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A REYN

Publications and source records attributed to A REYN.

At least 19 recordsLinked to original sources
PubMed1965

A NEW SOLID MEDIUM FOR THE ISOLATION OF NEISSERIA GONORRHOEAE.

Biological products have been widely used in media intended for the primary isolation of Neisseria gonorrhoeae. Most of these substances are expensive and, in some places, difficult to procure. Ascitic fluid, which has been extensively used, is becoming increasingly rare. On the other hand, attempts to replace these biological substances by chemical compounds have met with little success, and a satisfactory synthetic medium does not exist. The authors describe the laboratory preparation of a reproducible medium which does not contain any fresh biological substances. It was developed from a routine "chocolate medium" which contained ascitic fluid and heated horse blood. Experiments with sparsely growing fresh laboratory strains showed that the ascitic fluid could be replaced by a combination of yeast and liver autolysates and the horse blood by haemoglobin. This Haemoglobin-Yeast-Liver (HYL) medium proved to be well suited for the primary isolation of N. gonorrhoeae and preliminary experiments indicated that it might also be suitable for use as a reference medium in sensitivity determinations. Attempts to use yeast and liver autolysates to replace ascitic fluid in a fermentation medium which did not contain blood or haemoglobin were less successful. Germination on the modified medium was relatively poor and it seems that the addition of a protective agent, such as albumin or starch, will be necessary.

Animals↗
PubMed1965

RESULTS OF COMPARATIVE EXPERIMENTS USING DIFFERENT METHODS FOR DETERMINING THE SENSITIVITY OF NEISSERIA GONORRHOEAE TO PENICILLIN G.

Between 1957 and 1960 a decrease in the sensitivity of Neisseria gonorrhoeae to penicillin was observed in many parts of the world, but the ranges of sensitivity and the distribution of strains within these ranges varied in different countries. It was not known, however, whether these differences were real or due to the different methods of sensitivity determination used. The collaborative study described in this paper was sponsored by WHO with the object of developing an international reference method for use in epidemiological and interlaboratory studies. Fourteen gonococcal strains, representing a wide range of sensitivity to penicillin, were tested in the three participating laboratories, using two plate dilution methods and a tube dilution method. When the strains were arranged in order of sensitivities, the order was the same whichever method was used, but the levels of sensitivity showed considerable differences, particularly for the less sensitive strains. Good agreement was obtained when the technique of one laboratory was repeated in another. On the basis of the results, it is recommended that an international reference method should use a plate dilution technique and a provisional medium is suggested for this method. It is probable that better agreement between different methods could be achieved by the use of reference strains which would enable a correction factor to be applied. Three gonococcal strains that might prove suitable for this purpose are suggested.

Drug Resistance, Microbial↗
PubMed1965

DETERMINATIONS OF THE SENSITIVITY OF NEISSERIA GONORRHOEAE TO PENICILLIN PERFORMED ON SOLID MEDIA OF DIFFERENT COMPOSITION.

The increasing frequency of strains of Neisseria gonorrhoeae with reduced sensitivity to penicillin is making it more and more important to determine the sensitivity of individual strains before and after treatment with this antibiotic. It was recently demonstrated that the concentrations of penicillin inhibitory to Neisseria gonorrhoea depend upon the medium employed. This important observation made it desirable to have available for interlaboratory comparisons a non-commercial reproducible medium which would support the growth of the vast majority of the gonococcal strains in circulation. Using a plate dilution procedure, various modifications of the HYL medium described elsewhere were compared with the routine medium for carrying out sensitivity determinations. Both stock and fresh strains of Neisseria gonorrhoeae were used in the experiments. The 50% inhibitory concentrations observed on the two media did not differ to any great extent, being only about 40% higher on the routine medium than on the HYL medium. The difference between the HYL medium and the routine medium was somewhat greater for the less sensitive strains than for the more sensitive strains. The variations in the difference from strain to strain were larger for the more sensitive fresh strains than for the less sensitive strains and the stock strains. This observation limits the value of a correction method employing, for example, three reference strains as a means of ensuring comparability between the results of different laboratories.

Anti-Bacterial Agents↗
PubMed1961

Possible effects of antibiotic treatment on the senstivity and growth requirements of Neisseria gonorrhoea.

The decreased sensitivity to penicillin of Neisseria gonorrhoeae has been a cause of concern during recent years. About 25% of strains sent in for routine diagnosis to the Statens Seruminstitut in 1957 were found to require roughly 20 times as much penicillin to inhibit development completely as was required for strains isolated in 1944. The stability of this reduced sensitivity to penicillin was studied in 20 strains which were subcultured daily on medium without penicillin. A comparison was also made between the sensitivity levels to penicillin and streptomycin for 1957 and 1958. A phenomenon possibly resulting from penicillin therapy of gonorrhoea was noted by the authors in June 1957, when they recorded the appearance of atypical strains having special growth requirements, low viability and weak or absent glucose-fermentation. The incidence, serology and sensitivity to antibiotics of these atypical strains were examined; further research on their different behaviour in response to changes in medium, as compared with that of typical strains, may give rise to some interesting findings.

Anti-Bacterial Agents↗