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

We are presenting a case of endocarditis due to a penicillin-tolerant Streptococcus bovis in a 65-year-old patient. The minimal bactericidal concentration of penicillin (40 mg/l) was more than 100-fold the minimal inhibitory concentration (0.08 mg/l). The MBC of penicillin was 0.31 mg/l in the presence of 1.25 mg/l gentamicin. Cross-sectional echocardiography revealed endocarditis of the anterior leaflet of the tricuspid valve and a vegetation on the aortic valve which appeared to be pedunculated and which prolapsed into the left ventricular outflow tract during diastole. During therapy, the pedunculated part of the vegetation disappeared without signs of embolization. After initial clinical improvement, the patient died of cerebral bleeding caused by a mycotic aneurysm of the left median cerebral artery. The patient's final outcome suggested an asymptomatic embolus. Cross-sectional echocardiography was distinctly superior to M-mode echocardiography in estimating changes in the size and shape of the valve vegetation. The results of the post-mortem examination of the aortic and tricuspid valves corresponded to the echocardiographic findings.
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PMID:Endocarditis due to a penicillin-tolerant streptococcus bovis: microbiological findings and echocardiographic follow-up. 666 68

The efficacies of mezlocillin and ticarcillin, each alone and in combination with gentamicin, in the therapy of experimental left-sided Enterobacter aerogenes endocarditis in rabbits were compared. Each beta-lactam was administered intramuscularly at a dose of 180 mg/kg every 6 h either alone or with gentamicin (1.7 mg/kg intramuscularly every 8 h). Bacterial populations at the start of therapy (7 days after initiation of infection) were 9 to 10 log10 CFU/g of vegetation. Ticarcillin produced concentrations in serum that were twice those produced by mezlocillin, but the therapeutic ratios of mezlocillin and ticarcillin (ratio of peak level in serum to MBC) were the same. All of the therapeutic regimens given for either 5 or 10 days were effective in reducing vegetation counts when compared with the untreated controls (P less than 0.01 for all comparisons), except mezlocillin alone and ticarcillin alone, which caused insignificant reductions in counts after 5 days of therapy (P greater than 0.05). After 10 days of therapy, the only regimen that was significantly different from another was that of mezlocillin plus gentamicin, which was significantly better than that of ticarcillin alone (P less than 0.01). These studies document that mezlocillin and ticarcillin were both effective in reducing the numbers of E. aerogenes CFU in vegetations in rabbits with experimental endocarditis when the drugs were given over a prolonged course. More rapid and extensive reduction in vegetation counts was achieved with combinations of an aminoglycoside plus mezlocillin or ticarcillin. Mortality was significantly less among rabbits treated with mezlocillin plus gentamicin.
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PMID:Mezlocillin and ticarcillin alone and combined with gentamicin in the treatment of experimental Enterobacter aerogenes endocarditis. 674 13

A patient was referred to our hospital with a tentative diagnosis of fungal endocarditis based upon clinical symptoms, suggestive travel history, and microscopic visualization in blood cultures of gram-negative bulbous filaments that appeared to be fungal elements. Subcultures of the blood culture bottles were unsuccessful on all media with the exception of blood agar plates, which had been cross-streaked with Staphylococcus aureus. These plates grew vitamin B6-dependent streptococci. This nutritionally variant organism was determined by biochemical tests to be Streptococcus mitis (mitior). It had a penicillin MIC and MBC of 0.015 micrograms/mL and 0.03 micrograms/mL, respectively and streptomycin MIC and MBC of 0.78 micrograms/mL and 1.56 micrograms/mL, respectively. The patient was treated with these two agents and recovered. We stress the importance of suspecting vitamin B6-dependent streptococci, even when gram stains may suggest presence of other microorganisms.
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PMID:Vitamin B6-dependent Streptococcus mimicking fungi in a patient with endocarditis. 685 59

Two cases of bacterial endocarditis in children, caused by viridans group Streptococcus which requires vitamin B6 or thiol compounds for growth are reported. It is important to recognize these organisms as a possible cause of endocarditis because supplemented media are needed for their isolation and sensitivity testing. These organisms may be penicillin-sensitive, -resistant, or -tolerant. An organism is considered tolerant to an antibiotic when the minimum bactericidal concentration of that antibiotic is greater than or equal to 32 times the minimum inhibitory concentration. One of our patients relapsed when treated with a single antibiotic to which the B6-dependent viridans group Streptococcus was tolerant. If a B6-dependent viridans group Streptococcus is isolated from a patient with endocarditis, therapy should be initiated with penicillin and an aminoglycoside until sensitivities are available. Sensitity testing should include both the MIC and MBC and adequate therapy can be confirmed by determing the serum bactericidal activity.
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PMID:Bacterial endocarditis caused by vitamin B6-dependent viridans group Streptococcus. 740 19

