Failure of treatment with teicoplanin at 6 milligrams/kilogram/day in patients with Staphylococcus aureus intravascular infection. The Infectious Diseases Consortium of Oregon

Patients with blood cultures positive for gram-positive cocci were enrolled in a prospective randomized double-blind comparative trial of vancomycin at 15 mg/kg every 12 h versus teicoplanin at 6 mg/kg every 12 h for three doses and then 6 mg/kg every 24 h. A total of 54 patients were randomized, and 40 were evaluable. Of the 40, 9 had infection of indwelling vascular catheters. Four infections were due to Staphylococcus aureus, and five were due to Staphylococcus epidermidis. In concert with catheter removal, all patients were treated successfully, regardless of which drug they were taking. Of 31 patients without an indwelling catheter, 19 were infected with S. aureus, and 12 of the 19 had either endocarditis or mycotic aneurysm. Six of eight patients given teicoplanin failed treatment, as opposed to one of four patients given vancomycin (P = 0.14). Of greater concern, four of four patients with left-sided endocarditis or mycotic aneurysm failed to recover when given teicoplanin, as opposed to one of three patients given vancomycin (P = 0.07). Although not quite statistically significant, the unexpectedly high number of treatment failures with teicoplanin resulted in a decision to discontinue patient enrollment. It is suggested that future trials explore the efficacy of larger doses of teicoplanin.

Bovine atrial natriuretic peptide in heart failure

The present study describes the concentration and molecular form of atrial natriuretic peptide (ANP) in Holstein dairy cattle with mild (bacterial endocarditis; BEC) or severe (dilated cardiomyopathy; DCM) heart failure. Significant increases in plasma concentration of ANP were observed in cattle with DCM (73.3 +/- 16.02 pmol/l, n = 4, P less than 0.01) and BEC (20.6 +/- 3.45 pmol/l, n = 7, P less than 0.05), when compared with those in control cattle (14.5 +/- 1.84 pmol/l, n = 12). The concentration of ANP in cattle with DCM was significantly (P less than 0.01) higher compared with that in cattle with BEC. Plasma concentration of ANP correlated significantly with right atrial pressure (r = 0.95, P less than 0.01) and left ventricular end-diastolic pressure (r = 0.84, P less than 0.01). Gel-permeation chromatography of ANP in plasma and the right atrium from control and cattle with BEC revealed a single peak corresponding to the elution position of authentic human ANP(99-126) in plasma, and two peaks corresponding to those of authentic human ANP(99-126) and pro-ANP in the atrial extract. In cattle with DCM, however, peaks corresponding to the elution positions of authentic human beta-ANP and/or pro-ANP were detected in addition to the peak corresponding to ANP(99-126). The content of ANP in the right atrium of cattle with DCM was significantly (P less than 0.05) increased compared with that in control cattle and those with BEC. The present study therefore suggests that the synthesis and secretion of ANP might be stimulated by atrial distention induced by increased atrial pressure.(ABSTRACT TRUNCATED AT 250 WORDS)

Intravegetation antimicrobial distribution in aortic endocarditis analyzed by computer-generated model. Implications for treatment

The distribution of antibiotics into cardiac valvular tissues is incompletely understood. By integrative computer modeling, we have used previously obtained pharmacokinetic data in experimental endocarditis to characterize aminoglycoside distribution within various geographic sectors of aortic vegetations of rabbits and humans in the current study. In rabbits with pseudomonal aortic endocarditis receiving a standard regimen of amikacin (15 mg/kg every eight hours), sub-MBC levels of the drug for the infecting organism were calculated in the center of 0.38-cm vegetations; this occurred despite supra-MBC levels calculated in plasma and more peripheral loci of the vegetation. In contrast, with a high-dose regimen of amikacin (40 mg/kg every eight hours), supra-MBC drug levels were calculated throughout the entire vegetation for at least 50 percent of the dosing interval. Using similar computer-generated approaches, these data in the rabbit were approximately in simulated aminoglycoside penetration of 10-mm human aortic vegetations. Aminoglycoside regimens designed to yield supra-MBC serum levels in both normal and rapid drug eliminators consistently achieved sub-MBC levels in the center of the vegetation. Computer simulations also confirmed that daily doses of aminoglycoside at least two to four times higher than those ordinarily recommended are necessary to consistently achieve uniform supra-MBC intravegetation levels for an entire dosing interval. Such computer-generated data support the concept of maldistribution of aminoglycosides in aortic endocarditis and provide a rationale for investigating the use of high-dose regimens of aminoglycoside in treating experimental endocarditis.

