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

To study the effect of antimicrobials on bacterial growth in blood cultures, we used both simulated blood cultures and cultures obtained from rabbits with experimental endocarditis. Four strains of bacteria were incubated individually with six antimicrobials in nine blood culture media. Positivity rates varied with the ratio of the antimicrobial concentration to the MIC of the organism: 161 of 162 cultures (99%) were positive when the ratio was less than 1/10; 52 of 108 (48%) were positive when the ratio was between 1/10 and one; and none of 54 were positive when the ratio was greater than one. Endocarditis was produced in 28 rabbits with either E. coli, P. aeruginosa, S. aureus, or viridans streptococcus. Following a single dose of an antimicrobial, blood was taken for culture in eight media. Only for viridans streptococcus did recovery rates vary significantly in different media. Recovery rates for this organism in two supplemented peptone broths (78% and 89%) and in hypertonic supplemented peptone (78%) were each higher than in thioglycolate (22%), Columbia (22%), Bactec aerobic and anaerobic (11%), and trypticase soy broths (11%) (p less than 0.05 for each pair). Growth of bacteria in blood cultures containing antimicrobials depended on the ratio of the antimicrobial concentration to the MIC and, for viridans streptococcus, the blood culture medium.
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PMID:Effect of antimicrobials on blood cultures in endocarditis. 312 19

The in vivo efficacies of pefloxacin, a new fluoroquinolone, and amikacin-ceftazidime were compared in 50 rabbits with experimental aortic endocarditis caused by Pseudomonas aeruginosa. Animals were randomly chosen to receive 4 or 10 days of no therapy (controls), pefloxacin (40 mg/kg [body weight] per day, intramuscularly [i.m.]), or amikacin (30 or 80 mg/kg per day, i.m.)-ceftazidime (150 mg/kg per day, i.m.). Pefloxacin and both amikacin regimens significantly reduced vegetation bacterial densities compared with controls at days 4 and 10 of treatment (P less than 0.0005). By day 10 of therapy, between 33 and 40% of vegetations from amikacin-ceftazidime recipients contained ceftazidime-resistant bacteria (MICs, greater than 25 micrograms/ml); nitrocefin agar overlay confirmed that these ceftazidime-resistant variants were constitutive overproducers of beta-lactamase. At therapy days 4 and 10, approximately 30% of vegetations sampled from pefloxacin recipients contained bacteria for which pefloxacin MICs were four- to eightfold higher than the MIC for the parental strain used to initially induce endocarditis (MIC, 0.19 microgram/ml). These variants also exhibited increases in ciprofloxacin and ticarcillin MICs, as well as pleotropic resistance to chloramphenicol (but not to amikacin, ceftazidime, or tetracycline). Amikacin-ceftazidime, as well as pefloxacin, was effective in this model of aortic pseudomonal endocarditis. However, in vivo development of ceftazidime resistance and step-ups in pefloxacin MICs among intravegetation isolates were associated with inability to completely eradicate P. aeruginosa from aortic vegetations.
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PMID:Development of beta-lactam resistance and increased quinolone MICs during therapy of experimental Pseudomonas aeruginosa endocarditis. 312 85

Enterococci isolated from different body sites were tested for high-level gentamicin resistance. A total of 259 enterococcal isolates were screened for resistance (MIC, greater than 2,000 micrograms/ml) by a broth-tube method. Thirty-nine (15.1%) were found to exhibit resistance and were confirmed by agar screening (1,000 micrograms/ml) and agar dilution MIC determinations. The majority of isolates also showed high-level resistance to kanamycin and streptomycin. The remaining isolates showed high-level resistance to gentamicin and kanamycin but not streptomycin. Synergy testing of several isolates confirmed the correlation between lack of synergy and high-level resistance. A retrospective clinical review was performed. Most patients had a source of definite or likely infection (79%). Serious infections such as endocarditis or meningitis were not observed during the course of this study. Retrospective clinical data suggest that in cases not involving endocarditis or meningitis, neither infection refractory to therapy nor relapse of infection is a common sequela of infection with gentamicin-resistant enterococci in hospitalized patients.
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PMID:Multiply high-level-aminoglycoside-resistant enterococci isolated from patients in a university hospital. 313 46

Susceptibilities of methicillin-resistant Staphylococcus aureus (MRSA, n = 32), methicillin-sensitive S. aureus (MSSA, n = 32), and S. epidermidis (SE, n = 24) were determined to fleroxacin, amifloxacin, ciprofloxacin, difloxacin, enoxacin, norfloxacin, and ofloxacin. All organisms were isolated from the blood of patients with infective endocarditis. MRSA and MSSA MIC90s were less than 1.0 mg/l of fleroxacin, ciprofloxacin, difloxacin, and ofloxacin while amifloxacin and norfloxacin produced MIC90s of less than 2.0 mg/l and enoxacin MIC90s of less than 4.0 mg/l. For S. epidermidis MIC90s were less than 1.0 mg/l of all quinolones except amifloxacin whose MIC90 was less than 2.0 mg/l. Two strains from each staphylococcal group were used in time-kill trials performed with all seven quinolones. Within 8 h, all quinolones colony counts were decreased by one log. At 24 h, most quinolones decreased MRSA, MSSA, and SE colony counts by two to four logs; however, exceptions were found with (1) difloxacin, enoxacin, and norfloxacin against MRSA, (2) ciprofloxacin and enoxacin against MSSA, and (3) ciprofloxacin against SE in which all colony counts increased one to three logs in 24 h. When quinolone time-kill trials did not show a decrease in colony counts at 24 h, the MIC's for the 24 h growth showed a four- to 250-fold increase when compared with pre-trial MICs. No selection or emergence of resistant organisms was found with fleroxacin, amifloxacin or ofloxacin.
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PMID:In-vitro susceptibility of staphylococci to fleroxacin in comparison with six other quinolones. 314 47

Methicillin activity against 149 penicillin-resistant, methicillin-susceptible Staphylococcus aureus strains from bacteraemia cases with endocarditis (n = 89) or without endocarditis (n = 60), from the years 1976-1981, was studied with broth dilution and agar dilution. While no differences in methicillin susceptibility were found in relation to the origin of the strains, Staph. aureus of the phage type complex 94,96 showed significantly higher MIC and IC50 by agar dilution than strains of other phage groups/complexes. This difference probably has no clinical importance but is of epidemiological interest. Broth dilution MIC was generally one dilution higher than agar dilution MIC, possibly explained by methodological factors. The MBC/MIC ratios never exceeded two in any of the strains, indicating a lack of tolerance in these clinically important isolates.
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PMID:In-vitro activity of methicillin against clinical isolates of Staphylococcus aureus. 315 38

Cefotaxime, a third generation cephalosporin, is used throughout the world over a wide range of doses. The purpose of this paper is to discuss the rationale for determination of the optimal dosage and of adequate modes of administration. Among the factors determining in vivo activity, the most important are: (1) the time dependence of the antibacterial effect of cephalosporins, (2) the limited effect of increasing the drug concentration in contact with the bacteria and (3) the absence of a significant post-antibiotic effect. Combined with the rather short elimination half-life of cefotaxime, these factors argue for the use of a unitary dose of 1g in adult patients and for a 6- or 8-hour interval between doses. Information obtained from various animal models of infection are discussed. Clinical and bacteriological studies published in the international literature report a high rate of cure (between 80 and 100%) according to the type of infection and to the criteria of efficacy, with daily doses ranging from 2 to 4g bid or qid. The results obtained with the lowest doses are detailed, particularly for infections permitting the use of a low dosage. The necessity for increasing the dose is discussed in the following situations: (1) in specific infections requiring high local drug concentrations such as meningitis and endocarditis, (2) against micro-organisms exhibiting moderate susceptibility to cefotaxime (MIC greater than or equal to 1 mg/L) and (3) in immunocompromised patients. It is now well established that third generation cephalosporins have to be combined with other antimicrobial agents (e.g. aminoglycosides) for the treatment of patients with infections caused by bacteria able to become resistant. For susceptible strains, it has not been established that a synergistic effect of cefotaxime with another agent allows a reduction of the dosage of each member of the combination.
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PMID:Cefotaxime optimal dosage in adult patients. A reappraisal. 329 77

Thirty-two patients were treated by ofloxacin on bacteriological documented infections. They were Enterobacterias: n = 15 (MIC less than or equal to 0.06 to 0.5 microgram/ml); Pseudomonas aeruginosa and Acinetobacter: n = 1 (MIC 0.5 and 4 micrograms/ml); Staphylococcus: n = 6 (MIC less than or equal to 0.06 to 4 micrograms/ml); Pneumococcus: n = 1; Mycoplasma: n = 1; Chlamydia psittaci: n = 2; Legionella pneumophila: n = 1; Rickettsias: n = 4 (three mediterranean fevers one query fever). Ofloxacin was given orally from 400 to 800 mg per day (5 to 15 mg/kg/day). It was used alone 26 times and on 6 occasions it was associated with rifampin on 6 staphylococcal infections. On 19 cases it was used after failure or intolerance of initial therapy. Thirty times it was the first antibiotic substance used. Results were good mainly: 1) on nine pneumonitis (enterobacterias: 4; Pneumococcus: 1; Mycoplasma: 1; Chlamydia: 2; Legionella: 1) during a mean duration of twenty days; 2) urinary infections (n:7) provoked by E. coli and Enterobacter cloacae (mean duration: 20 days); 3) 4 osteo-articular-infections (mean duration: 77 days); 4) Rickettsial infections (n:4) during a mean duration of 11 days. Results are particularly noteworthy because patients treated had severe infections: 12 bacteremias, 1 endocarditis and 1 purulent meningitis. None severe adverse effect was observed.
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PMID:[Ofloxacin (RU 43280). Clinical study]. 330 73

Septicemia is a rare but serious complication of infection with Yersinia enterocolitica (Y.e.). Seven cases of Y.e. septicemia are presented. Five of the patients had no underlying disease predisposing to septicemia. Five patients displayed recurrent episodes of septicemia, despite treatment with recommended doses of antibiotics to which the isolates were sensitive in vitro. One patient developed endocarditis which required surgical replacement of the aortic valve. Other clinical manifestations were arthritis, diverticulitis and pulmonary abscesses. The outcome was fatal to 3 elderly patients. The serological response to Y.e. was followed by tube agglutination and a diffusion-in-gel enzyme-linked immunosorbent assay. One patient, with a benign course of illness, had transient elevated Y.e. antibody titres, while the 3 cases with a protracted disease showed sustained antibody responses for 6-18 months. Blood isolates of Y.e. had ordinary virulence characteristics identical to fecal isolates and produced extracellular beta-lactamase. All isolates were sensitive in vitro to trimethoprim-sulfamethoxazole, mecillinam, piperacillin, cefotaxime, ceftazidime, chloramphenicol and gentamicin. The lowest MIC values were recorded for mecillinam. Full synergistic activity was demonstrated when mecillinam was combined with trimethoprim-sulfamethoxazole, cefuroxime or rifampicin.
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PMID:Yersinia enterocolitica septicemia: clinical and microbiological aspects. 353 2

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

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


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