In vivo comparison of two silver sulfadiazine antimicrobial agents on burn wound infection.

A controversy exists with regard to the relative efficacy of two preparations of silver sulfadiazine (AgSD), Silvadene and Flint's Silver Sulfadiazine Cream. We compared the susceptibility of Staphylococcus aureus and clinical Gram-positive cocci, Gram-negative rods, and mixed floral isolates by the Nathan's agar well diffusion method and found no differences. However, when S aureus-infected rat burn wounds were treated with these antimicrobial creams over a period of ten days, Silvadene significantly lowered bacterial counts, whereas results after treatment with Flint's Silver Sulfadiazine Cream were no different from those of the control group, which received no treatment. These data imply that Silvadene controls S aureus-generated burn wound infections better than the Flint product.

The role of thromboxane in experimental inadvertent intra-arterial drug injections.

Inadvertent intra-arterial injection of drugs produces a well-defined clinical syndrome whose pathophysiology remains unclear. This study was designed to determine the role of the inflammatory mediator, thromboxane, in intra-arterial drug injections. The rabbit ear model, as described by Kinmonth and Sheppard, was used. Five of the experimental groups were treated with specific or nonspecific thromboxane blocking agents and two groups served as controls. Immunohistochemical staining of the control ears showed elevated levels of thromboxane within the first 6 hours postinjury. The specific thromboxane blocking agents, methimazole and Aloe vera, showed almost complete blockade of thromboxane production. The percentage of ear survival was significantly greater in the group treated with topical Aloe vera (p less than 0.05) and even greater survival was achieved in the combined Aloe vera/methimazole group (p less than 0.01). On the basis of these results, we have begun treatment of such injuries with specific and nonspecific thromboxane blocking agents.

Control of burn wound sepsis: a comparison of in vitro topical antimicrobial assays.

The Minimal Inhibitory Concentration (MIC) and the Nathan's Agar Well Diffusion (NAWD) tests are bacterial antimicrobial susceptibility predictors. Some suggest that the NAWD is not as reliable as the MIC test. We compared the MIC and NAWD tests as to how well they agree to bacterial sensitivity or resistance and predicted clinical outcome of burn wound infections. Using 65 bacterial isolates from burned patients, the MIC and NAWD tests agreed in 60.0% of the isolates (vs. a perfect agreement of 100%, p less than 0.001), implying that these tests are not interchangeable. From 18 burned patients treated with nitrofurazone or mafenide acetate, 28 infectious isolates were evaluated. The outcome of these infections was correctly predicted by NAWD in 92.8% and the MIC in 72.0% of the cases (p less than 0.05). It seems that for burns treated with topical antimicrobials, the NAWD is a more reliable predictor of bacterial susceptibility.

Effect of medium temperature on recovery of gonococci.

The temperature of the isolation medium exerted no significant effect on the rate of positive cultures for Neisseria gonorrhoeae. However, significantly more colonies were obtained on ambient-temperature medium than on cold (4C) medium. A small number of specimens (six) failed to grow on cold medium but grew on ambient-temperature medium. Viable counts showed essentially no effect of medium temperature on the nondiscriminating strain, a 90% reduction on the cold medium for the cold-intolerant strain, and for the strains with warm medium preference, about twice as many colonies on warm as on cold or ambient-temperature medium.