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, a new semisynthetic injectable streptogramin, was compared with that of erythromycin, rifampicin and ciprofloxacin against 189 Legionella spp. Rifampicin was the most active agent tested. RP 59500 was found to be more active than erythromycin against most strains, but less active than ciprofloxacin. Legionella pneumophila serogroups 1, 3, 4, 5 and 6 were more susceptible to RP 59500 than were L. pneumophila serogroups 2, 7, and 8. Legionella micdadei was the least susceptible species to RP 59500 and erythromycin. RP 59500 was similar in activity against isolates obtained from both patients and environmental sources. This activity was generally better than that of erythromycin.
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PMID:In-vitro activity of RP 59500, a new synergic antibacterial agent, against Legionella spp. 139 54

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

Since the discovery of Legionella pneumophila in the late 1970s, this organism and other Legionella sp have been an important cause of pneumonia in solid organ transplant recipients. Legionella sp are obligate aerobes that require a source of amino acids, iron, and L-cystine. Growth is enhanced in a 5% CO2 atmosphere at 37 degrees C in the presence of charcoal. Legionella sp reside in water supplies and hospital outbreaks associated with contaminated water have been described. Transplant recipients are particularly susceptible to Legionella infection. Legionella pneumonia tends to occur within several weeks after transplantation and frequently coincides with episodes of rejection. A prodrome of influenza-like symptoms is followed by a sometimes "explosive" pneumonia with patchy lobular or interstitial infiltrates on chest radiograph. High fever, abdominal pain, and mental status changes are sometimes seen. Diagnosis is made by examination of respiratory secretions by the direct fluorescent antibody technique or culture of the organism. Intravenous erythromycin is the treatment of choice. Rifampin is added if there is a lack of response. Both erythromycin and rifampin have important and opposite effects on cyclosporine metabolism, which may result, respectively, in increased cyclosporine toxicity or graft loss. Patients who must continue cyclosporine will, therefore, require frequent monitoring of cyclosporine levels.
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PMID:Legionella infection in transplant patients. 218 18

The combinations of erythromycin with rifampicin, with ciprofloxacin or with amoxycillin, and ciprofloxacin plus rifampicin were tested by the time-kill curve method to assess their bactericidal activity against Legionella pneumophila. Rifampicin-resistant strains were found in broth cultures of the micro-organism even before exposure to the drug. In the presence of MBCs of rifampicin, the sensitive organisms were killed, allowing the resistant mutants to multiply. In broths containing both erythromycin and rifampicin, the rifampicin-resistant mutants were killed more rapidly than by erythromycin alone. In addition, erythromycin was effective in preventing the growth of amoxycillin- and ciprofloxacin-resistant organisms. Fortunately resistance to erythromycin was not detected by these time-kill studies. Thus for patients with severe forms of Legionnaires' disease, erythromycin should be combined with other more inhibitory drugs, such as rifampicin or ciprofloxacin, to enhance bactericidal activity.
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PMID:The effects of single and combined antibiotics on the growth of Legionella pneumophila using time-kill studies. 221 46

The in vitro activity of lomefloxacin (SC-47111 or NY-198) was compared with those of erythromycin and rifampin against a total of 180 Legionella spp. strains isolated from nosocomial or acquired respiratory tract infections and from environmental sources. Rifampin was the most active agent tested (MIC90, 0.008 microgram/ml) against Legionella spp. However, lomefloxacin was found 2-to-4-fold more active than erythromycin against most Legionella strains tested. Against Legionella pneumophila, lomefloxacin (MIC90, 0.12 microgram/ml) was significantly more than erythromycin (MIC90, 0.5 micrograms/ml). L. pneumophila serogroup 2, 3, and 5 strains (MIC90, 0.06 micrograms/ml) were more susceptible than L. pneumophila serogroup 1, 4, 6, 7, and 8 (MIC90, 0.12 microgram/ml). L. dumoffii was the most resistant species with a MIC90 of 0.25 microgram/ml and 0.5 microgram/ml, respectively, to lomefloxacin and erythromycin. The activity of lomefloxacin was similar against the isolates obtained from patients or from environmental sources.
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PMID:In vitro activity of lomefloxacin (SC 47111 or NY-198) against isolates of Legionella spp. 279 4

