摘要:

Using an in vitro system based upon radioisotope technique, the opsonizing and bactericidal effects uponE. coliof sera from germfree,E. coliandB. subtilismonocontaminated, and conventionalized rats, were investigated. Sera from the germfree animals were found to possess opsonizing as well as bacteriotoxic properties. The opsonizing activity was highest in sera from rats monocontaminated withE. coli, and lowest in sera from germfree animals. The bactericidal activity was lowest in sera from germfree rats. Specific and unspecific monocontaminations as well as conventionalization increased the serum bactericidal activity against the strain ofE. coliused.

ISSN:0365-5563    

DOI:10.1111/j.1699-0463.1970.tb04264.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

Two hundred and forty‐six patients with acute respiratory illness and 68 control patients, hospitalized in Copenhagen between March 1966 and March 1968, were examined. By isolation procedures and/or by tests for specific antibodies and cold agglutinins, 2 per cent of the patients with pneumonia were found to be infected withMycoplasma pneumoniaein the first year, while the percentage in the following year was 18. This variation in incidence was also found on examination of sera from patients from the whole of Denmark hospitalized during and beyond the same period. No seasonal variation in the incidence was observed.Mycoplasma pneumoniaeinfection was diagnosed exclusively in patients suffering from pneumonia. Mycoplasmas other thanMycoplasma pneumoniaewere found to be without aetiological significance; they were isolated most frequently from adult

ISSN:0365-5563    

DOI:10.1111/j.1699-0463.1970.tb04265.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

Thermal full‐thickness burns involving 2 per cent of the body surface area were produced in guinea pigs. DNase‐ and coagulase‐negative staphylococci cultured from the animals' normal bacterial flora were used as interference strain. They were applied to the burns of the test guinea pigs. As controls, guinea pigs were used, which were burned in the same way but not inoculated with the interference strain. An easily identifiable strain ofStaphylococcus aureuswas subsequently sprayed on the burns in some of the series. In the burns which were not sprayed with this test strain, records were kept only of spontaneously occurringStaphylococcus aureus.In all the series the animals in the test groups showed significantly less growth ofStaphylococcus aureusboth with respect to the percentage of positive animals and to the colony counts from these animals.Staphylococcus aureuspositive guinea pigs thus were found in only 27 per cent in the test groups, but in 73 per cent of the controls. From the number of colonies per culture plate “growth scores” were calculated from 0 to 4 according to an arbitrary scale. The mean growth scores per animal ofStaphylococcus aureuswithin the first two weeks after burning was 3.1 in the test guinea pigs and 8.8 in the controls. Possible practical consequenses of the observations made in the experiments are discussed, as for instance the possibility of bacteria belonging to the indigenous flora or other bacteria of lower pathogenicity to act as interference strains against hospital strains of pathogenic stap

ISSN:0365-5563    

DOI:10.1111/j.1699-0463.1970.tb04266.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

InStaphylococcus aureusstrains of type 83A/6557, and in “type 6557” and other group III strains insusceptible to phage 83A, two kinds of temperate phages were frequently found, belonging to the serological group A (α phages) and B (β phages), respectively. The two phages have been characterized by conventional criteria including plaque morphology, serological grouping, host range, and ultrastructure. To meet with the need for more specific identification the following characteristics were included: lysogenic conversion—in casuthe ability to convert a positive Tween 80 reaction to a negative one—, ability to block susceptibility to certain typing phages, and kinetics of inactivation with specific anti‐phage sera. These tests were found valuable and may deserve wider application as criteria in phage identification. It is made probable that the β phage has been responsible for the evolution from type 83A/6557 to “type 6557”, due to its ability to block susceptibility to phage 83A. Suggestive evidence is presented for an actual “epidemic” spread of this particular phage within the existing population of susceptible hospital staphylococci, contributing materially to the recently observed change in prev

ISSN:0365-5563    

DOI:10.1111/j.1699-0463.1970.tb04267.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

The influence of prior virus infection on the antibacterial activity of mouse alveolar macrophagehibition of phagocytosis in the total reduction of host defence after virus infection.

