Showing papers on "Typing published in 1979"

"Fingerprinting" beta-haemolytic streptococci by their production of and sensitivity to bacteriocine-like inhibitors.

Abstract: A scheme for the "fingerprinting" of streptococci according to their production of (P typing) and sensitivity to (S typing) bacteriocine-like inhibitory substances has been developed. P typing of 450 beta-haemolytic streptococci by their action on a set of nine standard indicator strains revealed that 80% of strains produced one or more detectable inhibitors, and that 17 different P types could be recognised. Production of some inhibitors seemed to be a property of strains of a particular serological group or type. Bacteriocine-like substances were produced by streptococci of serological groups, A, B, C, D, E, F and G. Nine strains were selected as standard producers for S typing. These strains differed in their spectra of inhibition, but all seemed to be active only against gram-positive bacteria. One producer, a group-F streptococcus, specifically inhibited group-A streptococci. The conditions of incubation were critical for demonstration of inhibitor production. A requirement for blood and for incubation at 32 degrees C were important factors. None of the inhibitors was induced by ultraviolet irradiation. The observed inhibitory effects were not attributable to either hydrogen peroxide or low pH, but to the production of a variety of substances having diverse physicochemical properties and production requirements. Most of the inhibitors do not seem to be produced in liquid media. The "fingerprinting" procedure is simple and inexpensive, and provides a reliable means of subdividing streptococcal strains that may find application as a supplement to the existing serological typing schemes.

Comparison of Pasteurella multocida serotyping systems.

Abstract: Thirty-two type specific cultures used in four typing systems for serologically classifying Pasteurella multocida were compared as originally described for: (1) Little and Lyon's plate agglutination test; (2) Carter's indirect hemagglutination test, hyaluronidase decapsulation test, and acriflavine reaction; (3) Namioka's plate and tube agglutination tests; and (4) Heddleston's gel diffusion precipitin test. In addition, seven cultures from Robert's five passive protection groups were included. When reference cultures were examined by the typing system from which they were described, the results generally correlated with those results published. However, serotypes determined by one typing system generally did not correlate with serotypes determined by another system. Cultures of a single serotype in one system often represented more than one serotype in another system. Results indicated that cultures with one or two serotyping antigens in common may differ in other antigens. Because of the antigenic complexity of P multocida and the nature of the antigens involved in each test, a reliable correlation or equality between serotypes determined by different typing systems could not be made.

The development and assessment of a bacteriocin typing method for Klebsiella.

Abstract: Klebsiellas are generally typed by the method of capsular serotyping but, although this is a reliable method, it is time consuming, requires the production of a large number of antisera and is not generally available. For this reason another method for typing klebsiellas was sought. A bacteriocin typing method involving mitomycin C induction was developed and the cultural conditions giving optimum klebecin production and the best methods of testing the sensitivity of the organisms to klebecins were determined. Of 190 klebsiella strains screened for bacteriocinogeny, only 68 (35.8%) produced klebecin and after calculation of similarity values by computer analysis, a typing set of 15 producers was selected. This typing set allowed over 96% of klebsiella strains to be typed and tests of the reproducibility of the method and the variability of typing patterns in natural populations of klebsiella indicated that results of acceptable accuracy could be obtained, while retaining good discrimination if two or more differences were required between patterns before they were regarded as distinct. A complete set of capsular antisera were prepared, enabling the results obtained from klebecin typing to be compared with those from serotyping. There was generally close agreement between the results from the two typing methods and greater discrimination was obtained between similar strains when the two methods were combined. Klebecin typing and serotyping revealed relationships between strains from five outbreaks of infection, and strains of the same serotype from different hospitals could frequently be distinguished by their klebecin typing patterns.

Bacteriophage typing of Salmonella weltevreden.

Abstract: Salmonella weltevreden has been found to be one of the commonest Salmonella serotypes isolated from diverse sources in India and has also been isolated in a number of other countries. A phage typing scheme was developed for this serotype using a set of six typing phages. These phages had been selected out of 146 phage strains isolated and purified from stool samples of man, laboratory animals and other animals, sewage and surface water sources, and the lytic mutants of temperate phages from S. weltevreden.

Phage typing of Vibrio cholerae using a new collection of phages.

Abstract: The authors formed a collection of typing phages in order to differentiate cholera vibrios of both biotypes. The collection consists of 7 phages proposed by Mukerjee for typing vibrios of the classical biotype and 3 El Tor phages isolated at the period of the 7th pandemy of cholera. In forming the typing collection the authors observed the following principles: 1) to crate a single set of typing phages and a single scheme of phage type differentiation of classical cholera and El Tor vibrios; 2) to use virulent phages; 3) to form a collection of serologically different phage types. The proposed collection allows to reveal a larger number of phage types as compared with phages proposed by Mukerjee phage typing a larger number of strains enhancing thus the epidemiological significance of the method of phage typing cholera vibrios.

