Infections of intracardiac devices

Effect of pocket irrigation with antimicrobial on prevention of pacemaker pocket infection: a meta-analysis

Background

The presence of cardiac implantable electronic devices (CIEDs) pocket infection is difficult to treat, causing serious clinical outcomes, but little is known for prevention. Results from some studies suggested that pocket irrigation could reduce infection while others showed conflicting results. We pooled the effects of pocket irrigations on the prevention of pocket infection by meta-analysis methods.

Method

Relevant studies published before June, 2017 were retrieved mainly by the computer-based search of PubMed, Cochrane, EMBASE, Web of Science, Chinese BioMedical, Global Health and BIOSIS Previews databases. Estimations of relative ratios (RRs) and 95% confidence intervals (95% CIs) were pooled. Subgroup analyses according to potential key factors affecting the effects were conducted, which was confirmed by meta-regression. Sensitivity analysis and test for publication bias were also performed.

Results

We identified 10 studies providing data of 5467 patients receiving CIEDs implantations. Pooled infection rates were 1.48 and 3.49% respectively for medication and saline irrigation groups. Meta-analysis showed that medication irrigation conferred protection to pocket infection (RR = 0.44, 95% CI: 0.31-0.63). Subgroup analysis showed that antibiotics, rather than non-antibiotics (antiseptics) exerting the protection. The first and second lines antibiotics against staphylococcus aureus, which is the main pathogen for pocket infection, were both effective (RR = 0.42, 95% CI: 0.24-0.75 and RR = 0.34, 95% CI: 0.20-0.58 respectively for first line and second line therapies). Meta-regression revealed that region and class of irrigation medication completely explained the variance among studies and implied that effects of region were masked by medication types. Sensitivity analysis did not showed any significant change of the result and publication bias were not statistical significance.

Conclusion

Pocket irrigation with antibiotics were effective for reducing pocket infection and should be encouraged in CIEDs implantation.

Risk factors of cardiac device infection: Glove contamination during device procedures

BACKGROUND

Infections in cardiac implantable electronic devices (CIEDs) constitute a serious complication. We sought to identify contamination of gloves before handling the device in primary and replacement CIED procedures.

METHODS

Two groups of 30 patients underwent primary CIED implantation or replacement. Before the device entered the surgical field, surgeon and assistant imprinted their outer gloves on aerobe and anaerobe agar plates, and a wound swab was performed. Samples were cultured, and the presence of bacteria was identified, counted as the number of colony forming units, and characterized to the level of genus and species.

RESULTS

Samples from 40 (67%) procedures revealed bacteria on surgeons' or assistants' gloves. Contamination occurred in 80% of replacements and 67% of primary implantations (risk difference, 13%; 95% confidence interval [CI], -8.8 to 35.5). Contamination of surgeons' and assistants' gloves occurred in 55% and 44% of procedures, respectively. Coagulase-negative Staphylococcus (CNS) occurred in 52%, and Propionibacterium spp (PS) occurred in 84% of positive cases. For every 15 minutes of procedure time, colony levels increased by 7.4% (95% CI, 1.4%-13.4%).

CONCLUSIONS

Contamination of gloves is common during CIED procedures before handling the device. Therefore, devices are often handled with contaminated gloves. The most prevalent bacteria were PS and CNS, which are associated with clinical CIED infections. Changing outer gloves before handling the device might improve sterile state and lower infection risk.

Development and evaluation of a novel fast broad-range 16S ribosomal DNA PCR and sequencing assay for diagnosis of bacterial infective endocarditis: multi-year experience in a large Canadian healthcare zone and a literature review

Background

The study aimed to explore the sensitivity and specificity of a novel fast 16S rDNA PCR and sequencing assay for the improved diagnosis of infective endocarditis (IE) in patients with suspected native or prosthetic heart valve (HV) infection over a multi-year period at our cardiovascular center.

Methods

Sixty-eight patients were prospectively enrolled who underwent HV replacement for suspected or confirmed IE between February 1, 2009 and September 1, 2014. Patient demographics, medical co-morbidities, Duke’s criteria, culture results, and antibiotic therapy were collected by detailed chart reviews. Dual-priming oligonucleotide primers targeted to 500 bps of the V1-V3 region of the 16S rRNA gene were used to perform fast broad-range 16S rDNA PCR and Sanger sequencing on ribosomal DNA extracted from HV tissues. The performance/diagnostic efficiency of the molecular test was evaluated against blood cultures and Gram stain and culture of HV tissue in patients’ with definite IE according to Duke’s criteria.