This study compares the effects of a total daily dose of gentamicin given once a day (q.d.) or three times a day (t.i.d.) in the therapy of experimental endocarditis in rabbits caused by penicillin-susceptible, penicillin-tolerant, or penicillin-resistant viridans streptococci. Four isolates were used in vivo: one penicillin susceptible (MIC < or = 0.03 microgram/ml), one penicillin tolerant (MBC/MIC, < or = 0.03/ > 32 micrograms/ml), and two penicillin resistant (MICs = 0.5 and 2 micrograms/ml). Animals were infected with one of the four isolates and assigned to one of the following treatment regimens: no treatment, procaine penicillin at 1.2 million IU intramuscularly (i.m.) t.i.d., procaine penicillin plus gentamicin at 1 mg/kg of body weight i.m. t.i.d., procaine penicillin plus gentamicin at 3 mg/kg i.m. q.d., or procaine penicillin plus gentamicin at 1 mg/kg i.m. q.d. (only animals infected with the penicillin-susceptible isolate). Serum drug concentrations measured 30 min after administration of 1.2 million IU of penicillin and 1 or 3 mg of gentamicin per kg were 22.6, 3.8, and 8.5 micrograms/ml, respectively. The reduced total daily dose of gentamicin was ineffective among animals infected with penicillin-susceptible viridans streptococci; treatment with 1 mg of gentamicin per kg per day plus penicillin was less effective (P < 0.05) than was treatment with 3 mg of gentamicin per kg per day plus penicillin. The 1-mg/kg/day gentamicin treatment regimen was not further studied. The gentamicin dosing interval did not significantly affect (q.d. versus t.i.d., P > 0.05) the relative efficacy of penicillin plus gentamicin for treatment of experimental endocarditis among animals infected with each of the four isolates tested.
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PMID:Effect of gentamicin dosing interval on therapy of viridans streptococcal experimental endocarditis with gentamicin plus penicillin. 854 Jul 23

A 33-year-old, active intravenous drug-abusing male infected with the human immunodeficiency virus developed endocarditis due to Arcanobacterium haemolyticum. Empirical treatment with ampicillin plus gentamicin failed to achieve a marked clinical improvement. When the results of antibiotic susceptibility were available (ampicillin MIC < or = 0.06 mg/l; ampicillin MBC 2 mg/l; MBC:MIC ratio > 32) therapy was changed to vancomycin plus gentamicin. During the following days progressive clinical and radiological improvement was observed. The patient received antibiotics for 30 days and no relapse occurred during a 14-month follow-up. The literature of endocarditis due to this uncommon bacterium is reviewed here.
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PMID:Endocarditis caused by Arcanobacterium haemolyticum. 868 85

Infective endocarditis is an uncommon disease but retains a high mortality. Glycopeptides are used for patients with resistant pathogens, those allergic to penicillins or for those outside the hospital. The once daily administration of teicoplanin and its low toxicity suggest that it would be suitable for use in the long courses required for endocarditis. However, the dosage and combinations to be used require further study. A retrospective review has been made of 104 episodes of endocarditis treated with teicoplanin in 101 patients seen over 7 years. Most patients had been referred to major London hospitals following failure of medical treatment. After three loading doses of 400 mg, teicoplanin was given at a dose of 400 mg/day in combination with other antibiotics such as gentamicin. Follow up was for one year. The most common pathogens were Streptococcus sanguis (15 cases), Staphylococcus aureus (13 cases) and Staphylococcus epidermidis (10 cases). Of 80 patients febrile at the start of treatment with teicoplanin, 63 (79%) lost their fever within a median of 2 days (1-35 days). Cure without surgery was effected in 50 (48%) and 75% of patients survived. Other antibiotics, usually gentamicin or rifampicin, were used in 92 (90%) of patients. Two strains of Streptococcus spp. were said to be resistant but there was no relationship between MIC of teicoplanin and outcome. Pathogens with a high MBC tended to be more likely to resist treatment. Adverse effects resulted in the withdrawal of teicoplanin in 20 cases (19%) but most events were mild and renal deterioration occurred in only five patients. Teicoplanin was effective in the treatment of endocarditis and appeared to be safe given the severity of disease in the patients treated.
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PMID:Treatment of endocarditis with teicoplanin: a retrospective analysis of 104 cases. 888 25