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.

Procoagulant activity of endocardial vegetations and blood monocytes in rabbits with Streptococcus sanguis endocarditis

To investigate activation of the coagulation system in bacterial endocarditis, we determined the procoagulant activity of blood monocytes isolated from rabbits with Streptococcus sanguis-infected or sterile catheter-induced endocardial vegetations. This activity was determined directly after isolation from the peripheral blood and after stimulation in vitro by either endotoxin or by phagocytosis of S. sanguis. The procoagulant activity of the vegetations of these rabbits was also determined. The procoagulant activity of blood monocytes of rabbits with S. sanguis endocarditis was found to be similar to the activity of monocytes of rabbits with sterile vegetations, both at the time of isolation and after stimulation in vitro by exposure to endotoxin or phagocytosis of bacteria. The procoagulant activity of infected vegetations was significantly higher than that of sterile vegetations. We conclude that in bacterial endocarditis the coagulation system is activated locally at the site of the vegetation. Triggering probably occurs by thromboplastin generated by monocytes activated by phagocytosis of bacteria on the vegetational surface.

T lymphocyte disorder after Capnocytophaga ochracea endocarditis

Capnocytophaga species are gram-negative rods which may cause disease in both non-immunocompromised and immunocompromised hosts. We describe a case of endocarditis due to Capnocytophaga ochracea in a non-immunocompromised patient with a decrease of blood CD4/CD8 ratio and lymphocyte proliferative response to ConA during infection. In vitro experiments showed that C. ochracea decreased lymphocyte proliferation to mitogens (ConA, PHA), cell surface CD4 antigen and IL2 receptor expression on peripheral blood mononuclear cells (PBMC) from normal volunteers.

Bacteriostatic versus bactericidal activity

Antibiotics alone or in combination may either inhibit or kill bacteria. Laboratory methods are available to determine the activity of various antimicrobial agents and can aid the physician in selecting appropriate antimicrobial therapy for specific infectious disease disorders. A few infectious processes appear to require bactericidal antimicrobial therapy for cure. Additional multicenter trials of the ability of a standardized SBT to predict therapeutic outcome in specific bacterial diseases are required.

Role of adherence in pathogenesis of Enterococcus faecalis urinary tract infection and endocarditis

Enterococcus faecalis strains isolated from urinary tract infections (UTIs) and endocarditis were analyzed for their ability to adhere to urinary tract epithelial cells (ECs) and Girardi heart (GH) and human embryonic kidney (HEK) cell cultures. UTI isolates adhered to urinary tract ECs more efficiently than to the cultured cells, at the same time showing the least affinity for GH cells. In contrast, endocarditis isolates adhered to GH cell cultures more readily than to urinary tract ECs. Moreover, although strains isolated from endocarditis adhered to GH cells more efficiently than those derived from UTI, the latter strains adhered to urinary tract cells better than the former. Studies of the ability of GH and HEK cells to internalize E. faecalis showed that for UTI isolates, 9 to 74% of adhered bacteria were internalized, while for endocarditis isolates, the percentage varied from 76 to 82%. All strains were able to associate with human neutrophils; endocarditis strains, however, associated less efficiently than UTI isolates. Growth in serum raised the adherence of all tested strains by at least 1.5- to 3-fold, with the greatest increase being observed in UTI strain adherence to GH cells (8-fold). In contrast, the association of serum-grown cells with polymorphonuclear leukocytes was reduced by two- to fivefold. In both cases, the observed serum-dependent alterations were cancelled by a few subcultures in brain heart infusion broth. These results indicate that adhesive properties are important virulence factors in the pathogenesis of UTI and endocarditis and also suggest that UTI strains showing the highest invasion and adhesive potential invade the kidneys, cause bacteremia, and, after having expressed the serum-dependent surface modification, colonize the heart.

The value of C-reactive protein as a marker of bacterial infection in patients with septicaemia/endocarditis and influenza

In order to evaluate the capacity of C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), white blood cell count (WBC) and polymorphonuclear neutrophils (PMNs) to differentiate between bacterial and viral infection we studied 176 patients with septicaemia/endocarditis (SE), 59 patients with uncomplicated influenza (UI) and 22 patients with complicated influenza (CI) retrospectively. All 4 parameters were significantly more elevated in SE and CI than in UI. Among patients with SE 10 176 had a CRP value less than 50 mg/l and in patients with UI 5/56 had a CRP value greater than 100 mg/l. Patients with SE caused by pneumococci had the highest CRP levels and patients with alfa-haemolytic streptococci the lowest. The sensitivity and specificity favours the use of CRP as an indicator of bacterial superinfection in influenza.