Results

Fifty patients (73.5 %) had definite IE and another 8 (11.8 %) had possible IE according to Duke’s criteria. Cardiac surgery was delayed an average of 15.4 days from the time of the patient’s last positive blood culture, and appropriate antibiotic therapy was given in the pre-operative period. While 44/50 (88 %) patients had a positive blood culture, HV tissue culture was only positive in 23 (46 %) of them. Molecular testing of all HV tissues had sensitivity, specificity, NPV and PPV of 92, 77.8, 77.8 and 92 % compared to 44, 100, 39.1 and 100 % respectively for culture for diagnosis of definite IE. For prosthetic HV tissue, 16S rDNA PCR had sensitivity of 93 % and specificity of 83 % compared to 35 and 100 % respectively for culture. A literature review showed that the diagnostic accuracy of our novel fast broad-range 16S rDNA PCR assay was similar or better than that of previously published studies.

Conclusions

This novel fast broad-range 16S rDNA PCR/sequencing test had superior sensitivity compared to tissue Gram stain and culture for identifying underlying bacterial pathogen in both native and prosthetic valve endocarditis.

Incidence of and risk factors for infectious complications in patients with cardiac device implantation

OBJECTIVES

The use of cardiac implantable electronic device (CIED; pacemakers, implantable cardioverter-defibrillators [ICD], cardiac re-synchronized therapy [CRT]) implantation, one essential treatment for cardiac arrhythmias, is increasing. Infectious complications related to implants are the main reason for device removal and patient morbidity. We sought to identify the incidence of infectious complications among patients with cardiac device implantation and analyze the risk factors for infectious complications.

METHODS

A retrospective analysis was conducted of 1307 patients (61.5±14.2 years-old, 49.6% male) with cardiac device implantation from January 1990 to April 2013. We analyzed the incidence of infectious complications during the follow-up period. To investigate risk factors associated with infectious complications, we conducted a 1:2 matched case-control study of patients with infectious complications and controls without infectious complications who had the same implantation period and physician.

RESULTS

Among 1307 patients, 12 had a confirmed device-related infection: 7 with a pocket infection and 5 with infective endocarditis. Over a total of 9091.9 device-years, the incidence of infectious complications was 1.3/1000 device-years, based on the 12 patients with an infection. ICD (5.1/1000 device-year) had a higher incidence of infectious complications than other cardiac devices, and no infectious complications were observed among patients with CRT implantation. Mean duration from the time of implantation to infection was 2.02±1.65 years. In a multivariate analysis, the number of prior procedures including wound revision or scar revision was an independent risk factor for infectious complications (OR=10.88, 95% CI 1.11->999, p=0.040).

CONCLUSIONS

Infection was a rare complication of cardiac device implantation, but repeated procedures were associated with infectious complications.

Prevention of infections in cardiovascular implantable electronic devices beyond the antibiotic agent

The increase in incidence/prevalence of infections of implantable pacemakers and defibrillators (implantable cardioverter defibrillator, ICD) is outweighing that of the implanting procedures, mainly favored by the changes in patient profile. Despite the high impact on patient's outcome and related costs for healthcare systems, we lack specific evidence on the preventive measures with the exception of antibiotic prophylaxis. The aim of this study is to focus on common approaches to pacemaker/ICD implantation to identify the practical preventive strategies and choices that can (potentially) impact on the occurrence of this feared complication. After a brief introduction on clinical presentation, pathogenesis, and risk factors, we will present the results from a survey on the preventive strategies adopted by different operators from the 25 centers of the Emilia Romagna region in the northern Italy (4.4 million inhabitants). These data will provide the basis for reviewing available literature on this topic and identifying the gray areas. The last part of the article will cover the available evidence about pacemaker/ICD implantation, focusing on prophylaxis of pacemaker/ICD infection as a 'continuum' starting before the surgical procedure (from indications to patient preparation), which follows during (operator, room, and techniques) and after the procedure (patient and device follow-up). We will conclude by evaluating the relationship between adherence to the available evidence and the volume of procedures of the implanting centers or operators' experience according to the results of our survey.

Trends in hospitalization rates and outcomes of endocarditis among Medicare beneficiaries

OBJECTIVES

The aim of this study was to determine the hospitalization rates and outcomes of endocarditis among older adults.

BACKGROUND

Endocarditis is the most serious cardiovascular infection and is especially common among older adults. Little is known about recent trends for endocarditis hospitalizations and outcomes.

