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Biomedical subjects

R Malinverni

Publications and source records attributed to R Malinverni.

62 records · Page 4Linked to original sources
PubMed1987

Treatment of Staphylococcus aureus endocarditis in rats with coumermycin A1 and ciprofloxacin, alone or in combination.

The efficacy of a 5-day treatment with coumermycin A1 (hereafter referred to as coumermycin) (at three dosage regimens), with ciprofloxacin, or with coumermycin plus ciprofloxacin was tested in experimental aortic valve endocarditis induced in rats by a strain of methicillin-susceptible Staphylococcus aureus and was compared with the efficacy of a 5-day treatment with cloxacillin plus gentamicin. While coumermycin was far less effective than cloxacillin plus gentamicin in reducing the bacterial counts in vegetations (P less than 10(-8), ciprofloxacin was as effective as cloxacillin plus gentamicin. Coumermycin plus ciprofloxacin was less effective than ciprofloxacin alone (P = 0.01). For endocarditis induced by two additional methicillin-susceptible S. aureus strains, the high-dosage regimen of coumermycin (12 mg/kg every 12 h) had the same low efficacy. Coumermycin-resistant variants of S. aureus emerged in most of the vegetations during coumermycin treatment. The ciprofloxacin susceptibility of S. aureus was unchanged during ciprofloxacin treatment. The addition of ciprofloxacin to coumermycin in the treatment did not prevent the emergence of coumermycin-resistant variants. Twelve additional S. aureus strains isolated from the blood of patients with endocarditis were tested in vitro against coumermycin with precautions to avoid carry-over of the antibiotic. Coumermycin exhibited a bacteriostatic activity at very low concentrations (MIC, less than 0.004 microgram/ml) but only a weak bactericidal activity (MBC for 90% of strains, 8 micrograms/ml), a finding contrasting with that of others. Furthermore, coumermycin-resistant mutants could be selected in vitro from the 15 S. aureus strains tested. These results indicated no evidence in vivo of a synergistic activity of coumermycin and ciprofloxacin. More importantly, these results suggested that coumermycin might not be adequate for the treatment of serious s. aureus infections in humans.

Aminocoumarins↗
PubMed1987

Comparison of single and multiple doses of prophylactic antibiotics in experimental streptococcal endocarditis.

Single-doses or short-term administration of beta-lactam antibiotics alone or combined with aminoglucoside antibiotics have failed to consistently prevent experimental streptococcal endocarditis induced by high inocula of bacteria poorly susceptible to killing by these antibiotics. The optimal duration of administration of antibiotics for successful prophylaxis under these circumstances has not been established. We therefore tested, in rats with catheter-induced sterile aortic vegetations, the duration of administration of antibiotic necessary to prevent endocarditis induced by bacterial inocula 100 to 10,000 times the 90% infective dose of two tolerant viridans-group streptococci and two Streptococcus faecalis strains. Multiple-dose regimens of amoxicillin alone or of amoxicillin combined with gentamicin were studied. Against the two viridans group streptococci, successful prophylaxis was achieved with multiple doses of amoxicillin alone given over 24 to 48 hr and by the combination of amoxicillin and gentamicin given for 6 to 24 hr. Against the two S. faecalis strains, multiple-dose regimens with amoxicillin alone failed, but the combination of amoxicillin and gentamicin was successful when administered for 48 to 72 hr. Thus, after challenge with high bacterial inocula, repeated doses of a beta-lactam antibiotic alone were sufficient to prevent viridans streptococcal endocarditis, but multiple doses of a bactericidal combination (beta-lactam plus aminoglucoside), as necessary for the treatment of established endocarditis, were a prerequisite for successful prophylaxis of S. faecalis endocarditis.

Amoxicillin↗
PubMed1986

[Acute purulent Listeria seelingeri meningitis in an immunocompetent adult].

