[Personal experience in testing for E. coli enterotoxigenicity]. / Nase skúsenosti z testovania enterotoxinogenity u kmenov E. coli.

When testing the production of the thermolabile enterotoxin by strains of E. coli, using six different methods, the highest positivity (100%) was recorded when using the modified test of oedema on mouse paws and the lowest one (5%) when using the Biken test. The strains were isolated from diarrhoeal infections in young children.

[Killing of seroresistant plasmid bearing E. coli strains in polymorphonuclear leukocytes]. / Usmrcovanie sérorezistentných kmenov E. coli vybavených plazmidmi v polymorfonukleárnych leukocytoch.

Killing of 61 seroresistant E. coli strains equipped with virulence plasmids (F, Ent, Hly, Col) and resistance plasmids (R) in polymorphonuclear leukocytes (PMNL) of healthy donors was determined by the cultivation plate and fluorescence methods of phagocytosis. Killing of the control E. coli strain K12 which does not possess any plasmids was studied by the fluorescent method. Compared to the fluorescent method, the cultivation plate method yielded a significantly higher killing rate of the bacteria after opsonization by 5% (p less than 0.05) and concentrated serum (p less than 0.001). Compared to the control E. coli strain K12, the killing rate of seroresistant E. coli strains in PMNL of healthy donors was significantly lower (p less than 0.001).

[Evaluation of phagocytosis of alpha hemolytic strains of Escherichia coli using the fluorescence method]. / Hodnotenie fagocytózy alfa hemolytických kmenov Escherichia coli fluorescencnou metódou.

The authors investigated phagocytosis in 37 alpha haemolytic strains of E. coli by the fluorescent method, after opsonization of bacteria with 5% and concentrated human serum. The strains were isolated from infants with gastrointestinal and extraintestinal infections and belonged to eleven serogroups. During opsonization of the strain with concentrated serum, as compared with opsonization of strains with 5% serum, higher rates of killing were recorded. As compared with a control strain of E. coli K12 after opsonization with concentrated serum in the examined strains the value of killing was on average by 20% lower. Differences in the killing of examined strains were recorded also within a single serogroup which may be ascribed to the different provision of strains with plasmids.

[Escherichia coli in diarrheal disease in young children]. / Escherichia coli pri hnackových ochoreniach malých detí.

The authors describe a lower incidence of enteropathogenetic serogroups of Escherichia coli (EPEC) in 1981-1987. Of 85 EPEC strains tested for the presence of factors of virulence (fimbrim, enterotoxins, haemolysins, colicins) and factors of virulence against six antimicrobial substances (tetracycline, streptomycin, chloramphenicol, kanamycin, ampicillin, sulfamethoxidine) only three strains did not possess any of the mentioned factors. The authors draw attention to other pathogenetically important groups of E. coli in the aetiology of diarrhoea in young children.