Antibiotics and the Aberdeen typhoid outbreak in 1964.
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This paper gives an abbreviated account of part of a research programme which followed the Aberdeen typhoid outbreak in 1964. Chloramphenicol, the main antibiotic used in treatment, was shown to have a minimum inhibitory concentration (MIC) of between 5 and 2-5 mug./ml. for the S. typhi phage type 34 of the outbreak. The MIC for methacycline was between 5 and 2-5 and 2 mug./ml. Whereas the deep and shallow broth techniques used gave similar results with these antibiotics, the MIC for ampicillin, and also cephaloridine, was less in the deep than in the shallow broths. Serum assays in patients given ampicillin or cephaloridine yielded abnormally high concentrations of both antiboitics when S. typhi phage type 34 was the test organism whereas, with other test organisms, the concentrations were within expectation. These abnormally high values fell within expected values when the sera under investigation had first been heated to 56 degrees C. for 30 min. before assay against the S. typhi of the outbreak. The findings with ampicillin suggested that dosages given were satisfactory. With cephaloridine the concentrations found in patients' sera seemed to show that twice daily doses of 0-5 g. fell short of adequacy. (+info)
Lysozyme-enhanced europium(III)-metacycline luminescence and its application to the determination of metacycline.
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A new spectrofluorometric method is described for the determination of metacycline (MC), based on modified enzyme-amplified lanthanide luminescence. Under the optimum conditions, Eu3+-MC forms a ternary complex with lysozyme in close proximity. Then lysozyme can remarkably enhance the characteristic fluorescence intensity of Eu3+ at 612 nm in metacycline-Eu3+ binary complex. The enhanced fluorescence intensity is in proportion to the concentration of MC. The limit of detection is 1.6 x 10(-8) mol L(-1), with a linear range from 6.2 x 10(-6) to 1.7 x 10(-5) mol L(-1). Interferences of other coexisting substances were studied. The developed method was successfully applied to the determination of MC in serum and urine samples. The mechanism of fluorescence enhancement was also studied. (+info)
Quantitative analysis of methacycline hydrochloride by direct potentiometry using the internal solid contact sensor.
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An internal solid contact sensor (ISCS) for the determination of methacycline hydrochloride (MC.Cl), Pt/PPy/PVC(MC-PT), is described, based on the use of conducting poly(pyrrole) (PPy) as solid contact material and MC-phosphotungstate (PT) as the ion exchanger and dibutyl phthalate (DBP) as the plasticizer. A direct potentiometric method for the quantitative analysis of MC.Cl is also described. Under the condition of pH 2.7, the linear concentration range, slope (25 degrees C) and detection limit of the sensor are 6.4 x 1.0(-6) - 3.0 x 1.0(-3) M, 52.4 +/- 0.2 mV/decade and 4.4 x 1.0(-6) M, respectively. The response time is <5 s. The determinations of MC.Cl in tablets were carried out by direct potentiometry. The average recovery and relative standard deviation are 100.1 and 0.7% (n = 4), respectively. (+info)
International standards and international reference preparations: amphotericin B, vancomycin, capreomycin, cefalotin, demethylchlortetracycline, gentamycin, gramicidin S, kanamycin and kanamycin B, lincomycin, lymecycline, methacycline, paromomycin, rifamycin SV, ristocetin and ristocetin B, spiramycin, and triacetyloleandomycin.
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Each of the preparations described here was obtained and evaluated at the request of a WHO Expert Committee on Biological Standardization. Unless otherwise stated, a standard procedure was used to distribute the material into individual ampoules. The procedure was as follows. Upon receipt by the National Institute for Medical Research (NIMR), London, materials were stored temporarily in the dark at a temperature of -10 degrees C or lower, and protected from moisture. At a convenient time they were brought back to room temperature, mixed, and distributed into individual neutral glass ampoules so that each ampoule contained 50-100 mg of powder. If it was known that the material was light-sensitive non-actinic glass ampoules were used. After exhaustive drying in vacuum over phosphorus(V) oxide, the ampoules were either constricted (up to 1963) or fitted with capillary leak plugs, dried for a further period under the same conditions, filled with dry nitrogen, and sealed by fusion of the glass. The total drying period varied from 8 to 38 days according to the nature of the material. After they had been tested for leaks, the ampoules were stored in the dark at -20 degrees C. (+info)
The effect of minocycline on Candida albicans.
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Minocycline, a new tetracycline derivative, was found to inhibit the growth of Candida albicans. Inhibition was much affected by the composition of the medium and was difficult to demonstrate in fluid cultures. Study of the rate of budding in shallow broth cultures in Petri dishes showed that the addition of 20 mug/ml minocycline prolonged the lag phase by three hours. C. tropicalis was similarly inhibited and C. guilliermondii and C. parapsilosis to a lesser degree. Six other tetracyclines were tested and found to inhibit Candida only in very high concentrations. (+info)
Activity of methacycline, related tetracyclines, and other antibiotics against various L-forms and their parent bacteria in vitro.
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The activity of methacycline against microbial L-forms and their parent bacteria was compared with that of oxytetracycline, chlortetracycline, tetracycline, and demethylchlortetracycline, as well as with that of 22 other antibiotics which included examples of major groups of antibiotics. The L-forms and bacteria used were Streptococcus faecalis, S. faecium, S. faecalis var. zymogenes, Staphylococcus aureus (three strains), Proteus mirabilis (two strains), Pseudomonas aeruginosa, Escherichia coli (two strains), Sarcina flava, Serratia marcescens, and Klebsiella pneumoniae. The five tetracyclines had similar activities and were more active against L-forms than bacterial forms, except that the bacterial form of S. flava was more susceptible than the L-form. In general, other antibiotics (except the penicillins) were more active against L-forms than bacterial forms. There were certain exceptions where the bacterial form was more susceptible than the L-form. These included the effect of polymyxin B and colistin on P. aeruginosa, E. coli, and P. mirabilis, and the effect of gentamicin on P. aeruginosa, E. coli, S. flava, and S. marcescens. (+info)
Susceptibility in vitro and in vivo of Pseudomonas pseudomallei to rifampin and tetracyclines.
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Tests were performed on 64 strains of Pseudomonas pseudomallei to compare rifampin, various tetracyclines, and other antibiotics for inhibitory activity in vitro. Rifampin minimum inhibitory concentration (MIC) values generally fell between 25 to 50 mug/ml. For deoxycycline, methacycline, tetracycline, and minocycline, MIC means ranged from 1.3 to 2.7 mug/ml. Delayed treatment tests in subacute mouse infections revealed a better rifampin activity than was expected from its weak activity in vitro, whereas of the others, minocycline appeared superior. None of these five antibiotics demonstrated fully curative effectiveness in terms of mouse survival or eradication of residual infection in organs. (+info)
Interference of iron with the absorption of tetracyclines in man.
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Ferrous sulphate administered together with tetracycline and three of its derivatives-oxytetracycline, methacycline, and doxycycline-was found seriously to impair the absorption of these antibiotics. Thus even small doses of iron taken simultaneously should be avoided during tetracycline treatment. (+info)