[Surgical aortic valve replacement for acute Streptococcus viridans endocarditis with simultaneous moderate hemophilia A]

This is a report of a 25-year-old patient with known aortic valve stenosis since early youth and hemophilia A, showing recurrent joint bleeding. Acute Streptococcus endocarditis induced aortic valve insufficiency resulting in cardiac failure. Aortic valve replacement was performed after substitution of factor VIII, during which intra- and postoperative bleeding was prolonged by pericardial adhesions. Heparin was administered during cardiopulmonary-bypass as usual, but usual postoperative cumarin therapy was not initiated due to prolonged PTT time. One year postoperatively, the patient was in an excellent condition and fully rehabilitated.

Serum C reactive protein in infective endocarditis

C reactive protein (CRP) was measured serially in 29 patients with infective endocarditis. Twenty one patients were initially treated with antimicrobial drugs. In 13, serial measurement of CRP concentrations showed a progressive return to normal (less than 10 mg/l), which correlated with a satisfactory recovery. Of the remainder (eight patients), five had persistently high concentrations of CRP, indicating a failure to respond to antimicrobial treatment alone. Two of these five patients died and three underwent valve replacement. Of 11 patients treated with antibiotics and valve replacement, CRP concentrations returned to normal in nine. Two patients had infective complications and the CRP concentration did not return to normal. A transient rise in CRP concentration during an otherwise uneventful fall to normal was a sign of allergic reaction in two and of intercurrent infection in three more patients. Serial measurements of CRP concentrations in patients with infective endocarditis may be useful to monitor treatment and also to detect other infections and complications.

Ciprofloxacin versus vancomycin in the therapy of experimental methicillin-resistant Staphylococcus aureus endocarditis

We compared the efficacy of ciprofloxacin with that of vancomycin by using the rabbit model of methicillin-resistant Staphylococcus aureus endocarditis. Endocarditis was treated with ciprofloxacin (25 mg/kg [body weight] intravenously every 8 h) or vancomycin (17.5 mg/kg intravenously every 6 h) for 3 days. Vancomycin and ciprofloxacin were equally efficacious in clearing bacteremia. Both reduced vegetation bacterial counts by 5 log10 CFU/g and renal and splenic bacterial counts by more than 3 log10 CFU/g as compared with untreated control rabbits after 26 h of infection (P less than 0.001). Both antimicrobial agents were able to eradicate the infectious process in an equivalent proportion of animals. No methicillin-resistant S. aureus that was recovered from ciprofloxacin-treated rabbits developed resistance to ciprofloxacin during therapy. Peak concentrations of ciprofloxacin in the sera of rabbits with endocarditis were significantly higher than those predicted by single-dose studies in uninfected rabbits. This finding was likely due to changes in the pharmacokinetics of the drug with multiple dosing and in infected versus uninfected rabbits. This study demonstrated that intravenously administered ciprofloxacin is as efficacious as vancomycin is in an in vivo model of a serious systemic methicillin-resistant S. aureus infection.

Chemoprophylaxis with oral amoxycillin against bacterial endocarditis: when should second doses be administered after dentistry?

The adequacy of serum bactericidal activity after oral amoxycillin given as prophylaxis against infective endocarditis was studied using a double blind randomised protocol in healthy volunteers having dentistry. One hour before their procedure 38 patients received 3 g amoxycillin syrup and 12 received matching placebo. Venous blood samples were drawn before and one and nine hours after dosing and serum amoxycillin concentrations determined using a standard bioassay. Samples containing amoxycillin had inhibitory titres measured against two reference isolates of viridans streptococci known to have caused infective endocarditis. The susceptibility to amoxycillin of one strain was high and the other low, respective minimal bactericidal and inhibitory concentrations being 0.08 and 0.04 mumol/l (0.03 and 0.015 microgram/ml) and 2.74 and 1.37 mumol/l (1 and 0.5 microgram/ml). Amoxycillin was detected in only post-treatment samples of patients given the active drug. There were no significant correlations between one or nine hour drug concentrations and age or physical characteristics, nor was there any relation to preceding food consumption. Correlations between drug concentrations at one and nine hours were weak (r = 0.34; p less than 0.05), but between corresponding drug concentrations and serum inhibitory titres there were consistent correlations (r = 0.46-0.48; p less than 0.005). Against the low susceptibility reference isolate bactericidal amoxycillin concentrations were encountered in only 20 of the 38 nine hour samples (95% confidence limits 34% and 66%). When repeat doses of amoxycillin are indicated after dentistry they should be given about four hours later, not eight hours later as commonly practised.

