Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:Q29983 (MIC)
 21,138 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Indole-3-propionic acid (IPA), a phytohormone derivative, is a potent inhibitor of growth of Legionella pneumophila cultivated extracellularly in a chemically defined hypotonic medium and intracellularly in human monocytes. The inhibitory activity turns into bactericidal activity with increasing concentrations. The susceptibility of the microorganism to IPA was more evident in "fast-growing" cultures (under conditions of vigorous shaking) than in static cultures growing under an atmosphere of 5% CO2-95% air, which resulted in a decreased growth rate. The MIC, after incubation with the drug for 48 h and as determined by counting of the CFU, was 1.58 microM for fast-growing cultures and 2.64 microM for those grown under static conditions. The MBCs were 5.28 and 26.43 microM, respectively. Tryptophan (Trp) at 150 microM prevented the inhibition caused by 2.64 microM IPA, increased the MIC about 3-fold, and increased the MBC by 10-fold. The effect of Trp was less remarkable in "slow-growing" cultures. The susceptibility of L. pneumophila proliferating in human monocytes was markedly lower than that when it was cultivated extracellularly in the chemically defined hypotonic medium. The MIC after incubation for 48 h was 5.28 microM, and a decrease in viable count was achieved with 105.70 microM. The lower susceptibility was apparently due (at least partially) to the presence of Trp (24.50 microM) in the RPMI 1640 medium that was used for the monocyte cultures. The effect of IPA was time dependent, and prolonged exposure enhanced the bactericidal activity and turned the inhibitory dose into a bactericidal dose. The present data demonstrate that IPA is a potent anti-L. pneumophila factor, although it has a markedly lower activity against bacteria growing intracellularly compared with its activity against extracellularly proliferating microorganisms.
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PMID:Susceptibility of Legionella pneumophila grown extracellularly and in human monocytes to indole-3-propionic acid. 181 Jan 85

Clarithromycin is metabolised in man mainly to the 14-hydroxy derivative, which is also biologically active. As this metabolite is not produced in rodents, we used a murine model of Haemophilus influenzae pulmonary infection to compare the in-vivo activity of clarithromycin and 14-hydroxy clarithromycin, alone and in combination, and erythromycin. In terms of bacterial killing, clarithromycin's 14-hydroxy metabolite was much more active than clarithromycin and erythromycin at doses of 100 mg/kg. For the combination tests, low doses of 14-hydroxy clarithromycin (12, 16 and 24 mg/kg) were ineffective alone but potentiated the bactericidal activity of clarithromycin (100 mg/kg) (P less than 0.01-0.001). The in-vivo results can be explained by in-vitro and pharmacokinetic data: the MIC and MBC of 14-hydroxy clarithromycin are half those of clarithromycin and erythromycin, while the combination of clarithromycin and its metabolite was synergistic in terms of bacteriostatic and bactericidal activities. Potentially useful levels of 14-hydroxy clarithromycin were found after oral administration of low doses, with a prolonged half-life compared with that of the parent compound. On the basis of these results it appears that the 14-hydroxy metabolite may have an important role to play in the treatment of bronchopulmonary infections in man due to H. influenzae.
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PMID:Individual and combined activities of clarithromycin and its 14-hydroxy metabolite in a murine model of Haemophilus influenzae infection. 182

Mycobacterium avium complex bacteria are opportunistic human pathogens, and their chemotherapy remains a challenge since these organisms are resistant to a majority of routine antituberculous drugs. Recently, a wide range of new macrolide antibiotics has been developed, among which the drug clarithromycin appears to have a selective action against M. avium bacteria. In the present study, we have investigated the action of clarithromycin alone (MIC and MBC determinations) and in association with the routine antimycobacterial drugs ethambutol and rifampin at sublethal concentrations (1 micrograms/ml; below concentrations obtainable in human serum) against M. avium. Our viable count data showed that clarithromycin was bactericidal against all 10 strains of M. avium studied and that its activity was enhanced by ethambutol (in 8 of 9 strains) and rifampin (in 3 of 9 strains). The use of all three drugs in association resulted in higher bactericidal effects than found with any of the drugs used alone or in two-drug combinations in seven of nine strains. The bactericidal effects of various drugs used alone and in combination at concentrations obtainable in human serum were investigated against the type strain ATCC 15769 by using 7H9 broth and BACTEC radiometry (extracellular action) and a J-774 macrophage cell line (intracellular action). A good agreement between the extracellular and intracellular activities was found. Electron microscopy using a ruthenium red cytochemical staining of the bacteria showed that clarithromycin disorganized the outer wall layer and the cytoplasmic membrane in the mycobacterial cell envelope and resulted in formation of large vacuoles inside the cytoplasm, with solubilization of ribosomal structures and consequent plasmolysis. Its association with ethambutol and rifampin resulted in more drastic alterations in the bacterial morphology than were seen with any of the drugs used alone, leading to the removal of the bacterial outer layer, homogenization of cytoplasm, complete cell lysis, and formation of ghosts.
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PMID:Extracellular and intracellular activities of clarithromycin used alone and in association with ethambutol and rifampin against Mycobacterium avium complex. 182 35

