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

Rifampin was studied for determination of its spectrum of activity against many bacteria of clinical importance. Most of the minimum inhibitory concentrations (MICs) were determined by agar dilution but some were determined by broth microdilution. Staphylococci were the most susceptible, with mode MICs of 0.015 microgram/ml, but most streptococcal strains, except Streptococcus faecalis, had mode MICs less than or equal to 1 microgram/ml. Haemophilus influenzae, Neisseria gonorrhoeae, Neisseria meningitidis, and Listeria monocytogenes were susceptible and had mode MICs of 1, 0.25, 0.03, and less than or equal to 0.12 microgram/ml, respectively. Legionella species had geometric mean MICs ranging from 0.027 to 0.25 microgram/ml. The rapidly growing mycobacteria, Mycobacterium chelonei and Mycobacterium fortuitum, were resistant, with mode of greater than 64 micrograms/ml. Enterobacteriaceae, Acinetobacter species, and Pseudomonas species had mode MICs ranging from 4 to 64 micrograms/ml. Thus, the authors conclude that, on the basis of these in vitro data and an MIC breakpoint of less than or equal to 2 micrograms/ml, gram-positive cocci (except for some enterococci), H. influenzae, N. gonorrhoeae, N. meningitidis, Legionella, and L. monocytogenes may be clinically susceptible to rifampin.
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PMID:Rifampin: spectrum of antibacterial activity. 663 33

The efficacy of erythromycin, gentamicin and rifampicin has been compared in the treatment of experimental airborne Legionnaires' disease in guinea-pigs. Evaluation was based on survival of animals after 1LD50 or 10LD50 infection, on numbers of Legionella pneumophila in the lungs and on the extent of histopathological lesions. All three drugs were effective in increasing survival in 1LD50 infections, but only rifampicin gave any protection against 10LD50 infection. Rifampicin was the most effective agent in eliminating viable L. pneumophila from the lungs and also in preventing pulmonary lesions.
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PMID:Antibiotic therapy of experimental airborne Legionnaires' disease. 666 81

A parenteral formulation of rifampicin (Rimactan i.v., Ciba-Geigy, Basel, Switzerland) was administered to 237 critically ill or comatose patients, or patients with gastro-intestinal or absorption problems. There were 160 patients suffering from tuberculosis, 77 suffering from non-tuberculous (non-tb) infections including 30 cases of sepsis, 8 cases of bacterial meningitis and/or cerebral abscess and 9 patients with Legionnaires' disease. The usual daily dose of rifampicin was 450-600 mg, administered in most cases by i.v. bolus (122 cases) or i.v. drip infusion (79 cases) for a period of 1-113 days. Rifampicin was in all cases combined with one or more antimicrobial drug(s). The physicians considered the therapy as successful when the treatment with oral rifampicin could be instituted soon after parenteral administration or when the patients markedly improved their clinical condition. Of a total of 123 tuberculous patients for whom assessment of efficacy was possible, 100 (81.3%) showed favourable clinical results. Of 40 non-tb patients who could be analysed for clinical progress, 32 (80.0%) had a favourable outcome. Special attention should be drawn to the 11 patients with proven staphylococcal infections, of whom 10 were cured clinically and/or bacteriologically. Thrombophlebitis occurred in 10 out of the 237 (4.2%) patients, almost always in patients who were treated for more than 30 days. Systemic unwanted effects occurred in 14 (5.9%); the relationship to the treatment was not always established. Treatment was withdrawn due to unwanted effects in 5 (2.1%) of the 237 patients. Taking into account the severe, life-threatening infections reported, the results suggest that i.v. rifampicin is useful and in some critically ill patients even life-saving. Tolerability was good, even in long-term i.v. administration, although there seems to be the possibility that thrombophlebitis might develop if treatment is continued over 30 days.
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PMID:Parenteral rifampicin in tuberculous and severe non-mycobacterial infections. Clinical data on 237 patients. 709 64

