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)

WIN 57273 is a new fluoroquinolone that has an expanded spectrum of activity against Staphylococcus spp. (MIC for 90% of isolates [MIC90], 0.008 microgram/ml), Enterococcus faecalis (MIC90, 0.06 microgram/ml), Bacillus spp. (MIC90, 0.03 micrograms/ml), Listeria monocytogenes (MIC90, 0.06 microgram/ml), Streptococcus spp. (MIC90, 0.03 microgram/ml), and Bacteroides fragilis group strains (MIC90, 0.5 microgram/ml). Like other fluoroquinolone compounds, WIN 57273 was active against members of the family Enterobacteriaceae (97% of strains inhibited by less than or equal to 2 micrograms/ml), Haemophilus, Branhamella, and Neisseria strains (100% susceptible), Acinetobacter spp. (100% susceptible), and Pseudomonas aeruginosa (68% susceptible). We observed that WIN 57273 was very active against cephalosporin- or aminoglycoside-resistant gram-negative strains but shared cross-resistance with other fluoroquinolones. Increasing inoculum concentrations had minimal effects on WIN 57273 MICs, and the drug was considered to be bactericidal based on reference MBC and kill curve analyses. Unlike most previously studied drugs in this class, WIN 57273 had increased activity (three- to fourfold) at low pH. Rates of mutation to WIN 57273 resistance at eight times its MIC were in the range of 5.6 x 10(-8) to greater than 1.4 x 10(-9). This new compound possesses a wide potential spectrum of use, and it should be evaluated further by in vitro and in vivo studies.
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PMID:In vitro evaluation of WIN 57273, a new broad-spectrum fluoroquinolone. 232 79

Four methods of MIC and MBC determination were examined to compare their reproducibility and ability to detect penicillin tolerance. The MIC and MBC of penicillin were determined for 28 strains of viridans streptococci by a microdilution method, a macrodilution method, a membrane method, and a gradient-plate method using a spiral-plating device. The macrodilution, membrane and gradient plate methods were found to be acceptable for MIC determination with a reproducibility to within one doubling dilution, but only the gradient method gave acceptable reproducibility for MBC determinations. The consequence of these findings with respect to penicillin tolerance is discussed.
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PMID:Comparison of four methods for the determination of MIC and MBC of penicillin for viridans streptococci and the implications for penicillin tolerance. 232 99

Inactivation of a range of antibiotics acting at different points in the metabolism of the bacterial cell was detected by estimating the MIC and MBC in the presence of liver and other tissue preparations. High temperature treatment and sonication of liver cells increased their ability to inactivate antibiotic action. This treatment would have almost completely destroyed enzyme activity, which was, therefore, not thought likely to be the cause of the phenomenon. The loss of antibiotic activity may be related to "protein binding" and a dialysis experiment showed that penicillin binding with liver homogenate was very much greater than with human albumin. It may be that increased disruption of tissue cells by physical methods exposes more active binding sites which reduces the bioavailability of antibiotics. Some degree of binding specificity was indicated in experiments in which DNA was shown to block antibiotics acting primarily on DNA--related synthesis and RNA blocked antibiotics acting on RNA--related metabolism. Suggestions are made for the cause of failure of antibiotic treatment in certain clinical situations.
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PMID:In-vitro antibiotic inactivation by mammalian cell and killed bacterial preparations. 244 Aug 44

A clinical isolate of Staphylococcus aureus was found to be tolerant (MBC much greater than MIC) to a number of beta-lactam antibiotics, including oxacillin. Biophotometric analysis showed that a number of concentrations of oxacillin were capable of stimulating rapid cellular lysis in this organism, but the extent of lysis was antibiotic concentration dependent and limited. Cell cultures treated with an antibiotic concentration yielding the maximum rate and extent of lysis were analyzed for protein and RNA synthesis by pulse-labeling techniques. RNA synthesis was initially stimulated and then severely inhibited. Protein synthesis was not inhibited initially; however, the increase in the rate of synthesis expected as the result of logarithmic growth was not observed. Instead, the antibiotic-treated culture maintained for approximately 50 min the rate of protein synthesis ongoing at the time of antibiotic addition. The rate of protein synthesis declined thereafter. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of protein samples taken 1 and 3 h after antibiotic addition showed that the shutdown of protein synthesis was not coordinate but rather was suggestive of the operation of a stress regulon perhaps similar to those responsible for heat shock, SOS, and oxidation stress.
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PMID:Oxacillin-induced inhibition of protein and RNA synthesis in a tolerant Staphylococcus aureus isolate. 245 Aug 70

