Sanitation Effect of Gaseous Ozone in the Treatment of Experimental Infected Pancreatic Necrosis: Microbiological Evaluation

Introduction. Search for new means and methods of sanitation of the abdominal cavity remains significant related to growing antibiotic resistance of bacterial pathogens in surgical infection. This challenge is of particular relevance in the development of purulent complications of acute pancreatitis due to the complexity of radical control of the inflammation source.
The aim of the study was to evaluate outcomes of microbiological examination of peritoneal exudate, biopsies of the pancreas, arterial blood in the topical application of gaseous ozone for the treatment of experimental infected pancreatic necrosis.
Methods. This prospective experimental study included 43 laboratory animals - Soviet Chinchilla rabbits. Group 1 consisted of 13 animals, groups 2 and 3 consisted of 12 animals each. All animals were infected with pancreatic necrosis simulated using a clinical strain of A. baumannii. Sanitation relaparotomies were performed in 24 hours and 60 hours under anesthesia: with 0.9% sodium chloride solution in animals of group 1, with 0.02% aqueous solution of chlorhexidine bigluconate in animals of group 2, with ozone-oxygen gas mixtures in animals of group 3. The control group included six sham-operated animals. Animals were withdrawn from the experiment in 96 hours with taking samples for microbiological investigations.
Results. Animals of group 1 showed an increased frequency (from 23.1 to 100.0%, p=0.003) and degree (from 3.5 (3.0; 4.5) to 7.0 (5.5; 7. 5) lg COE/ml, p<0.001) of bacterial contamination of peritoneal exudate within 24 to 96 hours. Most parameters in animals of group 2 were not significantly different from those achieved in animals of group 1. Notably, the bacterial count of A. baumannii in the peritoneal exudate in 60 hours (6.0 (5.7; 6.7) lg COE/ml), and the degree of secondary (enterogenic) contamination of the pancreas (5.5 (5 .0; 6.7) lg CFU/g) and peritoneal exudate in 96 hours (7.7 (7.0; 8.0) lg CFU/ml) in animals of group 2 significantly exceeded those in animals of group 1 (p≤ 0.010). Intraperitoneal application of a directed flow of gaseous ozone in 24 and 60 hours allowed achieving elimination of A. baumannii in 80.0% of pancreatic biopsy samples by the end of the fourth day (p=0.002 and p=0.007 when compared with results of groups 1 and 2, respectively), prevent its spread into the peritoneal exudate and systemic circulation. The treatment with gaseous ozone was also accompanied by the decreased bacterial count of A. baumannii and the degree of secondary (enterogenic) contamination by other opportunistic microorganisms in the analyzed samples.
Conclusion. Perspectives for translating the results obtained into clinical practice determine the relevance of studying modern molecular methods of bacteriological analysis. This should be combined with an adequate assessment of the safety of various targeted treatment options of the abdominal tissues and organs with an ozone-oxygen gas mixture.