Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0023241 (Legionella)
 6,990 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The in-vitro activity of RP 59500 was determined against 1051 recent clinical bacterial isolates. The susceptibility to RP 59500 was determined with an agar dilution technique for all the isolates, while MICs and MBCs were determined for 82 selected strains in broth. Isolates of both Staphylococcus aureus and coagulase-negative staphylococci appeared to be potentially susceptible to RP 59500, independent of susceptibility to methicillin or MLS resistance. (S. aureus: methicillin-sensitive, MIC90, 1.0 mg/L; methicillin-resistant, MIC90 1.0 mg/L; coagulase-negative staphylococci: methicillin-sensitive, MIC90 0.5 mg/L). Lancefield group A, B, C and G streptococci (MIC50 0.5 and MIC90 1.0 mg/L) and Streptococcus pneumoniae (MIC50 0.5 and MIC90 1.0 mg/L) appeared to be susceptible to RP 59500. Some Streptococcus spp. and enterococci as well as Listeria monocytogenes were inhibited by a higher concentration of RP 59500 (enterococci: MIC90 4 mg/L, range 0.125-16 mg/L). Comparatively low MICs were seen when Legionella spp., Neisseria gonorrhoeae and Gardnerella vaginalis were tested. Broth dilution MIC/MBC determinations showed no evidence of tolerance, as MIC values were within two dilutions of MBC values. RP 59500 might be a useful compound in the treatment of infections caused by a range of Gram-negative and Gram-positive bacteria, including those resistant to methicillin and/or macrolides.
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PMID:A collaborative study of the in-vitro sensitivity to RP 59500 of bacteria isolated in seven hospitals in France. 139 51

The in vitro activity of MC-352, 3,4'-dideoxy-5-O-mycaminosyltylonolide, was compared with those of erythromycin, clarithromycin, and rokitamycin. The MC-352 MIC90 (MIC for 90% of isolates) for erythromycin-susceptible Staphylococcus aureus and Staphylococcus epidermidis was less than or equal to 1 microgram/ml, similar to those of the other agents. The MC-352 MIC50 for erythromycin-resistant S. aureus was 2 micrograms/ml, similar to that of rokitamycin. The MC-352 MIC90 (0.12 micrograms/ml) for Streptococcus pyogenes was similar to those of erythromycin and clarithromycin and superior to that of rokitamycin, and the MC-352 MIC90 for group B, C, and G streptococci was 0.25 microgram/ml. MC-352 and clarithromycin had an MIC90 of 0.12 microgram/ml for Streptococcus pneumoniae. Erythromycin-susceptible Enterococcus faecalis was inhibited by MC-352 at 1 microgram/ml, but the MIC for constitutively erythromycin-resistant isolates was greater than 16 micrograms/ml. Legionella pneumophila was inhibited by less than or equal to 0.25 microgram/ml. MC-352 was the most active agent against Bacteroides fragilis, with an MIC90 of 8 micrograms/ml, and was more active than the other agents against Haemophilus influenzae, with an MIC90 of 4 micrograms/ml. Moraxella spp. were inhibited by MC-352 at less than or equal to 0.25 microgram/ml. The MIC90 for Escherichia coli, Klebsiella pneumoniae, and Salmonella, Shigella, Yersinia, Enterobacter, Citrobacter, and Serratia spp. was greater than or equal to 32 micrograms/ml. MC-352 was bactericidal for S. pyogenes and S. pneumoniae, and its activity was not altered by human serum.
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PMID:In vitro activity of MC-352, a new 16-membered macrolide. 141 53

The activities of fleroxacin against 22 clinical Legionella isolates were determined by agar and broth microdilution susceptibility testing. The fleroxacin MIC required to inhibit 90% of strains tested on buffered charcoal yeast extract agar medium supplemented with 0.1% alpha-ketoglutarate was 0.64 micrograms/ml and was 0.04 microgram/ml when testing was done with buffered yeast extract broth supplemented with 0.1% alpha-ketoglutarate. Fleroxacin (0.25 microgram/ml) reduced the bacterial counts of two L. pneumophila strains grown in guinea pig alveolar macrophages by 1 log10 CFU/ml, but regrowth occurred over a 3-day period; fleroxacin was significantly more active than erythromycin in this assay. Single-dose (10 mg/kg of body weight given intraperitoneally) pharmacokinetic studies performed in guinea pigs with L. pneumophila pneumonia revealed peak levels in plasma and lungs to be 3.3 micrograms/ml and 3.5 micrograms/g, respectively, at 0.5 h and 0.8 microgram/ml and 0.8 microgram/g, respectively, at 1 h. The half-life of the terminal phase of elimination from plasma and lung was approximately 2 h. All 17 infected guinea pigs treated with fleroxacin (10 mg/kg/day) for 2 days survived for 14 days post-antimicrobial therapy, as did all 16 guinea pigs treated with the same dose of fleroxacin for 5 days. Only 1 of 16 animals treated with saline survived. The animals treated with fleroxacin for 2 days lost more weight and had higher temperatures than those treated with the antibiotic for 5 days. Fleroxacin is effective against L. pneumophila in vitro and in a guinea pig model of Legionnaires' disease. Fleroxacin should be evaluated as a treatment for human Legionnaires' disease.
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PMID:In vitro activities of fleroxacin against clinical isolates of Legionella spp., its pharmacokinetics in guinea pigs, and use to treat guinea pigs with L. pneumophila pneumonia. 148 82

