Experimental investigation of the effectiveness of local application of a combination of antiseptic and anesthetic on the model of contaminated wound

Abstract

Annotation. A high risk of infections in surgery is associated with microbial contamination with opportunistic microorganisms Staphylococcus aureus. Objective: to study the antimicrobial and analgesic effect of decamethoxine combined with lidocaine applied locally to the model of a postoperative infectious wound. Fifty-two male rats weighing 250-300 grams were randomly divided into four groups. We modeled surgical wounds in the interscapular area, and then injected a suspension culture of S. aureus 47 (dose 108 CFU/ml) into the wounds. On the 2nd, 3rd, 7th and 10th day of the experiment, the wounds contaminated with staphylococcal culture were treated with 3 ml doses of the tested drugs: 0,9% saline in the control group (group A, n=13), 0,02% decamethoxine antiseptic (DCM) (group B, n=13), 10% lidocaine (group C, n=13) and their combination in the 1:1 ratio (group D, n=13). On days 3, 7 and 10, the wound area in each group was determined using contour planimetry by the L.N. Popova method and the average area (M±m) and the percentage of reduction in wound area from the initial size were calculated. The antimicrobial efficacy of the antiseptic and anesthetic was evaluated on days 3, 5, 7 and 10 using a standard microbiological study of the number of microorganisms in the wounds, the numerical values of which were expressed as the decimal logarithm of colony-forming units per ml (lg CFU / ml). To study the analgesic activity of DCM and 10% lidocaine in animals, the minimum threshold of pain sensitivity in the wound was determined using calibrated Von Frey monofilaments (VFMs). Statistical processing was performed using standard biometric methods. Differences at p<0.05 were considered significant. Results: As a result of microbiological examination of the wound surface, it was found that the number of S. aureus on the wound surface significantly decreased on the 5th day when using decamethoxine alone and in combination with lidocaine 10%. The use of antiseptic and its combination with lidocaine on the 10th day revealed almost complete eradication of S. aureus on the wound surface compared to the control group (p<0.01). When applying the combined antiseptic with lidocaine, it was found that the threshold of pain sensitivity increased by 12.2 times, which was practically no different from that of lidocaine monotherapy (11.9%). It was found that the healing and wound epithelization rate was the highest in group D (71.12% of the baseline). So, the combination of antiseptic with lidocaine 10% in the treatment of wounds has a high antimicrobial efficacy with a pronounced anesthetic effect. Thus, it opens the prospect of combined local use of antiseptic and anesthetic in the treatment of wounds.