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Query: UMLS:C0023241 (Legionella)
 6,990 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Lomefloxacin is a new difluoro-quinolone. In this study, we have determined the in vitro activity of lomefloxacin against a wide range of clinical bacterial isolates and compared it with that of other fluoro-quinolones and some unrelated antimicrobials. Lomefloxacin was very active against Enterobacteriaceae (MIC90, 0.5 micrograms/ml) with activity comparable to that of ofloxacin (MIC90, 0.25 micrograms/ml). Lomefloxacin was moderately active against isolates of Pseudomonas aeruginosa (MIC90, 4 micrograms/ml), and again the activity was comparable to ofloxacin (MIC90, 4 micrograms/ml) but was eightfold less than ciprofloxacin (MIC90, 0.5 micrograms/ml). Lomefloxacin was also active against isolates of Staphylococcus aureus (MIC90, 1 micrograms/ml), irrespective of methicillin susceptibility, and this activity was most comparable to ofloxacin (MIC90, 0.5 micrograms/ml) and ciprofloxacin (MIC90, 0.5 micrograms/ml). Lomefloxacin was fourfold less active than either ofloxacin or ciprofloxacin against isolates of Enterococcus faecalis (MIC90, 8 micrograms/ml) and Streptococcus pneumoniae (MIC90, 8 micrograms/ml). In common with ofloxacin and ciprofloxacin, lomefloxacin was very active against isolates of Neisseria spp. (MIC90, less than or equal to 0.06 micrograms/ml), Haemophilus spp. (MIC90, less than or equal to 0.06 micrograms/ml), Legionella spp. (MIC90, less than or equal to 0.06 micrograms/ml), Vibrio spp. (MIC90, less than or equal to 0.06 micrograms/ml), and Campylobacter jejuni (MIC90, 1 microgram/ml). Lomefloxacin showed poor activity against isolates of Bacteroides spp. (MIC90, 16 micrograms/ml) or Clostridium difficile MIC90, 32 micrograms/ml) and was only moderately active against isolates of Clostridium perfringens (MIC90, 2 micrograms/ml), Peptostreptococcus spp. (MIC90, 4 micrograms/ml), Chlamydia trachomatis (MIC90, 4 micrograms/ml), Mycoplasma hominis (MIC90, 2 micrograms/ml), and Urea-plasma urealyticum (MIC90, 8 micrograms/ml). Lomefloxacin was found to be bactericidal at concentrations generally close to the MIC with greater than 3 log10 reduction in viability of exponentially dividing cultures of Escherichia coli and S. aureus within 5 hr of exposure to concentrations at eight times the MIC. These results indicate a potential clinical role for lomefloxacin in the treatment of genitourinary tract infections caused by Gram-positive and Gram-negative bacteria, respiratory tract infections caused by susceptible organisms, and soft tissue infections caused by S. aureus.
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PMID:Comparative in vitro activity of lomefloxacin, a difluoro-quinolone. 279

The inhibitory (MIC) and bactericidal (MBC) activities of a new macrolide A-56268 (TE-031) against 306 clinical aerobic bacterial isolates was compared with that of erythromycin. The MIC90/MBC90 ratios for A-56268 were: Campylobacter jejuni 4/16, Haemophilus influenzae 8/8-16, H. parainfluenzae 8/8-16, Legionella pneumophila 0.06/0.5, methicillin-sensitive isolates of Staphylococcus aureus 0.5/1, and coagulase negative staphylococci 1/8, methicillin resistant isolates of Staph. aureus and coagulase negative staphylococci greater than 16/ greater than 16, Streptococcus pneumoniae 0.06/0.125, streptococcus Group A 0.06/2-4, streptococcus Group B 0.06/8- greater than 16, streptococcus Groups C and G 0.125/8 and Str. faecalis 4/64. Compared with erythromycin, A-56268 had greater inhibitory and bactericidal activity against isolates of L. pneumophila, with an MIC90 16-fold less and an MBC90 eight-fold less than that of erythromycin. Except for enterococci, A-56268 showed inhibitory activity equal to or greater than that of penicillin G against isolates of streptococci and an MIC two-fold less than that of erythromycin. For other strains tested, the inhibitory and bactericidal activities of A-56268 and erythromycin were similar. The clinical importance of the differences between these two macrolides will depend on the pharmacokinetic and tissue penetration properties of the new compound.
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PMID:Comparative in-vitro activities of A-56268 (TE-031) and erythromycin against 306 clinical isolates. 296 68

