Streptococcal Endocarditis Research Articles

Diffusion of Ofloxacin in the Endocarditis Vegetation Assessed with Synchrotron Radiation UV Fluorescence Microspectrocopy

The diffusion of antibiotics in endocarditis vegetation bacterial masses has not been described, although it may influence the efficacy of antibiotic therapy in endocarditis. The objective of this work was to assess the diffusion of ofloxacin in experimental endocarditis vegetation bacterial masses using synchrotron-radiation UV fluorescence microspectroscopy. Streptococcal endocarditis was induced in 5 rabbits. Three animals received an unique IV injection of 150 mg/kg ofloxacin, and 2 control rabbits were left untreated. Two fluorescence microscopes were coupled to a synchrotron beam for excitation at 275 nm. A spectral microscope collected fluorescence spectra between 285 and 550 nm. A second, full field microscope was used with bandpass filters at 510–560 nm. Spectra of ofloxacin-treated vegetations presented higher fluorescence between 390 and 540 nm than control. Full field imaging showed that ofloxacin increased fluorescence between 510 and 560 nm. Ofloxacin diffused into vegetation bacterial masses, although it accumulated in their immediate neighborhood. Fluorescence images additionally suggested an ofloxacin concentration gradient between the vegetation peripheral and central areas. In conclusion, ofloxacin diffuses into vegetation bacterial masses, but it accumulates in their immediate neighborhood. Synchrotron radiation UV fluorescence microscopy is a new tool for assessment of antibiotic diffusion in the endocarditis vegetation bacterial masses.

Oral antibiotic treatment of left-sided infectious endocarditis verified by 16S-PCR: A case report

Treatment of infectious endocarditis (IE) comprises intravenously administered antibiotic medications given at high doses for 4-6 weeks--sometimes even longer. Approximately 50% of patients referred to tertiary care centres require additional surgical intervention. At present there are few papers describing the effects of oral antibiotic treatment in IE, and only in patients with right-sided endocarditis. In this case report we present a patient with left-sided Streptococcus endocarditis successfully treated with oral antibiotic drugs.

The role of streptococcal plasmin(ogen) binding in infective endocarditis

The ability of viridans group streptococci (VGS) to bind human plasminogen and its subsequent activation into plasmin may contribute to the pathogenesis of streptococcal endocarditis. The increased proteolytic activity acquired through cell-bound plasmin may lead to a decreased stability of the streptococcal vegetation and possible embolisation. Twenty-two infective endocarditis isolates and 16 non-infective endocarditis isolates were screened for their ability to bind plasminogen through the quantification of its active form plasmin, using the colorimetric substrate D-Val-Leu-Lys p-nitroanilide. The species of the VGS assessed expressed a universal capability to bind human plasminogen, although they did so with differing affinities and independently of the site of isolation.

Endocardite tricuspide du post-partum à streptocoque B

The B streptococcal endocarditis are very rare. They primarily affect the left heart valves, the achievement of the tricuspid valve is exceptional. We report a young patient aged of 36 years who presented in postpartum a tricuspid endocarditis with streptococcus B. She was treated by third-generation cephalosporin and aminoglycoside. The evolution after 5 days of antibiotic therapy was marked by a rapid valvular destruction with worsening tricuspid insufficiency leading to death of the patient. This is the 23rd case of tricuspid endocarditis streptococcal B reported in the literature. The mortality of this disease reached 36% in the absence of surgical treatment. The medico-surgical approach is the treatment of choice for these patients.

Fourier Transform Infrared Microspectroscopy of Endocarditis Vegetation

The objectives of this work were to compare the infrared spectra of bacterial endocarditis vegetation with those of native valvular tissue and the infrared spectra of vegetation bacterial masses with those of surrounding vegetation tissue. Streptococcal aortic endocarditis was induced in three rabbits. Vegetation slices were cryo-sectioned for study by Fourier transform infrared (FT-IR) microspectroscopy. Valvular apparatus, vegetation, and bacterial masses within the vegetation were localized on hematoxylin and eosin (H&E) stained contiguous slices. Infrared images of whole vegetations and images of bacterial masses were acquired with apertures set to 80 x 80 and 20 x 20 microm, respectively. Valvular apparatus and vegetation showed different infrared spectra, mainly in the amide I and amide II bands (1674-1518 cm(-1)), and at about 1450, 1400, 1340, 1280, 1240, 1200, 1080, and 1030 cm(-1). Valvular collagen, elastin, and proteoglycans may explain these differences. Bacterial masses and surrounding vegetation showed different infrared patterns, mainly in the amide I and amide II bands and in the 1142-991 cm(-1) carbohydrate spectral range. Bacterial nucleic acids and polysaccharides may partly explain these differences. Study of experimental endocarditis vegetation using FT-IR microspectroscopy distinguishes (1) the vegetation from the valvular tissue, and (2) the bacterial masses from the surrounding tissue. This study demonstrates for the first time that FT-IR microspectroscopy is able to detect bacterial growth in infected tissue. FT-IR microspectroscopy appears to be a useful tool for investigation of the biochemical structure of endocarditis vegetation.

A Rare Case of Group A Streptococcal Endocarditis with Absence of Valvular Vegetation

Group A streptococcal endocarditis has been described in intravenous drug misusers and as a post-varicella infection in children. We report a 64-year-old man with no prior risk factors who presented with a persistent fever, malaise, polyuria and cola-colored urine. On examination peripheral stigmata of endocarditis without a cardiac murmur and asymptomatic pharyngeal exudates were found. Blood and urine analysis revealed renal failure from suspected glomerulonephritis. Blood cultures revealed fully sensitive Group A streptococci. Transthoracic and transesophageal echocardiographies revealed no vegetation. The Modified Duke's Criteria aided in the diagnosis of definite infective endocarditis, despite the absence of valvular vegetation.

Ceftriaxone plus gentamicin or ceftriaxone alone for streptococcal endocarditis in Japanese patients as alternative first-line therapies

This study included 31 patients who had definite or possible infectious endocarditis as defined by the modified Duke's criteria Of these patients, 27 were treated with ceftriaxone plus gentamycin combination therapy and four with ceftriaxone monotherapy. Of these 31 cases, 29 had infections with Streptococcus species, and showed good responses to penicillin G and cefotaxime. Excluding one patient who died because of the underlying disease, all patients achieved clinical cure after treatment with either of the two regimens, showing no recurrence during a follow-up period of 6 months after completion of drug treatment. Although valve replacement was performed in 10 patients during the follow-up period, there were no recurrences in any of these patients 6 months postoperatively. Ceftriaxone allows a simple regimen of once-daily administration. Although indications are limited, ceftriaxone therapy is feasible on an outpatient basis, offering favorable medical economics. Consistent with previous reports, the therapeutic effect of ceftriaxone was equivalent to that of penicillin G in this study, showing this agent to be an alternative first-line drug for infectious endocarditis.

Green urine, but no infection

In September, 2007, an unconscious 88-year-old woman was brought to the emergency room. She had undergone a hysterectomy and radiotherapy because of carcinoma of the cervix 30 years previously; 10 years later she had developed neurogenic bladder dysfunction, requiring intermittent self-catheterisation. She had had mild renal insuffi ciency (creatinine 100 μmol/L) and mild hydronephrosis unilaterally, because of ureteric obstruction following the irradiation. Her medical history also included bilateral femoral artery angioplasty, a transient ischaemic attack, and group B streptococcal endocarditis with remaining mild mitral valve insuffi ciency. Medications included an ACE-inhibitor, aspirin, and dipyridamole for the past 4 years. On presentation she was unresponsive and hyperventilating (20 breaths per min) with a body temperature of 33·0°C, an irregular pulse (110 beats per min), and a blood pressure of 110/60 mm Hg. Auscultation showed no new cardiac abnormalities, and neurological evaluation was unremarkable. The electrocardiogram showed atrial fi brillation (110 beats per min). Blood gas analysis on supplemental oxygen, corrected for hypothermia, showed a pH of 7·08, pCO2 1·85 kPa, bicarbonate 3·6 mmol/L, and pO2 18·5 kPa, indicative of metabolic acidosis with incomplete respiratory compensation. 1300 mL of green purulent urine was emptied from the bladder on catheterisation. Urosepsis was suspected, blood samples were taken, and she was rehydrated with saline and treated with ceftriaxone and 8·4% NaHCO3. 1 h later laboratory test results showed a normal anion gap hyperchloraemic acidosis (anion gap 16, sodium 147 mmol/L, and chloride 127 mmol/L). Lactate (1 mmol/L), potassium (4·3 mmol/L), albumin (34 g/L), and glucose (7·9 mmol/L) were normal. Until this point she had received 1250 mL 0·9% NaCl (saline) and 200 mL of 8·4% NaHCO3. Repeat analysis showed sodium 159 mmol/L, chloride 131 mmol/L, potassium 3·4 mmol/L, and bicarbonate 7·0 mmol/L. Although the saline was replaced by 5% glucose solution, 1·5 L/day, with 4 mmol potassium added, plasma sodium and chloride concentrations inceased to 170 mmol/L and 143 mmol/L, respectively, over the next 2 days. Urine cultures were negative. Hyperchloraemia and hypernatraemia because of endogenous reuptake of urinary chloride in the bowel was suspected. Cystoscopy showed a large bladder wall defect with a vesicojejunal fi stula on CT (fi gure). Our patient refused additional procedures and was discharged to a nursing home with oral bicarbonate supplementation. She passed away 2 months later. Our patient had a hyperchloraemic metabolic acidosis because of a fi stula between bladder and jejunum caused by previous radiotherapy; it is possible that the fi stula caused the group B streptococcal endocarditis 3 years before presentation. The ileal and colonic mucous membrane harbours a Cl/HCO3 transporter that exchanges intraluminal chloride (in our patient, a large amount via the communication to the bladder) for bicarbonate; sodium is actively reabsorbed, leading to potassium excretion. This explains the hyperchloraemic acidosis that can be seen in patients following ureter implantation into the sigmoid commonly presenting with hypokalaemia. However, in our patient, renal insuffi ciency and ACE-inhibitor use induced normokalaemia, and correction of the acid-base status provoked hypokalaemia. Saline infusion and bicarbonate supplementation during initial resuscitation resulted in additional sodium re-uptake and worsening of hyperchloraemia and hypernatraemia. Several other factors may have contributed to the observed acidosis, for example elevated bladder pressure between the selfcatheterisations promoting fl uid movement through the fi stula. In addition, the proximal localisation of the fi stula could have extended ileal and colonic transit time, augmenting intestinal chloride uptake. Enterovesical fi stula can occur years after pelvic radiotherapy; the importance of taking into account the patient’s history cannot be emphasised enough.

Severe Infections in HIV-Exposed Uninfected Infants: Clinical Evidence of Immunodeficiency

We describe the clinical and basic immunological findings of eight HIV-exposed uninfected infants hospitalized with serious infectious morbidity and referred for immunological evaluation. The median age at presentation was 5.5 (1.5-15) months. Infections included Pneumocystis jiroveci pneumonia (three), cytomegalovirus colitis with perforation (one), Pseudomonas sepsis (two), hemorrhagic varicella (one) and Group A streptococcal meningitis and endocarditis (one). Five required intensive care, four for assisted ventilation and one for post-surgical care. Follow-up to 36 months suggested resolution of a transient immunodeficiency in two infants, one of whom had CD4 and the other B-cell depletion. Further studies are indicated in HIV-exposed uninfected infants.

Aminoglycoside drugs in clinical practice: an evidence-based approach--authors' response

Sir, We thank Keuleyan and Kirilov for their comments and beg to differ with most of them. The question of the advantages and disadvantages of aminoglycosides compared with other drugs is discussed in our review. Based on observational studies, we believe that treatment with an aminoglycoside is less effective than b-lactam treatment in septic patients with Gram-negative infections in sites other than those in the urinary tract. Randomized controlled trials on aminoglycosides as single treatment (for infections other than the urinary tract) are few and included a small number of septic patients. To the best of our knowledge, Acinetobacter spp. are not inherently resistant to aminoglycosides. Resistance is mediated through several mechanisms, mainly aminoglycoside-modifying enzymes, and its prevalence is dependent on local epidemiology and strain distribution. In our centre, aminoglycosides are the fourth most active antibiotic class against Acinetobacter baumannii, following colistin, carbapenems and ampicillin/ sulbactam. Other Acinetobacter spp. are susceptible to aminoglycosides. In the SENTRY survey, more than 50% of clinical Acinetobacter spp. strains resistant to ceftazidime were susceptible to amikacin and tobramycin, which were second only to imipenem. In the MYSTIC survey, 58% and 53% of nosocomial Acinetobacter spp. in Europe in 2007 were susceptible to gentamicin and tobramycin, respectively. The data shown for the ‘usual’ in vitro spectrum of activity of aminoglycosides against Acinetobacter spp. in textbooks should probably be adapted to current epidemiology to avoid confusion among clinicians and microbiologists. Our respect for guidelines is expressed in the quote from the review (‘Practitioners would be well advised to use published guidelines, but within their limits, to take into account the fact that combination treatment is not supported by evidence’.). The worrisome point about the management of staphylococcal and streptococcal endocarditis with aminoglycosides is not lack of evidence but weak evidence that points in the opposite direction to the guidelines. Our point is well emphasized by a recent report about the nephrotoxicity of aminoglycosides in Staphylococcus aureus endocarditis and by the accompanying editorial. We would certainly advise clinicians not to steer their practice by apprehension regarding future ‘medico-legal investigation’. We think that Oxman et al. offer good advice: ‘. . . clinicians need guidelines and use them all the time, but they should not accept recommendations uncritically. To serve their patients well, they must be able to make informed judgments about which guidelines are appropriate’. Keuleyan and Kirilov ask ‘. . . why the superiority of antibiotic combinations for infective endocarditis and sepsis, already proven in vitro and in animal experiments, has not been confirmed in the studies cited by the authors’ (i.e. in a synthesis of all randomized controlled trials addressing this question and performed on humans). This is indeed a major concern. Mechanisms or drugs that are allegedly efficacious in vitro and in animal models but do not work in humans – 14 should encourage us to examine whether the models that have been used were appropriate, and whether the results were interpreted correctly.

Group B streptococcal tricuspid valve endocarditis after abortion, presenting with septic emboli to the lungs.

Group B streptococcal endocarditis following elective abortion is a rare complication seen in patients colonized with Group B Streptococci. Screening and prophylaxis for Group B Streptococci should be considered for all patients undergoing elective abortion.

GROUP B STREPTOCOCCAL ENDOCARDITIS AFTER ELECTIVE ABORTION IN AN ADOLESCENT

We describe a case of group B streptococcal endocarditis in a 15-year-old girl after an elective abortion. There are only 6 reports of group B streptococcal endocarditis in older children. It is a well described but rare complication of surgical abortions, and tends to have an aggressive course.

Aminoglycoside drugs in clinical practice: an evidence-based approach

Resistant bacteria have renewed our interest in the aminoglycoside drugs. Evidence on the efficiency of aminoglycosides in their different clinical uses is available from numerous randomized controlled trials and has been accrued and examined in recent systematic reviews and meta-analyses. Their results show that aminoglycosides should not be added to broad-spectrum beta-lactams to achieve synergism in treating Gram-negative infections as combination does not improve efficacy and adds side effects. The evidence from randomized trials in humans does not support the use of aminoglycosides in staphylococcal or streptococcal endocarditis, and is lacking for endocarditis caused by enterococci. Aminoglycosides are efficacious and safe as single drugs for the treatment of pyelonephritis and sepsis of a urinary source, but their efficacy might be lower than that of beta-lactams in Gram-negative infections of other sources. In patients with no risk factors, aminoglycosides are as safe as beta-lactams regarding side effects. They probably induce less resistance. Pragmatic large trials are needed to answer open clinical questions on the use of aminoglycosides.

Daptomycin in endocarditis and bacteraemia: a British perspective

Assessment of the place of daptomycin in the treatment of endocarditis and bacteraemia requires assimilation of data from one open-label randomized comparative clinical trial sized for equivalence, from registry data and from case reports. Selected relevant animal models and in vitro data are also considered in an effort to produce an integrated assessment of the current place of daptomycin in treatment. The evidence for the use of daptomycin is best in Staphylococcus aureus bacteraemia and endocarditis, but also includes some data on infections due to Enterococcus spp., especially if vancomycin-resistant. The emergence of resistance in a minority of patients on current dose regimens may mean that trials have to be repeated with higher doses, or the drug used in a combined therapy where rifampicin may be the best choice. In general, equivalence to comparator antibiotic regimens and a correlation for in vitro and in vivo findings have been demonstrated, but there are important gaps in the clinical data including a comparative equivalence trial in streptococcal and enterococcal endocarditis. Clinical benefit might be anticipated, but has not been proved, over aminoglycoside-containing regimens, and economic assessments are critical in the decision as to when and how daptomycin is deployed.

