The objective of this study was to provide an epidemiological characterisation of rough Salmonella strains and to evaluate their genetic relationship with some representatives of serovars noted in animals. Genome macrorestriction by means of pulsed field gel electrophoresis of 57 rough strains revealed 8 groups showing high genetic similarity to the profiles observed in Salmonella Enteritidis, Salmonella Mbandaka, Salmonella Typhimurium, Salmonella Goldcoast, Salmonella Infantis, Salmonella Hadar, Salmonella Oranienburg and Salmonella Derby. Some of them showed profiles indistinguishable from the representatives of the above- -mentioned serovars. These included also the most numerous group of “Salmonella Enteritidis-like” strains. This proves epidemiologic relationships within this group as well as with the reference strains, representing serovars found in animals. It was concluded that the molecular typing of rough strains provides additional epidemiological information and could sufficiently support routine Salmonella diagnostics, including autoaglutinating isolates.
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.
Monophasic Salmonella Typhimurium (1,4,[5],12:i:-), a worldwide emerging pathogen, has been occurring in Poland since 2008. Characterization of swine, cattle, geese, food, feed and human isolates obtained in the years 2011-2012 by pulsed field gel electrophoresis, antimicrobial resistance typing with microbroth dilution method was performed for the evaluation of their epidemiological importance for human public and animal health. The prevalence of monophasic Salmonella Typhimurium in Poland has recently increased and its proportion to classical biphasic variants reached 15.5% in 2012. The isolates revealed microbiological resistance to at least one tested compound and ten resistance profiles were found. The most frequent profile covered resistance to ampicillin, streptomycin, sulphonamides and tetracycline. Fourteen XbaI-PFGE profiles with an overall similarity of 52.4% were noted. Most of the isolates were classified to two PFGE profiles showing a 95.4% similarity. Finding of monophasic S. Typhimurium originating from people within the same XbaI-PFGE profile comprising also swine and cattle isolates indicate a possible role of animal sources in the spread of this pathogen.
Data collection on the occurrence of Salmonella along the food chain is an important element of the implementation of Salmonella control programs in EU Member States. Consequently, it is possible to evaluate the current epidemiological situation and trends of infection over time, as well as identify the sources and routes of the pathogen’s spread. The article presents the occurrence of Salmonella serovars in the years 2005-2010 in Poland and shows their epidemiological significance as a cause of infections in animals. Slide agglutination was used to identify Salmonella serovars of 5264 isolates originating from animals, foods, feeds, organic fertilizers and sewage sludge. A decrease in the occurrence of Salmonella Enteritidis and Salmonella Typhimurium in poultry was found, probably as a consequence of the implementation of national control programs in breeding flocks of Gallus gallus, laying hens, and broilers. Simultaneously, the epidemiological impact of other serovars, such as S. Mbandaka or S. Kentucky has increased. During the last six years Salmonella Typhimurium, Enteritidis and Derby were the most frequently found serovars in pigs. The swine-specific S. Choleraesuis as well as S. Bredeney, S. Goldcoast, S. Infantis, S. Hadar, S. Mbandaka and autoagglutinating isolates were found in less than 10% of investigated isolates. Serovars S. Typhimurium and S. Enteritidis were most prevalent in geese and ducks. Occurrence of the same Salmonella serovars in humans and animals and food might indicate their epidemiological links . There was no explicit domination of particular Salmonella serovars in isolates from feed and the environment of their production. Eight out of ten of the most prevalent Salmonella serovars for animals and humans were found in organic fertilizers and sewage sludge, which confirmed the crucial role of animal reservoirs in the circulation of this pathogen in nature. The presented epidemiological data might also be useful in laboratories for the selection of diagnostic sera for Salmonella identification and thus improve their work.
Standard Salmonella isolation procedure is focused on the detection of strains showing properties typical for Salmonella enterica subsp. enterica. The paper describes a case of the isolation of sucrose-fermenting Salmonella Anatum strain. Atypical biochemical properties might influence the sensitivity of method used in Salmonella diagnostics. The performed comparison study revealed the unique property of Salmonella Anatum strains. Compared to other Salmonella strains those strains degradated a higher number of carbohydrates and alcohols. But in contrast to other serovars they were not lysed by Salmonella specific bacteriophage O-1. A relatively low antimicrobial resistance provides the possibility for effective treatment of Salmonella Anatum infections in humans. Recently Salmonella Anatum strains have been isolated along the food chain and from humans in several European countries. Therefore the authors draw attention to the possible public health implications of Salmonella Anatum occurrences.