Zentralblatt fur Bakteriologie. 1. Abt. Originale. A: Medizinische Mikrobiologie, Infektionskrankheiten und Parasitologie最新文献

Leptospira species are difficult to isolate from sperm specimens because rapid growth of the contaminant flora will kill the pathogen. The resistance of 5 Leptospira strains to 5 different antibiotics was examined with a view to an inhibition of such contaminant growth. Neomycin (10, 20, 30 mg/l), vancomycin (5, 8, 10 mg/l), nalidixic acid (50, 75, 100 mg/l), streptomycin (5, 8, 10 mg/l) and chloramphenicol (5, 10, 20 mg/l) were added separately to Korthof's culture medium containing rabbit serum. The comparative growth rates of the leptospires were evaluated. Against the control medium, all 5 antibiotics were found to have an adverse influence on the multiplication phase. In conformity with literature data, vancomycin (10 mg/l) and nalidixic acid (50 mg/l) were found to have the lowest effect. In the cases of streptomycin and chloramphenicol, there was a high reduction of the leptospiral count and even a complete lack of multiplication. A combination of vancomycin (10 mg2l) and nalidixic acid (50 mg/l) was used for the recovery of leptospires from porcine sperm. To inhibit a growth of Ps. aeruginosa, 5000 U/l polymyxin B were added. The strongly inhibitory action of polymyxin B on leptospiral growth could be eliminated by subculturing in a medium free from inhibitory substances after 2 days.

A new Salmonella serotype (S. 6,7:z:l,w) was isolated from a stool specimen of a 40 years old businessman after a several weeks journey in Nigeria with a two days stay in Lagos. The strain was finally confirmed as a new Salmonella serotype on January 1th, 1980, by Prof. Le Minor, International Salmonella Center, Paris. The strain was introduced as Salmonella bruck into the Kaufmann-White-Scheme, Supplément No. XXIII (1979).

Mutants of Salmonella typhimurium with spontaneous chromosomal resistance against oleandomycin, streptothricin, nalidixic acid and rifampicin were investigated for their virulence behaviour with the i.p. mouse model. The strains resistant against the special antibiotic consists of a spectrum of various clones with a different behaviour of virulence: Additionally to obvious unchanged virulent strains there are such with a weak or strong attenuation. The majority of the attenuated strains protect the immunized mice against a following lethal wild strain infection. High-immunogenic attenuated double-marker mutants for application as potential vaccine strains may be isolated with the aid of a step by step introduction of a second attenuating "resistance"-marker in a one-marker strain, attenuated for another reason. These strains show the following parameters: -stability under the conditions of practical vaccine application, because a simultaneous back-mutation in both attenuating markers by reason of the unrealizable germ numbers will not occur, -immunogenicity by one immunization only, -separation from homologous wild strains of another origin with simple laboratory methods. This obvious generally acting biological principle is explained on the basis of molecular biological considerations and by referring to the literature. A test for orientation using an attenuated RNA-polymerase mutant showed, the resistance against rifampicin and attenuation are transferred together by co-transduction.

Mice (NMRI) were immunized twice with acetone-killed bacteria from 13 different Salmonella R-mutant and 6 Salmonella S form strains. Of the R mutants one strain was a semirough mutant, 9 strains belonged to the chemotype Ra, one to chemotype Rb2 and 2 to chemotype Re. Of the S forms 2 strains derived from serological group B, 2 from group D1 and one strain from each of group C1 and C2. Ten days after immunization the animals were challenged with increasing numbers of S-form bacteria (the same S strains as those used for immunization) administered intraperitoneally. The virulence (LD50) of the strains used was between 6 x 10(2) and 3 x 10(5) cells. The results show that every mutant was capable of affording protection to the S-form bacteria used, i.e. the protection was not confined to the species used for immunization; nevertheless differences in the degree of protection were present. These differences were found both in the ability of the different mutants to protect towards the same infecting microorganism and in the protection obtained by individual mutants towards infection with the different S-forms. With certain strains a relatively high degree of protection was obtained, with others the protection was low compared to that seen with homologous S form vaccines. In infection with s. typhimurium, unlike infection with other S-forms, the homologous R mutants were superior to the other mutants in their immunizing properties. Immunization with heterologous S-forms yielded similar results as those obtained with R mutants. S-forms with identical O-antigens were not necessarily comparable in their protective properties. Although the protective effect of R mutants was generally lower than that produced by homologous S-form vaccines, the present results show that in a few cases an equally high protection may also be obtained by R mutants. The present results lead to the conclusion that the cell-surface of Salmonella contains, in addition to the known antigens, other components playing an important role in inducing immunity to infection. A partial divergence in the pattern of such components among the different vaccines, would explain the extension of immunity obtained by the heterologous species also.