The bactericidal activities of four injectable antituberculosis drugs, streptomycin, amikacin, kanamycin, and capreomycin, against Mycobacterium avium and M. tuberculosis were tested. All four drugs were highly bactericidal against M. tuberculosis, with low MBC/MIC ratios and MBCs significantly lower than the maximum achievalbe concentrations in serum (Cmax). In contrast, all four drugs had very low bactericidal activities against M. avium: the broth-determined MBCs were significantly higher than the Cmax. On a basis of comparisons with the broth-determined MICs found for susceptible M. tuberculosis strains and with the Cmax, about one-third of 100 M. avium strains tested can be tentatively considered as susceptible to three aminoglycosides (streptomycin, amikacin, and kanamycin) but not to capreomycin. In regard to the MBCs and MICs, the three aminoglycosides tested have about identical potentials as drugs of choice in combination with other drugs for chemotherapy of M. avium disease. The low bactericidal activities of these drugs against M. avium in vitro do not exclude their therapeutic usefulness, because they may produce a synergistic effect in combination with other drugs. Such an option is especially promising for patients whose isolates can be considered susceptible on the basis of the MIC. We found no differences in susceptibility to the four drugs tested for M. avium strains (identified by Gen-Probe) isolated from 50 patients with and 50 patients without acquired immune deficiency syndrome.
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PMID:Comparison of bactericidal activities of streptomycin, amikacin, kanamycin, and capreomycin against Mycobacterium avium and M. tuberculosis. 232 85

The association of penicillin-tolerant streptococci with reported epidemics of streptococcal pharyngitis in Israel was studied. The streptococcal strains had been isolated during 11 epidemics of community-acquired pharyngitis and 6 food-borne epidemics of pharyngitis occurring in the last 15 years. Strains were stocked lyophilized. Isolates were defined as tolerant if the MBC/MIC ratio for penicillin was greater than or equal to 32. All 122 group A streptococcal strains isolated during the epidemics of community-acquired infection showed tolerance to penicillin. In contrast, none of the 52 strains from food-borne epidemics (24 group A, 18 group C and 8 group G) was tolerant.
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PMID:Association of penicillin-tolerant streptococci with epidemics of streptococcal pharyngitis in closed communities. 250 25

The in vitro activity of the 4-quinolone compound fleroxacin (Ro-23-6240) was compared with that of 14 other antimicrobials against a total of 50 recent clinical isolates of 25 slime- and 25 non-slime-producing coagulase-negative staphylococci. Susceptibility testing (MIC/MBC) was performed by a microtiter broth dilution technique and the combination effect of fleroxacin plus rifampin was studied by checkerboard titration in microtiter trays. Fleroxacin inhibited the most slime- and non-slime producing coagulase-negative staphylococci at MIC90 0.25 and I micrograms/ml, respectively. Overall fleroxacin was as active or even better as ofloxacin, cefotiam, cefazolin, cefamandole, clindamycin or vancomycin but 2- to 8-fold less active than rifampin. The fleroxacin-rifampin combination was indifferent in 17%, additive in 78.7% and synergistic in 4.3%.
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PMID:In vitro activity of fleroxacin and 14 other antimicrobials against slime- and non-slime-producing Staphylococcus epidermidis. 250 34

