Fimbriation, surface hydrophobicity and serum resistance in uropathogenic strains of Escherichia coli.

A total of 80 Escherichia coli strains were examined for expression of P-fimbriae, mannose-sensitive haemagglutination (MSHA) and mannose-resistant haemagglutination (MRHA) of human group A erythrocytes and guinea pig erythrocytes, cell surface hydrophobicity and resistance to serum bactericidal activity. Isolates were obtained from urine of children and adults, either with acute pyelonephritis (n = 15 and n 12) or lower urinary tract infection (UTI) (n = 30 and n = 23, respectively). Results obtained showed that, in E.

Virulence-associated factors in Escherichia coli strains isolated from children with urinary tract infections.

One hundred and sixty-eight strains of Escherichia coli were isolated from cases of pyelonephritis (24) and lower urinary tract infections (UTI) (144) from hospitalised and outpatient children up to 2 years old. These strains were investigated for the expression of P fimbriae (PF), mannose-resistant and mannose-sensitive haemagglutination, cell-surface hydrophobicity, serum resistance and the production of alpha-haemolysin (AH), colicins and aerobactin. PF, AH, aerobactin production and serum resistance were significantly more frequent amongst strains expressing mannose-resistant haemagglutination.

Characteristics of Pseudomonas aeruginosa strains isolated from urinary tract infections.

Thirty-three uropathogenic strains of Pseudomonas aeruginosa were investigated for hemolytic activity in both bacterial broth culture filtrates and isolate lyzates, resistance to bactericidal activity of fresh human serum, resistance to six antibiotics and plasmid DNA profile. Twenty-four of the 33 (73%) bacterial filtrates showed lysis of rabbit erythrocytes, as did the three after guinea-pig erythrocyte treatment. Twelve of 33 isolate lysates showed in parallel lysis of both types of erythrocytes used.

[Verotoxin as an important factor in the virulence of E. coli strains].

Verotoxin as a factor of virulence of E. coli strains is involved in the pathogenesis of hemorrhagic colitis, hemolytic-uremic syndrome and thrombotic thrombocytopenic purpura. The most frequent producers of verocytotoxin are E.

[Sorbitol-negative E. coli 016 in a 10-year-old child diagnosed with hemolytic-uremic syndrome and in his asymptomatic father].

In Escherichia coli strains isolated from faeces and smears from the rectum in haemolytic-uraemic syndrome of a child and healthy relatives the authors assessed the biochemical activity, antigenic characteristic, sensitivity to twelve antimicrobial substances and factors of virulence. Sorbitol negative strains were isolated from the ill child and his father. The strains belonged into serogroup 016.

Enterohaemolysin production in Escherichia coli strains.

Enterohaemolysin production was found in 11 (20.3%) out of 54 Escherichia coli strains isolated from stools of infants with dyspepsia and in 3 (2.3%) out of 130 E.

[Virulence factors in strains of Escherichia coli isolated in urinary tract infections].

In 21 strains of E. coli isolated from patients with cystitis and asymptomatic bacteriuria the authors assessed the group, mannososensitive and mannoresistant agglutination of human, bovine, chick, guinea pig, sheep and pig erythrocytes, the production of haemolysis, colicins, aerobactin, the capacity of strains to induce oedema on mouse paws, the lethal effect in mice, the resistance to tetracycline, streptomycin, chloramphenicol, kanamycin, ampicillin and sulfamethoxidine, the transmission of resistance and sensitivity of strains to the action of fresh human serum. In ten strains the authors recorded also the production of haemolysin and the lethality for mice, in four strains the production of colicin V.

Killing of alpha-haemolytic and non-haemolytic Escherichia coli strains in human serum and polymorphonuclear leucocytes.

The role of alpha-haemolysin (AH) in the resistance of Escherichia coli strains, isolated from patients with extra-intestinal diseases or diarrhoea, to the bactericidal activity of human serum and intracellular killing in polymorphonuclear leucocytes (PMNL) was investigated in vitro. Sets of alpha-haemolytic and non-haemolytic E. coli strains and sets of isogenic E.

[New findings on alpha-hemolytic strains of E. coli in urinary tract infections. II. Antigen structure, resistance, production of colicins and siderophores].

Alphahaemolytic uropathogenic strains of E. coli (UPEC) belong mostly into the serogroup 04, 06, 018 and 075. UPEC are resistant against antibacterial substances and against the bactericide action of serum.

[New findings on alpha-hemolytic strains of E. coli in urinary tract infections. I. alpha-hemolysin and adhesins].

Alphahaemolysin (AH) is one of the important factors of virulence of E. coli strains in urinary infections. The synthesis and secretion of AH is coded by four HLA genes which in the majority of strains are located on the chromosome.

[Alpha-hemolytic strains of Escherichia coli isolated in urinary tract infections in small children].

The authors focused attention on testing of biological properties of alpha-haemolytic strains of E. coli in infections of the urinary pathways in children and on the antibody response against alpha-haemolysin. The strains belonged into serogroups 02, 04, 06, 018, 075, 0112.

[Characteristics of E. coli strains isolated in infantile diarrhea].

In a group of 50 strains of E. coli isolated from infants hospitalized on account of diarrhoea the authors investigated, based on the phenotypic manifestation and in a selected number of strains also genotypic factors of virulence: fimbrial adhesins, aerobactin, haemolysins, colicins, toxic and lethal action in mice, seroresistence and resistance against tetracycline, streptomycin, chloramphenicol, kanamycin, ampicillin and sulfamethoxidine. All strains had one to eight factors of virulence.

[Personal experience in testing for E. coli enterotoxigenicity].

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.

Partial purification of alpha-hemolysin in Escherichia coli.

The present paper describes isolation and purification of alpha-hemolysin of Escherichia coli. The optimum production medium was found to be the Todd-Hewitt broth. Out of thirteen fractions obtained after separation on Sephadex G-200, two fractions possessed the highest relative specific activity.

Response of Escherichia coli strains carrying plasmid(s) and their plasmidless derivatives to bactericidal activity of human serum and polymorphonuclear leukocytes.

Ten virulence plasmid(s) and antibiotic resistance plasmid(s) carrying Escherichia coli strains isolated from stool of infants with diarrhoea and their plasmidless derivatives were examined for response to bactericidal activity of human serum and intracellular killing of polymorphonuclear leukocytes (PMN). Plasmid(s) carrying isolates exhibited a significantly higher resistance to serum and phagocytosis.

[Killing of seroresistant plasmid bearing E. coli strains in polymorphonuclear leukocytes].

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.

[New findings on enteroinvasive strains of E. coli].

The group of enteroinvasive strains of E. coli (EIEC) comprises at present eleven serogroups. Diarrhoeal diseases caused by EIEC strains are found sporadically or epidemically.

[Evaluation of phagocytosis of alpha hemolytic strains of Escherichia coli using the fluorescence method].

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.

[Escherichia coli in diarrheal disease in young children].

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.