Survival studies were conducted on Legionella pneumophila cells that had been grown intracellularly in Acanthamoeba polyphaga and then exposed to polyhexamethylene biguanide (PHMB), benzisothiazolone (BIT), and 5-chloro-N-methylisothiazolone (CMIT). Susceptibilities were also determined for L. pneumophila grown under iron-sufficient and iron-depleted conditions. BIT was relatively ineffective against cells grown under iron depletion; in contrast, iron-depleted conditions increased the susceptibilities of cells to PHMB and CMIT. The activities of all three biocides were greatly reduced against L. pneumophila grown in amoebae. PHMB (1 x MIC) gave 99.99% reductions in viability for cultures grown in broth within 6 h and no detectable survivors at 24 h but only 90 and 99.9% killing at 6 h and 24 h, respectively, for cells grown in amoebae. The antimicrobial properties of the three biocides against A. polyphaga were also determined. The majority of amoebae recovered from BIT treatment, but few, if any, survived CMIT treatment or exposure to PHMB. This study not only shows the profound effect that intra-amoebal growth has on the physiological status and antimicrobial susceptibility of L. pneumophila but also reveals PHMB to be a potential biocide for effective water treatment. In this respect, PHMB has significant activity, below its recommended use concentrations, against both the host amoeba and L. pneumophila.
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PMID:Relationship between Legionella pneumophila and Acanthamoeba polyphaga: physiological status and susceptibility to chemical inactivation. 151 90

Table 5 summarizes the activity of the newer quinolones against various bacteria including intracellular bacteria and the other microorganisms. In this table, the overall MIC ranges of NFLX, ENX, OFLX, and CPFX, for susceptible isolates of each bacteria are schematically presented. The newer quinolones are considered to have sufficient activity against gram-negative enteric bacteria, N. gonorrhoeae, and H. influenzae and Legionella spp. Since OFLX and CPFX show only moderate activity against staphylococci, streptococci, and P. aeruginosa, improvement is expected. As shown in Table 3, TFLX and the recent investigational quinolones such as SPFX and KB-5246 show higher and promising activity against gram-positive bacteria. However, further studies are needed with longer periods to indicate whether these newer agents will be able to stop the increase of quinolone-resistant staphylococci. Furthermore, the activity of the newer quinolones against obligate anaerobes such as clostridia and bacteroides are considered to be insufficient for clinical use. Whether it will be possible to synthesize quinolones with anti-anaerobic activity sufficiently for clinical treatment is uncertain. Although Mycobacterium tuberculosis is susceptible to the newer quinolones, other mycobacteria are somewhat less susceptible to this class of agents. In addition, the newer quinolones have adequate activity against mycoplasma, chlamydia and rickettsia. From a microbiological viewpoint the prospects for the newer quinolones would be primarily to find agents that have higher anti-staphylococcal and anti-streptococcal activity. Secondly, agents possessing superior activity against obligate anaerobes such as Bacteroides spp. and Clostridium spp. are expected to synthesize. Furthermore, it may be possible to synthesize compounds that are sufficiently active for clinical use against atypical mycoplasma, chlamydia, and rickettsia.
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PMID:In vitro properties of the newer quinolones. 160 15

