Course Of Bacterial Endocarditis Research Articles

Dysregulation of monocyte oxidative burst in streptococcal endocarditis.

Streptococcal subacute endocarditis is characterized by low-grade systemic inflammation. Although structural cardiac defects are pivotal, phagocytic cells, i.e. monocytes and neutrophils, are involved in the induction and the course of bacterial endocarditis. Decreased production of reactive oxygen metabolites was described in long-lasting infections. We hypothesized that the oxidative burst of phagocytes induced by the infecting organism is defective in patients with streptococcal endocarditis. The monocytes and neutrophils of 11 patients with streptococcal native valve endocarditis were challenged with the respective pathogens and two control streptococcal strains, and the oxidative burst was determined by fluorescence-activated cell sorter analysis. These experiments were done before any antibiotic therapy was administered, and repeated at least 12 months after recovery. Eight volunteers served as healthy controls. The monocyte response to the respective pathogens was decreased in the patient groups compared to the response to the control streptococci. After cure the monocyte response to the pathogens was not different to the response to the control strains. The monocyte response of the healthy volunteers did not show any differences between the patients' pathogens and the control strains. The neutrophil oxidative burst to the pathogens was similar to that to the control streptococci in both patient and the volunteer group. The decreased response of patient monocytes to the pathogens may contribute to the low-grade inflammatory response and to the course of streptococcal endocarditis.

Role of monocytes and bacteria in Staphylococcus epidermidis endocarditis.

The endocardial vegetation which is formed in the course of bacterial endocarditis (BE) contains tissue factor (TF)-dependent procoagulant activity. Earlier studies showed that monocytes are the main source of TF in the vegetations. The TF activity (TFA) of vegetations isolated from Streptococcus sanguis-infected rabbits depended on the numbers of bacteria as well as monocytes in the vegetation. In this study, we investigated whether for Staphylococcus epidermidis, a frequent pathogen in BE, an effect similar to that found for S. sanguis could be shown. In vitro, S. epidermidis was found to stimulate TFA of fibrin adherent monocytes significantly. This stimulation was maximal at a bacterium-to-monocyte ratio of 7. In vivo, TFA was found to be significantly higher in S. epidermidis-infected than in sterile catheter-induced vegetations. Reduction of vegetational bacterial numbers by teicoplanin treatment lead to a small but significant decrease of TFA. Reduction of monocyte numbers by etoposide did not affect vegetational TFA. Comparison of data for S. epidermidis and S. sanguis revealed that at equivalent bacterial numbers, vegetational TFAs were approximately the same for both microorganisms. Combining the results of the present study with those of a previous study using S. sanguis, we conclude that the main factor determining monocyte-dependent vegetational TFA is the number of vegetation-associated bacteria. The lower TFA found for S. epidermidis-infected than for S. sanguis-infected vegetations can be explained by the significantly lower bacterial numbers in the infected vegetations and consequently a lower stimulation of vegetation-associated monocytes.

Influence of monocytes and antibiotic treatment on tissue factor activity of endocardial vegetations in rabbits infected with Streptococcus sanguis.

A main feature in the pathogenesis of bacterial endocarditis is the activation of the coagulation system via the extrinsic pathway, resulting in the formation of infected endocardial vegetations. Earlier studies gave indirect evidence that monocytes play an important role in the procoagulant response during the course of the disease. In this study, we assessed the role of monocytes more directly. We compared weights and tissue factor activities (TFA) of endocardial vegetations of normal rabbits infected with Streptococcus sanguis with those of rabbits which were treated with the cytostatic drug etoposide (Vepesid; Bristol-Myers Squibb B.V.) to induce a selective monocytopenia. Furthermore, the importance of the presence of bacteria was determined through the influence of antibiotic treatment on TFA, vegetational weight, and infection of the vegetations. The TFA of the vegetations was measured chromogenically by monitoring the factor VII-dependent activation of factor X with an amidolytic assay for factor Xa. We found that the degree of infection and the weight of vegetations of rabbits treated with the cytostatic drug etoposide did not differ from that of untreated rabbits. Their TFA, however, was significantly lower than the TFA of vegetations of rabbits not treated with etoposide. We also found that, as with the monocytopenic rabbits, the weight of the vegetations was not reduced in penicillin G-treated rabbits. The degree of infection and TFA, however, were significantly lower. We conclude that monocytes indeed are involved in the activation of the coagulation system during the course of bacterial endocarditis and that the degree of infection is positively correlated to the TFA of the vegetations.