METHODS

Using Medicare inpatient Standard Analytic Files, we identified all fee-for-service beneficiaries age ≥65 years with a principal or secondary diagnosis of endocarditis from 1999 to 2010. We used Medicare Denominator Files to report hospitalizations per 100,000 person-years. Rates of 30-day and 1-year mortality were calculated using Vital Status Files. We used mixed-effects models to calculate adjusted rates of hospitalization and mortality and to compare the results before and after 2007, when the American Heart Association revised their recommendations for endocarditis prophylaxis.

RESULTS

Overall, 262,658 beneficiaries were hospitalized with endocarditis. The adjusted hospitalization rate increased from 1999 to 2005, reaching 83.5 per 100,000 person-years in 2005, and declined during 2006 to 2007. After 2007, the decline continued, reaching 70.6 per 100,000 person-years in 2010. Adjusted 30-day and 1-year mortality rates ranged from 14.2% to 16.5% and from 32.6% to 36.2%, respectively. There were no consistent changes in adjusted rates of 30-day and 1-year mortality after 2007. Trends in rates of hospitalization and outcomes were consistent across demographic subgroups. Adjusted rates of hospitalization and mortality declined consistently in the subgroup with a principal diagnosis of endocarditis.

CONCLUSIONS

Our study highlights the high burden of endocarditis among older adults. We did not observe an increase in adjusted rates of hospitalization or mortality associated with endocarditis after publication of the 2007 guidelines.

Complement c5a generation by staphylococcal biofilms

Biofilms production is a central feature of nosocomial infection of catheters and other medical devices used in resuscitation and critical care. However, the very effective biofilm forming pathogen Staphylococcus epidermidis often produces a modest host inflammatory response and few of the signs and symptoms associated with more virulent pathogens. To examine the impact of bacterial biofilm formation on provocation of an innate immune response, we studied the elaboration of the major complement anaphylatoxin C5a by human serum upon contact with S. epidermidis biofilms. Wild-type S. epidermidis and mutants of sarA (a regulatory protein that promotes synthesis of the biofilm-forming polysaccharide intercellular adhesin [PIA]) and icaB (responsible for postexport processing of PIA) were studied. C5a release, as a function of exposed biofilm surface area, was on the order of 1 fmol · cm · s and was dependent on the presence of PIA. Experimental results were used to inform a physiologically based pharmacokinetic model of C5a release by an infected central venous catheter, one of S. epidermidis' primary means of causing human disease. These simulations revealed that the magnitude of C5a release on a superior vena cava catheter completely covered with S. epidermidis would be lower than necessary to alert circulating leukocytes. Combined, the experimental and computational results are highly consistent with clinical observations in which the clinical signs of central line-associated bloodstream infection are often muted in association with this important pathogen.

Staphylococcus lugdunensis: the coagulase-negative staphylococcus you don't want to ignore

Staphylococcus lugdunensis is a virulent coagulase-negative staphylococcus (CoNS) that behaves like Staphylococcus aureus. Toxic shock syndrome, osteomyelitis, septic arthritis and postoperative endopthalmitis have been observed. Endocarditis complicated by heart failure, periannular abscess formation and embolic phenomenon have brought particular attention to this CoNS. Mortality rates for endocarditis appear higher when compared with other CoNS. Owing to the laboratory methods used, identification may be misleading. β-lactam antimicrobials are recommended pending sensitivities. Evaluation for endocarditis should be pursued in bacteremic patients due to its pathogenic potential.

Early Aspergillus pacemaker pocket infection: Case and review

We report the first case to our knowledge of an early pacemaker pocket infection due to Aspergillus fumigatus. Several cases of late pacemaker pocket infection by Aspergillus have been reported, but it remains exceedingly rare. Recognition of Aspergillus infection as a potential early or late complication of placement of pacemakers or implantable cardioverter defibrillator devices may help clinicians diagnose and treat future cases of this potentially devastating infection.