The in vitro activity of sparfloxacin (AT-4140; RP 64206), a new fluoroquinolone, was compared with those of 10 other agents against 1,222 clinical isolates. Sparfloxacin and ciprofloxacin were the most active quinolones against members of the family Enterobacteriaceae and nonfermenting gram-negative bacilli; sparfloxacin had superior activity against gram-positive cocci in comparison with the activities of ciprofloxacin and the other quinolones tested (norfloxacin, lomefloxacin, and pefloxacin). Among the inhibited strains, several were resistant to the tested beta-lactam antibiotics or to aminoglycosides. The activity of sparfloxacin was not influenced by the medium that was used; lowering of the pH to 5 had a marked effect on the MICs for two strains each of Enterobacter cloacae and Pseudomonas aeruginosa and one strain each of Escherichia coli and Staphylococcus aureus; the MBC of sparfloxacin was within 1 to 2 dilution steps of the MIC for the strains that were tested.
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PMID:Comparative in vitro antibacterial activity of sparfloxacin (AT-4140; RP 64206), a new quinolone. 185 67

Sanguinaria extract, which contains benzophenanthridine alkaloids, has been used as a folk medicine for many years. Minimum inhibitory and minimum bactericidal concentrations (MIC and MBC values) for sanguinarine were determined for common and etiologically important plaque bacteria. Because the efficacy of sanguinarine is believed to be enhanced by zinc, isobolograms were assessed to determine their mode(s) of interaction. Hydrogen ion concentration influenced the inhibitory activity of both sanguinarine and zinc. For sanguinarine, at the optimum pH (6.5), MIC values were 4 or 8 micrograms/ml for Streptococcus mutans, Streptococcus sobrinus, Streptococcus sanguis, Actinomyces viscosus and Actinomyces naeslundii. MIC values were 0.125-0.50 mmol Zn/ml. MBC values ranged from 1 to 8 mmol Zn/ml at pH 5.5. Isobologram data revealed that sanguinarine and zinc interacted synergistically. Viadent oral rinse, which contained 300 micrograms sanguinaria extract/ml and 0.2% zinc chloride (14.9 mmol Zn/l), was inhibitory to all strains tested. MIC values were 1 or 2% (ml Viadent oral rinse/100 ml aqueous solution) for all strains except A. viscosus for which the MIC value was 12% (vol/vol).
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PMID:Interactions of sanguinarine and zinc on oral streptococci and Actinomyces species. 187 16

Lomefloxacin has marked activity against Gram-negative bacilli including Enterobacteriaceae, non-fermenting strains and Haemophilus influenzae with 98% of all isolates tested having MICs of 0.25 mg/l or less. Sixty-eight per cent of Pseudomonas aeruginosa strains were sensitive to 1 mg/l with a few strains resistant to 8 or 16 mg/l. Gram-positive cocci were more resistant, particularly streptococci, where the MICs vary between 1 and 8 mg/l. Bactericidal activity was similar to inhibitory activity and the effect of increasing serum concentrations and bacterial inocula was minimal. The MIC and MBC were increased in the presence of urine, particularly at an acid pH 5. Comparative MICs showed that lomefloxacin was more active than ofloxacin and pefloxacin, similar to norfloxacin but less active than ciprofloxacin for Gram-negative bacteria but not for Gram-positive cocci. Comparative studies with sensitivity disc concentrations showed that a 5 micrograms disc was more satisfactory than the 10 micrograms disc as the zone sizes were more suitable for routine testing. Solutions of lomefloxacin showed instability in bright sunlight when 52% of activity was lost in 1 h. Similar instability was shown in impregnated discs which lost up to 40% activity in 6 h exposure. Lomefloxacin showed a wide range of activity against Gram-negative bacteria including multiresistant strains and Pseudomonas spp. Gram-positive bacteria were less susceptible, with streptococci more resistant than staphylococci. Lomefloxacin is well absorbed after oral administration giving high blood and urine concentrations and its prolonged half-life means once daily dosing in the treatment of many types of bacterial infection may be possible.
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PMID:Antibacterial activity of lomefloxacin. 188 17