The pathogenicity of Legionella pneumophila, serogroup 1, strain Nottingham N7, was assessed in terms of LD50 data and the ability of the organism to induce pathological lesions in the fertile hen's egg. Histopathological examination of embryo organs after inoculation with 1, 10, 100 and 1000 times the yolk sac LD50 revealed a disseminated infection. Systemic spread of the organism resulted in widespread necrosis and evidence of consolidation together with generation of copious amounts of oedema fluid. These were particularly severe in the liver, heart, spleen and kidney. The infection elicited a massive inflammatory response typified by infiltration with polymorphonuclear leucocytes and lymphocytes. Selected antimicrobial chemotherapeutic agents were investigated in protection studies for their capacity to ameliorate or control disease processes in this test system. Of those examined ciprofloxacin was most effective in reducing the incidence of lesions in these tissues and for prolonging embryo viability. Rifampicin, and to a lesser degree, erythromycin and doxycycline, also showed antimicrobial activity in these in vivo trials. These results indicate that the fertile hen's egg may be a useful alternative to other animal systems for the in vivo testing of clinically putative antimicrobial agents in the treatment of Legionnaires' disease.
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PMID:Pathogenesis and chemotherapy of experimental Legionella pneumophila infection in the chick embryo. 280 57

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

We evaluated the in vitro susceptibility of Legionella pneumophila ATCC 33152 (serogroup I) to 13 antibiotics alone and in combination with rifampin (0.1 mg/liter) by three methods. Extracellular susceptibility was determined by MIC determinations and time kill curves in buffered yeast extract broth, while intracellular susceptibility was determined by peripheral human monocytes in RPMI 1640 culture medium. Antibiotic concentrations equal to or greater than the broth dilution MIC inhibited or killed L. pneumophila by the time kill method, except this was not the case for trimethoprim-sulfamethoxazole. Antibiotic concentrations below the broth dilution MIC did not inhibit Legionella growth. The only antibiotic-rifampin combinations which produced improved killing of L. pneumophila by the time kill method were those in which the logarithmic growth of L. pneumophila occurred during the experiment (rosoxacin, amifloxacin, cinoxacin, trimethoprim-sulfamethoxazole, clindamycin, and doxycycline). Neither direct MICs nor time kill curve assays accurately predicted intracellular L. pneumophila susceptibility. Rifampin, erythromycin, ciprofloxacin, rosoxacin, enoxacin, amifloxacin, gentamicin, clindamycin, and doxycycline all inhibited intracellular L. pneumophila growth at readily achievable concentrations in serum. Cefoxitin and thienamycin showed no inhibition of growth, although they were present extracellularly at concentrations that were 20 to 1,000 times their broth dilution MICs. Clindamycin was the only antibiotic that was able to inhibit intracellular L. pneumophila growth at an extracellular concentration below its MIC. The gentamicin (5 mg/liter)-rifampin combination was the only antibiotic-rifampin combination which demonstrated decreased cell-associated Legionella survival in this model of in vitro susceptibility.
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PMID:Effect of quinolones and other antimicrobial agents on cell-associated Legionella pneumophila. 343 1

The genus Legionella, belonging to the family of Legionellaceae, comprises nowadays seven species, among which Legionella pneumophila might be the most important. The identification of the agent is difficult because L. pneumophila is very pretentious requiring peculiar conditions concerning culture medium, temperature, and time. The initial cultivation will succeed the best in an atmosphere enriched with CO2. The demonstration of serum antibodies will succeed by means of indirect immunofluorescence; recently the micro-agglutination test is vastly applied. The clinical picture of Legionellosis is characterized by an atypical pneumonia with a serious course in most cases. The Pontiac Fever is an illness with milder course than the classical form of Legionellosis. Erythromycin and Rifampicin are the chemotherapeutics of choice.
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PMID:[The detection of the agent of Legionnaires' disease--a confirmation of Koch's postulates]. 635 47

A brief survey of the epidemiology, clinical manifestations, differential diagnosis and treatment of infections with Legionella species is given, with particular emphasis on Legionella pneumophila. Because of recent epidemiological evidence that this species may be an important cause of both community-acquired and hospital-acquired pneumonia, particularly in the immunosuppressed patient, it is suggested that this microbial agent should be considered more often in the differential diagnosis of pneumonia. This has practical implications for therapy, since the drug of choice in Legionella infections is erythromycin, with doxycycline as an alternative. Rifampicin may be added to one of the drugs mentioned, in serious infection.
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PMID:Legionella pneumonia--a neglected diagnosis? 659 28


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