Increased Antibacterial Activity of Cephalosporins against Francisella Tularensis

Abstract

The aim of the study is to determine the effect of surfactants on the level of resistance of tularemia microbe to ß-lactam antibiotics (penicillins and cephalosporins). Material and methods. 26 strains of F.tularensis of the three main subspecies were used in the study. The effect of surfactants on the resistance of bacteria to ß-lactam antibiotics was studied by serial dilutions in a dense nutrient medium with and without subinhibitory concentrations of detergents. Results. It was shown that cationic and anionic detergents do not affect the resistance of F.tularensis to third generation cephalosporins. It was found for the first time that nonionic detergents significantly reduce the level of natural resistance of F.tularensis to cephalosporins (10-20 times). Moreover, all studied surfactants did not lead to a decrease in the resistance of the tularemia pathogen to ampicillin. An analysis of the results on the different effects of nonionic detergents on the resistance of the tularemia pathogen to penicillins and cephalosporins suggests that F.tularensis resistance to these antibiotics is formed by various mechanisms. The use of ceftazidime in combination with nonionic detergents in experimental tularemia in white mice led to an improvement in the effectiveness of etiotropic treatment of infection. Taking into account the urgency of improving the schemes of etiotropic therapy of infectious diseases caused by antibiotic-resistant forms of pathogens, it seems promising to continue the study in this direction.