Chapter VIII Methods for Bacteriophage Typing of Mycobacteria

Abstract: Publisher Summary This chapter discusses methods for bacteriophage typing of mycobacteria. The acceptance of the atypical mycobacteria into the realm of human infection (tuberculosis) appears to have stimulated several investigators to seek means of identifying and of showing relationships among the organisms that cannot be hustled. The first isolations of bacteriophages showing activity on the mycobacteria were followed by attempts to identify various strains or species of mycobacteria by phage typing. Phages that were active on more than one or two types appeared to have activity on saprophytic, atypical, and pathogenic bacteria, rendering them of little value as typing phages. The routine test dilution (RTD) has been defined as the high dilution of phage that can produce complete lysis of the propagating strain of bacteria. For typing Mycobacterium Tuberculosis , a given prototype strain is used to determine the RTD of each phage. Despite some problems, the RTD method of phage typing appears to be the most satisfactory procedure. The major difficulties encountered are because of the variations in susceptibility to the typing phages of bacterial strains from different sources.

Chapter V Bacteriophage Typing of Shigella

Abstract: Publisher Summary This chapter discusses bacteriophage typing of Shigella . Shigellosis constitutes a very significant problem on a world scale. In many countries—for example, in Scandinavia, shigellosis is now infrequent and usually not endemic but reflects imported cases. Shigella sonnei ( S. sonnei ) dominates with only rare isolates of Shigella Flexneri ( S. flexneri ). In non-industrialized countries, Shigella dysenteriae is more frequent than in industrialized nations, where S. sonnei and S. flexneri are the dominating species. Elucidating the source of a Shigella infection may present a considerable problem. Phage typing of the isolates may be an essential tool in both endemic and epidemic situations. Typing may be the only way to determine the source of infection of persons who have been exposed to several possible sources. Shigella is typed by a number of procedures, such as serological typing, biotyping, and bacteriocin typing, in addition to phage typing. Serotyping is not sufficiently distinctive in an epidemiological context but is invaluable for species diagnosis in this genus ( vide infra ).

Chapter III Methods of Typing Erysipelothrix insidiosa

Abstract: Publisher Summary This chapter discusses methods of typing Erysipelothrix insidiosa Bacteriophage and haemadsorption tests provide useful auxiliary typing methods They are simple to perform and can be carried out in most laboratories Undoubtedly, however, the most useful method is serological typing based on microprecipitation in agar In hemadsorption method desrcribed in the chapter, erythrocytes for the test were prepared from poultry, rabbit, sheep, and guinea pigs, and they were carefully washed several times with physiological saline The ability of strains to adsorb erythrocytes was determined by an examination of colonies grown on the surface of agar In view of this association of specific serogroups with different forms of the disease and with non-specific carriers, the development of rapid and simple methods of typing Erysipelothrix insidiom has assumed some importance in the study of the epidemiology of this organism Bacteriophage and hemadsorption tests provide useful auxiliary typing methods They are simple to perform and can be carried out in most laboratories

Phage typing and lysogen typing of Staphylococcus aureus

Abstract: A comparison was made between the results of phage and lysogenic typing of S. aureus strains isolated during several outbreaks of staphylococcal infection and S. aureus cultures isolated from the same carriers at different periods. The study of the groups of strains having the same origin showed that the differences in the number of reactions were more pronounced in lysogenic typing than in phage typing. For this reason lysogenic typing can be recommended only for the identification of those strains which cannot be identified with the use of the phages of the International Basic Set. The results of the experiments with induced phages proliferating in a restriction-defective strain indicated that restriction and modification were mainly responsible for the specificity of lytic reactions.

Epidemiological markers for Pseudomonas aeruginosa. VII. Nosocomial occurrence in urological ward. Comparison of two phage typing sets, pyocine typing, and serogrouping.

Abstract: A comparison of two pyocine typing methods with serogrouping, and two phage typing sets has been made. In one instance, a contaminated bladder irrigation fluid of 0.05% silver nitrate solution caused a series of urinary tract infections. By all systems, fewer of the presentstrains were typable than usual. Among the phage typing sets the one developed by LINDBERG et al. typed only 66% whereas that selected by BERGAN typed 83%, both less than observed previously. The set of LINDBERG et al. also rendered longer pattern codes, and yielded more variable results with related strains. A set of pyocine indicator strains, selected among the strains to be typed, was more suitable than one developed elsewhere. Comparison of five different methods of epidemiological typing of Ps. aeruginosa indicated that phage typing alone is not entirely satisfactory for this species and should therefore always be combined with serogrouping.

Pneumococcal type 4 typing sera cross-react with type 2 pneumococcus.

Abstract: Howard, A. J. (1977). Ampicillin resistance in Haemophilus influenzae (Leading article). Journal of Antimicrobial Chemotherapy, 3, 535-537. Kjellander, J., and Myrbach, K. E. (1964). A simple test for penicillinase-production (Abstract). Acta Pathologica et Microbiologica Scandinavica, 61, 494. O'Callaghan, C. H., Morris, A., Kirby, S. M., and Shingler, A. H. (1972). Novel method for detection of fi-lactamases by using a chromogenic cephalosporin substrate. Antimicrobial Agents and Chemotherapy, 1, 283-288. Slack, M. P. E., Wheldon, D. B., and Turk, D. C. (1977). A rapid test for ,-lactamase production by Haemophilus influenzae. Lancet, 2, 906. Smith, A. L. (1976). Antibiotics and invasive Haemophilus influenzae. New England Journal of Medicine, 294, 1329-1331. Thornsberry, C., Baker, C. N., Kirven, L. A., and Swenson, J. M. (1976). Susceptibility of ampicillinresistant Haemophilus influenzae to seven penicillins. Antimicrobial Agents and Chemotherapy, 9, 70-73.