Asymptomatic Malaria Associated with Protection: Not Causal

An otherwise healthy 44-year-old woman (a resident of a mountainous region of Switzerland) presented to the emergency department with acute onset of fever myalgia and disorientation. On physical examination she was in shock without an evident infectious source. Laboratory analyses revealed leukocytosis (WBC count 27000_109 cells/L) and an elevated C-reactive protein level (260 mg/ L). The patient had a history of congenital left ventricular inflow and outflow tract obstruction that was surgically corrected at the age of 15 years. In 1986 and 1996 she had infectious endocarditis of the aortic valve due to Staphylococcus aureus; the aortic valve was replaced by a homograft in 1990. Transesophageal echocardiography showed vegetations on the aortic valve and possibly also on the mitral valve with severe aortic and moderate mitral regurgitation. Therapy with vancomycin gentamicin and rifampicin was initiated. Blood cultures grew methicillin-sensitive S. aureus supporting a diagnosis of S. aureus prosthetic valve endocarditis and treatment was changed to flucloxacillin and rifampicin. The clinical course was complicated by acute renal failure severe thrombopenia and multiple septic emboli (in the brain skin retina and spleen). After 4 weeks of antibiotic therapy the aortic and mitral valves were replaced by mechanical prostheses. Cultures of the aortic valve were sterile but broad-range eubacterial PCR had results positive for Coxiella burnetii. Serologic results confirmed chronic Q-fever (phase 1 IgG titer 1:6400; phase 1 IgA titer 1: 200; phase 2 IgG titer 1:12800; and phase 2 IgA titer 1:400); analysis of stored serum samples from the patient revealed that the infection had been acquired in the previous 12 months. Thus the final diagnosis was chronic Q-fever prosthetic valve endocarditis complicated by acute S. aureus prosthetic valve endocarditis. The postoperative course was uncomplicated. S. aureus prosthetic valve endocarditis was treated for a total of 6 weeks with flucloxacillin and rifampicin. For Q-fever endocarditis therapy with doxycycline and hydroxychloroquine was introduced and will be continued until the phase 1 IgG titer is !1:400 with a minimum treatment duration of 18 months. At the most recent follow-up visit 10 months after the initial presentation the patient was asymptomatic and titers of anti-Coxiella antibodies were decreasing (phase 1 IgG titer 1:3200; phase 1 IgA titer 1:50; phase 2 IgG titer 1: 6400; phase 2 IgA titer 1:100). This case is remarkable for the simultaneous implication of two different bacterial species in the pathogenesis of infective endocarditis with one of the pathogens being discovered incidentally. Reports in the literature on dual-pathogen endocarditis are scarce; 2 cases with concomitant streptococcal and Q-fever endocarditis have been previously described in a large prospective French study [1]. Our patient had underlying cardiac abnormalities predisposing her to C. burnetii endocarditis and resided in an area of Switzerland with a seroprevalence of Coxiella species infection up to 30% [2]. Nevertheless C. burnetii infection was not suspected because all clinical manifestations were compatible with staphylococcal prosthetic valve endocarditis. The diagnosis of Q-fever endocarditis was thus a lucky strike which is disconcerting given the poor prognosis of unrecognized chronic Coxiella infection. In view of our experience we believe that C. burnetii serologic analysis or PCR testing of heart valve tissue are worth performing in all patients with infective endocarditis who have a preexisting valvulopathy and live in a region in which Q-fever is endemic regardless of whether another etiological agent has been identified or not. (full-text)

Characteristics and regional variations of group D streptococcal endocarditis in France