ISSN:0365-5563    

DOI:10.1111/j.1699-0463.1970.tb04268.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

Thehspgene (the genetic determinant for host‐controlled restriction and modification) was transferred from anE. coliK12 strain into aSh. flexneristrain, and in reverse the same gene from aShigellastrain was introduced intoE. coliK12. The presence of the heterologoushspgene was tested by phage T5. It was demonstrated in interrupted mating experiments with the hybrids as recipients that thehsphybrids had acquired changed recipient characters resembling those of the strains from which thehsporiginate

ISSN:0365-5563    

DOI:10.1111/j.1699-0463.1970.tb04269.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

In a previous genetic study of a highly ampicillin resistant mutant ofEscherichia coliit was observed that certain classes of recombinants always showed smooth colony morphology. The present work was undertaken in order to investigate a possible correlation between ampicillin resistance and capsule production, giving smooth colony morphology. Two methods for preparing capsular material were compared: ethanol precipitation and negative pressure concentration. Chromatographic examination of these preparations indicated that the negative pressure concentration method gives a more native product with a larger molecular weight than was obtained by the ethanol precipitation procedure. We have compared the amount of capsular material produced by seven different strains, two rough and five smooth. Large variations were observed in the amount of capsule produced but there was no obvious correlation between capsule production and ampicillin resistance. The surface structure of five of the strains was studied by electron microscopy. The smooth strains showed two types of structures closely adhering to the outermost layer of the wall, small vesicles of the order of 40–150 mμ in diameter and minute lamellated units measuring from 80 to 400 Å in length. The rough strains showed very few of these structures. When capsule producing strains were grown at room temperature more capsular material was produced and more of these extra‐surface structures were observed. It is suggested that the small vesicles and minute lamellated units may represent cell wall material produced in excess am

ISSN:0365-5563    

DOI:10.1111/j.1699-0463.1970.tb04270.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

The virulence of R‐mutants derived from the S‐strainSalmonella typhimurium395 MS has been investigated and compared with their phage pattern, chemical composition of the lipopolysaccharide, agglutination by O‐specific serum and absorption of O‐specific antibodies. No strict relationship between phage pattern or chemical composition and virulence could be established. The most virulent mutants (R4a, R9) seemed to have O‐specific antigen at their surface, whereas no O‐specific antigen could be demonstrated in the least virulent one (R10), which also showed strong spontaneous agglutination. Two rough‐resistant mutants, R5 and R6, with large quantities of O‐specific antigenic determinants at their surface showed low and almost no virulence, respectively. Mucin reduced the lethal dose considerably, the factors ranging between 102and 10‐5. Mice surviving for 5 weeks after infection often demonstrated a chronic disease with enlargement of the spleen and sometimes yellow‐white patches in the spleen and in the liver. Mice surviving doses of R‐bacteria that might be lethal to some animals in the same group often survived challenge with S‐bacteria. Particularly R9, a galactose‐4‐epimerase‐less mutant, gave a high degree of

ISSN:0365-5563    

DOI:10.1111/j.1699-0463.1970.tb04271.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

In cultures from the pharynx, one frequently observed Gram‐positive, catalase positive cocci with characteristic transparent to grayish white colonies with a coherent consistency. These often adhered firmly to the agar surface. Eighteen such strains, including one from bronchial secretion and three from blood cultures, were subjected to detailed biochemical, serological and pathogenicity studies. They were also examined for lysostaphin sensitivity and the DNA base composition was determined. All the strains appeared as members of the same species. On the basis of a careful review of the literature, we found that this species had been namedStaphylococcus salivariusAndrewes&Gordon 1907 and was reisolated byGordon(19). However, the per cent (G + C) of these strains, their lysostaphin resistance and lack of anaerobic glycolysis are compatible only with the genusMicrococcus.The strains are not identical toGaffkya tetragena, Diplococcus crassus, Micrococcus hyicus, orM. freudenreichii.On the other hand, they possess all the properties ofM. mucilaginosusMigula 1900 which is therefore the earliest available epithet for this species and must be adopted. Micrococci have been reported to be typically novobiocin resistant. Neither the strains ofM. mucilaginosus, nor those ofM. freudenreichiiexamined by us adhered to this concept.M. mucilaginosusis important for its frequency of occurrence in cultures from the human pharynx, mostly without clear relation to disease. The possibility of potential pathogenicity in man cannot be decide

ISSN:0365-5563    

DOI:10.1111/j.1699-0463.1970.tb04272.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

The first case of blood group chimerism in a Danish pair of twins is reported. Twin A (Mr. T. S.) is group O with 27 per cent B red cells in his circulating blood, while twin B (Mrs. M. R.) is group B with 31 per cent O cells in her circulating blood.

ISSN:0365-5563    

DOI:10.1111/j.1699-0463.1970.tb04273.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY