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

Penicillin--"tolerant" Staphylococcus aureus strains are resistant to the lethal action of penicillins, but are inhibited by normal (low) concentrations. They are deficient in autolytic enzyme activity which appears to be necessary for bacteriolysis and the lethal action of penicillins. This "deficiency" is caused by a large excess of an inhibitor of autolysin. Seven such tolerant strains have been isolated from blood, bone, or sputum of patients who responded poorly to penicillin treatment of endocarditis, osteomyelitis, or staphylococcal pneumonia. These isolates were of different phage-types, and most showed cross-tolerance to the killing action of cephalosporins or vancomycin, antibiotics to which they were sensitive (inhibited). They were killed at normal rates by gentamicin, cycloserine, and rifampicin. Population analysis indicated that the proportion of tolerant organisms within a resistant strain is 7% or less; their ability to inhibit autolytic activity within their own and neighbouring cells appears to account for the net decreased autolytic activity of the entire strain; 44% of the bacteraemic strains studied showed penicillin tolerance. Tolerance is thus a common, clinically important form of penicillin resistance, that differs from previously described forms of pencillin resistance, that due to beta-lactamase, and that due to "intrinsic" (e.g., methicillin resistance) mechanisms.
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PMID:A new type of penicillin resistance of Staphylococcus aureus. 6 61

(1) Neurologic complications remain a significant problem in bacterial endocarditis. Of 218 patients with endocarditis, 84 (39%) had a neurologic complication and 58% of these 84 patients died. In contrast, the mortality rate was only 20% among those endocarditis patients without neurologic complications. (2) Of the neurologic complications, cerebral embolism is the most frequent and important. An embolic stroke occurred in 37 (17%) of our patients, with 30 of these patients dying. Emboli are important not only in terms of the direct morbidity and mortality they cause via cerebral infarction, but also because of their role in the causation of mycotic aneurysms, brain abscesses, and abnormal CSF formulae. (3) Cerebral emboli are particularly common in patients with mitral valve infection, and in patients with infection due to virulent organisms, particularly S. aureus and enteric gram-negative bacilli. (4) Mycotic aneurysms occur more frequently in the course of acute endocarditis rather than late in the course of subacute disease. Management of angiographically demonstrated mycotic aneurysms is dependent upon the presence or absence of hemorrhage, the anatomic location of the aneurysm, and the clinical course of the patient. Healing of mycotic aneurysms can occur during the course of effective antimicrobial therapy, thus obviating the need for neurosurgical intervention in all such patients. (5) Macroscopic brain abscess is a rare complication of bacterial endocarditis. Miliary microscopic abscesses are more common than larger abscesses, particularly in patients with acute disease and miliary infection in other organs of the body. (6) Focal seizures occur most commonly in endocarditis patients with acute embolic disease; generalized seizures are of diverse etiologies, with metabolic factors being most important. Penicillin neurotoxicity should be considered in patients with impaired renal function who are receiving high dose penicillin. (7) With the exception of hemorrhagic complications, lumbar puncture results tend to reflect the nature of the infecting organism rather than the nature of the neurologic complication. Endocarditis due to virulent organisms such as S. aureus is usually associated with a purulent CSF formula while nonvirulent organisms, such as viridans streptococci, susually have aseptic or normal CSF formulae.
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PMID:Neurologic complications of bacterial endocarditis. 58 Jul 94

Vitamin B6-dependent viridans streptococci were isolated from two patients with microbial endocarditis. Because of their unique requirement for pyridoxal hydrochloride, these organisms did not grow normally in the media usually used in diagnostic laboratories. When tested in supplemented media, both strains were resistant to penicillin G and relatively sensitive to streptomycin. Penicillin-streptomycin synergy was demonstrated in vitro as well as in experimental endocarditis. These laboratory findings confirmed the clinical observations in these two patients that penicillin-streptomycin therapy should be used in vitamin B6-dependent streptococcal endocarditis. Nutritionally varient streptococci may be important pathogens in microbial endocarditis and must be considered in patients with suggestive clinical findings but negative blood cultures.
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PMID:Antimicrobial therapy of vitamin B6-dependent streptococcal endocarditis. 88 95