The proportion of infective endocarditis (IE) caused by group D streptococci (GDS; formerly Streptococcus bovis) increased markedly in France, to account for 25% of all cases of IE by 1999. In an attempt to explain this phenomenon, a comparative analysis of GDS and oral streptococci (OS) causing IE was performed. This study was based on data collected from a large cross-sectional population-based survey that was conducted in 1999. In total, 559 cases of definite IE were recorded, of which 142 involved GDS and 79 involved OS. Patients with GDS IE were older (62.7 vs. 56.6 years, p 0.01) and had a history of valve disease less frequently than did patients with OS IE (33.8% vs. 67.1%, p <0.0001). At-risk procedures for IE were performed less frequently in patients with GDS than in patients with OS (14.8% vs. 24.1%, p 0.08), but co-morbidities were more frequent in the GDS group (59.9% vs. 32.9%, p 0.0001). Diabetes, colon diseases and cirrhosis were also more frequent in the GDS group (p 0.006, p <0.0001 and p 0.08, respectively). Rural residents accounted for 31.0% of the GDS group, but for only 15.2% of the OS group (p 0.001). Likewise, the proportion of GDS IE was higher in regions with mixed (urban and rural) populations (Franche-Comté 81.8%, Marne 68.7%, Lorraine 70.3% and Rhône-Alpes 65.3%) than in exclusively urban regions (Paris and Ile de France 58.0%). Further investigations are required to elucidate the link in France between the incidence of GDS IE, rural residency and nutritional factors.

Genome of the Opportunistic Pathogen Streptococcus sanguinis

The genome of Streptococcus sanguinis is a circular DNA molecule consisting of 2,388,435 bp and is 177 to 590 kb larger than the other 21 streptococcal genomes that have been sequenced. The G+C content of the S. sanguinis genome is 43.4%, which is considerably higher than the G+C contents of other streptococci. The genome encodes 2,274 predicted proteins, 61 tRNAs, and four rRNA operons. A 70-kb region encoding pathways for vitamin B(12) biosynthesis and degradation of ethanolamine and propanediol was apparently acquired by horizontal gene transfer. The gene complement suggests new hypotheses for the pathogenesis and virulence of S. sanguinis and differs from the gene complements of other pathogenic and nonpathogenic streptococci. In particular, S. sanguinis possesses a remarkable abundance of putative surface proteins, which may permit it to be a primary colonizer of the oral cavity and agent of streptococcal endocarditis and infection in neutropenic patients.

Mycotic superior mesenteric aneurysm

A 36-year-old man with a history of aortic valve replacement secondary to streptococcal endocarditis 8 years before admission presented with unexplained severe epigastric pain. After an extensive work-up, a 5-cm superior mesenteric artery (SMA) aneurysm was identified by computer tomography (CT). Three-dimensional CT reconstruction (Cover) and selective arteriography (A) demonstrated that the aneurysm arose from the main trunk of the SMA beyond the first segmental branches. The aneurysm was thought to be mycotic due to the patient’s history and the absence of any other vascular disease. The densely scarred SMA aneurysm was exposed through the transverse mesocolon (B) (note that a vessel loop surrounds the proximal SMA at the base of the mesocolon), the aneurysm resected, and a saphenous vein interposition graft performed (C). The patient’s recovery was unremarkable, and he was discharged home on postoperative day 5. As anticipated, cultures of the aneurysm were negative due to long-term (6 weeks) postoperative antibiotics 8 years ago.

Group B Streptococcus Endocarditis Following an Elective Abortion: A Case Report and Review of Literature

Endocarditis caused by Streptococcus agalactiae, a group B streptococcus (GBS), is unusual; however, it can occur in association with obstetrical procedures and carries a high mortality rate. We describe a previously healthy patient who developed GBS mitral valve endocarditis after an elective abortion, and compare and contrast prior case reports.

Endocarditis por Streptococcus agalactiae

Streptococcus agalactiae infective endocarditis Streptococcus agalactiae is an unusual cause of infectious endocarditis. We describe the clinical characteristics, therapy and evolution of this infection in four patients diagnosed between 1996 and 2003. All four cases had native valve involvement and vegetations. All the patients had severe aortic failure and three of them also developed heart failure. Valve replacement surgery was performed in all four cases. Mortality was 50%. Infectious endocarditis due to S. agalactiae is very aggressive. Early surgery should be considered to prevent valve destruction and serious complications.