Showing papers on "Typing published in 1975"

World Health Organization studies on bacteriophage typing of mycobacteria. Subdivision of the species Mycobacterium tuberculosis.

Abstract: The ability of lytic mycobacteriophages to subdivide the species Mycobacterium tuberculosis reliably has been studied using a series of 100 strains isolated from cases of tuberculosis in the Netherlands. Techniques for the propagation and application of the viruses have been standardized, as have the conditions for growth and preparation of bacterial strains. On the basis of lytic results with 11 mycobacteriophages, it is proposed that the species Mycobacterium tuverculosis may be subdivided into at least 3 major phage types, A, B, and C, and into 2 subjects, Ax and A2. The reliability of the individual bacteriophage lytic result has been assessed, and the relationship between phage reliability and the degree of certainty with which a strain may be assigned to a phage type is described. The effect of rigorous standardization of techniques on the reliability of bacteriphage typing is demonstrated, and a standard protocol is proposed.

Titres and cross reactions of commercial antisera for the capsular typing of Klebsiella species.

Abstract: Ninety commercially supplied sera for the capsular typing of Klebsiella species were tested in a full chequerboard against 72 type strains. Only four of 144 homologous reactions could not be detected. Of the 6336 possible heterologous reactions, 91 actual cross reactions were found. All positive reactions were titrated and working dilutions deduced. This provides essential information for the successful typing of unknown strains with these sera.

Pyocin-sensitivity testing as a method of typing pseudomonas aeruginosa : use of "phage-free" preparations of pyocin

Abstract: Summary A method for pyocin-sensitivity typing by means of “phage-free” preparations of pyocin is described. The method was tested on 227 isolates of P. aeruginosa, collected from 34 different foci of infection in hospitals in the British Isles and the results were compared with those for combined serological and phage typing of all strains and pyocin production of 105 of the isolates. It is concluded that pyocin-sensitivity typing is a simple and reliable method giving a high degree of discrimination, comparable to that of combined serological and phage typing, and it is suitable for use in routine hospital laboratories.

Reevaluation of bacteriocinogeny in Neisseria gonorrhoeae.

Abstract: Bacteriocin typing has been described previously and proposed for typing gonococci. A survey has been made of 150 strains of N. gonorrhoeae from various places to determine the feasibility of a gonocin typing system. All strains were found to produce an inhibitory substance which inhibited all strains of gonococci tested, one strain of Neisseria flavescens, two strains of Neisseria meningitidis, as well as the producing strain itself. The inhibitory activity was enhanced by supplementary glucose, reduced by supplementary serum, and unaffected by the addition of HEPES buffer, by the temperature of incubation, or by the exposure of potential producer strains to sublethal concentrations of mitomycin C. This nonspecific inhibitory activity differed from that of a putative bacteriocin produced by a strain of N. meningitidis, in that the latter inhibited most other meningococci but not the producer strain itself. Bacteriocinogeny has not yet been convincingly demonstrated in N. gonorrhoeae, and gonocin typing has not yet been shown to be feasible. Production of the nonspecific inhibitor may have obscured past attempts to demonstrate type-specific gonococcal bacteriocin.

Phage typing of Staphylococcus aureus strains isolated in Sweden from bovine milk.

Abstract: Both the human and the bovine international sets of phages were used for typing of 372 bovine Staphylococcus aureus (Sa) strains, whereas the bovine set alone was used for typing of a further 1183 strains. In addition, 338 of the strains were tested for antibiotic sensitivity. Out of 372 Sa strains 85.5% could be typed with the human and 89.8% with the bovine phage set. Of all the 1555 Sa strains used 92.4% were lysed by the bovine phage set. Several phage types can be present in one and the same herd and some of them can predominate. Resistance to most of the tested antibiotics was very low. The incidence of resistance to penicillin and ampicillin was 10.0% and 4.4% respectively.

MLG Results among Unrelated can be Predicted

Abstract: Typing for LD determinants which has been practicable for some time is shown to be very predictive for the MLC response between unrelated, since LD identical individuals - selected and paired solely on the basis of LD typing - mutually show very low or no MLG reaction.

Hl‐a typing in dried blood stains. ii. comparative studies on microcytotoxicity and microcomplement fixation tests*

Abstract: Summary With an improved method for extraction of HL-A soluble antigen from dried blood stains, eighteen HL-A antigens were tested in the microcytotoxicity test as described in the preceding paper (Rittner & Waiyawuth, 1974). With the antisera available, seven antigens could not be detected with sufficient confidence. As a serious handicap of the microcytotoxicity test, a selected panel of donor lymphocytes must be permanently available. A comparison between the microcytotoxicity and the microcomplement fixation test performed on platelet material recovered from the stains led to the conclusion that the microcomplement fixation test is better suited for a routine laboratory. Encouraging results were obtained in a larger series of microcomplement fixation tests with white blood cells from dried blood stains. Significant chi-squared values were calculated for fourteen of sixteen antigens tested. The possible causes of false positive and negative reactions are discussed. Anticomplementary reaction of anti-HL-A sera in microcomplement fixation tests should be taken into account.

Validity of a screening test for typing serum cholinesterase variants among Greek populations.

Abstract: A screening method for determining the abnormal phenotypes of human serum cholinesterase variants in a population survey was investigated. The test appeared to be satisfactory in detecting abnormal genotypes, but not assigning them into correct classification. The results of the population survey indicate that there may be a higher frequency of ChU1ChD1 genotype than those reported earlier. Family studies of the suxamethonium-sensitive propositi in this population demonstrate that abnormal genes ChD1, ChF1 and ChS1 are segregating, according to the usual Mendelian type of inheritance pattern. The possibility of a relatively high frequency of these abnormal genotypes among the Greek population has been indicated.

[Typing of vibrions by specific O-sera].

Abstract: Vibrios which were not agglutinated with cholera O-serum in various areas of the USSR from persons suffering from intestinal diseases, carriers, from the water and hydrobionts (550 in all) were typed serologically Forty three specific O-sera were used ofr serological typing A determination was made of the serological type in 93% of the strains of vibrios isolated from humans The given sera were also capable of typing 87% of vibrio strains belonging to the I group Heiberg, isolated from water and hydrobionts, 56% of the strains of the II group and individual strains of the III group, whereas cultures belonging to the IV-VIII groups were not agglutinated by these sera Circulation of 33 serological types of vibrios not agglutinable by cholera O-serum was revealed in the Soviet Union