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Biomedical subjects

L Emödy

Publications and source records attributed to L Emödy.

At least 37 records · Page 2Linked to original sources
PubMed1989

Toxic shock syndrome toxin-1 (TSST-1) production in staphylococcal infections and serological implications with patients and healthy controls.

TSST-1 production occurred in 4.6% among Staphylococcus aureus strains isolated from divergent clinical sources in South-West Hungary. Patients suffering from staphylococcal infections, whether or not harbouring TSST-1 positive strains, exhibited low anti TSST-1 titres in their acute phase sera compared to the healthy control population. A S. aureus strain isolated from toxic shock syndrome (TSS) was a high collagen binder and a low fibronectin and fibrinogen binder suggesting the role of connective tissue adhesion in colonization and low invasive property of TSS strains.

Bacterial Toxins↗
PubMed1988

Mannose-resistant haemagglutination by Campylobacter pylori.

10 Campylobacter pylori strains were screened for the presence of presumptive colonization factors by measuring cell surface hydrophobicity and haemagglutination. All 8 clinical isolates and 2 reference strains caused haemagglutination of rabbit, human and/or sheep erythrocytes in the presence of mannose. None of the strains expressed a hydrophobic cell surface. In preliminary experiments the haemagglutination could be inhibited with monosialogangliosides suggesting that these strains express sialic acid specific haemagglutinin(s) which could be involved in colonization of mucosal surfaces.

Animals↗
PubMed1986

Influence of cloned Escherichia coli hemolysin genes, S-fimbriae and serum resistance on pathogenicity in different animal models.

The virulence of the uropathogenic E. coli strain 536 (O6:K15:H31) which produces the S-fimbrial adhesin (Sfa+), is serum-resistant (Sre+) and hemolytic (Hly+) and its derivatives were assessed in five different animal models. Cloned hemolysin (hly) determinants from the chromosomes of O6, O18 and O75 E. coli strains and from the plasmid pHly152 were introduced into the spontaneous Sfa-, Sre-, Hly- mutant 536-21 and its Sfa+, Sre+, Hly- variant 536-31. As already demonstrated for the 536-21 strains (Infect. Immun. 42: 57-63) the O18-hly determinant but not the plasmid-encoded hly determinant of pHly152 transformed into 536-31 contribute to lethality in a mouse peritonitis model. Similar results were obtained with both Hly- host strains and their Hly+ transformants in a chicken embryo test and in a mouse nephropathogenicity assay in which the renal bacterial counts were measured 15 min to 8 hours after i.v. infection. S-fimbriae and serum resistance had only a marginal influence in these three in vivo systems. In contrast all three factors, S-fimbriae, serum resistance and hemolysin, were necessary for full virulence in a respiratory mouse infection assay. In a subcutaneously-induced sepsis model in the mouse restoration of S-fimbriae and serum resistance and separately chromosomally-encoded hemolysis increased virulence to a level comparable to that of the parental 536 strain.

Animals↗
PubMed1986

Alteration of phage- and biotypes of Listeria strains.

Ethyl-methyl-sulphonate mutants of Listeria monocytogenes might be different from the parent strain in phage type and in splitting of lactose, maltose, melezitose, sucrose and trehalose. Differences were observed in repeated control studies in phage type and carbohydrate-decomposition of 550 Listeria strains isolated from a variety of sources (patients, healthy and dead animals). It has been concluded that certain carbohydrate tests are unsuitable for distinguishing biotypes of Listeria. An improvement of the evaluation of phage typing results is recommended.

Animals↗
PubMed1986

ELISA detectable virulence marker antigen of enteroinvasive Escherichia coli is coded by a 140 megadalton plasmid.

The ELISA reactive virulence marker antigen, characteristic of enteroinvasive Escherichia coli and virulent Shigella, expressed in an E. coli K-12 recipient after the 140 Md plasmid of an enteroinvasive E. coli strain had been introduced into it. Similarly to the epithelial cell penetration and Congo red binding capacities--known to be coded by the above plasmid--the virulence marker antigen expressed also only at 37 degrees C but not at 30 degrees C. These data suggest the plasmid coded nature of the virulence marker antigen.

