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PubMed1983

[Comparative study of the phospholipase activity of pathogenic and saprophytic Leptospira cultured on a serum-lecithin agar].

The phospholipase activity of leptospires cultivated on serum-lecithin agar has been studied. Two zones of changes in the medium have been found to appear around the colonies of saprophytic Leptospira strains: transparent (5.25 +/- 2.09 mm wide) and turbid (6.90 +/- +/- 1.46 mm wide), which is linked with the production of phospholipases A and C. Only a single clear zone is formed around the colonies of pathogenic strains due to the production of phospholipase A. At the same time virulent Leptospira strains show greater phospholipase activity (the zones are 6.0 +/- 1.2 mm wide) than avirulent strains (the zones are 1.6 +/- +/- 0.04 mm wide).

Agar↗
PubMed1978

Studies of antigenic variants of leptospira isolated from experimentally infected mice.

Antigenic variants were isolated from mice inoculated with a virulent strain of Leptospira interrogans serotype copenhageni by cultivating the kidney cortex in the liquid or the solidified serum media containing the immune serum against the parent strain. The variants, which were isolated from the mice from 7 to 113 days after infection, were found to be antigenically different from the parent by the agglutinin-absorption test, precipitin-absorption test in gel and guinea pig protection test. The variants were antigenically stable and different from the 18 serotypes of the Icterohaemorrhagiae serogroup. The significance of antigenic variants of leptospira which appear in vivo is discussed.

Animals↗
PubMed1978

Gas-liquid-chromatography of trimethylsilyl derivatives from whole cell methanolysates of Leptospira : preliminary evaluation of its applicability to the taxonomy of the genus.

Gas-liquid-chromatography of trimethylsilyl derivatives from whole cell methanolysates was investigated as a supplmentary means for taxonomical classification within the genus Leptospira. Reproducibility of this technique was assessed through the peak height variations occurring in chromatograms of strain Patoc 1, serotype patoc, when samples either from the same or different batches of culture were used. From each chromatogram seven peaks were selected. Their heights were measured and calculated as percent values of the seven peaks total height. The values of relative standard deviation reported show that the reproducibility of this technique lies within the usual limits of biological methods. Four out of seven different serotypes analyzed gave elution patterns dissimilar enough to allow a clear distinction among them by the simple visual examination. Differentiation of the other three had to be done comparing the relative heights of the seven selected peaks. One not yet classified new strain was submitted to this technique; results seemed to confirm available serological information about it. Data reported encourage further research in order to evaluate the potential of GLC as an useful aid in the taxonomy of genus Leptospira.

Chromatography, Gas↗
PubMed1982

Hemolytic activity of Leptospira interrogans serovar canicola cultured in protein-free medium.

Hemolytic activity of the culture supernatant of Leptospira interrogans serovar canicola strain Moulton grown in protein-free medium was demonstrated. The activity began to appear in the late logarithmic phase of growth of the organism and reached a plateau after 2 weeks of cultivation. It was inactivated by the addition of dipotassium ethylenediaminetetraacetate, but was effectively restored by Mg2+. Hemolysis by the culture supernatant was stimulated by "hot-cold" incubation. Sleep erythrocytes treated with the culture supernatant of the organism were transformed into spherocytes, in which invagination was observed. A hemolysis inhibitor in rabbit serum was found to be in the chloroform-methanol soluble fraction of the serum. The hemolysin of Leptospira may be phospholipase C.

Animals↗
PubMed1983

In vitro effect of Leptospira icterohaemorrhagiae on human mononuclear leukocytes procoagulant activity: comparison of virulent with nonvirulent strain.

The in vitro effect of a virulent and a nonvirulent strain of Leptospira interrogans serotype icterohaemorrhagiae on human peripheral mononuclear cells was investigated. After addition of bacteria to citrated whole blood the production of mononuclear cell procoagulant activity (tissue factor) was observed. Indeed mononuclear cells isolated from whole blood bacteria mixtures after prolonged incubation shortened the recalcification time of normal plasma. The virulent strain induced a significantly higher procoagulant activity than nonvirulent and this effect was dependent on the number of bacteria. The production of tissue factor, a potent trigger of blood coagulation, by Leptospira icterohaemorrhagiae could help to understand the mechanism(s) responsible for the activation of intravascular coagulation associated with leptospirosis.

Blood Coagulation↗
PubMed1981

Antigenic variants of leptospiras selected by antiserum-complement mediated-killing.

The presence of antigenic variants of leptospiras was confirmed by the leptospiricidal reaction mediated by the antiserum plus complement. More than 99% of the organisms of virulent L. copenhageni Shibaura were destroyed microscopically after treatment with the anti-L. copenhageni Shibaura antiserum (1: 2000) plus guinea pig complement (1: 20). The leptospiras which survived treatment with the antiserum plus complement produced colonies on the solid serum medium at a rate of 0.09%. Eighty-seven percent of the survivors were found to be antigenic variants. The antigenicity of these variants reversed to that of the parent after 3--5 passages in the liquid normal serum medium.

Animals↗
PubMed1982

Leptospira interrogans serovar pomona associated with abortion in cattle: isolation methods and laboratory animal histopathology.