The susceptibility of Legionella pneumophila to a new quinolone, fleroxacin, was studied in both an extra- and an intracellular system. The activity of fleroxacin was compared with that of erythromycin, cefoxitin, and rifampicin. In the extracellular system, erythromycin inhibited while cefoxitin killed the organism. Extracellularly, fleroxacin performed similarly to cefoxitin. Rifampicin was initially bactericidal for L. pneumophila but resistant bacteria emerged at 48 h. The Horwitz monocyte model was used for studies of intracellular antimicrobial activity. At ten times the MIC, cefoxitin did not inhibit intracellular L. pneumophila. Fleroxacin was as active as erythromycin and rifampicin in inhibiting intracellular L. pneumophila. No intracellular, rifampicin-resistant L. pneumophila emerged. Addition of rifampicin to cefoxotin, erythromycin or fleroxacin provided neither synergy nor antagonism.
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PMID:Inhibition of Legionella pneumophila multiplication within human macrophages by fleroxacin. 314 49

Ofloxacin was evaluated as an antibiotic for possible use in the therapy of Legionnaires' disease in relation to its ability to penetrate alveolar phagocytes and inhibit Legionella pneumophila intracellular replication. A comparison with two other antibiotics used in the treatment of Legionnaires' disease, ciprofloxacin and erythromycin, was also made. Ofloxacin was found to be the most effective antibiotic, eliminating viable L. pneumophila from alveolar phagocytes at 0.001 mg/l. This was followed by ciprofloxacin, eliminating intracellular organisms at 0.01 mg/l. Erythromycin was shown to be much less effective, requiring a much higher concentration, of 0.1 mg/l. All three antibiotics had approximately similar MIC values and the considerable differences in intracellular penetration shown by these antibiotics indicate how discrepancies between in-vitro and in-vivo estimates of efficacy can occur.
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PMID:The effect of ofloxacin on the intracellular growth of Legionella pneumophila in guinea pig alveolar phagocytes. 318 62

The in vitro and in vivo effects of NY-198 against Legionella pneumophila were compared with those of ciprofloxacin. The MIC of NY-198 against 15 standard reference strains of Legionella of various species, between 0.03 and 0.125 micrograms/ml, was the same as that of ciprofloxacin. The peak concentration of NY-198 in the lungs and sera of guinea pigs with experimentally induced Legionella pneumonia was higher than that of ciprofloxacin after oral administration. The overall survival rate was higher in animals treated with NY-198 than in those treated with ciprofloxacin. Thus, NY-198 appears valuable in the treatment of Legionnaires disease.
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PMID:Efficacy of NY-198 against experimental Legionnaires disease. 319 3

For the treatment of Legionella pneumophila infections erythromycin and rifampicin are the antibiotics of choice. In view of reported therapy failures other antibiotics, e.g. the quinolones, are currently under investigation. The sensitivity of L. pneumophila to four antibiotics and to combinations of antibiotics was investigated and the rate of mutations was calculated. For 20 L. pneumophila strains we determined the MIC of rifampicin (0.002-0.004 mg/l), erythromycin (0.063-0.125 mg/l), norfloxacin (0.125 mg/l) and ciprofloxacin (0.016-0.032 mg/l). Mutation rates ranged from 1 x 10(-8) for ciprofloxacin to greater than 1 x 10(-7) for erythromycin, resulting in high-level resistance to rifampicin in most strains and erythromycin resistance in one strain, but not in resistance to the quinolones. The combination of erythromycin and rifampicin was synergistic (FIC index less than 0.5) against four of the L. pneumophila strains and showed indifference (FIC index 0.5-2.0) for the remainder (mean FIC index 0.79). Combinations of ciprofloxacin and erythromycin and of rifampicin and ciprofloxacin showed only indifference (mean FIC index respectively 1.05 and 1.21). Combining rifampicin with ciprofloxacin was not effective in reducing the number of mutants for either of these antibiotics, whereas the other combinations did prevent this.
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PMID:Sensitivity and resistance of Legionella pneumophila to some antibiotics and combinations of antibiotics. 320 75