[Use of intravenous irradiation by quantum generators in congenital heart defects complicated by septic endocarditis]

The article presents results of examinations of 70 patients with congenital heart diseases with phenomena of secondary septic endocarditis subjected to the intravenous irradiation by quantum generators by the method described. A considerable positive effect of the intravenous laser irradiation on the development of septic endocarditis was confirmed by clinical and laboratory findings. The immunological examination of 8 patients from this group has revealed an immunostimulating effect of the intravenous laser irradiation: elevated concentration of immunoglobulins in blood, increased amount of immune-competent cells. A conclusion is made that the intravenous laser irradiation is an effective method of correction of the immune deficient states in congenital heart diseases.

The serum bactericidal test

The serum bactericidal test (SBT) has been used for almost 40 years to monitor therapy in patients with bacterial endocarditis, osteomyelitis, and other serious infections. The SBT is basically a variation of the broth dilution test adapted to assess the activity of a treated patient's own serum against the infecting microorganism. Only recently, however, have rigorous attempts been made to standardize all the relevant variables that affect results of the SBT. The widely recommended goal of a peak bactericidal titer of 1:8 in the therapy for infective endocarditis may be inadequate for the treatment of some patients. Peak titers of 1:64 or greater in the microdilution SBT should be sought if they can be achieved without toxicity. Titers of less than 1:8 may be acceptable, although they are less often successful, if serious toxicity would result from increased dosage. Peak SBT titers of 1:8 or greater yield high cure rates for acute osteomyelitis in children; data are limited in adults. A defined SBT method is necessary for additional multicenter clinical trials on which firmer recommendations for its future use can be made.

Relationship of staphylococcal tolerance, teichoic acid antibody, and serum bactericidal activity to therapeutic outcome in Staphylococcus aureus bacteremia

A randomized cooperative study of therapy for Staphylococcus aureus bacteremia was conducted in which nafcillin was given for four or six weeks to patients with clinical endocarditis and for two or four weeks to those without evidence of endocarditis. Eighty-four patients were enrolled, and 32 completed treatment, all of whom had bacteriologic cures. Three patients, treated for two weeks, had complications that were undetectable by assay of serum teichoic acid antibody. Data were insufficient to allow conclusions regarding the optimal duration of therapy for patients with or without endocarditis. However, the results suggest that neither clinical nor immunologic methods can reliably detect complications in patients treated for two weeks only. In addition, patients infected with tolerant organisms remained febrile longer than those infected with nontolerant strains but did not require additional antibiotics for cure. Peak serum bactericidal activity at a dilution of 1:8 or greater was present in all patients. Serum bactericidal activity of 1:8 prior to an antibiotic dose was not necessary for cure.

Incidence and clinical characteristics of "culture-negative" infective endocarditis in a pediatric population

Sixty episodes of infective endocarditis were analyzed in 56 pediatric patients over a 10-year period from 1974 to 1984. Culture-negative infective endocarditis was noted on five occasions or 8.3% of all episodes. In addition to the physical findings, a combination of laboratory parameters including anemia, erythrocyte sedimentation rate, elevated rheumatoid factor, C1q activation and microhematuria supported the diagnosis. The clinical characteristics of these patients are described in detail. Pretreatment with an antimicrobial agent was only one factor associated with the failure to isolate an organism. Empiric treatment with penicillin and gentamicin and in one case nafcillin/ampicillin and gentamicin was satisfactory.

Role of granulocytes and monocytes in the prevention and therapy of experimental Staphylococcus epidermidis endocarditis in rabbits

Rabbits with endocarditis caused by Staphylococcus epidermidis were studied to determine the parts played by granulocytes and monocytes in the prevention or outcome of therapy with cloxacillin. Both monocytes and granulocytes influenced prophylaxis with cloxacillin. The amount of cloxacillin needed to prevent infection in 50% of the rabbits was significantly less in control rabbits than in those selectively depleted of monocytes, as it was also in rabbits selectively depleted of monocytes compared with those that had both granulocytopenia and monocytopenia. Granulocytes strongly potentiated the effect of cloxacillin during prophylaxis, whereas the contribution of monocytes was merely additive. Monocytes also contributed to the effect of therapy with cloxacillin, partially via a cloxacillin-independent mechanism and partially by potentiation of the effect of cloxacillin. Granulocytes did not appear to affect cloxacillin therapy. Results of this study suggest that currently used regimens for prophylaxis and treatment of S. epidermidis endocarditis may need to be adjusted for neutropenic patients.