Meropenem was compared with imipenem and nine other antimicrobial agents, against 101 strains of the Bacteroides fragilis group. Meropenem was active against all strains tested, and its activity was similar to, and in many cases better than, that of imipenem. The activity of meropenem was similar to that of metronidazole, and greater than that of the other antimicrobial agents tested. The bactericidal activity of meropenem against B. fragilis was impressive, since the MBC to MIC ratios were no greater than two. The bactericidal activity was confirmed by time-killing curve assays with two strains which showed that meropenem was rapidly bactericidal and reduced the initial inoculum significantly during the first 4-6 h. The postantibiotic effect of meropenem (2-4 h) and a sub-inhibitory concentration of 1/4 x MIC suggested that meropenem interferes with the normal growth of B. fragilis, even when administered concentrations fall below the MIC. MICs of meropenem were affected minimally by the pH of the medium or by an increase in inoculum size. Meropenem continued to have good activity against a B. fragilis strain that had been induced for the production of cephalosporinase. The in-vitro data presented in this paper indicate that meropenem is a promising antimicrobial agent which may be useful in the treatment of problematic mixed infections.
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PMID:Meropenem: in-vitro activity and kinetics of activity against organisms of the Bacteroides fragilis group. 188 18

Minimal inhibitory and bactericidal concentrations (MIC and MBC) of isoniazid and ethionamide were determined in 7H12 broth in experiments with 68 Mycobacterium avium strains and 14 wild drug-susceptible M. tuberculosis strains. MICs of isoniazid for M. tuberculosis were from 0.025 to 0.05 microgram/ml, and for M. avium from 0.6 to greater than 10.0 micrograms/ml. MICs of ethionamide for M. tuberculosis were from 0.3 to 1.25 micrograms/ml, and 42.7% of M. avium strains were within the same range. Isoniazid and ethionamide were highly bactericidal against M. tuberculosis, but they had very low bactericidal activity against M. avium.
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PMID:Comparison of bacteriostatic and bactericidal activity of isoniazid and ethionamide against Mycobacterium avium and Mycobacterium tuberculosis. 189 26

Because persistence of infections associated with prosthetic material despite the use of appropriate antibiotics is a major clinical problem, the antimicrobial susceptibility of bacteria responsible for a chronic subcutaneous tissue cage infection in rat was investigated ex vivo. Three to 6 weeks after the initiation of infection, suspensions of two strains of Staphylococcus aureus recovered from the foreign body surface and surrounding fluid were exposed to either oxacillin, vancomycin, fleroxacin, gentamicin, or rifampin. The MBCs of these bacteria were markedly elevated, in most cases 128 to greater than 256 times higher than the MBC of batch culture S. aureus in either logarithmic or stationary phase. Kinetic studies showed the bacteria did not grow when incubated for 2 h in Mueller-Hinton broth, possibly reflecting dormancy. Their killing was slow and incomplete by all antibiotics at greater than 8 times their MIC. These data provide direct evidence of a decreased susceptibility of S. aureus to the killing effect of antimicrobials during chronic foreign body infections in vivo.
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PMID:Resistance of Staphylococcus aureus recovered from infected foreign body in vivo to killing by antimicrobials. 190 1

The in vitro and in vivo activity of cefpirome (CF) against Enterococcus faecalis GK strain was examined. The ratio of minimal inhibitory to bactericidal concentration (MIC/MBC) values in microgram/ml were (a) ampicillin 0.8/1.5; (b) gentamicin 2/25; (c) vancomycin, 0.8/50; and (d) CF, 8/32. A time-kill study using 10(7) organisms per milliliter showed a drop of 3 logs10 at 4 hr in the tube containing cefpirome (10 micrograms/ml) as well as the tube containing cefpirome (5 micrograms/ml) plus gentamicin (GM) (2 micrograms/ml), as compared to the control and the tube containing GM at 4 micrograms/ml. At 8 and 24 hr, however, regrowth to control levels occurred. Of this enterococcal strain consisting of 10(8) organisms, 1 ml was then injected intravenously by tail vein into 150 male Wistar rats weighing 120 g each. Eleven days after injection, 10 rats were killed and the remaining ones were randomized into four treatment groups: (a) untreated control; (b) BM, 0.9 mg; (c) CF, 10 mg; and (d) CF + GM. The rats received the injections intramuscularly twice daily. At least 10 rats from each group were killed for quantitative kidney cultures at 1, 2, and 4 weeks after start of therapy. At the end of 4 weeks of therapy, the results were significantly better in the combination group compared to the other three groups.
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PMID:Cefpirome, alone and in combination with gentamicin for enterococcal pyelonephritis in the rodent model. 190 13


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