Efficacy of Wound Cleansers on Wound-Specific Organisms Using In Vitro and Ex Vivo Biofilm Models.

Biofilms are believed to be a source of chronic inflammation in non-healing wounds. PURPOSE: In this study, the pre-clinical anti-biofilm efficacy of several wound cleansers was examined using the Calgary minimum biofilm eradication concentration (MBEC) and ex vivo porcine dermal explant (PDE) models on Pseudomonas aeruginosa, methicillin-resistant Staphylococcus aureus (MRSA), and Candida albicans biofilms. METHODS: A surfactant-based cleanser and antimicrobial-based cleansers containing ionic silver, hypochlorous acid (HOCl), sodium hypochlorite (NaOCl), and polyhexamethylene biguanide (PHMB) were tested on the MBEC model biofilms with a 10-minute application time. Select cleansers were then tested on the mature PDE biofilms with 10-minute applications followed by the application of cleanser-soaked gauze. The PDE model was further expanded to include single and daily applications of the cleansers to mimic daily and 72-hour dressing changes. RESULTS: In the MBEC model, PHMB- and HOCl-based cleansers reduced immature MRSA, C albicans, and P aeruginosa biofilm regrowth by > 3× when compared with silver, surfactant, and saline cleansers. The major differences could be elucidated in the PDE model in which, after daily application, 1 PHMB-based cleanser showed a statistically significant reduction (3-8 CFU/mL log reduction) in all mature biofilms tested, while a NaOCl-based cleanser showed significant reduction in 2 microorganisms (3-5 CFU/mL log reduction, P aeruginosa and MRSA).The other PHMB-based cleanser showed a statistically significant 3 log CFU/mL reduction in P aeruginosa. The remaining cleansers showed no statistically significant difference from the saline control. CONCLUSION: Results confirm that there are model-dependent differences in the outcomes of these studies, suggesting the importance of model selection for product screening. The results indicate that 1 PHMB-based cleanser was effective in reducing mature P aeruginosa, MRSA, and C albicans biofilms and that sustained antimicrobial presence was necessary to reduce or eliminate these mature biofilms.

Contamination levels of in-use disinfectants in a teaching hospital in Lagos, Nigeria.

In-use testing of the disinfectants; Hibitane (5% w/v Chlorhexidinegluconate), Hibiscrub (4% w/v Chlorhexidinegluconate), Savlon (3% w/v Chlorhexidine/Cetrimide), hydrogen peroxide (6% w/v hydrogen peroxide with stabilizer) and a common household bleach Jik (3.5% w/v sodium hypochlorite), was carried out over a two-month period at a university teaching hospital in Nigeria. Contamination levels were high with 82 (63.1%) of the 130 in-use disinfectants contaminated. However, a few of the stock solutions remained sterile. One hundred and thirty-four isolates were obtained of which 120 (91%) were gram-negative with Pseudomonas species being the commonest, constituting 67.2% of all the isolates. Gram-positive organisms made up the remaining 12 (9.0%) isolates. All the Pseudomonas spp. were resistant to gentamicin, ceftazidime, nalidixic acid and perfloxacin. Contributory factors for the high contamination levels were dilution of disinfectants with tap water, inadequate care of stock solution bottles and long storage of the diluted disinfectants in the wards.

The oral clearance of chlorhexidine solutions and gels.

The oral clearance of 4 chlorhexidine (CH) preparations was investigated. Two 0.2% CH-solutions, Plak-Out liquid, a 10% alcoholic CH-solution and an aqueous ICI-Hibitane solution were compared with two chlorhexidine gels, Corsodyl gel (0.1%) and a test CH-gel (1.0%) prepared in this laboratory. Thirty subjects, 17 to 57 years of age and exhibiting a variety of oral hygiene conditions, participated in supervised rinsing with CH-solutions and toothbrushing with gels carried out at weekly intervals to eliminate carry-over effects. Mixed saliva samples were taken 7.5, 15, 30, 60 and 120 minutes following each administration and were analysed spectrophotometrically. The relative oral CH-retention values were for Plak-Out liquid 91%, aqueous Hibitane solution 69%, Corsodyl gel 46% and with the laboratory chlorhexidine gel 37%.