Thirty-two patients were treated by ofloxacin on bacteriological documented infections. They were Enterobacterias: n = 15 (MIC less than or equal to 0.06 to 0.5 microgram/ml); Pseudomonas aeruginosa and Acinetobacter: n = 1 (MIC 0.5 and 4 micrograms/ml); Staphylococcus: n = 6 (MIC less than or equal to 0.06 to 4 micrograms/ml); Pneumococcus: n = 1; Mycoplasma: n = 1; Chlamydia psittaci: n = 2; Legionella pneumophila: n = 1; Rickettsias: n = 4 (three mediterranean fevers one query fever). Ofloxacin was given orally from 400 to 800 mg per day (5 to 15 mg/kg/day). It was used alone 26 times and on 6 occasions it was associated with rifampin on 6 staphylococcal infections. On 19 cases it was used after failure or intolerance of initial therapy. Thirty times it was the first antibiotic substance used. Results were good mainly: 1) on nine pneumonitis (enterobacterias: 4; Pneumococcus: 1; Mycoplasma: 1; Chlamydia: 2; Legionella: 1) during a mean duration of twenty days; 2) urinary infections (n:7) provoked by E. coli and Enterobacter cloacae (mean duration: 20 days); 3) 4 osteo-articular-infections (mean duration: 77 days); 4) Rickettsial infections (n:4) during a mean duration of 11 days. Results are particularly noteworthy because patients treated had severe infections: 12 bacteremias, 1 endocarditis and 1 purulent meningitis. None severe adverse effect was observed.
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PMID:[Ofloxacin (RU 43280). Clinical study]. 330 73

Direct effects of antimicrobial agents on macrophages functions are not well precised. However, antimicrobials can enhance phagocytosis of bacteria by macrophages in vitro, at subinhibitory concentrations. This enhancement is related to the antibiotic effect. It is dependent of the nature of the antimicrobial agent, of the experimental procedure and some discrepancies appeared in the results. The precise mechanism, effect on the bacterial wall, or on the bacterial protein synthesis is uncertain. The third type of interaction concerns the intracellular penetration and activity of antimicrobial agents within macrophages. In a human monocyte-derived macrophage model, the intracellular growth of Legionella pneumophila was inhibited by erythromycin, rifampicin and fluoroquinolones at concentrations clearly lower than their MICs; doxycycline and cotrimoxazole were inhibitory at concentrations closed to their MICs. Cefoxitin was not inhibitory even at high concentrations despite a low MIC value. This confirms the good intracellular activity of macrolides and fluoroquinolones and the low intracellular activity of beta-lactams.
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PMID:[Interactions between macrophages and anti-infective agents]. 332 8

Roxithromycin (RU 28965) is a new semi-synthetic derivative of erythromycin. Its antibacterial activity is of the same order as that of other macrolides, although its MIC's against Legionella pneumophila are lower. In double-blind comparative studies there was no significant difference in therapeutic effectiveness between roxithromycin and the reference antibiotics tested. However, this new macrolide exhibits exceptional pharmacological properties (prolonged half-life, excellent tissue penetration and intracellular activity), and it is very well tolerated both clinically and biochemically.
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PMID:[New aspects of macrolides: contribution of roxithromycin]. 332 52

The activity of roxithromycin against Legionella pneumophila in vitro was approximately the same as that of rokitamycin and superior to those of erythromycin and josamycin. In experimental pneumonia due to L. pneumophila none of the animals in the roxithromycin and rifampicin groups died by day 10 of the infection. The MIC ranges of roxithromycin, erythromycin and rokitamycin for Mycoplasma pneumoniae were 0.008-0.063, 0.004-0.008 and 0.016-greater than 125, respectively. In experimental pneumonia caused by M. pneumoniae, roxithromycin showed good activity similar to that of erythromycin.
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PMID:Activity of macrolides against organisms responsible for respiratory infection with emphasis on Mycoplasma and Legionella. 342 89


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