Incidence and clinical implication of nosocomial infections associated with implantable biomaterials - catheters, ventilator-associated pneumonia, urinary tract infections

Health care associated infections, the fourth leading cause of disease in industrialised countries, are a major health issue. One part of this condition is based on the increasing insertion and implantation of prosthetic medical devices, since presence of a foreign body significantly reduces the number of bacteria required to produce infection. The most significant hospital-acquired infections, based on frequency and potential severity, are those related to procedures e.g. surgical site infections and medical devices, including urinary tract infection in catheterized patients, pneumonia in patients intubated on a ventilator and bacteraemia related to intravascular catheter use. At least half of all cases of nosocomial infections are associated with medical devices.Modern medical and surgical practices have increasingly utilized implantable medical devices of various kinds. Such devices may be utilized only short-time or intermittently, for months, years or permanently. They improve the therapeutic outcome, save human lives and greatly enhance the quality of life of these patients. However, plastic devices are easily colonized with bacteria and fungi, able to be colonized by microorganisms at a rate of 0.5 cm per hour. A thick biofilm is formed within 24 hours on the entire surface of these plastic devices once inoculated even with a small initial number of bacteria.The aim of the present work is to review the current literature on causes, frequency and preventive measures against infections associated with intravascular devices, catheter-related urinary tract infection, ventilator-associated infection, and infections of other implantable medical devices. Raising awareness for infection associated with implanted medical devices, teaching and training skills of staff, and establishment of surveillance systems monitoring device-related infection seem to be the principal strategies used to achieve reduction and prevention of such infections. The intelligent use of suitable antiseptics in combination with medical devices may further support reduction and prevention of such infections. In addition to reducing the adverse clinical outcomes related with these infections, such reduction may substantially decrease the economic burden caused by device-related infection for health care systems.

Surgical removal of a giant vegetation on permanent endocavitary pacemaker wire and lead

Pacemaker lead infections are rare. There are only about 0.4%-1.1% of the patients who have been implanted permanent pacemakers suffering from serious infections which lead to endocarditis. Generally, removal of the infected pacemaker wire and lead, long-term anti-infection therapy, and implantation of a new pacemaker to another anatomic site are accepted approaches for these patients.

Noninvasive imaging of prosthetic cardiac devices

The major advances in cardiovascular care can be linked to the combined growth of advanced imaging modalities and the variety of treatment options available for patients with complex structural, acquired and congenital, valvular, myocardial and aortic diseases. Paralleling this growth are the number and spectrum of complications - such as device failures and infections - that these patients will inevitably encounter. The keys to successful implementation of advanced cardiac therapy are the real-time images, 3D reconstructions, and the hemodynamic and tissue profiles that can be obtained to evaluate these patients and their devices. We will review the roles of echocardiography, multidetector computed tomography and MRI in the evaluation of normal and abnormal cardiac device function.

Intracardiac lead endocarditis due to Staphylococcus lugdunensis

Staphylococcus Lugdunensis is a rare but potentially aggressive pathogen in the family of coagulase negative staphylococcus (CoNS). It can cause a wide variety of infections ranging from superficial skin to fulminant infections like endocarditis. Both native and prosthetic valve endocarditis due to S. lugdunensis have been documented in the English literature. Eight cases of pacemaker lead endocarditis due to S. lugdunensis have been described so far. We present the ninth case of pacemaker lead and first case of automatic implantable cardioverter defibrillator (AICD) lead endocarditis due to S. lugdunensis.

Infective endocarditis of the Dacron patch-a report of 13 cases at autopsy

AIMS

One of the complications of using a synthetic material as a patch in correction of left-to-right shunts is the development of infection. This is an autopsy report of 13 patients who developed infective endocarditis of the Dacron patch as a postoperative complication.

METHODS

We retrospectively reviewed the autopsy records of patients with infective endocarditis over a 15-year period (1994-2008) and selected cases with Dacron-patch infective endocarditis. The patch infective endocarditis was classified into early-onset and late-onset infective endocarditis.

RESULTS

Patch infective endocarditis was seen in 13 patients affecting the patches covering an atrial septal defect and 12 ventricular septal defects. There were nine males and four females, with a mean age of 13.1 years. The episodes occurred 2 to 118 days (mean of 30) after operation, with early-onset infective endocarditis in 10 and late-onset infective endocarditis in three patients. Postoperative wound infection had been present in eight. The organisms isolated or demonstrated on microscopy included Staphylococcus aureus (5), gram-positive cocci (4), Pseudomonas (2), Aspergillus species (1), and Candida species (1). Death was related to embolization and/or accompanying septicemia.

CONCLUSIONS

Correction of simple or complex congenital cardiac defects offers new substrates for organisms to colonize resulting in infective endocarditis, which are often difficult to treat.