Surgical Treatment of Active Native Valve Endocarditis

A report is presented of 24 patients (23 male), mean age 38 years, who underwent surgery for active native valve endocarditis of the left heart in 1975-1988. The aortic valve was affected in all patients, and also the mitral valve in five. Pre-existing aortic valve disorder was present in 17 cases (13 congenitally bicuspid 4 rheumatic affection). There were five hospital deaths (20.8%). Staphylococci as causal organism and extensive infection predicted the highest mortality and morbidity. The mean follow-up time was 39.7 (range 2-114) months. Two reoperations because of prosthetic valve dehiscence revealed endocarditis of the implanted valve. Strong correlation was found between favourable postoperative course and rapid normalization of C-reactive protein levels, which did not fall in patients with persistent infection. Early surgery is recommended if the course of bacterial endocarditis is severely complicated.

Tricuspid Regurgitation Due to Sinus of Valsalva-Right Heart Fistula Diagnosed by Two-dimensional Echocardiography

The case of a 31-year-old woman with severe right heart failure in the course of bacterial endocarditis and systolic and diastolic murmur at the third left intercostal space is described. Two-dimensional echocardiography showed a vegetation moving from the noncoronary aortic sinus of Valsalva to the right atrium, encroaching upon the septal leaflet of the tricuspid valve. An acquired fistula was confirmed by aortography and surgery. This is an unusual case of tricuspid regurgitation due to acquired aortic sinus of Valsalva-right heart fistula diagnosed by two-dimensional echocardiography.

Effect of immunization on the induction and course of experimental streptococcus sanguis and staphylococcus epidermidis endocarditis

Immunization of rabbits withStreptococcus sanguis or Staphylococcus epidermidis results in specific agglutinating and opsonic antibodies against the corresponding micro-organisms. Non-immunized rabbits also developed these respective antibody activities against the infecting micro-organisms during the course of bacterial endocarditis, but at a lower level. Immune serum promoted phagocytosis in vitro but did not enhance intracellular killing of the corresponding bacterial strains by elicited rabbit peritoneal macrophages as compared with normal serum. The presence of specific antibodies in rabbits after immunization appeared to have no effect on the induction or course of streptococcal or staphylococcal infection of endocardial vegetations. The survival time of immunized rabbits with endocarditis was prolonged, probably due to a lower degree of bacteremia.

Bacterial endocarditis in idiopathic hypertrophic subaortic stenosis

Bacterial endocarditis complicating idiopathic hypertrophic subaortic stenosis (IHSS) is uncommon but endocarditis may be the first clinical manifestation of IHSS. In this report of such a case, the aortic and the mitral valves were the sites of the bacterial infection. Many chordae tendineae to the mitral valve were ruptured from the extension of the infectious process. The endothelial lesions, which served as the seat for the bacterial infection on the anterior mitral leaflet, likely resulted from its abutting action against the septal prominence. Damage to the aortic valve leaflet may have resulted from abnormal valve motion caused by IHSS and created an environment conducive to endocarditis. This patient developed aortic insufficiency during the course of bacterial endocarditis, suggesting that the occasional association of aortic insufficiency in patients with IHSS may be secondary to healed endocarditis of the aortic valve.

Nervous system complications in bacterial endocarditis.

<h2>Abstract</h2> Neuropsychiatric complications are common in bacterial endocarditis, and if sought for may be found in up to 40 to 50 per cent of patients. The nervous system is involved as frequently in the present era as in the decades prior to the introduction of antibiotics. Any acute neurologic syndrome or psychiatric illness arising in a patient with a fever and a cardiac murmur in the absence of arrhythmia should suggest bacterial endocarditis. Complications are mainly due to infected emboli; meningoencephalitis is the most common complication, but overt embolus and mycotic aneurysm are not rare. Brain abscesses are a more common complication in acute than in subacute bacterial endocarditis; the antibiotic era has seen an apparent decline in the incidence of this complication. Other, less well characterised, pathologic complications include cerebral micro-infarcts, purpura and edema as well as endarteritis with thrombosis or stenosis. A wide range of presentations can result from the cerebral lesions, the most dramatic being hemiplegia, aphasia, cranial nerve paralysis, cerebral hemorrhage and subarachnoid hemorrhage. The relatively common minor symptoms, such as headache or confusion, may portend a more serious outcome. The cerebrospinal fluid frequently shows abnormalities following embolisation of the brain. Although the usual finding is a sterile meningitis, a more serious underlying lesion may be present: in particular, a mycotic aneurysm may present as a sterile meningitis with few or no red blood cells appearing in the cerebrospinal fluid. Full investigation of sterile meningitis during the course of bacterial endocarditis should include cerebral angiography. since mycotic aneurysms frequently can be resected. Management of the cerebral complications of bacterial endocarditis does not, in general, require any departure from the usual treatment of endocarditis, but neurosurgical intervention may be required for mycotic aneurysms or cerebral abscesses.