Antigens, Bacterial↗
PubMed1985

Modified enzyme-linked immunosorbent assay for detecting enteroinvasive Escherichia coli and virulent Shigella strains.

Immune sera were produced in rabbits with living cells of an enteroinvasive O143 strain of Escherichia coli. To remove O and K antibodies, sera were absorbed with an avirulent derivative of the same strain. In the enzyme-linked immunosorbent assay, absorbed sera reacted specifically with only virulent Shigella strains and enteroinvasive E. coli strains of different geographical origin, regardless of species or serogroups. The investigation of 83 strains indicated complete agreement between enzyme-linked immunosorbent assay results and those of the keratoconjunctivitis test. It is assumed that the absorbed immune sera reacted with a possible virulence marker antigen. This inexpensive and simple method provides an alternative to other virulence tests. It has a definite advantage for screening large number of isolates within 24 h.

Animals↗
PubMed1982

The stability of enterotoxin production in Yersinia enterocolitica and the methanol solubility of heat-stable enterotoxin.

Twenty five strains of Yersinia enterocolitica serogroup O3, were isolated from human enteritis and studied for heat-stable enterotoxin production. Enterotoxin production was found even in the crude supernatant fluid of cultures that had been stored in stock agar for a year. According to the suckling mice and rabbit gut loop tests, after 1 to 5 years storage the filtrate showed heat-stable enterotoxin activity only in a purified and concentrated form. Following more than 5 years storage positive results could be obtained only in rabbit gut loop test. After 9 years the freeze dried strains still showed a full capacity of heat-stable enterotoxin production. Studies with concentrated substances showed that even after more than 9 years, there was no spontaneous loss of heat-stable enterotoxin production, only quantitative changes occurred. The methanol solubility of the heat-stable enterotoxin of Y. enterocolitica is--as distinct from the heat-stable enterotoxin of Escherichia coli--homogeneous and only the methanol soluble fractions showed any activity. The activity of methanol soluble enterotoxin from several years old subcultures could be demonstrated in an isolated rabbit gut loop model even when it failed to show any activity in suckling mice.

Animals↗
PubMed1980

New haemagglutinating fimbriae on Escherichia coli strains isolated from urine.

The haemagglutination patterns of 255 urinary Escherichia coli isolates were examined with human (A, Rh+), bovine, chicken and guinea pig erythrocytes in the presence and absence of D-mannose. The strains were divided into four groups according to their haemagglutination properties. About 40% of the isolated agglutinated human red blood cells in the presence of D-mannose. The haemagglutinin of one of these. E. coli O18a, c: K- strain No. 119 was stable, temperature sensitive, did not develop at 18 degrees C and could be isolated by the methods used for the production of fimbriae. Electron microscopy showed fimbriae on the surface of Strain No. 119. An absorbed serum prepared from a derivative cured of haemagglutinating property (No. 119/1) agglutinated all the strains haemagglutinating human erythrocytes in the presence of mannose, but none of those having other haemagglutination patterns. Serologically, the antigen of No. 119 is independent of the K88, K99, "987" and CF I factors and shows some relationship to CF II.

Animals↗
PubMed1980

alpha-Haemolysin: an additive virulence factor in Escherichia coli.

Haemolytic Escherichia coli, including human intestinal and extraintestinal as well as porcine enterotoxigenic and oedema disease isolates, and Proteus morganii strains were studied for their virulence. Hly+ wild type strains and Hly+ transconjugants were more virulent than Hly- derivatives as shown in mice and chick embryos. This enhanced virulence seems to be connected with the ability of diffusible alpha-haemolysin production because clones producing only non-diffusible, beta-haemolysin behaved as non-haemolytic ones. Haemorrhagic lung symptoms and haemoglobinuria were frequently observed after parenteral challenge of mice with alpha-haemolytic clones. Though the Hly- clone exhibited a high resistance against blood clearance, the number of circulating bacteria was significantly higher in the case of alpha-haemolytic clone. A causal connection between this phenomenon and the leukocidin activity of alpha-haemolysin is suggested.