Within the genus Listeria, the species L. monocytogenes most frequently causes disease in animals and humans. L. Seeligeri, a species recently described, has been considered experimentally nonpathogenic so far. The authors report the first case of human infection in a previously healthy adult presenting with acute purulent meningitis due to L. seeligeri. The patient recovered promptly after a course of ampicillin and gentamicin, but developed severe neurological sequelae (epilepsy, hydrocephalus) one year after the acute episode. The pathogenic properties of this isolate were investigated in two experimental animal models and the results were as follows. The clinical isolate of L. seeligeri was able to colonize the spleens of adult mice without bacterial multiplication, in contrast to the type strain of L. seeligeri (no colonization) and to a L. monocytogenes strain (colonization and multiplication). Previous infection of adult mice with the clinical L. seeligeri isolate protected moderately against spleen colonization and bacterial multiplication after challenge with L. monocytogenes. No lethal effect was observed after inoculation of suckling mice with the clinical L. seeligeri isolate, in contrast to L. monocytogenes strains. Thus, L. seeligeri, previously described as experimentally nonpathogenic for mice, may in fact be a heterogeneous species regarding its pathogenicity, and include strains that may cause life-threatening diseases in humans.

Humans↗
PubMed1985

[Epidemic listeriosis. Report of 25 cases in 15 months at the Vaud University Hospital Center].

25 cases (14 adults, 11 neonates) of Listeria monocytogenes infection were observed during a 15-month period (1983/1984) at the University Medical Center (CHUV) in Lausanne (Switzerland), in contrast to a mean of only 3 cases per year during the period 1974-1982. Eleven of 14 adults had neuromeningeal disease (3 meningitis, 7 meningoencephalitis, 1 encephalitis), and 3 patients had septicemia, two of whom were pregnant women. Among 8 adults with CNS parenchymal infection, 6 had involvement of the brainstem (rhombencephalitis), none of whom had an underlying disease characteristically predisposing to L. monocytogenes infection. Prominent clinical features in all patients with neuromeningeal disease included altered consciousness, headache and fever, and in 7 out of 8 patients with parenchymal CNS involvement an influenza-like illness was present prior to the development of neurological symptoms. Among the neuromeningeal cases the mortality rate was 45% (5 of 11), and 4 out of 6 survivors had severe neurological sequelae. During this 15-month period L. monocytogenes had become the leading cause of adult bacterial meningitis in this hospital. This is the first report on epidemic listeriosis in Switzerland, although sporadic cases have been described for 20 years. In contrast to previous years, analysis of the seasonal variation of the cases shows a peak of L. monocytogenes infections during the winter months of 1983/84. The high incidence of human listeriosis was not associated with an increase in animal cases. The human cases were uniformly distributed over the area, apparently in relation to population density.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1983

[Arterial thrombosis in the nephrotic syndrome].

It is not common knowledge that, besides venous thrombosis, arterial thrombotic events may also be associated with the nephrotic syndrome. Two patients are reported who were admitted because of thrombotic occlusions in the peripheral arteries and developed nephrotic syndrome due to membranous glomerulonephritis after various lapses of time. These two cases and the literature support the hypothesis that an identical pathogenetic mechanism may be responsible for the arterial thrombosis as well as the glomerular lesions.

Adult↗
PubMedDate not supplied

Comparative studies of fluoroquinolones in the treatment of urinary tract infections.

The results of comparative trials of fluoroquinolones for the treatment of uncomplicated and complicated urinary tract infections (UTI) were reviewed. Several randomized, comparative trials showed that in uncomplicated UTI norfloxacin, ciprofloxacin, and ofloxacin were at least as effective as trimethoprim-sulfamethoxazole (TMP-SMZ) and amoxicillin and usually more effective than nalidixic acid, pipemidic acid, and nitrofurantoin. Comparative trials of single-dose regimens have, however, been limited. A few randomized, comparative trials have shown that in complicated UTI norfloxacin, ciprofloxacin, and ofloxacin were at least as effective as amoxicillin and TMP-SMZ and usually more effective than pipemidic acid. Moreover, preliminary results indicate that fluoroquinolones might be effective for the oral treatment of complicated UTI that are difficult to treat, especially those due to Pseudomonas aeruginosa. Comparative trials are needed to establish the value of fluoroquinolones for chronic bacterial prostatitis. There are no conclusive data on fluoroquinolone treatment of UTI in patients with renal failure. Emergence of resistant pathogens during therapy with fluoroquinolones has been infrequent but might be more frequent in complicated UTI caused by P. aeruginosa.

Clinical Trials as Topic↗