Erythromycin is a macrolide antimicrobial chemically comprised of a 14-membered lactone ring substituted with a neutral (cladinose) and an amino (desosamine) sugar. Recently, a number of new macrolide molecules have been identified containing either 14-, 15- or 16-membered substituted lactone rings. In this study the authors have determined the in vitro activity of roxithromycin and clarithromycin (both 14-membered macrolides), azithromycin (a 15-membered macrolide or azalide) and midecamycin acetate (a 16-membered macrolide) against clinical isolates of Staphylococcus spp., (including methicillin-susceptible and -resistant isolates), Legionella spp., Mycoplasma spp. and Ureaplasma urealyticum. Minimum inhibitory concentrations of the macrolides for the clinical isolates of Staphylococcus spp. examined were widely distributed. However, midecamycin acetate retained activity against those isolates of Staphylococcus spp. exhibiting inducible resistance to erythromycin and the other macrolides tested. Isolates characterised by constitutive resistance to erythromycin were also resistant to midecamycin acetate. All of the macrolides were very active against Legionella spp., with clarithromycin demonstrating the greatest potency (MIC range: less than or equal to 0.03-0.06 mg/l). Isolates of Mycoplasma pneumoniae and Ureaplasma urealyticum were susceptible to all of the macrolides tested. However, erythromycin, roxithromycin, clarithromycin and azithromycin were poorly active against isolates of Mycoplasma hominis. By contrast, the same isolates were susceptible (MIC range: 0.008-0.12 mg/l) to midecamycin acetate.
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PMID:The in vitro activity of some 14-, 15- and 16- membered macrolides against Staphylococcus spp., Legionella spp., Mycoplasma spp. and Ureaplasma urealyticum. 165 Jun 94

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

Dirithromycin is a 9-N-11-O-oxazine derivative which is formed by condensation of 9(S)-erythromycylamine with 2-(2-methoxyethoxy)acetaldehyde. Dirithromycin is hydrolyzed, either under acidic conditions or in vivo, to its major active metabolite, 9(S)-erythromycylamine. The antimicrobial spectrum of dirithromycin is similar to that of erythromycin; both antibiotics are active against gram-positive bacteria, Legionella spp., Helicobacter pylori, and Chlamydia trachomatis. Comparable results were obtained for each antibiotic in MIC and MBC determinations and in the potential development of resistance in vitro. The effects of human serum, bacterial growth media, test methodology, and inoculum size on MICs were similar for each antibiotic. In standard mouse protection studies, dirithromycin was more efficacious than erythromycin against experimental infections after subcutaneous administration of antibiotic. These results were consistent with pharmacokinetic studies in rodents, which showed that dirithromycin gave more persistent concentrations of antibiotic in serum and tissues than were achieved with erythromycin. These studies indicate that dirithromycin possesses antimicrobial activity comparable to that of erythromycin in vitro but is more active than erythromycin in vivo, which may be attributable to the persistence of antimicrobial activity in the tissue(s) of the test animals.
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PMID:Synthesis and antimicrobial evaluation of dirithromycin (AS-E 136; LY237216), a new macrolide antibiotic derived from erythromycin. 192 52

YM133, the 4"-O-(4-methoxyphenyl)acetyltylosin, is a new macrolide. The in vitro activity of YM133 was compared with those of erythromycin, josamycin, and rokitamycin by an agar dilution method. YM133 inhibited 90% of the tested isolates of Streptococcus pneumoniae, Legionella spp., and anaerobic bacteria at less than or equal to 1.56 micrograms/ml. The drug inhibited 90% of erythromycin-resistant staphylococci and Streptococcus pyogenes at less than or equal to 50 micrograms/ml. YM133 showed activity against erythromycin-, josamycin-, and rokitamycin-resistant (MIC greater than or equal to 100 micrograms/ml) strains of staphylococci, streptococci, Bacteroides spp., and Clostridium spp. Enterococci were less susceptible to other YM133-like macrolides. Unlike other macrolides, YM133 showed killing activity, and the MBC/MIC ratios of YM133 for several strains were 1:32, whereas those of erythromycin were 4:1,024. In a time-kill curve study, the reduction of viable cells started within 2 h after the addition of YM133.
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PMID:In vitro activity of YM133, a new semisynthesized macrolide. 192 95

The effect of 14 antimicrobial agents, including new quinolones and a new macrolide, on the intracellular multiplication of Legionella pneumophila in cultured guinea pig peritoneal macrophages was examined. Gentamicin and beta-lactam antibiotics did not inhibit the intracellular growth of L. pneumophila. Minocycline, erythromycin and DR-3355 inhibited multiplication at concentrations of 1, 0.5 and 0.1 mg/l respectively. Rifampicin, the new macrolide roxithromycin, and the new quinolones ofloxacin, ciprofloxacin and AT-4140 all inhibited the intracellular growth of L. pneumophila at concentrations of less than 0.03 mg/l. The minimal extracellular concentration inhibiting intracellular multiplication (MIEC), compared with conventional MIC measurements, provides a better indication of antimicrobial efficacy against bacteria, such as L. pneumophila, which can multiply in phagocytes.
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PMID:Inhibition of Legionella pneumophila in guinea pig peritoneal macrophages by new quinolone, macrolide and other antimicrobial agents. 203 40


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