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Query: UMLS:C0014118 (endocarditis)
 15,629 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The combination of penicillin and streptomycin did not act synergistically in vitro against three streptomycin-resistant strains (MIC, greater than or equal to 1,000 micrograms of streptomycin/ml) of penicillin-susceptible streptococci. Using a model of experimental infective endocarditis, we infected rabbits with a control streptomycin-susceptible strain, with an intermediately streptomycin-resistant strain (MIC, 1,000 micrograms/ml), and with a highly streptomycin-resistant strain (MIC, greater than 32,000 micrograms/ml). Treating animals with a combination of procaine penicillin and streptomycin was more effective (P less than .01) than treating them with procaine penicillin alone only for those animals infected with the control streptomycin-susceptible strain. Treatment with procaine penicillin plus gentamicin was more effective (P less than .01) than treatment with procaine penicillin alone for all three treatment groups and was more effective (P less than .01) than treatment with procaine penicillin and streptomycin for those animals infected with an intermediately or highly streptomycin-resistant strain of streptococci.
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PMID:In vitro and in vivo studies of streptomycin-resistant, penicillin-susceptible streptococci from patients with infective endocarditis. 364 54

We determined the MBC of amoxicillin and vancomycin, two antibiotics advocated for treatment and prophylaxis of bacterial endocarditis, for 24 strains of viridans group streptococci isolated from patients with endocarditis. We found that the MIC of amoxicillin for all strains was less than or equal to 0.25 micrograms/ml and the MBC was either low (less than 0.5 micrograms/ml) in 6 nontolerant strains or high (greater than 128 micrograms/ml) in 18 tolerant strains. The MIC of vancomycin for the 24 strains was less than or equal to 1 microgram/ml, and the MBC was either low (less than 1 microgram/ml) for 3 nontolerant strains or high (greater than 128 micrograms/ml) for 21 tolerant strains. In addition to the MBC, we determined the actual reduction of the viable bacterial counts in each tube dilution after 24 h of incubation. This determination was made by subtracting the number of colonies observed on the subculture plate from the number of bacteria contained in the initial inoculum. For both antibiotics we found that the maximal reduction in viable counts was achieved at or very close to the MIC and did not increase with increasing antibiotic concentrations (up to 128 micrograms/ml). As expected, the six strains for which the amoxicillin MBC was less than 0.5 micrograms/ml and the three strains for which the vancomycin MBC was less than 1 microgram/ml had a reduction of viable counts of more than 3 log10 (greater than 99.9% killing). In contrast, among the strains defined as tolerant to amoxicillin and vancomycin, there were wide variations in the actual reduction of bacterial counts, ranging from 3 log10 to less than 1 log10. Therefore our observations suggest that the reduction of viable streptococcal counts reflects more accurately the bactericidal effect of amoxicillin and vancomycin than does the MBC, which artificially divides the strains into sensitive or tolerant strains.
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PMID:Discrepancies between MBC and actual killing of viridans group streptococci by cell-wall-active antibiotics. 371 42

We used two strains of streptomycin-susceptible enterococci (MIC, 64 and 128 micrograms of streptomycin per ml, respectively) isolated from patients with infective endocarditis. When combined with penicillin, 20 micrograms of streptomycin per ml killed both strains synergistically in vitro whereas combinations of 5 and 10 micrograms of streptomycin per ml did not act synergistically against either strain. By using the rabbit model of enterococcal experimental endocarditis, animals were treated for 3 days with procaine penicillin (1.2 X 10(6) U intramuscularly three times daily) together with low-dose streptomycin (3.5 mg/kg) or high-dose streptomycin (10 mg/kg) intramuscularly three times daily. The peak concentrations of streptomycin in serum at 0.5 h were 9.2 and 26.8 micrograms/ml in the low- or high-dose group, respectively. When combined with procaine penicillin, both dosages of streptomycin were more effective (P less than 0.01) than procaine penicillin alone for the treatment of enterococcal experimental endocarditis. There was no significant difference in the efficacy of procaine penicillin plus low-dose streptomycin versus procaine penicillin plus high-dose streptomycin therapy of enterococcal experimental endocarditis.
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PMID:Treatment of streptomycin-susceptible enterococcal experimental endocarditis with combinations of penicillin and low- or high-dose streptomycin. 380 Mar 48