Animals↗
PubMed1980

Enterotoxin production of Yersinia enterocolitica strains.

Eighteen Yersinia enterocolitica serogroup O3, rhamnose negative strains isolated in Hungary from human enteritis, have been studied for enterotoxin production. Freshly isolated strains cultivated at 25 degrees C produced heat stable (ST) enterotoxin demonstrable in sucking mice, whereas strains isolated earlier and maintained in subculture lost their toxin producing capacity. No heat labile enterotoxin (LT) was found in the filtrate of the cultures or in their sonicated lysate. The ST of one strain exerted a dilating effect on the intestinal loop of rabbits. Strains cultured at 37 degrees C produced no toxin. Toxin production was demonstrable in Syncase medium but not in the modified Sakazaki medium. None of the strains caused keratoconjunctivitis; three strains elicited mild conjunctivitis in guinea pigs.

Culture Media↗
PubMed1979

Shigella dysenteriae 1-like cytotoxic enterotoxins produced by Salmonella strains.

A Salmonella enteritidis strain produced a cytotoxin in addition to heat-labile (LT) and heat-stable (ST) enterotoxins. Two strains of serotypes Salmonella kapemba and Salmonella thompson were LT and ST negative, but exhibited a cytotoxic effect. After Sephadex G-100 fractionation of the crude S. enteritidis material, some high and low molecular fractions had both cytotonic and cytotoxic activities. Of the two other salmonellae, only some high molecular fractions contained the cytotoxic substance. Neutralization experiments revealed an antigenic relationship between the cytotoxins studied and Shigella dysenteriae 1 enterotoxin. On the basis of cross neutralization and other data, it seems that cytotoxic and LT-like characters are carried by the same molecule. In S. thompson and S. kapemba the LT fails to exert a biological effect, although it is antigenically related to the LT of Escherichia coli.

Animals↗
PubMed1979

Antitoxic immunity against the so-called lung toxin produced by Escherichia coli.

Cross neutralization test with antisera to crude haemolysins produced by some Escherichia coli strains indicated that there were no antigenic differences among the haemolysins tested. These crude preparates showed definite cytotoxicity which could also be cross neutralized by "antihaemolysin" sera. Neutralization experiments were performed in mouse lung test with homologous and heterologous anti-haemolysin sera, and with O and OK sera to the wild type strain and its toxic R mutant. The results showed that the immunity in the mouse lung model is antitoxic and antibacterial.

Animals↗
PubMed1979

An altered heart-labile enterotoxin (LT') produced by Escherichia coli serogroup O55 strain.

An Escherichia coli serogroup O55 strain produced heat-labile enterotoxin only, which exerted unusual effects on cell cultures; it caused elongation of CHO and HeLa cells but no changes in Y-1 cells. Injection of this substance, designated LT', into mouse foot pad and rabbit skin caused a well-expressed necrotic effect beside the LT-like activity. LT' showed no cytotoxic effect and failed to produce mouse lung oedema. The strain was not haemolytic. According to Sephadex G-100 fractionation, the LT' had a high molecular weight. The LT' and the necrotic activities could not be separated by fractionation. Neutralization experiments suggested an antigenic relationship between LT and LT'. The antigenic deficiency of LT' was closely related to the common antigenic component of LT and choleragen. The necrotic effect caused by crude LT' was neutralized only by the homologous serum.

Animals↗
PubMed1978

Mouse lung oedema caused by a toxic substance of Escherichia coli strains.

Some Escherichia coli strains isolated from patients and instilled into the nostrils of mice cause a rapidly developing fatal, haemorrhagic lung oedema. Lung toxic strains were found in different serogroups, with the predominance of 04, 06, and 018. The toxic material seems to be bound to the cells; the toxin yield is poor by different methods of extraction. The toxic principle causes toxic, haemorrhagic oedema in mouse foot pad test and shows cytotoxicity for AV-3 cells. The "lung toxin" is heat labile and after Sephadex fractionation has a molecular weight of about 100 000 dalton. There is a possible identity with a toxic haemolysin.

Animals↗