Despite in vitro demonstrations of synergism against enterococci, combinations of cephalosporin and aminoglycoside antibodies have been ineffective in the therapy of enterococcal endocarditis. Penicillin-gentamicin, cephalothin-gentamicin, and cefazolin-gentamicin were used to treat enterococcal endocarditis in rabbits. A direct relation was observed between the rate of cure and the degree by which the peak serum concentration of penicillin and the cephalosporins exceeded the minimal inhibitory concentration of the enterococcus. Thus, cephalosporin doses which produce serum concentrations which exceed the minimal inhibitory concentration of the enterococcus by several orders of magnitude may, in combination with aminoglycosides, be effective in treating human enterococcal endocarditis.
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PMID:Cephalosporin-aminoglycoside synergism in experimental enterococcal endocarditis. 93 28

Laboratories that reported isolations of Streptococcus sanguis from blood cultures to the Communicable Disease Surveillance Centre (CDSC) Colindale were requested to submit strains to Bath Public Health Laboratory to allow the prevalence of penicillin tolerance within different biotypes of this species to be studied. One hundred and fifty one Streptococcus spp were received from 78 United Kingdom laboratories in one year. Strains were identified using the API 20 Strep, and minimum inhibitory concentrations (MICs) of penicillin were determined using the spiral gradient plate method. Penicillin tolerance was detected by spraying beta-lactamase over inoculated gradient plates, reincubating for 48 hours and counting the number of surviving organisms represented by colonies. There were 57 different API identification profiles encountered in the survey. Most S sanguis I/1 strains were penicillin tolerant, most S sanguis II strains were non-tolerant. The overall geometric mean MIC of penicillin was considerably lower for S sanguis I/1 than for all other biotypes. The distribution of biotypes and the geometric mean MIC of penicillin for each biotype were not significantly different for infective endocarditis strains than for all strains tested, suggesting little or no association between penicillin tolerance and the seeding of endocardium. When the reactions obtained using API 20 Strep were compared with a recent taxonomic study of viridans streptococci, 22 of 38 S sanguis I/1 strains could be reclassified as S gordonii; all these strains were penicillin tolerant. Such reclassification would allow likely penicillin tolerant strains to be predicted.
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PMID:Incidence of penicillin tolerance among blood culture isolates of Streptococcus sanguis, 1987-88. 186 89

An in vitro bacteriostatic synergy between beta-lactam and glycopeptide antibiotics has been recently described against isolates of Enterococcus faecium moderately resistant to penicillin and highly resistant to vancomycin. The relevance of this synergy in a rabbit endocarditis model was evaluated. Penicillin was tested at low- (LoD) and high-dose (HiD) regimens, alone or combined with vancomycin and/or gentamicin. Compared with controls, after a 5-day treatment: LoD penicillin, vancomycin, gentamicin, LoD penicillin plus gentamicin or vancomycin, and vancomycin-gentamicin were not effective; LoD penicillin-vancomycin caused a small reduction of bacterial titers in vegetations that was strongly enhanced by adding gentamicin; HiD penicillin-gentamicin, the most effective regimen, was not significantly better than LoD penicillin-vancomycin-gentamicin. These results suggest that the relative in vivo inefficacy of penicillin-vancomycin might be related to the fact that this combination was poorly bactericidal, and the triple combination of LoD penicillin-vancomycin-gentamicin or the combination of HiD penicillin-gentamicin should be considered in the treatment of serious infections due to beta-lactam- and glycopeptide-resistant enterococci.
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PMID:Triple-combination penicillin-vancomycin-gentamicin for experimental endocarditis caused by a moderately penicillin- and highly glycopeptide-resistant isolate of Enterococcus faecium. 194 Apr 67