The penetration of ceftazidime, cefuroxime and methicillin into cardiac vegetations, normal aorta wall tissue, heart muscle and heart muscle tissue fluid was measured in rabbits with Staphylococcus aureus (853E) endocarditis. After a 100 mg/kg intramuscular injection, ceftazidime attained significantly higher peak concentrations than cefuroxime and methicillin in all compartments with the exception of aorta where no difference was observed between ceftazidime and methicillin. The half life of ceftazidime in each compartment (50-65 min) was approximately twice that of cefuroxime and methicillin. The area under the concentration/time curve for ceftazidime in vegetations over a post dosing 6 h period was approximately five times greater than that for cefuroxime and three times that for methicillin. Ceftazidime remained for a longer time period in all compartments, however cefuroxime persisted the longest at supra-MIC concentrations in all compartments except serum. Compared to cefuroxime and methicillin where vegetation and aorta tissue levels were similar, ceftazidime attained peak levels in vegetations which were more than double those found in aorta tissue. Analysis of the percentage penetration from serum into vegetation, suggested that the higher concentrations of ceftazidime in vegetation tissue were probably not a function of increased fluid content relative to undamaged aorta but were more likely caused by an intrinsically better penetrating capacity for vegetation tissue.
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PMID:Penetration of beta-lactam antibiotics into cardiac vegetations, aorta and heart muscle in experimental Staphylococcus aureus endocarditis: comparison of ceftazidime, cefuroxime and methicillin. 390 61

Staphylococcus aureus strains were exposed in vitro to continuously decreasing cefotaxime concentrations. The initial concentration was approximately 4 X MIC and decreased at t1/2 = 60 min. A reduction in the colony count was seen even after the concentration had dropped below the MIC level. Sixteen patients with blood cultures positive for S. aureus were treated with cefotaxime. Four patient died of underlying diseases. The condition of one patient with staphylococcal endocarditis under treatment with vancomycin in combination with cefotaxime deteriorated when cefotaxime was discontinued, suggesting possible synergism between these two drugs against staphylococci.
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PMID:Staphylococcus aureus septicaemia treated with cefotaxime. 405 53

Twenty adult surgical patients aged between 15 and 83 years (mean:45), 10 of whom had wound infections (one complicated with septicaemia), 2 with septicaemia, 1 with gynecological infection complicated with endocarditis, 5 with urinary tract infections and 2 with lower respiratory tract infections, were treated with parentally-administered cefotaxime. Aetiology was Proteus 7, E. coli 4, Pseudomonas 3, Enterobacter 2, Klebsiella 2 and 2 Serratia. Susceptibility testing was determined by the agar dilution method, with MIC values ranging from 0.01 to 5 microgram/ml, with two urinary isolates of Pseudomonas with MIC of 20 microgram/ml. Clinical responses were excellent in 13 (65 per cent) cases, moderate in 2 (10 per cent) and 3 (15 per cent) failed to respond to therapy. Clinical assessment was not possible in three patients. Bacteriological responses were excellent in 14 (70 per cent) cases, poor in 4 (20 per cent) and in two there was no follow-up. Systemic tolerance was good in all patients except one.
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PMID:Clinical experience with cefotaxime (HR-756) in surgical patients. 626 19

Seventy-six strains of various species of streptococci isolated from patients with infective endocarditis were tested for their susceptibility to 13 antibiotics by an agar dilution method. The antibiotics tested were: benzyl-penicillin, ampicillin, cefotaxime, vancomycin, erythromycin, rifampicin, pristinamycin, gentamicin, netilmicin, tobramycin, amikacin, dibekacin and streptomycin. Excluding enterococci, 91% of strains were sensitive to benzylpenicillin. Resistance to benzylpenicillin was only found in some strains of S. sanguis I, S. sanguis II and S. mitis. Enterococci were more sensitive to ampicillin. Cefotaxime was highly active against all strains, except enterococci. Vancomycin was active against all strains. Resistance to erythromycin was found in 16% of isolates. Rifampicin and pristinamycin were highly active against all strains, except some enterococci. Gentamicin and netilmicin were the most active of the six aminoglycosides tested. High level resistance to streptomycin was seen in six strains. Overall, S. agalactiae was more resistant to the aminoglycosides than the other species. Among the non-groupable streptococci, strains of S. mitis, S. sanguis I and S. sanguis II were the least sensitive to many antibiotics. Benzylpenicillin remains the antibiotic of choice for the treatment of IE caused by streptococci. If the MIC exceeds 0.1 mg l-1, an aminoglycoside (netilmicin or gentamicin) should be added and the duration of treatment increased from 4 to 6 weeks.
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PMID:Antibiotic susceptibility of streptococcal strains associated with infective endocarditis. 639 32

