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M G Täuber

Publications and source records attributed to M G Täuber.

120 records · Page 7Linked to original sources
PubMed1985

Antimicrobial activity of gentamicin in experimental enterococcal endocarditis.

The in vitro activity of gentamicin was compared with its therapeutic efficacy in rabbits with Streptococcus faecalis endocarditis. The test strain was resistant to gentamicin as measured by MICs and MBCs determined in Mueller-Hinton broth alone or in broth supplemented with 50% rabbit serum. Gentamicin also failed to manifest anti-enterococcal activity when evaluated by time-kill studies in broth. However, the addition of serum to the medium did enhance the activity of gentamicin. In the therapy of experimental endocarditis, gentamicin used alone demonstrated anti-enterococcal activity equivalent to that of ampicillin used alone. Vegetation titers in animals treated with gentamicin alone were lower than those of untreated controls (P less than 0.01) and comparable to those in animals treated with ampicillin alone. Thus, gentamicin demonstrated anti-enterococcal activity in vivo despite the resistance observed in vitro, as measured by conventional assays to determine MICs and MBCs.

Ampicillin↗
PubMed1985

Influence of the developmental state of valvular lesions on the antimicrobial activity of cefotaxime in experimental enterococcal infections.

Cefotaxime has little antimicrobial activity in vitro against most strains of enterococci, as measured by conventional MICs and MBCs. However, the MICs of cefotaxime against many enterococci are markedly reduced by the addition of serum to the test medium. To assess the relevance of this observation in vivo, we examined the efficacy of cefotaxime in experimental Streptococcus faecalis endocarditis. Since response to antimicrobial agents may vary with the degree of vegetation development, therapeutic efficacy was assessed both in rabbits with newly formed vegetations and in rabbits with well-developed endocardial lesions. Peak serum levels of cefotaxime (50.1 +/- 20.0 micrograms/ml) exceeded the MIC in medium supplemented with serum (4 micrograms/ml), but not in Mueller-Hinton broth alone (greater than 64 micrograms/ml). After 4 days of therapy, animals with newly formed lesions (therapy initiated 1 h after infection, transvalvular catheters removed) had lower mean vegetation bacterial titers than did untreated controls. Among animals with mature vegetations (therapy initiated 12 h after infection, catheters indwelling), the rate of mortality was significantly reduced by cefotaxime therapy. However, no difference in vegetation titers was observed. Thus, cefotaxime demonstrated antienterococcal activity within newly formed vegetations, but did not inhibit bacterial proliferation within well-established vegetations.

Animals↗
PubMed1985

New cephalosporins cefotaxime, cefpimizole, BMY 28142, and HR 810 in experimental pneumococcal meningitis in rabbits.

Four new cephalosporins, cefotaxime, cefpimizole (U 63196E), BMY 28142, and HR 810 were evaluated in experimental pneumococcal meningitis. Cefotaxime penetrated only moderately into the cerebrospinal fluid of rabbits with meningitis, whereas cefpimizole, BMY 28142, and HR 810 all exhibited unusually good penetration. The bactericidal activity in infected cerebrospinal fluid was comparable for the four drugs.

Animals↗
PubMed1985

Pefloxacin therapy for experimental endocarditis caused by methicillin-susceptible or methicillin-resistant strains of Staphylococcus aureus.

The therapeutic efficacy of pefloxacin in experimental endocarditis caused by methicillin-susceptible or methicillin-resistant Staphylococcus aureus was evaluated. In rabbits infected with a methicillin-susceptible strain, 4 days of pefloxacin therapy significantly reduced both the number of bacteria per gram of vegetation and the mortality rate compared with untreated controls, and pefloxacin was equivalent to cephalothin. Pefloxacin was also as effective as vancomycin in reducing vegetation titers and mortality rate in animals with endocarditis caused by a methicillin-resistant strain. These results suggest that pefloxacin may be an effective agent in the therapy of serious infections caused by either methicillin-susceptible or -resistant strains of S. aureus.

Animals↗
PubMed1984

Principles in the treatment of bacterial meningitis.

The pathophysiologic aspects of bacterial meningitis impose some specific requirements on successful antimicrobial therapy of this disease. Because infections of the subarachnoid space rapidly produce destruction of the brain tissue, treatment must be instituted as early as possible. In the subarachnoid space, efficient host defense mechanisms are absent, particularly at the start of the infection, and therefore antibiotics have to produce a bactericidal effect to eliminate the microorganisms. As animal studies indicate, only drug concentrations 20- to 100-fold higher than the minimal bactericidal concentration are effective in vivo. Because penetration of antibiotics to the site of infection is limited by the blood-brain barrier, the high cerebrospinal fluid concentrations necessary to kill the bacteria may be difficult to achieve and therapy may be limited by toxicity. Even with optimal antibiotic therapy, the morbidity and mortality remain high, and new therapeutic interventions are necessary and should be aimed at modifying selective components of the inflammatory process.

Animals↗
PubMed1984

Pathogenesis of bacterial meningitis: contributions by experimental models in rabbits.

