubation. All tested organisms have an MIC of 25% or less of the original concentration of a new catheter lock. Bacteria strains did not develop resistance over more than 40 passages of culture suspensions. The C/MB/P solution is able to kill nearly all sessile bacteria in biofilm growth on plastic or glass discs in 1 h. Microscopic methods demonstrated extensive physical elimination of biofilm deposits from treated coupons. In contrast, heparin had a minimal effect on planktonic or biofilm organisms. CONCLUSIONS: The new multicomponent lock solution has strong antimicrobial properties against both planktonic and sessile microorganisms. By comparison, heparin with preservative has weak antibacterial properties against planktonic and biofilm bacteria. The tested catheter lock may have usefulness in preventing bacterial colonization of haemodialysis catheters and diminishing the incidence of catheter-related bacteraemia.

Catheter related bacteremia in rats: A preliminary report on the effect of methylene blue coated catheter.

The safety and efficacy of methylene blue (MB) coated indwelling jugular vein/cranial vena cava catheter made up of polyurethane material was tested in a rat model, receiving bacterial culture suspension of Pseudomonas aeruginosa, and Staphylococcus aureus. Daily blood samples were collected from the catheter and peripheral vein for bacterial culture. The clinical parameters (rectal temperature, respiratory rate, total white blood cell count, and loss in body weight) were not different between the groups. All the rats became bacteremic with similar changes in the number of colony forming units in the catheter and peripheral samples. Histopathological lesions were not different between the groups. The findings suggest that rats receiving MB coated catheters behaved similar to non-coated catheters. Based on the results it can be concluded that for this type of gross contamination, catheter coating alone may not eliminate infection/bacteremia.