Silvazine™ (silver sulfadiazine and chlorhexidine) activity against 200 clinical isolates

The study was undertaken to examine the in vitro efficacy of Silvazine™ against micro-organisms commonly found in burn wounds. Two hundred non-replicative sequential clinical isolates were collected over a 2-month period. These comprised 50 Staphylococcus aureus (methicillin sensitive), 50 Staphylococcus aureus (methicillin resistant), 50 coagulase negative staphylococci and 50 Pseudomonas aeruginosa. As there is no standard test method, the method chosen was a pour plate overlay of micro-organisms placed on a Mueller Hinton base containing duplicate wells of 0.1 ml Silvazine™. Plates were incubated at 35°C for up to 48 h prior to examination. All organisms tested showed zones of growth inhibition. The mean diameters of the zones of growth inhibition were similar within genera. S. aureus 19.7 ± 1.6 mm, MRSA 16.9 ± 1.6 mm, P.aeruginosa 15.3 ± 1.1 mm and coagulase negative staphylococci 20.8 ± 2.1 mm. There was no bacterial regrowth within the zones of growth inhibition following long-term plate storage. In vitro testing of Silvazine™ has confirmed its efficiency against common burn wound isolates.