Ocena skuteczności metod inwersji faz antygenów rzęskowych Salmonella

Expression of flagellar antigens is necessary to determine the complete antigenic structure of a Salmonella isolate. In many cases, this involves techniques that make it possible to select bacterial cells capable of expressing the currently inhibited antigen phase. The aim of the study was to compare the effectiveness of three available methods used for phase inversion of the flagellar antigens of Salmonella: Gard’s plate, Craigie’s tube and the paper bridge method. A total of 137 isolates with the expression of somatic antigen and only one of the two flagella phases were selected for the study. The three techniques identified Salmonella serovars in 83.2% (114/137) of the isolates tested. The paper bridge method proved to be the most effective technique, identifying inhibited antigens in 97.3% of isolates, followed by Gard’s plate and Craigie’s tube, which were successful in, respectively, 60.5% and 40.3% of cases. The specificity of each method was 100%. The test lasted 24 hours for all isolates tested by Gard’s plate method, from 48 to 96h in the paper bridge method, and at least 48 h in Craigie’s tube method. The results show that the paper bridge method is a simple and inexpensive technique of phase inversion, highly effective in Salmonella identification. However, if rapid identification is required, Gard’s plate can be used simultaneously with the paper bridge method, so that the test can be continued by the latter method if the expected result is not achieved within the first day.