[The characteristics of staphylococcal enterotoxins produced by strains isolated from mastitic cows, including epidemiological aspects]. / Charakterystyka enterotoksyn gronkowcowych wytwarzanych przez szczepy izolowane od krów z zapaleniem gruczolu mlekowego (mastitis), z uwzglednieniem elementów epidemiologicznych.

Staphylococcal enterotoxins (SEs) are big heterogenic group of exotoxins, rather differential in respect of their nucleotide and amino-acid homology, as well as the location of their genes, molecular weight and iso-electric point value. SEs were identified in 1959 as the extra-cellular proteins produced by some Staphylococcus aureus strains. These enterotoxins are known as the pyrogenic toxins and this group contains also other staphylococcal toxins (staphylococcal toxic-shock syndrome toxin--TSST-1, A and B exfoliative toxins and streptococcal scarlet fever toxin). Twenty one serological types of staphylococcal enterotoxins are distinguished. All of them are structurally and functionally similar to the toxic shock syndrome toxin (TSST-1). SEs are thermo-stabile proteins, resistant to many proteolytic enzymes (pepsin, trypsine, chymotrypsine, renine and papain), but this resistance depends on the temperature and pH. Staphylococcal enterotoxin-encoding genes are located as well in the chromosomal DNA, as on the pathogenicity island, in phages, transposones and plasmids. Enterotoxins are staphylococcal virulence factors responsible for food poisonings in humans. These proteins are also isolated from cows with mastitis. In various countries, the percentage of enterotoxin-producing S. aureus strains ranges from 5 to 60%, depending on the enterotoxine type. The variability and prevalence of enterotoxins produced by staphylococci isolated from mastitic cows is very important clinical and epidemiological problem. The analysis of enterotoxins interrelations, their structure, properties and occurrence, will provide better revealing their role in the emerging, development and spreading of human and animal diseases. Classical enterotoxins, as well as the new types of these proteins, are variable element of staphylococcal virulence that connects the occurence of mastitis with human food poisonings.

[Using the PCR-RFLP method for comparative analysis of the pathogenic Escherichia coli strains]. / Wykorzystanie techniki PCR-RFLP do porównawczej analizy wybranych chorobotwórczych paleczek Escherichia coli.

The purpose of the study was to identify differences and similarities between Escherichia coli strains which do or do not utilize disaccharide sucrose by PCR-RFLP method. Investigations were done on chromosomal DNA level using cscA gene associated with conservative sequences. The cscA gene may be found in all of the analysed strains. Genotypic analysis demonstrated presence of the same restriction model consisted of 2 DNA fragments with size of 161 bp and 110 bp in all of E. coli strains. Results of these investigations have shown that there are no differences between E. coli strains.

[Virulence of Yersinia pseudotuberculosis strains isolated from environment as a threat to human epidemic]. / Zjadliwosc szczepów Yersinia pseudotuberculosis wyizolowanych ze srodowiska zewnetrznego, w kontekscie zagrozenia dla czlowieka.

The purpose of the work has been to identify Yersinia pseudotuberculosis strains and to demonstrate their potential pathogenicity using PCR reaction. Investigations included 167 samples of the water and 32 samples of the soil from westpomeranian region. Based on the analysis of PCR reactions the research confirmed the presence of DNA Y. pseudotuberculosis strain in 6 of the water samples and in 1 of the soil sample. The strains have been identified by nucleotide sequence of the ypm gene, which is specific only for mentioned species. Genotypic analysis demonstrated also the presence of genes, which confirmed their virulence. The PCR reaction should be used in the microbiological diagnostic of Y. pseudotuberculosis strains, isolated from animals and from environment, because it is very specific, fast and sensitive method.