Leptospira interrogans serovar pomona was successfully isolated from cattle urine in the western Transvaal after an abortion storm had occurred. Direct inoculation of EMJH medium proved the most successful method. The selective agent, 5-fluorouracil, was most effective in controlling contamination when used at the 0,4 mg/ml level. The strain isolated was pathogenic in hamsters, but specific lesions and the leptospirae were seen only where overwhelming infection occurred.

Abortion, Veterinary↗
PubMed1982

Production and characterization of monoclonal antibodies to lipopolysaccharide antigen of Leptospira interrogans serovar kremastos and canicola.

Monoclonal antibodies to Leptospira interrogans were provided by cell fusions between a myeloma cell line, P3/X63-Ag8.653, and spleen cells of BALB/c mice immunized with two different leptospiral lipopolysaccharide antigens. One antigen was prepared from Leptospira interrogans serovar kremastos strain Kyoto and the other from serovar canicola strain Hond Utrecht IV. Eighteen hybridoma cell lines secreting monoclonal antibodies to the former organisms and five hybridoma cell lines secreting monoclonal antibodies to the latter organisms were established during 6 month cultivation. On the basis of their microscopic agglutination reactivities, 18 anti-kremastos Kyoto monoclonal antibodies were classified into 10 distinct groups, and 5 anti-canicola monoclonal antibodies into 3 distinct groups.

Agglutination Tests↗
PubMedDate not supplied

In vitro effect of Leptospira icterohaemorrhagiae on human mononuclear leukocytes: comparison of virulent with non virulent strain.

The in vitro effect of a virulent and a non virulent strain of Leptospira interrogans serotype icterohaemorrhagiae on human peripheral mononuclear cells was investigated. After addition of bacteria to citrated whole blood the production of mononuclear cell procoagulant activity (tissue factor) was observed. Indeed mononuclear cells isolated from whole blood-bacteria mixtures after prolonged incubation shortened the recalcification time of normal plasma. The virulent strain induced a significantly higher procoagulant activity than non virulent and this effect was dependent on the number of bacteria. The production of tissue factor, a potent trigger of blood clotting, by Leptospira icterohaemorrhagiae could help to understand the mechanism(s) responsible for the activation of intravascular coagulation sometimes associated with leptospirosis.

Blood Coagulation Factors↗
PubMed1981

Leptospira parva sp.npv.: some morphological and biological characters.

Two lines of a spirochete were isolated as contaminants in a culture of a leptospire and from a bottle of uninoculated medium. Studies on morphological and biological characters led to the conclusion that these lines represent a new species of the genes Leptospira, Leptospira parva sp. nov. The morphology of the cells was rather similar to that of previously examined leptospires, but the cells were shorter and had a shorter wavelength (more tightly wound). Furthermore, the surface layer of cells of L. parva formed numerous small blebs with no apparent substructure when detached during preparation for negative staining, while the surface layer of previously studied leptospires formed cross-striated tubules under similar conditions. L. parva shows biological characteristics of both parasitic and saprophytic leptospires. The deoxyribonucleic acid base composition of cells of this organism differed from that found in leptospires, as well as from that found in cells of Leptonema illini.

Base Composition↗
PubMed1978

[1st isolation of serovar Sorex--Jalna leptospirae from humans].

Leptospira strain "Patient No. 84", identical to the international standard of sorexjalna serovar, of Javanica serogroup was for the first time isolated on the 5th day of the disease from a patient suffering from leptospirosis in seeding his blood in Vervoort-Wolf's fluid medium. Antibodies heterologous against the strain isolated were also determined in the patient's blood on the 5th day. Their titre was 1 : 200(++), and they proved to react with leptospira of Cynopteri and Pomons serogroup.

Adolescent↗
PubMed1994

Effective treatment with dihydrostreptomycin of naturally infected cows shedding Leptospira interrogans serovar hardjo subtype hardjobovis.

The efficacy of dihydrostreptomycin in stopping the shedding of Leptospira hardjo subtype hardjobovis was studied in naturally infected cows. Blood and urine samples were collected from dairy cows kept on a farm where the farmer had contracted L hardjobovis infection. A microscopic agglutination test and an ELISA were used to determine specific antibody responses in serum. Polymerase chain reaction was used to detect bacterial shedding in urine. On the first sample collection date, 6 cows were seropositive, and 3 of those shed leptospires in the urine. These 3 cows were treated once with 25 mg of dihydrostreptomycin/kg of body weight. Within 1 week, the 3 cows stopped shedding leptospires. Six weeks later, 8 more lactating cows were found to be shedding leptospires. These cows were also treated once with dihydrostreptomycin, and they too stopped shedding leptospires within 1 week. From then on, the whole herd was examined weekly for a period of 2 months, and all cows Leptospira-positive by polymerase chain reaction were treated once with dihydrostreptomycin. Again, all cows stopped shedding leptospires in the urine within 1 week after treatment with dihydrostreptomycin. After a single treatment of the whole herd at the same time, new infections were not seen.

Amoxicillin↗
PubMed1994

A neutral sugar is responsible for serovar specificity of the antigenic determinant of Leptospira interrogans serovar canicola.