Angiography in the Management of Intracranial Mycotic Aneurysms

Neurologic abnormalities during the course of bacterial endocarditis have been observed in as many as half the cases in some series.¹Although mycotic aneurysm is one of the less common neuropathologic lesions in such cases, it is of particular importance because of the potential danger of lethal subarachnoid hemorrhage from this lesion which is often amenable to surgical excision. The present report of three patients with cerebral mycotic aneurysm will emphasize the following: (1) the clinical features and cerebrospinal fluid (CSF) findings that may be produced by a mycotic aneurysm prior to major hemorrhage; (2) the urgency of performing carotid angiography if there are clinical indications that this lesion may be present; and (3) the value of surgical treatment of intracranial mycotic aneurysms in many cases. <h3>Patient Summaries</h3><h3>Patient 1.</h3> —A 52-year-old white man was admitted to the University of California at Los Angeles (UCLA) Hospital on Feb 19,

Ventricular septal defect and aortic insufficiency in the same patient caused by bacterial endocarditis.

Two cases of perforation of the ventricular septum, in association with aortic insufficiency, in the course of bacterial endocarditis, due to streptococcus viri-dans, are described. In both cases the perforation also included the base of the septal tricuspid leaflet, permitting a part of the left-to-right shunt to enter the right atrium. Both cases were successfully operated upon with repair of all three lesions simultaneously.

Aortic valve perforation

This paper describes fifteen patients with aortic valve perforation, in fourteen of whom this complication developed during the course of bacterial endocarditis. Aortic cusp perforation should be suspected whenever moderately severe or severe aortic insufficiency appears during bacterial endocarditis. The murmur of aortic insufficiency caused by cusp perforation is of the common decrescendo blowing quality, and is only occasionally of musical quality. In patients with aortic cusp perforation and attendant severe aortic insufficiency, congestive heart failure often develops within a few days or weeks. In our series heart failure appeared within one week to four and a half months in eleven of the fifteen patients. Eight of these patients, who had not been treated by aortic valve surgery, died within one day to six months after the appearance of heart failure. Three of our patients with acute bacterial endocarditis apparently died of a cardiac arrhythmia resulting from infection of the atrioventricular node or bundle of His. In seven of our patients the aortic insufficiency was treated surgically. In two patients the perforation was small enough to be closed by direct suturing; in five the aortic valve was excised and replaced by a Starr-Edwards prosthesis. Five of these seven patients survived to be discharged from the hospital, but one of the five died suddenly three months postoperatively, and another died of Candida endocarditis four and a half months after insertion of the prosthesis.

Aortic valve perforation in bacterial endocarditis.

This report describes 10 patients with bacterial endocarditis who during observation developed signs of dynamic aortic insufficiency or experienced marked worsening of the manifestations of pre-existing aortic insufficiency. The autopsy findings in these patients provide evidence that the clinical signs were associated with perforation or rupture of the aortic valve cusps. It is suggested that this sequence of events in the course of bacterial endocarditis is common and that its occurrence must be regarded as an ominous prognostic sign.

Bacterial endocarditis with special reference to the cardiac irregularities: A clinical and pathological study of 191 cases

1. 1. The literature is reviewed with reference to the cardiac irregularities in the course of bacterial endocarditis, rheumatic heart disease, and rheumatic fever. 2. 2. A study of 192 cases of bacterial endocarditis, with electrocardiographic studies in 67 cases, revealed 4 cases of auricular fibrillation, 2 of auricular flutter, 9 of heart-block, 2 of prolonged QRS interval, 1 of prolonged Q-T interval, 1 of left bundle-branch block, 9 of gallop rhythm, 15 of extrasystoles, 21 of left axis deviation and 6 of right axis deviation. 3. 3. Prolongation of the P-R interval occurs more commonly in the cases of bacterial endocarditis with involvement of the aortic valves alone, or in combination, than in cases of mitral involvement. 4. 4. Disturbances in conduction time, particularly intraventricular block and bundle-branch block, are far less common in bacterial endocarditis than in rheumatic heart disease. The same is true of gallop rhythm and premature beats. 5. 5. A statistical study, including all other reported cases, leads one to conclude that auricular fibrillation and auricular flutter are rare in the course of bacterial endocarditis. 6. 6. The occurrence of auricular fibrillation and flutter in the course of bacterial endocarditis appears to be related to the functional integrity of the myocardium rather than to any grade of mitral stenosis in itself.