Therapeutic efficacy of three silver dressings in an infected animal model.

The organic salt AgNO3 has been available as a topical armamentarium to the medical arena for centuries and for burns for the past 60 years. Thirty-five (1968) years later, Charles Fox introduced and popularized a new topical agent known as silver sulfadiazine. More recently, several new slow-release silver dressings came to the forefront. Acticoat (Smith & Nephew, Largo, FL) Silverlon (Argentum, Lakemont, GA) & Silvasorb (Medline Industries, Inc, Mundelein, IL). Because the standard of care is to change dressings daily, our study focused in on weekly dressing changes as a cost-containment issue. Sprague-Dawley rats received a standard contact burn (20% TBSA). On day 3, the wound was excised and infected with Pseudomonas aeruginosa and Staphylococcus aureus at 5.0 x 10 cfu/ml. The animals were divided into four groups (n = 5 each group): untreated control, Acticoat group, Silvasorb group, and Silverlon group. The dressings remained on the wounds for 10 days when the wounds were quantitatively assessed. Mean wound counts of the control ranged from 1.2 x 10(5) to 6.5 x 10(5) for P. aeruginosa and S. aureus, respectively. Acticoat dressing counts for both organisms were 0 and 1.8 x 10(3) (median alpha); Silvasorb was 0 and 6.3 x 10(3) and Silverlon was 1.5 x 10(4) x 7.4 x 10(4) (median), Acticoat and Silvasorb were both significantly lower (P < .05) than the control for P. aeruginosa, and Acticoat was significantly lower (P < .05) than the control for S. aureus. Although counts for Silvasorb (M) appear significantly lower than the controls for S. aureus, the numbers were not sufficient to be significant. However, Silverlon did achieve a slight significance. These preliminary data suggest that weekly dressing changes with these new silver dressings are feasible and economically and medically congruous.

The effectiveness of processed grapefruit-seed extract as an antibacterial agent: I. An in vitro agar assay.

OBJECTIVES: Grapefruit-seed extract (GSE) Citricidal has, in recent reports, been reported to be successful in combating a variety of common infectious agents. In our study, drops of concentrated grapefruit-seed extract were tested for antibacterial properties against a number of gram-positive and gram-negative organisms. DESIGN: Sixty-seven (67) distinct biotypes were tested for their susceptibilities to the GSE as well as to 5 other topical antibacterials (Silvadene, Sulfamylon, Bactroban, Nitrofurazone, and Silvadene, Nystatin). Wells were punched into Mueller-Hinton agar plates, which were then inoculated with the organism to be tested; each well was then inoculated with one of the antibacterial agents. After an overnight incubation period, the plates were checked for zones of bacterial susceptibility around the individual wells, with a measured susceptibility zone diameter of 10 mm or more considered a positive result. RESULTS: The GSE was consistently antibacterial against all of the biotypes tested, with susceptibility zone diameters equal to or greater than 15 mm in each case. CONCLUSIONS: Our preliminary data thus suggest an antibacterial characteristic to GSE that is comparable to that of proven topical antibacterials. Although the GSE appeared to have a somewhat greater inhibitory effect on gram-positive organisms than on gram-negative organisms, its comparative effectiveness against a wide range of bacterial biotypes is significant.

The effectiveness of processed grapefruit-seed extract as an antibacterial agent: II. Mechanism of action and in vitro toxicity.

OBJECTIVES: Recent testimonials report grapefruit-seed extract, or GSE (Citricidal) to be effective against more than 800 bacterial and viral strains, 100 strains of fungus, and a large number of single and multicelled parasites. This study investigated GSE for antibacterial activity at varying time intervals and concentration levels and tissue toxicity at varying concentrations in an effort to determine if a concentration existed that was both microbicidal and nontoxic and in what period of time. DESIGN: Gram-negative and gram-positive isolates were introduced into graduated dilutions of GSE (twofold concentrations ranging from 1:1, through 1:512) for determination of bacterial activity. In vitro assays with human skin fibroblast cells were also performed at the same dilutions to determine toxicity. RESULTS: These tests indicated that from the 1:1 through the 1:128 concentrations, GSE remained toxic as well as bactericidal. However, test results indicated that at the 1:512 dilution, GSE remained bactericidal, but completely nontoxic. CONCLUSIONS: The initial data shows GSE to have antimicrobial properties against a wide range of gram-negative and gram-positive organisms at dilutions found to be safe. With the aid of scanning transmission electron microscopy (STEM), the mechanism of GSE's antibacterial activity was revealed. It was evident that GSE disrupts the bacterial membrane and liberates the cytoplasmic contents within 15 minutes after contact even at more dilute concentrations.