[Bacteriologic surveillance of patients with infectious endocarditis. Value and limitations of the determination of minimal inhibitory concentration and serum bactericidal activity]

This is a retrospective study of the records of 17 patients who suffered from infectious endocarditis with positive blood cultures, and concerns the possibilities of predicting immediate infectious signs in patients:--by testing each of the antibiotics used for the minimal inhibitory concentration;--by determining the peak of the serum bactericidal activity of patients. All the patients were under observation, as outpatients, for more than a year and proved completely cured of their infectious endocarditis. A satisfactory minimal inhibitory concentration does not necessarily prevent an infectious evolution in the immediate future. The determination of the peak serum bactericidal activity does not reflect faithfully and instantaneously the anti-infectious action of the treatment; this is shown by the excellent and rapid evolution 13 times out 20 although serum bactericidal activity was considered insufficient (less than 1/8). This level of 1/8 is not a guarantee of therapeutic efficiency. Finally the antiinfectious treatment has been, in the majority of cases, determined by clinical signs and in very few cases by serum bactericidal activity results.

Serum triglyceride elevations in patients with septicemia

Among 239 patients with septicemia or endocarditis 41 (17%) had serum triglyceride levels in excess of 2.2 mmol/l (mean 3.1 mmol/l). This was more common in infectious with gram-negative rods than gram-positive cocci (p less than 0.001). A return to normal levels occurred in 22/37 patients during the course of the infection.

Two coagulase-variant forms of Staphylococcus aureus isolated from blood cultures

Two coagulase-variant forms of Staphylococcus aureus were isolated from blood cultures of a patient with infective endocarditis. The coagulase-positive isolate was hemolytic, whereas the coagulase-negative isolate was nonhemolytic. All other properties examined were identical in both strains. Since coagulase-negative S. aureus strains have been isolated from clinical specimens, laboratories should consider using a combination of other biological properties along with coagulase production for the identification of S. aureus.

Mezlocillin and ticarcillin alone and combined with gentamicin in the treatment of experimental Enterobacter aerogenes endocarditis

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.

The significance of nongonococcal, nonmeningococcal Neisseria isolates from blood cultures

Nongonococcal, nonmeningococcal neisseriae are part of the normal respiratory flora and infrequently cause disease. These organisms include Neisseria lactamica, Neisseria mucosa, Neisseria sicca, Neisseria flavescens, Neisseria subflava , Neisseria perflava , Neisseria flava , and Branhamella catarrhalis (previously classified as Neisseria catarrhalis). Blood cultures positive for these bacteria have been associated with serious infections, including endocarditis, septicemia, and meningitis. In a retrospective survey of a 10-year period, 1970-1980, eight patients were identified at Hartford Hospital (Hartford, Conn.) whose blood cultures were positive for nongonococcal, nonmeningococcal neisseriae. In four patients, the neisseria blood isolates were associated with serious infections: two with endocarditis, one with sepsis, and one with meningitis. In four other patients, the neisseria blood isolates were contaminants.

Role of granulocytes and monocytes in experimental Staphylococcus epidermidis endocarditis

The role of granulocytes and monocytes during the induction and course of Staphylococcus epidermidis endocarditis was investigated by the selective depletion of monocytes with the drug VP16-213 and of both granulocytes and monocytes with nitrogen mustard. The induction of endocarditis was influenced only by the depletion of monocytes: the 50% infective dose differed significantly, being 3.4 X 10(5) CFU in control rabbits and 3.4 X 10(4) CFU in the monocyte-depleted rabbits, whereas no significant differences were found between the latter and those depleted of both granulocytes and monocytes. Also, control rabbits injected with 10(6) or 10(7) CFU had a significantly higher incidence of sterile vegetations than did rabbits selectively depleted of granulocytes or monocytes. Compared with baseline values, mean monocyte numbers at the time of bacterial inoculation were significantly increased in control rabbits whose vegetations remained sterile, whereas this effect was not seen in rabbits whose vegetations became infected. The course of the endocarditis appeared to be significantly influenced by both granulocytes and monocytes. Comparison showed that a decrease of the same numbers of these cells per microliter of blood was accompanied for the monocytes by an approximately fourfold higher increase of the number of staphylococci in the vegetations. The correlation between the number of granulocytes and of monocytes on the one hand and the number of staphylococci in the vegetations on the other was not substantially influenced by the duration of the disease or the number of staphylococci injected to induce the endocarditis. The number injected proved to be significantly correlated with the number of staphylococci in the vegetations. In rabbits with numbers of CFU per gram of vegetation exceeding 10(7), blood cultures were usually positive. This finding applied rarely to control rabbits, but generally to drug-treated rabbits. In the latter animals a significant correlation between the number of staphylococci in the vegetations and in the circulation was found. We conclude that only monocytes have a measurable effect on the induction of Staphylococcus epidermidis endocarditis but during its course both granulocytes and monocytes keep the endocardial infection in check.