In-vitro synergy testing was performed against ten blood or valve isolates of Staphylococcus epidermidis taken from patients with endocarditis. A three-dimensional microtitre checkerboard method was used for evaluation of vancomycin-rifampicin-gentamicin. The triple combination of vancomycin plus rifampicin plus gentamicin was found to be synergistic in 70% of the isolates. Vancomycin plus rifampicin was not synergistic. Oral agents including dicloxacillin, rifampicin, and fusidic acid were also evaluated. Four methicillin-resistant isolates were relatively resistant to dicloxacillin (MIC greater than 0.79 mg/l) but all four isolates were susceptible to fusidic acid alone and rifampicin alone. The triple combination of dicloxacillin plus fusidic acid plus rifampicin was found to be synergistic in 50% of the isolates and generally superior to any two-drug combination raising the possibility of an effective oral combination of antibiotics.
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PMID:In-vitro synergy testing of triple antibiotic combinations against Staphylococcus epidermidis isolates from patients with endocarditis. 650 Nov 29

The efficacy of imipenem alone or in association with gentamicin against Staphylococcus aureus experimental endocarditis was compared to the efficacy of cloxacillin alone or in association with gentamicin. Parenteral treatment was started 24 h after intravenous bacterial challenge of rats with catheter-induced aortic valve vegetations. The cloxacillin MIC and MBC for Staph. aureus were 0.125 and 32 mg/l and the imipenem MIC and MBC 0.008 and 8 mg/l, respectively. In-vitro killing curves showed a synergistic effect between cloxacillin and gentamicin, and an additive effect between imipenem and gentamicin. Only large doses of cloxacillin (400 mg/kg tid) (producing serum levels above those obtained after intravenous injection of 2 g in man) achieved results comparable to those of imipenem 80 mg/kg tid (producing serum levels similar to those obtained after an intravenous dose of 750 mg in man) in reducing the bacterial numbers in vegetations after 3 and 5 days of treatment. There was a significantly greater reduction of bacterial numbers in vegetations after treatment with the association of cloxacillin and gentamicin than with cloxacillin alone. In contrast, the addition of gentamicin to imipenem did not improve significantly the results of treatment with imipenem alone, but imipenem alone was as good as the combination cloxacillin and gentamicin after 5 days of treatment. We conclude that imipenem is a highly bactericidal drug in this animal model, worth considering for clinical trials in the treatment of Staph. aureus infections.
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PMID:Comparative imipenem treatment of Staphylococcus aureus endocarditis in the rat. 658 98

The penicillinase-resistant penicillins (methicillin, oxacillin, nafcillin) have been the mainstay of antibiotic therapy for S. aureus septicaemia and endocarditis. In experimental rabbit S. aureus endocarditis, these three antibiotics were equally effective. There has been no prospective comparative clinical studies to determine the relative effectiveness of these antibiotics. In experimental rabbit S. aureus endocarditis, cephalothin and cefazolin are less effective than methicillin and nafcillin. The results of therapy with cephalosporins in patients with S. aureus endocarditis are variable. Clindamycin therapy of S. aureus endocarditis has been associated with clinical relapse. Vancomycin has been used to treat S. aureus septicaemia and endocarditis with good results. Fusidic acid has been used in combination with another effective drug in treating S. aureus septicaemia and endocarditis. Although the combination of a cell-wall acting antibiotic with an aminoglycoside has been shown to have an enhanced anti-staphylococcal activity in vitro and in animal studies, there is no evidence that such a combination reduces morbidity or mortality clinically. Rifampin in combination with a cell-wall acting antibiotic is antagonistic against S. aureus in vitro and in experimental endocarditis in rabbits. The use of such a combination has not shown consistent benefits clinically. The clinical importance of tolerance (MBC/MIC greater than or equal to 32) of cell-wall acting antibiotics to S. aureus is not clear. It appears not to be important in animal studies. Cephalosporins appear not to be effective in the treatment of methicillin-resistant S. aureus infections. The treatment of choice of sepsis and endocarditis due to such strains is vancomycin which is effective against all strains of methicillin-resistant S. aureus.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:A general survey of antibiotic treatment of staphylococcal septicaemia and endocarditis. 658 52


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