Bacteriophages and bacteriophage-derived endolysins as potential therapeutics to combat Gram-positive spore forming bacteria.

Since their discovery in 1915, bacteriophages have been routinely used within Eastern Europe to treat a variety of bacterial infections. Although initially ignored by the West due to the success of antibiotics, increasing levels and diversity of antibiotic resistance is driving a renaissance for bacteriophage-derived therapy, which is in part due to the highly specific nature of bacteriophages as well as their relative abundance. This review focuses on the bacteriophages and derived lysins of relevant Gram-positive spore formers within the Bacillus cereus group and Clostridium genus that could have applications within the medical, food and environmental sectors.

[Ability of acceptance for bacteriophages during verotoxin production by bacilli of the Enterobacteriaceae family]. / Zdolnosc akceptacji bakteriofagów warunkujacych produkcje verotoksyn przez paleczki z rodziny Enterobacteriaceae.

Lysogenised verotoxigenic strains are the source of structural genes of verocytotoxins (stx-1 and stx-2) for the others intestinal bacili. The aim of the study was to estimate the ability of transfer of bacteriophages induced with UV irradiation from reference verotoxigenic strains of E. coli O157:H7 (CB571 and EDL933) into 125 wild-strains of bacili of Enterobacteriaceae family. None of tested recipient strains showed the production of cytotoxin on Vero and HeLa cell lines, what was acknowledged as the lack of six genes. Contrary to the laboratory strain of E. coli C600 none of 125 tested recipient strains accepted the phages. Obtained lysogenised laboratory strains of E. coli C600/CB571 and E. coli C600/EDL933, besides of the ability to produce verotoxins (with the presence of stx-1 and stx-2 genes), did not differ phenotypically and genotypically from parent strain of E. coli C600. The estimation of the ability to transfer of phages carried stx-1 and/or stx-2 genes was impossible because of too small number of tested wild strain of bacili or because of really low frequency of acceptation of phages by wild strains of intestinal bacili.

[Adherence patterns of Escherichia coli strains isolated from children with diarrhea]. / Typy adhezji szczepów Escherichia coli izolowanych z przypadków biegunek.

Among enteropathogenic E. coli strains (EPEC) there are different patterns of adherence to the culture cells in vitro assay: localized, localized-like and diffuse. The adherence pattern is dependent on the ability of E. coli strains to cause of diarrhea. The strains locally adhering possess a 60 MDa plasmid--E. coli adherence factor (EAF), and produce characteristic histopathologic intestinal lesions linked with the presence of chromosomal eae gene. The pathogenicity of diffusely adherent as well as cells detaching E. coli (CDEC) remains controversial. The aim of the study was to identify the adherence patterns of E. coli strains isolated from children with diarrhea and to compare that patterns with the serotypes and the presence of EAF and/or pO157 plasmids, fimbriae and eae, stx1, and stx2 specific sequences. Nine out of examined E. coli strains showed the localized pattern of adherence. About half (46.8%) of strains were diffusely adherent and six isolates were cells detaching E. coli (CDEC). A total of 22 (23%) examined strains showed the presence of specific for verocytotoxins sequences. The results showed that many strains recognized on the ground of agglutination with specific EPEC antisera as unpathogenic could be an etiologic agents of diarrhea which are able to produce histopathologic lesions in the intestinal epithelium. In turn, many strains classified as EPEC could be unpathogenic on the basis of diffuse pattern of adherence.

[Characteristic of verotoxigenic strains of Escherichia coli]. / Charakterystyka verotoksycznych szczepów Escherichia coli.

The aim of the study was the isolation from faecal samples of patients with diarrhoea of verotoxigenic strains of E. coli (VTEC) on the basis of characteristic biochemical properties and production of enterohaemolysin and comparison of isolated verotoxigenic strains with reference strains of VTEC. For isolation of VTEC from 257 stool samples derived from patients with diarrhoea were used selective medium sorbiol--Mac Conkey agar (SMAC) and media supplemented with unwashed and washed in PBS sheep erythrocytes for detection of haemolysins of E. coli. In all haemolytic and sorbitolo-positive or -negative strains isolated from 93 stool samples were examined the activity of beta-glucuronidase using MUG (4-methylumbelliferyl-beta-D-glukuronid) as a substrate for that enzyme. All isolated haemolytic strains as well as reference VTEC were examined on Vero cell line. Verotoxigenic strains from examined samples were investigated by agglutination assay with antiserum to E. coli O157 and then with antisera to eneropathogenic E. coli (EPEC). After that they were examined with ID GN and ATB GN tests. In 93 (36.2%) examined samples there were haemolytic strains of E. coli which fermented or not sorbitol and were MUG-positive or negative. Only in 2 (0.2%) stool samples there were verotoxigenic strains of E. coli which were sorbiol-positive and MG-positive. Both strains belonged to O26 serotype and were derived from samples of two children with diarrhoea. Isolated verotoxigenic strains of E. coli O26 were susceptible on all tested antibiotics.

Phage types and plasmid profiles of Salmonella enteritidis strains.

112 strains of Salmonella enteritidis were tested according to phage typing method and plasmid profile analysis. 66 strains were classified as PT4, 29 strains as PT6 and 17 strains as PT10. The strains were differentiated into 17 groups according to plasmid profiles.