Anti-infective therapy of infectious endocarditis

Because of its high morbidity and mortality, endocarditis will remain an important pediatric problem. Obtaining adequate culture information prior to starting antibiotics to ensure an accurate early diagnosis coupled with aggressive medical and surgical management is likely to give the best outcome. These patients are generally best handled by a team approach with the child's primary physician, cardiologist, infectious disease consultant, and cardiovascular surgeon working in close harmony.

Serial C-reactive protein measurements in infective complications following cardiac operation: evaluation and use in monitoring response to therapy

Serum C-reactive protein (CRP) was studied serially in 100 patients who underwent cardiac operation and in another 17 patients in whom serious infections including prosthetic valve endocarditis developed in the early postoperative period. Eleven patients with late onset of prosthetic valve endocarditis and infective endocarditis were also investigated. The assay method used was radial immunodiffusion. Patients without postoperative infective complications showed a rapid increase in CRP levels, which reached a peak within 72 hours after operation followed by a progressive decline. The differences between the CRP levels in infected and uninfected patients were significant (p less than 0.01). Serial measurements were of prognostic value in evaluating the response to chemotherapy and in predicting the outcome of the disease.

Association between serum inhibitory and bactericidal concentrations and therapeutic outcome in bacterial endocarditis

Several recent reviews on the therapy of bacterial endocarditis have recommended that a serum inhibitory and/or bactericidal concentration (SIC/SBC) of 1:8 or more be achieved to ensure successful therapeutic outcome. We conducted a methodologic and statistical analysis of the available literature on endocarditis to determine the association between SIC/SBC titers of 1:8 or more and therapeutic outcome. We reviewed 17 studies published between 1948 and 1980 in which both SIC/SBC and therapeutic outcome were available. Factors that affect outcome, such as age, duration of symptoms, organism, and valve status, varied widely among the 226 patients. The methods used to measure SIC/SBC differed with respect to the time of obtaining the blood specimen relative to the antibiotic dose, size of the bacterial inoculum, type of broth, and definition of the bactericidal end-point. None of the 17 studies showed a significant association between SIC/SBC titers of 1:8 or more and survival or bacteriologic cure. Fifteen of the 17 also failed to demonstrate a significant association between SIC/SBC titers of 1:8 or more and medical cure. However, each of the studies that failed to demonstrate an association between SIC/SBC titers of 1:8 or more and improved therapeutic outcome had an insufficient sample size to confidently exclude a false-negative result. Analysis of the published data reveals insufficient evidence to demonstrate that SIC and SBC titers are of prognostic value in the therapy of patients with bacterial endocarditis.

A thrombotic tendency in patients with infective endocarditis

An attempt was made to evaluate a thrombotic tendency in cases of infective endocarditis (IE) from the viewpoint of the changes of platelets and coagulo-fibrinolysis. Qualitative changes of platelets by thrombi formation were detected by showing activated responses of platelets to adenosine diphosphate or collagen and by showing a high level of plasma beta-thromboglobulin which is released by platelets during aggregation. A mild hypercoagulable state without acceleration of fibrinolysis was also detected by showing low levels of plasma antithrombin III which is the most potent antithrombin in the blood and normal levels of plasma alpha 2-plasmin inhibitor in the blood. From above findings, it was concluded that a thrombotic tendency in cases of IE was clearly detected by qualitative changes of platelets by thrombi formation and by mild hypercoagulability without acceleration of fibrinolysis.

Role of granulocytes in experimental Streptococcus sanguis endocarditis

We investigated the role of granulocytes during the induction and course of experimental Streptococcus sanguis endocarditis in rabbits by depleting blood granulocytes with nitrogen mustard. The induction of the endocarditis was not influenced by granulocytopenia: the 50% infectious dose was 5.4 X 10(4) colony-forming units in normal and granulocytopenic rabbits. However, granulocytopenia influenced the curse of the endocarditis, as shown by a significant increase in the number of colony-forming units per gram of vegetation (P less than 0.02) from 24 to 72 h after the injection of 10(5) colony-forming units of S. sanguis. This rise did not occur in the control rabbits. Furthermore, bacteremia was significantly higher in the granulocytopenic rabbits (P less than 0.05) during the first 48 h compared with the control rabbits. This was not because of altered clearance of the streptococcus inoculum or seeding of streptococci from extracardiac bacterial foci. We concluded that granulocytes have no measurable effect on the induction of S. sanguis endocarditis, but during the course of the endocarditis, granulocytes keep the endocardial infection in check.

