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

Imipenem was evaluated for its activity against Staphylococcus epidermidis in vitro and in a rabbit model of endocarditis. The MBC for imipenem of 55 methicillin-resistant S. epidermidis isolates from patients with prosthetic valve endocarditis increased by eightfold or greater with increasing inoculum size; there was no inoculum-associated increase in the imipenem MBC for 20 methicillin-susceptible S. epidermidis isolates. Endocarditis was produced in rabbits with either a methicillin-susceptible or a methicillin-resistant S. epidermidis isolate to investigate the correlation in vivo of the in vitro inoculum effect for imipenem. Six days of imipenem treatment eradicated methicillin-susceptible S. epidermidis from vegetations of infected rabbits significantly better than no therapy but was less effective against methicillin-resistant S. epidermidis in this regard. Among methicillin-resistant S. epidermidis-infected rabbits, 6 days of imipenem therapy (i) was not significantly better than that of the control and was significantly worse than that of vancomycin in eradicating bacteria from infected vegetations and (ii) increased the frequency of imipenem-resistant subpopulations in infected vegetations. Resistant subpopulations were not seen in vegetations from untreated or imipenem-treated, methicillin-susceptible S. epidermidis-infected rabbits. Imipenem may not be effective therapy for serious human methicillin-resistant S. epidermidis infections.
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PMID:Imipenem therapy of experimental Staphylococcus epidermidis endocarditis. 346 May 23

The pharmacokinetics of gentamicin and latamoxef (moxalactam) were examined in serum, normal heart valves, sterile cardiac vegetations and vegetations infected with Escherichia coli. Penetration of antibiotics into heart valves and vegetations was rapid; the maximum concentration was achieved in both sites at the end of a 20 min iv infusion. However, both antibiotics penetrated better into vegetations than into normal heart valves. In rabbits with left-sided endocarditis, similar antibiotic levels were found in infected vegetations after one or 22 im injections. After 11 im injections (one every 8 h) of latamoxef (15 mg/kg) the bacterial titre (cfu/g) was significantly reduced, but not nil, despite concentrations about 40 times the MBC for this antibiotic in the vegetations. Afer 22 im injections, vegetations in rabbits receiving latamoxef were sterile and were significantly reduced in those receiving gentamicin (1.5 mg/kg/im), concentrations of which in the vegetations were inferior to the MBC. Our results suggest that the in-vivo antibacterial effect depends on local antibiotic levels, kinetics of killing and duration of contact between antibiotic and bacteria.
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PMID:Kinetics and bactericidal effect of gentamicin and latamoxef (moxalactam) in experimental Escherichia coli endocarditis. 351 63

Imipenem and cilastatin in combination have a broad spectrum in vitro with a strong killing activity on most bacteria. Using a multicenter study design, we investigated 41 patients with moderate or severe infections: septicemia in 18 cases (Gram negative rods in 10, Gram positive cocci in 7 and combination of both in 1), pneumonia in 7, osteitis in 4, soft tissue infection in 7, infection of the genitourinary tract in 6 and miscellaneous infections in the remaining cases (1 abscess of the pancreas, 1 typhoid fever, 1 presumptive endocarditis). All of the bacteria were susceptible to imipenem/cilastatin: MICs ranged from 0.02 to 0.8 mg/l and MBCs from 0.015 to more than 10 mg/l. All patients except one recovered or improved under imipenem/cilastatin. The patient who failed to respond had septicemia due to a methicillin-resistant Staphylococcus aureus with a MBC and MIC above 10 and 0.5 mg/l respectively. Tolerance was outstanding: only 4 patients had adverse effects requiring withdrawal of the drug.
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PMID:[Treatment of moderate or severe infections using imipenem/cilastatin. 41 cases based on a multicenter protocol]. 353 23

In vitro activity of ciprofloxacin against 27 strains of enterococci was inoculum dependent. Using inocula of 10(5) to 10(6) or 10(7) to 10(8) CFU of enterococci per ml, the MICs for 50 and 90% of strains tested increased from 1 to greater than or equal to 128 micrograms of ciprofloxacin per ml with the higher inoculum compared with the lower inoculum. The MBC for 50% of strains tested increased from 2 to greater than 128 micrograms/ml and the MBC for 90% of strains tested increased from 8 to greater than 128 micrograms of ciprofloxacin per ml with the lower and higher inocula, respectively. The combination of penicillin-gentamicin was more effective in vitro than the combination of ciprofloxacin-gentamicin against the low or high inoculum of enterococci. Using two strains of enterococci, we studied the efficacy of ciprofloxacin in the treatment of enterococcal experimental endocarditis in rabbits. Ciprofloxacin used alone or combined with gentamicin was significantly less effective (P less than 0.01) than procaine penicillin alone or procaine penicillin combined with gentamicin for the treatment of enterococcal experimental endocarditis. The combination of ciprofloxacin-procaine penicillin was not a more effective therapy than procaine penicillin alone.
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PMID:In vitro and in vivo activity of ciprofloxacin against enterococci isolated from patients with infective endocarditis. 357 60

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.
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PMID:Treatment of Staphylococcus aureus endocarditis in rats with coumermycin A1 and ciprofloxacin, alone or in combination. 360 60

The efficacy of ciprofloxacin for experimental aortic valve endocarditis in rabbits infected by either a methicillin-susceptible or a methicillin-resistant strain of Staphylococcus aureus was compared with standard therapy of nafcillin or vancomycin, respectively. After 4 days of therapy, ciprofloxacin reduced the counts of organisms in aortic valve vegetations as effectively as the standard regimen for both susceptible and resistant strains. Mean concentrations of ciprofloxacin in serum achieved 1 h after a dose exceeded the MBC for each strain by twofold or less. In these experiments ciprofloxacin was as efficacious as standard regimens currently used to treat staphylococcal infections in humans.
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PMID:Efficacy of ciprofloxacin for experimental endocarditis caused by methicillin-susceptible or -resistant strains of Staphylococcus aureus. 364 May 90

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

Aortic valve endocarditis due to a penicillin G (PNC) and ceftizoxime (CZ)-sensitive group B streptococcus (GBS) was induced in 72 rabbits. Animals received either procaine PNC (300 mg/kg per day) or CZ (150 mg/kg/day) for 3, 6, or 9 days. PNC rapidly sterilized blood cultures (less than or equal to 3 days) and significantly reduced vegetation GBS titers versus controls at all three sacrifice times (p less than 0.0005). In contrast, CZ exerted a slow in vivo bactericidal effect with vegetation titers not significantly different from controls until day 9 of therapy. By day 9 of therapy, 65/89 (73%) of vegetations were sterilized by PNC versus only 24/94 (26%) sterilized by CZ (p less than 0.0005). This marked in vitro-in vivo disparity in CZ-treated animals occurred despite 100% of individual serum bactericidal titers greater than or equal to 1:32 and 100% of individual CZ serum levels greater than or equal to 100 times the GBS MBC. The suboptimal CZ in vivo effect was not related to: (1) development of CZ resistance on therapy; (2) CZ inactivation, or (3) inoculum-growth phase effect.
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PMID:Experimental group B streptococcal endocarditis treated with penicillin G versus ceftizoxime. In vitro-in vivo disparity. 631 93

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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