Strains of Legionella pneumophila from 10 geographic areas were evaluated for their in vitro susceptibility to 14 antimicrobial agents. Included in this study were clinical and environmental isolates as well as strains from all 4 known serogroups. The minimal inhibitory concentration was established by agar dilution with a Steers replicator. The inhibitory index was then calculated considering the mean peak serum level for the associated antibiotic. Rifampicin, cefoxitin, chloramphenicol, ticarcillin, and parenteral erythromycin had the highest inhibitory indices. The only difference among serogroups was the increased susceptibility among serogroup II isolates to the penicillins and the increased susceptibility of serogroups III and IV to sulfamethoxazole-trimethoprim. Though there have been recent reports of the inadequacy of oral erythromycin in clinical cases of Legionnaires' disease, there was no erythromycin resistance noted among the 14 isolates tested.
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PMID:Antimicrobial susceptibility of Legionella pneumophila Serogroups I--IV. 743 21

Legionnaires' disease is a relatively common cause of community-acquired pneumonia and of some outbreaks of hospital-acquired pneumonia. Moreover, Legionella pneumophila is frequently involved in the aetiology of the subset of pneumonias that is characterised by severe clinical course and high mortality. No sure clinical, radiographical or analytical features are useful in differentiating Legionella infection from other aetiologies of pneumonia. On the basis of these data, a rational initial therapeutic approach to community-acquired pneumonia, as well as to nosocomial pneumonia in certain circumstances, has to include an antimicrobial agent that is clinically effective against Legionella spp. Clinical studies have provided evidence that erythromycin is the first-line treatment. An intravenous dosage of 1g every 6 hours as initial therapy will be effective in most cases. Parenteral treatment may be switched to oral administration only after clinical response is observed. In vitro susceptibilities and preliminary experimental and clinical results suggest that clarithromycin will most likely become the preferred treatment once an intravenous preparation is available worldwide. However, orally administered clarithromycin at the dosage of 500 mg every 12 hours may be recommended in those developing countries in which health systems cannot afford the costs of intravenous therapy. In the case of clinically severe illness or in seriously immunosuppressed hosts with confirmed legionellosis, a combined therapeutic approach is warranted. Rifampicin 600 mg every 12 hours intravenously or orally has to be added to the usual dosage of erythromycin. Other alternative therapies, but with less distinct clinical efficacy, that can be combined with erythromycin are doxycycline 100 mg every 12 hours intravenously or orally, and intravenous ciprofloxacin 200 mg every 6 hours.
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PMID:Treatment of Legionnaires' disease. Current recommendations. 769 8

Legionella pneumophila is the second most common cause of severe community-acquired pneumonia requiring treatment with intermittent positive pressure ventilation. The prognosis of this condition and its complications have not been well documented. Erythromycin is the first-line antibiotic of choice based on clinical experience. Rifampicin has been recommended as an additional agent, though clinical experience has not been reported. We have retrospectively examined 30 cases of severe community-acquired legionella pneumonia. The mean age of the patients was 53 years, 24 were male and eight died (27%, mean age 57 years). During admission 26 patients received erythromycin (eight died) and 15 received rifampicin in addition (five died); four received neither drug and survived. Mean duration of intermittent positive pressure ventilation was 15.9 days for survivors and 14.1 days for fatal cases. Acute renal failure requiring dialysis developed in 13 (43%), of whom five died (38%). Positive inotropic drugs were used in 10 patients and of these six died. Jaundice occurred in 11 patients and was significantly more common (p = 0.028) in patients who received rifampicin (60%) than in those who did not (17%). Excess bilirubin was largely conjugated when measured and there was no consistent hepatitic or obstructive change in the liver enzymes. Severe community-acquired legionella pneumonia has a relatively good outcome with a mortality of 27%, though prolonged intermittent positive pressure ventilation may be required. Acute renal failure is common but reversible in survivors, and jaundice is more common in those who receive rifampicin.
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PMID:Severe community-acquired legionella pneumonia: treatment, complications and outcome. 832 50

The activity of trovafloxacin, a new fluorinated naphtheridone, was tested against 61 Legionella spp. isolates and compared with that of 4 fluoroquinolones, 2 macrolides, and rifampin. Trovafloxacin MICs were determined by a reference agar dilution method and E-test (Solna, Sweden) strips on buffered charcoal yeast extract agar. Among the fluoroquinolone compounds, the rank order of activity (on the basis of MIC90 results) determined with E-test strips was as follows: levofloxacin (MIC90, 0.094 microgram/ml) > trovafloxacin = sparfloxacin = ofloxacin (MIC90, 0.19 microgram/ml). Rifampin (MIC90, 0.008 microgram/ ml) and clarithromycin (MIC90, 0.032 microgram/ml) were the most potent of all drugs tested, and erythromycin and ciprofloxacin were the least active. In this study, the E-test strips with trovafloxacin were validated (100% of results +/- one log2 dilution compared to the reference value) for susceptibility testing with Legionella isolates.
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PMID:Anti-Legionella activity of trovafloxacin compared with seven other antimicrobial agents including an intermethod evaluation. 935 Apr 17