Group 'F' vibrios are a recently recognised group of bacteria that have been isolated from cases of diarrhoea and a variety of sources in the environment. They have been shown to cause accumulation of fluid in rabbit gut loops. The enterotoxic factor was found to be heat-labile as evidenced by heat treatment, time course of fluid accumulation and negative suckling mouse assay. It was associated with cytotoxic factor(s). These organisms were seen to be lacking in invasive capacity. Prostaglandins and 5-hydroxytryptamine were found to play no role in causation of fluid outpouring into the loops but chlorpromazine was found to inhibit the fluid outpouring completely thereby indicating that the enterotoxin may act through mediation of cyclic AMP.

Six prototype strains of human adenoviruses (Ad 1, 4, 7, 8, 12, 19) were passed and titrated comparatively in four strains of human diploid fibroblast cultures. The viruses were readily passed 5 times with cytopathic effect; no signs of adaptation or dimunition of CPE were apparent. The virus yield was about equal in fibroblasts and in HeLa cells. High and low passage fibroblasts were of equal susceptibility. In endpoint titrations, fibroblast cultures showed an about 10-fold lower susceptibility towards Ad1 and Ad7; however, they compared favorably for Ad4, 8, 12, and 19 with HeLa or (for Ad8) with human amnion cell cultures. In some instances differences in the susceptibility between fibroblast strains were observed. Fibroblast cultures and human amnion cells showed equal susceptibility for Ad8 from 9 original conjunctival specimens, while results with other types varied. For adenovirus isolation, fibroblast cultures are suitable as an adjunct to HeLa cell cultures, particularly for Ad8. However, the long duration till the appearance of CPE which sometimes exceeds 50 days is a disadvantage.

Effectiveness of a multi-component vaccine consisting of the common antigen (OEP) derived from Pseudomonas aeruginosa strain N 10 (serotype E) and toxoids of protease and elastase was compared with that of formalin-killed cells of strain N 10 on protection against enzootic of hemorrhagic pneumonia due to P. aeruginosa in mink. One administration of the multi-component vaccine (100 microgram each of OEP, protease toxoid and elastase toxoid) clearly prevented enzootic of hemorrhagic pneumonia due to P. aeruginosa (serotype G) in mink, while a vaccination of formalin-killed cells was much less effective in preventing an epidemic. The difference in mortality rates between two vaccines was remarkable.

The biochemical and serological examination of 31 strains of Levinea malonatica isolated from faeces, urine, sputum, wound infections and blood showed no correlation of bio- or serovars with the origin of the strains. Serological cross-reactions between O-antigens of L. malonatica and certain Salmonella, Shigella and Yersinia enterocolitica serovars were analysed. They are low-titred and seem to be of minor importance. Sensitivity testing revealed the resistance of L. malonatica against penicillin, ampicillin and carbenicillin.

Hyaluronate lyase of group C strain H 46A (Streptococcus equisimilis) was purified and characterized by isoelectric focusing, sodium-dodecylsulfate-acrylamide electrophoresis, polyacrylamide-gradient-electrophoresis and crossed immunoelectrophoresis. The purification of the hyaluronate lyase was performed successively by adsorption on Florisil, chromatography on DEAE-cellulose, and - for separation of streptokinase - stirring with CPG-pore-glass. The last step was Sepharose 6B. PUrified hyaluronate lyase showed a high specific activity. The purified enzyme was found to be antigenically homogeneous. No contaminating streptococcal components could be detected. The molecular size was determined as to be 90 000 dalton by gel filtration and 110 000 dalton by sodium dodecylsulfate-acrylamide electrophoresis. The amino acid composition was also determined. In the isoelectric focusing, using gels with reducing conditions, one protein band at a pI 4.95 was observed. Under nonreducing conditions two or three diffuse protein bands which showed lower enzymatic activity were found. It might be possible that the hyaluronate lyase exists in two different forms.