Two hundred microbiology laboratories in the UK took part in two separate experimental external quality assessment distributions related to the serum bactericidal test (SBT). In the first, Staphylococcus aureus NCTC 6571 (vancomycin MIC 1 mg/L), was tested against a human serum containing vancomycin 38 mg/L plus gentamicin 0.5 mg/L. In the second, Streptococcus oralis PAJ 112/4183 (penicillin MBC < or = 0.03 mg/L) and Streptococcus sanguis PAJ 107/4184 (penicillin MBC = 128 mg/L) were tested against human serum containing penicillin 15 mg/L. Respondents returned their laboratory results and a questionnaire on clinical interpretation and technical aspects. Most laboratories (194/199, 97.5%) recommend the use of the SBT in the management of infective endocarditis but only 48 (25.2%) often or always change therapy on the basis of the result. A wide range of interpretative criteria, definitions of bactericidal endpoints and methodologies are used. Performance in the first distribution was acceptable for 75% of laboratories but in the second only 34% could identify penicillin tolerance; 34 respondents reported an SBT result of < or = 2 for the tolerant strain, 81 laboratories reported one of > or = 16. Technical factors related to acceptable performance were: sonication of broth before counting the inoculum; knowing the inoculum size in cfu/mL; use of a 4-8 h broth culture to make the inoculum; incubation of recovery plates for > 36 h; use of a calibrated pipette to sample for surviving bacteria; use of measured volumes to add the inoculum. Use of uncalibrated pipettes or standard loops to recover survivors was related to poor performance. Microbiology departments in the UK should review the clinical need to perform the SBT in the light of their local circumstances and if they elect to continue to offer this test, revise their methodologies which could be producing misleading results when testing alpha-haemolytic streptococci.
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PMID:External quality assessment of the serum bactericidal test: results of a methodology/interpretation questionnaire. 906 54

The synergy between amoxicillin and cefotaxime against two strains of Enterococcus faecalis (JH2-2 and 6370) in vitro and in rabbit endocarditis was investigated. In vitro synergy was obtained only when amoxicillin concentrations were below the MBC and when cefotaxime concentrations were above 1 microg/ml. No synergy was observed in vivo, because of the short period of time during which these pharmacologic requirements were achieved.
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PMID:Critical importance of in vivo amoxicillin and cefotaxime concentrations for synergy in treatment of experimental Enterococcus faecalis endocarditis. 952 11

Treatment failures with vancomycin prompted us to investigate the phenomenon of tolerance to glycopeptides in recent clinical isolates of Staphylococcus aureus. We used both MBC/MIC determinations and time-kill measurements to study tolerance to vancomycin and teicoplanin in 35 blood or heart valve isolates of S. aureus from patients with endocarditis or bacteraemia. There was generally good agreement between vancomycin tolerance indicated by an MBC:MIC ratio of > or =32 and by < or =90% kill after 6 h incubation in the presence of 20 mg/L vancomycin. However, two isolates were tolerant according to their MBC:MIC ratios but non-tolerant as judged by time-kill measurements. Seven of 15 methicillin-resistant S. aureus (MRSA) isolates but only two of 20 methicillin-susceptible ones were tolerant as judged by time-kill experiments (chi2 = 4.27 with Yates' correction, P = 0.04). Seven of the 16 isolates from patients with endocarditis were tolerant, compared with only two of the 19 isolates from patients with other conditions (chi2 = 3.43 with Yates' correction, P = 0.06). Within the endocarditis and non-endocarditis subgroups, tolerance was associated more frequently with methicillin resistance than with susceptibility, but the numbers were too small for the differences to be statistically significant. Most of the vancomycin-tolerant isolates were also tolerant to teicoplanin. We conclude that glycopeptide tolerance is a real phenomenon in S. aureus, particularly amongst MRSA isolates, and can be reliably determined by our method of time-kill analysis. Tolerance may compromise glycopeptide therapy of serious S. aureus infection and should be taken into account when deciding treatment.
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PMID:Glycopeptide tolerance in Staphylococcus aureus. 973 36


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