We present a case history of 29-year old female with infective endocarditis, who was admitted 15 months after neurosurgical treatment of disruption of cerebral aneurysm. The diagnosis of organic heart disease had been established in her childhood. 6 months after discharge from neurosurgery she developed marked dyspnoea on exertion and became febrile (up to 39.0 C). The presumptive diagnosis of infective endocarditis was established 6 months later, when she developed the symptoms and signs of severe anaemia with ESR 170 mm/hr although blood cultures were negative. The patient underwent treatment with Penicillin and Debecillin. On admission to our Institute echocardiography showed a very large, mobile vegetation in the left ventricle, connected to the anterior leaflet of mitral valve. Decision of mitral valve replacement was made, but rupture of the next cerebral aneurysm was the reason of unexpected, sudden death of the patient. The postmortem examination revealed 7 x 4 cm large vegetation, with the mass of 7.0 g. Histologically the vegetation consisted of mass of fibrin strands, platelets and blood cell with inflammatory cells. On its base the signs of the process of organization were marked. This vegetation was the largest one that we found in literature on this subject.
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PMID:[Unusually large vegetation on the mitral valve in a patient with bacterial endocarditis]. 194 48

The clinical findings relating to 11 patients in Hong Kong (HK) and to 43 patients described elsewhere, all with Streptococcus zooepidemicus septicaemia, are reviewed. There was a particular association with cardiovascular disease (27%) with seven cases of endocarditis, three of abdominal aortic aneurysm and two of deep venous thrombosis. Associations not previously reported included two cases of pharyngitis and two patients with persistent post-operative fever. The overall mortality was 22%. Both human and porcine strains of S. zooepidemicus from HK did not hydrolyse aesculin in contrast to the aesculin-positive biotypes reported previously. HK strains also had very mucoid colonies and capsules of hyaluronic acid were seen in electron micrographs. Samples of chromosomal DNA, extracted by means of HindIII restriction endonuclease, of strains from human beings and pigs were identical. The MIC of penicillin for all strains was less than or equal to 0.03 mg/l but the MBC for all was greater than 32 mg/l. Penicillin alone is generally sufficient for cure but combination with an aminoglycoside may be indicated in seriously ill patients. In our locality, pigs were incriminated as a possible source of human infection whereas consumption of contaminated dairy products is important elsewhere.
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PMID:Streptococcus zooepidemicus (Lancefield group C) septicaemia in Hong Kong. 227 71

Abundant glycocalyx production by viridans streptococci in the rabbit model of endocarditis has been associated with delayed antimicrobial sterilization. Enzymatic digestion of the glycocalyx with dextranase enhances antibiotic activity. The effect of clindamycin (30 mg/kg, subcutaneous, three times daily) was studied in rabbits with experimental aortic valve endocarditis caused by high glycocalyx-producing viridans streptococci. Animals receiving clindamycin had smaller vegetations that were sterilized more quickly than did controls or animals receiving penicillin or dextranase alone (P less than .001). Penicillin plus dextranase treatment allowed greater bacterial killing than penicillin alone and did not differ significantly from clindamycin treatment. Electron micrographs revealed markedly less cell-adherent glycocalyx on organisms grown in vitro treated with clindamycin versus penicillin and controls. It is hypothesized that clindamycin inhibits glycocalyx production in vivo, allowing better antimicrobial penetration in the infected cardiac vegetation.
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PMID:Clindamycin effect on glycocalyx production in experimental viridans streptococcal endocarditis. 234 3

Most cases of endocarditis are caused by nonenterococcal streptococci. Some of these organisms are classified as relatively resistant to penicillin on the basis of minimum inhibitory concentrations (MICs) greater than 0.1-0.2 microgram/mL. Almost all authorities recommend that endocarditis caused by relatively resistant streptococci be treated with high doses of penicillin combined with 2-6 weeks of an aminoglycoside rather than the potentially shorter, less toxic, and more flexible regimens used for exquisitely sensitive streptococci (MIC, less than 0.1-0.2 microgram of penicillin/mL). The data to support this recommendation are limited and inconclusive. We review the relevant clinical experience, experimental models, and theoretical considerations. Penicillin alone is probably adequate therapy for most cases of native valve endocarditis caused by relatively resistant streptococci; in certain patients, it may be the preferred treatment.
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PMID:Treatment of endocarditis caused by relatively resistant nonenterococcal streptococci: is penicillin enough? 240 64


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