Culture-negative endocarditis

Etiologic factors in culture-negative endocarditis--better referred to as "apparent" culture-negative endocarditis--include (1) previous antibiotic therapy, (2) fastidious, slow-growing bacteria, (3) nonbacterial organisms, (4) right-sided endocarditis, and (5) noninfective endocarditis. Patients with apparent culture-negative endocarditis are more likely to have had prior antimicrobial therapy and to experience major emboli than are patients with endocarditis whose blood cultures are positive within 48 hours. The literature suggests that survival of patients with apparent culture-negative endocarditis is 92% if fever responds to therapy within 1 week but only 50% if they are still febrile after 1 week of therapy. Guidelines for diagnosis and therapy are outlined.

Control of heparinisation during cardiopulmonary bypass. Experience with the activated clotting time method

A rational approach to the control of heparinisation during open heart surgery is advocated. Some of the possible and potential shortcomings of the time-based heparin protocols in current use are presented. The use of a recent, simple automated device 'Hemochron' to estimate the Activated Clotting Time is described and it is found to be an economical and efficient method to monitor heparinisation during cardiopulmonary bypass.

Effects of monocytopenia and anticoagulation in experimental Streptococcus sanguis endocarditis

The role of blood monocytes in the attachment of streptococci to endocardial vegetations was investigated in an experimental Streptococcus sanguis endocarditis by depletion of blood monocytes with the cytostatic drug VP 16-213 alone and combined with anticoagulant treatment with warfarin sodium. The numbers of streptococci in the vegetations of control, monocytopenic, and monocytopenic/anticoagulated rabbits were comparable. In the vegetations streptococci were found mainly in areas free of phagocytic cells. It is concluded that streptococci do not have to be phagocytosed by monocytes in the circulation before being deposited on the surface of endocardial vegetations. Even the vegetations of intensively anticoagulated/monocytopenic rabbits showed colonies of streptococci embedded in polymerized fibrin and cellular material, this matrix possibly being held together by streptococcal dextran.

Synergy between carbenicillin and an aminoglycoside (gentamicin or tobramycin) against Pseudomonas aeruginosa isolated from patients with endocarditis and sensitivity of isolates to normal human serum

Isolates from the blood of 30 patients with endocarditis due to Pseudomonas aeruginosa were tested for synergy between carbenicillin and an aminoglycoside, either gentamicin or tobramycin, by in vitro checkerboard methods in modified (cation-supplemented) Mueller-Hinton broth. Twenty-five of the 30 isolates were affected synergistically. Whether given low (2.5--5 mg/kg) or high (8 mg/kg) doses of aminoglycoside along with 30 g of carbenicillin daily, all of the five patients infected with pseudomonads that were not synergistically affected were refractory to treatment with pseudomonads that were not synergistically affected were refractory to treatment with the carbenicillin-gentamicin combination, whereas the finding of synergy of carbenicillin with gentamicin (or tobramycin) did not assure a medical cure. Tests for synergy between carbenicillin and gentamicin yielded different results in Mueller-Hinton agar than in modified Mueller-Hinton broth. The majority (28) of 30 isolates of endocarditis-producing P. aeruginosa were resistant to the bactericidal effects of 50% pooled normal serum that had been freshly separated. One of the endocarditis-producing strains that was sensitive to 50% serum was resistant to 10% serum. However, sensitivity or resistance to freshly separated, pooled normal human serum did not predict the outcome of antibacterial therapy for pseudomonas endocarditis.

Enhancement of generation of monocyte tissue thromboplastin by bacterial phagocytosis: possible pathway for fibrin formation on infected vegetations in bacterial endocarditis

The deposition of fibrin on infected vegetations and the presence of mononuclear phagocytes that have phagocytized bacteria are remarkabe features in experimental bacterial endocarditis. In a study in vitro, we show that phagocytosis of bacteria by human monocytes enhances thromboplastin generation by these cells. Maximal enhancement of the generation of thromboplastin by monocytes was about six times compared with that in the control experiment without bacteria, and it was obtained by preincubation of the monocytes with 5 to 10 bacteria per monocyte. No quantitative difference was observed between Staphylococcus epidermidis and Streptococcus sanguis as to the enhancement of the monocyte thromboplastin generation. An enhancement of the procoagulant activity generation was also observed after addition of bacteria to human or rabbit whole blood. Probably, this generation was also due to synthesis of thromboplastin by monocytes. It is conceivable that fibrin deposition on infected vegetations during bacterial endocarditis is mediated by thromboplastin synthesis by monocytes.