Rabbits models of bacterial meningitis have contributed substantially to our understanding of the disease, although the technical characteristics of these models only allow the study of specific aspects of the disease. Bacterial multiplication in the subarachnoidal space is not substantially influenced by host defense mechanisms, mainly because of the lack of sufficient amounts of specific antibodies and functional complement in infected CSF. The multiplying bacteria induce profound changes in the blood-brain barrier, an influx of serum proteins into the CSF and the invasion of polymorphonuclear leukocytes at the site of the infection. The presence of polymorphonuclear leukocytes in CSF not only appears to be of limited value in combating the infection, but also seems to produce deleterious effects on the central nervous system. Components of the leukocytes, such as unsaturated fatty acids, arachidonic metabolites and free oxygen radicals, may contribute to the profound hydrodynamic, structural and metabolic changes that are currently under study in experimental models of the disease. A better understanding of the pathophysiology of bacterial meningitis may allow us to design more effective therapeutic strategies and improve the outcome of this disease.

Animals↗
PubMed1984

Antibacterial activity of beta-lactam antibiotics in experimental meningitis due to Streptococcus pneumoniae.

In order to define the characteristics of the antibacterial activity of beta-lactam antibiotics in the treatment of bacterial meningitis, the relationship between cerebrospinal fluid (CSF) drug concentrations and the rate of bacterial killing was investigated for penicillin G and four new cephalosporins in an animal model of meningitis due to Streptococcus pneumoniae. All five drugs showed a significant correlation between increasing drug concentrations in CSF and increasing bactericidal rates. Minimal activity was observed in CSF at drug concentrations of approximately the broth minimal bactericidal concentration (MBC). Maximal activity occurred with CSF concentrations 10-30 times higher. In vitro tests did not reproduce the unique correlation of increasing drug concentrations and killing activity found in vivo. When evaluating new beta-lactam antibiotics for the treatment of bacterial meningitis, it is reasonable to establish a minimum standard of CSF drug concentrations of greater than or equal to 30 times the MBC against the infecting organism.

Animals↗
PubMed1984

The postantibiotic effect in the treatment of experimental meningitis caused by Streptococcus pneumoniae in rabbits.

The relevance of a postantibiotic effect in the treatment of pneumococcal meningitis was evaluated in a rabbit model. After administration of a single intravenous bolus of ampicillin at various dosages, such an effect was observed in all animals. The duration of this effect in vivo (2.5-18 hr) was consistently longer than that in vitro (1-4.3 hr); however, in rabbits the postantibiotic effect was eliminated by the administration of intravenous plus intracisternal beta-lactamase. In an assessment of the potential therapeutic benefit of the postantibiotic effect, the efficacy to two regimens of treatment with different intervals between doses was compared. One group of animals received ampicillin every 4 hr and another every 12 hr. With sufficiently high doses, drug concentrations in cerebrospinal fluid exceeded the minimal bactericidal concentration for most of the 4-hr interval but for only about one-third of the 12-hr interval. The rate of cure was similar for the two regimens and approximated 100% when peak drug concentrations in cerebrospinal fluid exceeded the minimal bactericidal concentration by at least 10-fold.

Ampicillin↗
PubMedDate not supplied

Ciprofloxacin-induced hematuria.

We used ciprofloxacin, a quinolone-derivative, to treat a lung infection due to Pseudomonas aeruginosa in an adult cystic fibrosis patient. On three different occasions the use of ciprofloxacin was associated with the development of an asymptomatic hematuria with red blood cell casts. The mechanism responsible for this hematuria is presently unknown, but clinicians should be aware of this potential adverse effect of ciprofloxacin.

Adult↗
PubMedDate not supplied

Brain levels of neuropeptide Y in experimental pneumococcal meningitis.

Neuropeptide Y (NPY), which is found in high concentrations in several regions of the brain including nuclei of the brain stem and in nerve fibers surrounding cerebral vessels, has been proposed to play a role in regulating cerebral blood flow (CBF) and systemic vegetative functions. Since CBF is altered during meningitis, we examined whether NPY concentrations changed in various regions of the rabbit brain in response to experimental pneumococcal meningitis. Changes were most pronounced in the medulla, where NPY concentration increased threefold after 48 h of infection. Concomitantly, there was an increase in NPY immunoreactive fibers surrounding small vessels in the dorsolateral medulla, especially in the nucleus tractus solitarius. These results suggest that NPY may play a role in inducing some of the hemodynamic changes seen during pneumococcal meningitis.

Animals↗
PubMedDate not supplied

Outbreak among drug users caused by a clonal strain of group A streptococcus.

We describe an outbreak among drug users of severe soft-tissue infections caused by a clonal strain of group A streptococcus of M-type 25. Cases (n = 19) in drug users were defined as infections (mainly needle abscesses) due to the outbreak strain. Comparison with controls showed that infected drug users bought drugs more often at a specific place. Drug purchase and use habits may have contributed to this outbreak.

Abscess↗