We have tested the ability of hyperoxia (98% O2-2% CO2 at 2.8 atmospheres absolute [ca. 284.6 kPa]) to enhance killing of Escherichia coli (serotype O18 or ATCC 25922) by nitrofurantoin, sulfamethoxazole, trimethoprim, gentamicin, and tobramycin. We have also looked for interactions between hyperoxia and the aminoglycosides against Pseudomonas aeruginosa ATCC 27853. Hyperoxia significantly enhanced bacteriostatic activity of nitrofurantoin and trimethoprim as measured by MIC testing. The possibility exists that these effects might be due to the method required to tests MICs under hyperoxic conditions rather than to the effect of hyperoxia itself. In addition, hyperoxia enhanced killing of bacteria by trimethoprim as measured by MBC testing. Hyperoxia decreased numbers of E. coli by 1.3 log10 and P. aeruginosa by 2.7 log10 in cation-supplemented Mueller-Hinton broth medium. The bacteriostatic effects of hyperoxia did not affect MICs of gentamicin or tobramycin. The lack of interaction between hyperoxia and gentamicin or tobramycin was confirmed by determining the number of viable bacteria remaining after 24 h of exposure to hyperoxia by using a pour plate method. We conclude that hyperoxia potentiates the antimicrobial activity of the reduction-oxidation-cycling antibiotic tested (nitrofurantoin) and of one of the antimetabolites tested (trimethoprim). Hyperoxia does not enhance the bactericidal effects of gentamicin and tobramycin, which require oxidative metabolism for transport into bacterial cells.
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PMID:Hyperoxia and the antimicrobial susceptibility of Escherichia coli and Pseudomonas aeruginosa. 251 May 93

Cefixime (CFM) is a new hemi-synthetic orally active cephalosporin which exhibits a particular affinity for PBPs 3, 1a, 1bs. Its penetration through the Gram negative bacilli outer membrane is similar to that of third generation cephalosporins. The MICs were assessed by the agar dilution method against 2,489 bacterial strains collected in 10 hospitals. Against Enterobacteriaceae, MICs50 and 90 are respectively (mg/l): naturally non beta-lactamase-producing species: E. coli and Shigella: 0.25-0.5, Salmonella: 0.06 - 0.25, P. mirabilis: 0.008 - 0.0.32; chromosomal penicillinase producing species: Klebsiella: 0.06 - 2; chromosomal cephalosporinase producing species: E. cloacae and C. freundii: 1 - greater than 128, S. marcescens: 0.25 - 16, Proteus indole: + 0.06 - 4, P. stuartii: 0.032 - 0.5. CFM activity is not altered in strains producing an acquired penicillinase. On the other hand, CFM appears to be inactive against cephalosporinase hyperproducing mutants and its activity is variably decreased against expanded spectrum beta-lactamase producing strains. CFM is inactive against P. aeruginosa (MIC50 and 90: 64 - 128) and against A. baumannii (16 - 128). Haemophilus and gonococci, beta-lactamase producing or not, as well as meningococci, are highly susceptible to CFM (MIC 0.008 - 0.12). B. catarrhalis is usually inhibited by 0.03 to 0.5. CFM is moderately active against meticillin-sensitive staphylococci (MIC50 and 90: 1-64), and inactive against meticillin-resistant strains. Enterococci are usually resistant, whereas streptococci and pneumococci are inhibited by low concentrations: 0.08 to 1. CFM is a bactericidal antibiotic, as shown by MBC and killing curves determination. These antibacterial properties relate CFM to the third generation cephalosporins and position the compound in an excellent place among the orally active cephalosporins.
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PMID:[Antibacterial effect of cefixime]. 253 May 28

In vitro lomefloxacin was highly active against 208 penicillin-susceptible and -resistant isolates of Neisseria gonorrhoeae. However, its MIC and MBC against 10 isolates of Chlamydia trachomatis were 2 and greater than 4 micrograms/ml, respectively.
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PMID:In vitro activities of lomefloxacin, tetracycline, penicillin, spectinomycin, and ceftriaxone against Neisseria gonorrhoeae and Chlamydia trachomatis. 253 73


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