Blood chemistry abnormalities in bacterial endocarditis of narcotic addicts

We recently treated two narcotic addicts with bacterial endocarditis who developed the syndrome of inappropriate antidiuretic hormone secretion (SIADH). This prompted a retrospective review of blood chemistry studies in all narcotic addicts admitted to our hospital over a 30-month period because of a clinical suspicion of bacterial endocarditis. Patients with culture-positive endocarditis (group 1) had significantly lower plasma osmolality, sodium, calcium and albumin values (P less than .02, .001, .005, and .005 respectively) than addicts without endocarditis (group 2). More than 90% of those in group 1 had hyponatremia, and 48% had plasma hypoosmolality. These findings may be of value in the initial evaluation of ill narcotic addicts for hospitalization.

Antibiotic concentrations in serum, serum bactericidal activity, and results of therapy of streptococcal endocarditis in rabbits

The correlation between antibiotic concentrations in serum, serum bactericidal activity, and results of therapy was studied in rabbits with streptococcal endocarditis. Five days of procaine penicillin G reduced bacterial titers to <10 per g in 12 of 14 vegetations in rabbits receiving 75,000 U intramuscularly every 6 h and 10 of 20 in rabbits given 37,500 U. Ten days of 18,750 U every 6 h did not reduce the titers. To test for cure, rabbits were treated with 75,000 U every 6 h for 10 or 20 days and then received no therapy for 7 days. At the end of the 7-day period without therapy, vegetations were sterile in five of five and eight of eight animals, respectively. Rabbits received 37,500 U every 6 h for 5, 10, or 20 days and then no therapy for 7 days, after which vegetations were sterile in one of seven, four of nine, and seven of eight animals, respectively. The median maximal serum bactericidal dilutions at 1 h were 1/16 when 75,000 U of procaine penicillin G was administered, 1/8 to 1/16 with 37,500 U, and 1/4 to 1/8 with 18,750 U. Serum bactericidal activity could not be detected in 50% of the rabbits 6 h after administration of 37,500 U. Cure was related to a median maximal serum bactericidal dilution of at least 1/8 to 1/16 1 h after penicillin administration. A median maximal serum bactericidal dilution of 1/4 to 1/8 resulted in unsuccessful therapy.

Infective endocarditis: a current review

Infective endocarditis is a dynamic disease for which various infective organisms may be responsible in different patient populations. Antimicrobial therapy should be directed against the specific organism after it has been identified by blood culture. An agent with a spectrum that includes the enterococci should be given in the meantime. Prophylactic use of a bactericidal agent is necessary for patients with valvular or congenital heart disease. Recent advances in microbiologic and cardiac diagnostic procedures offer the clinician various methods of following the activity of the disease, and immunobiology has provided new insights into its pathogenesis.

Reversible neutrophil defect in patients with bacterial endocarditis

The bactericidal capacities of neutrophilic polymorphonuclear neukocytes (PMN) from five untreated adults with bacterial endocarditis (BE), eight untreated patients with other forms of acute bacterial infection (ABI), and fourteen drug-free uniinfected normal subjects (NS) were compared with a new technique that uses five increasing bacteria-to-neutrophil ratios ranging from 1.25 to 100 Staphylococcus aureus per neutrophil. PMN from uninfected NS or untreated patients with ABI demonstrated a similar and reproducible ability to kill increasing numbers of S. aureus in 8 per cent normal serum. In contrast, the bactericidal activities of the PMN from untreated patients with BE were significantly depressed and the defect was more apparent at high ratios. Neutrophils from some of these individuals had decreased bactericidal action only at high ratios, indicating a quantitative type of neutrophil defect. There was no morphologic deficiency in the uptake of bacteria by BE neutrophils and comparable rates of glucose [-1-14C] oxidation were found in BE and control neutrophils stimulated with various ratios of heat-killed bacteria. Therefore, the observed abnormality appeared to be that of intracellular killing rather than of ingestion. The proportions of bacteria killed by the MN of untreated patients with BE improved after antibiotic treatment and became equal to those of NS or untreated ABI patients. This rapid return to normal bactericidal function by the PMN during treatment indicates that the prior deficiency was an acquired consequence of the infectious process of BE.