Rifampin has clinical efficacy against a wide variety of organisms, including Staphylococcus aureus, Legionella pneumophila, group A Streptococcus, Brucella sp, Haemophilus influenzae, and Neisseria meningitidis, as well as in vitro activity against penicillin-resistant Streptococcus pneumoniae, Neisseria gonorrhoeae, Chlamydia trachomatis, Haemophilus ducreyi, and many gram-negative rods. Rifampin is a useful drug for several types of bacterial infections because of its broad spectrum of activity, excellent tissue penetration, and low side effect profile. In combination with other antibiotics, it may be effective when conventional therapies are not.
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PMID:Rifampin, a useful drug for nonmycobacterial infections. 954 54

Rifampin in combination with erythromycin is a recommended treatment for severe cases of legionellosis. Mutations in the rpoB gene are known to cause rifampin resistance in Escherichia coli and Mycobacterium tuberculosis, and the purpose of the present study was to investigate a possible similar resistance mechanism within the members of the family Legionellaceae. Since the RNA polymerase genes of this genus have never been characterized, the DNA sequence of the Legionella pneumophila rpoB gene was determined by the Vectorette technique for genome walking. A 4,647-bp DNA sequence that contained the open reading frame (ORF) of the rpoB gene (4,104 bp) and an ORF of 384 bp representing part of the rpoC gene was obtained. A 316-bp DNA fragment in the center of the L. pneumophila rpoB gene, corresponding to a previously described site for mutations leading to rifampin resistance in M. tuberculosis, was sequenced from 18 rifampin-resistant Legionella isolates representing four species (L. bozemanii, L. longbeachae, L. micdadei, and L. pneumophila), and the sequences were compared to the sequences of the fragments from the parent (rifampin-sensitive) strains. Six single-base mutations which led to amino acid substitutions at five different positions were identified. A single strain did not contain any mutations in the 316-bp fragment. This study represents the characterization of a hitherto undescribed resistance mechanism within the family Legionellaceae.
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PMID:Sequencing of the rpoB gene in Legionella pneumophila and characterization of mutations associated with rifampin resistance in the Legionellaceae. 1144 26

We evaluated the in vitro activity of antimicrobial agents against Legionella obtained from hotel and hospital water systems in three different regions of Turkey. Sixty-five Legionella strains (Legionella pneumophila serogroup 6 [n=32], L. pneumophila serogroup 1 [n=27], L. pneumophila serogroup 3 [n=2], and Legionella spp. [n=4]) were tested against levofloxacin, ciprofloxacin, clarithromycin, azithromycin, and rifampicin. The minimum inhibitory concentration (MIC) values of each antimicrobial agent for these strains was determined by the microdilution method using buffered yeast extract medium supplemented with 0.1% ketoglutarate broth. L. pneumophila ATCC 33152, Staphylococcus aureus ATCC 29213, and Escherichia coli ATCC 25922 were used as controls. Minimum inhibitory concentration values were in the following ranges: clarithromycin 0.001-0.5 mg/L, azithromycin 0.001-0.5 mg/L, levofloxacin 0.001-0.5 mg/L, ciprofloxacin 0.001-0.125 mg/L, and rifampicin 0.001- 0.5 mg/L. The MIC(90) for rifampicin, levofloxacin, ciprofloxacin, azithromycin, and clarithromycin were 0.015, 0.125, 0.06, 0.125, and 0.06 mg/L, respectively. To the best of our knowledge, this is the first study to determine in vitro activities of antimicrobial agents against Legionella species in Turkey. Rifampicin had the lowest MIC(90) value. It would seem that azithromycin and clarithromycin exhibit good activity as well as levofloxacin and ciprofloxacin against Legionella isolated from environmental water systems in Turkey.
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PMID:In vitro activity of antimicrobial agents against Legionella isolated from environmental water systems: first results from Turkey. 2004 25


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