To provide information on the chemical structures of antigenic determinants of leptospira, glycolipids of Leptospira interrogans serovar canicola strain Hond Utrecht IV (Ut-IV) and its antigenic variant selected in the presence of a serovar-specific monoclonal antibody were compared physicochemically. Gas-liquid chromatography-mass spectrometry analysis revealed that the glycolipid of Ut-IV contained 6 neutral sugar species; rhamnose, mannose, galactose, glucose, and unknown sugars III and IV, in addition to unknown sugars I and II that had been previously reported. On the other hand, the glycolipid of the variant lacked unknown sugar III, suggesting that this sugar is responsible for the serovar-specific antigenic determinant.

Animals↗
PubMed1995

Inhibition of Na,K-ATPase by an endotoxin extracted from Leptospira interrogans: a possible mechanism for the physiopathology of leptospirosis.

Clinical manifestations of leptospirosis include disorders of the electrolytical balance which might be related to inhibition of Na,K-ATPase. Although the physiopathological cellular mechanism of leptospirosis remains unknown, a bacterial endotoxin has been incriminated. Therefore, we evaluated whether a glycolipoprotein fraction extracted from Leptospira interrogans and known to be cytotoxic might inhibit Na,K-ATPase. This glycolipoprotein fraction (GLP) inhibited Na,K-ATPase activity in rabbit kidney epithelial cells as well as Na,K-ATPase purified from rabbit kidney medulla. Inhibition was dose-dependent, and at maximum it almost abolished Na,K-ATPase activity whereas it had no effect on other enzymes. The GLP did not change the apparent affinity of Na,K-ATPase for potassium whereas it increased that for sodium, revealing a mechanism of inhibition different from that of ouabain. Finally, the inhibitory principle present in the GLP preparation was thermostable and was curtailed by the presence of albumin. In conclusion, a glycolipoproteic fraction extracted from Leptospira interrogans contains a specific inhibitor of Na,K-ATPase. This glycolipoproteic fraction which is present in diseased tissues might induce, through this inhibitor, cellular dysfunctions responsible for the symptoms, in particular those associated with electrolytical disorders such as disturbances of renal electrolyte handling, cardiac arrhythmia or diarrhoea.

Animals↗
PubMedDate not supplied

[The connection of the antigenic activity of Leptospira to its virulence].

Virulence of Leptospira cultures isolated in leptospirosis centres of different regions of Ukraine has been studied. It is shown that certain strains of leptospiras with high virulence several times exceed in their antigenic activity the standard strains and their introduction into the set of strains for the reaction of microagglutination and use for making diagnostic and, probably, prophylactic preparations are promising.

Animals↗
PubMed1993

Comparative pathogenicity study of Leptospira interrogans serovar pomona strains.

The comparative pathogenicity study of two Leptospira interrogans serovar pomona strains isolated from pig herds of different epizootiological status is reported. Using monoclonal antibodies (Mabs), the isolates were identified as Leptospira interrogans serovar pomona. The results obtained for the reference strain of L. pomona were identical with those of the two isolates, with the exception of monoclonal serum designated 61-7, which gave a 1:30 titre with the reference strain. In a pig herd comprising 1,000 sows, strain XVIII caused abortion in 300 animals. In the hamster pathogenicity test, this strain killed the hamsters on postinoculation (PI) days 5 or 6. The pathogen was reisolated from their organs. Strain XV did not cause abortion in a herd of 600 sows; it only elicited seroconversion in a proportion of the animals (26 out of 274 blood samples were positive, corresponding to a seropositivity rate of 9.5%). This strain did not kill the hamsters and could be demonstrated from their organs neither by isolation nor by histological examination. The blood serum of two pregnant sows infected with strain XVIII contained high titres of antibodies (1:1,600 and 1:3,200) already on PI day 10. The first urine sample of these animals, taken on PI day 10, also contained large numbers of leptospires. The pathogen was reisolated from urine samples taken at 10-day intervals and from the kidneys of the slaughtered sows. One of the two infected sows delivered four non-viable and a viable piglet. From the kidneys of the non-viable piglets, leptospires were demonstrated by histological examination. In contrast, none of the four pregnant sows inoculated with strain XV aborted. The sows did not produce antibodies detectable by the microscopic agglutination test (MAT). The pathogen could not be isolated from urine samples and from kidney samples taken from the sows at slaughter. Histological demonstration of leptospires from the sows' kidneys also failed.

Animals↗
PubMedDate not supplied

[Leptospira infection under the natural conditions of the environs of Saint Petersburg].

The existence of valent natural foci of leptospirosis, stable and polyhostal, under the conditions of urban agglomerations has been established. In an intensively urbanized landscape, the foci of mixed (natural and anthropic) type can be found. Depending on the character of microlandscape in a given zone, the main hosts of leptospires are different species of small mammals in whose populations, as a rule, the circulation of at least three Leptospira species is observed. Introduction of the 'carriership index' will help determine the role of different species of small mammals as the potential source of leptospires in the foci, as well as the proportion of different circulating Leptospira species and their zonal distribution.

Animals↗