Production and purification ofEscherichia coli hemolysin

Asnani, P. J.; Bhatnagar, Nirupama; Bhandari, S.

doi:10.1007/bf02925850

Cited by 5 publications

(5 citation statements)

References 12 publications

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“…Hemolytic activity in culture supernatants is labile, decaying at a rate proportional to the temperature (233,442,497); this lability is not due to degradation of hemolysin (37), despite the sensitivity of hemolysin to proteases (442,489). The amount of hemolytic activity in culture supernatants varies depending on the composition of the medium (16,233,442,489,497), probably not because of altered rates of hemolysin production (234) but because of substances in the medium (233,442) that influence the rate of inactivation of hemolysin in the supernatant (331,370,489).…”

Section: Regulation Of Expressionmentioning

confidence: 99%

Virulence factors in Escherichia coli urinary tract infection

1991

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Uropathogenic strains of Escherichia coli are characterized by the expression of distinctive bacterial properties, products, or structures referred to as virulence factors because they help the organism overcome host defenses and colonize or invade the urinary tract. Virulence factors of recognized importance in the pathogenesis of urinary tract infection (UTI) include adhesins (P fimbriae, certain other mannose-resistant adhesins, and type 1 fimbriae), the aerobactin system, hemolysin, K capsule, and resistance to serum killing. This review summarizes the virtual explosion of information regarding the epidemiology, biochemistry, mechanisms of action, and genetic basis of these urovirulence factors that has occurred in the past decade and identifies areas in need of further study. Virulence factor expression is more common among certain genetically related groups of E. coli which constitute virulent clones within the larger E. coli population. In general, the more virulence factors a strain expresses, the more severe an infection it is able to cause. Certain virulence factors specifically favor the development of pyelonephritis, others favor cystitis, and others favor asymptomatic bacteriuria. The currently defined virulence factors clearly contribute to the virulence of wild-type strains but are usually insufficient in themselves to transform an avirulent organism into a pathogen, demonstrating that other as-yet-undefined virulence properties await discovery. Virulence factor testing is a useful epidemiological and research tool but as yet has no defined clinical role. Immunological and biochemical anti-virulence factor interventions are effective in animal models of UTI and hold promise for the prevention of UTI in humans.

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Section: Regulation Of Expressionmentioning

confidence: 99%

Virulence factors in Escherichia coli urinary tract infection

1991

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“…22 Cultures were incubated for 4-6 h at 37°C in alkaline meat extract broth then centrifuged (12000 rpm, OOC, 20 min) and the supernate was collected. An equal amount of sheep red blood cells (1 Yo, v/v), washed three times in normal saline, and broth supernate were incubated at 37°C for 2 h with intermittent agitation.…”

Section: A-haemolysin Productionmentioning

confidence: 99%

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

Siegfried

Kmeťová

Puzová

et al. 1994

Journal of Medical Microbiology

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Summary, 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 a-haemolysin (AH), colicins and aerobactin. PF, AH, aerobactin production and serum resistance were significantly more frequent amongst strains expressing mannose-resistant haemagglutination. PF and AH production was significantly more frequent in pyelonephritogenic strains than in lower UTI strains. Serotypes 0 6 and 0 1 12 were isolated most frequently and plasmids were found in the majority of strains tested.

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“…Various laboratory media have been used to obtain hemolysin in the culture supernatant for a number of different organisms (3,6,17,27). Generally, defined media are recommended for the production and characterization of bacterial hemolysins.…”

Section: Discussionmentioning

confidence: 99%

Partial characterization of Streptococcus suis type 2 hemolysin

et al. 1994

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Streptococcus suis type 2 was evaluated for hemolysin production. Supernatants of S. suis type 2 grown in Todd-Hewitt broth were assayed for hemolytic activity by a photometric assay. Twenty-two additional serotypes of S. suis (1, 3 to 22, and 1/2) were evaluated for hemolysin production; nine of them (1/2, 1, 4, 5, 14, 15, 17, 19, and 20) were positive. The effects of temperature, atmosphere, centrifugation, sonication, chemicals, bovine serum albumin, fetal calf serum, and enzymes on S. suis type 2 hemolysin activity were studied. Maximum hemolysis occurred after incubation in RPMI 1640 medium at 40°C in 6% CO2 and after growth in Todd-Hewitt broth at 37°C under anaerobic conditions. Hemolytic activity was absent after the addition of fetal calf serum and decreased after the addition of trypsin or amylase. However, treatment of erythrocytes with amylase or trypsin prior to incubation with supernatant also resulted in a decrease in hemolytic activity. The addition of bovine serum albumin caused increased hemolytic activity. Dipyridyl and EDTA had negligible effects on hemolysis. Hemolytic S. suis type 2 culture supernatant injected intraperitoneally failed to cause death in BALB/c mice. Data from our study indicate that S. suis type 2 hemolysin is a secreted or loosely cell bound, thermolabile molecule whose activity is growth condition dependent.

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Production and purification ofEscherichia coli hemolysin

Cited by 5 publications

References 12 publications

Virulence factors in Escherichia coli urinary tract infection

Virulence factors in Escherichia coli urinary tract infection

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

Partial characterization of Streptococcus suis type 2 hemolysin

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