Inhibition of Staphylococcus aureus biofilms by a novel antibacterial envelope for use with implantable cardiac devices

Biofilm formation on representative implantable medical devices using a known human pathogen (Staphylococcus aureus) was significantly reduced (p < 0.01) at all time points measured (24,48, and 72 hours) by employing a novel antibacterial envelope (AIGIS Rx). The result was demonstrated using a standard US Centers for Disease Control (CDC) bioreactor model and the results were confirmed by Scanning Electron Microscopy (SEM). The antibacterial envelope used in the study is coated with a proprietary combination broad spectrum antibiotics (rifampin and minocycline) embedded in a resorbable polymeric coating. The antibiotics are designed to elute out of the coating over a multi-day period for controlled, site-specific drug delivery. The infection rate for patients receiving pacemakers and defibrillators is increasing faster than the rate of new implants and the growing resistance of S. aureus strains suggests that conventional, systemic antibiotic prophylaxis may have limited future utility. Moreover, emerging evidence suggests that bacterial biofilms result in infections of implantable medical devices. These findings demonstrate the in vitro efficacy of a new means to address potential biofilm-derived Hospital Acquired Infections (HAIs) related to implantable medical devices composed of titanium inclusive of pacemakers and defibrillators by means of a locally delivered, low dose, combination antibacterial treatment.

Acute infective endocarditis

Acute infective endocarditis is a complex disease with changing epidemiology and a rapidly evolving knowledge base. To consistently achieve optimal outcomes in the management of infective endocarditis, the clinical team must have an understanding of the epidemiology, microbiology, and natural history of infective endocarditis, as well as a grasp of guiding principles of diagnosis and medical and surgical management. The focus of this review is acute infective endocarditis, though many studies of diagnosis and treatment do not differentiate between acute and subacute disease, and indeed many principles of diagnosis and management of infective endocarditis for acute and subacute disease are identical.

The selection of appropriate bacterial strains in preclinical evaluation of infection-resistant biomaterials

Implant-related infections are broadly recognized as one of the most serious and devastating complications associated with the use of biomaterials in medical practice. The growing interest and need for the development of implant materials with reduced susceptibility to microbial colonization and biofilm formation has necessitated the development of a series of in vitro and in vivo models for evaluation and preclinical testing. Current technologies provide these investigations with an ample choice of qualitative and quantitative techniques for an accurate assessment of the bioactivity and anti-infective efficacy of any new compound or device. These tests are typically performed using a reference bacterial strain designated as the test or reference strain. Recent molecular epidemiological studies have identified the complex clonal nature of most prevalent etiological agents implicated in implant-associated infections. New information which is continually emerging on the identity and the characteristics of both sporadic and epidemic clones must be considered when selecting a reference. A new emerging requirement is that the strain should be representative of the clones causing clinically relevant infections; they should, therefore, belong to the most prevalent epidemic clones rather than to sporadic ones, which may occur in only 1 out of 200 infections or even fewer. The correct choice of reference strain for preclinical tests is of crucial importance for the clinical significance of the achieved results. In this paper we report our experience and recommendations regarding this issue.

Swedish guidelines for diagnosis and treatment of infective endocarditis

Swedish guidelines for diagnosis and treatment of infective endocarditis (IE) by consensus of experts are based on clinical experience and reports from the literature. Recommendations are evidence based. For diagnosis 3 blood cultures should be drawn; chest X-ray, electrocardiogram, and echocardiography preferably transoesophageal should be carried out. Blood cultures should be kept for 5 d and precede intravenous antibiotic therapy. In patients with native valves and suspicion of staphylococcal aetiology, cloxacillin and gentamicin should be given as empirical treatment. If non-staphylococcal etiology is most probable, penicillin G and gentamicin treatment should be started. In patients with prosthetic valves treatment with vancomycin, gentamicin and rifampicin is recommended. Patients with blood culture negative IE are recommended penicillin G (changed to cefuroxime in treatment failure) and gentamicin for native valve IE and vancomycin, gentamicin and rifampicin for prosthetic valve IE, respectively. Isolates of viridans group streptococci and enterococci should be subtyped and MIC should be determined for penicillin G and aminoglycosides. Antibiotic treatment should be chosen according to sensitivity pattern given 2-6 weeks intravenously. Cardiac valve surgery should be considered early, especially in patients with left-sided IE and/or prosthetic heart valves. Absolute indications for surgery are severe heart failure, paravalvular abscess, lack of response to antibiotic therapy, unstable prosthesis and multiple embolies. Follow-up echocardiography should be performed on clinical indications.

Not the usual cardiac rhythm device infection: a fastidious pathogen with several teaching points

Because cardiac device infections may include fastidious pathogens, extended incubation of blood cultures is suggested. A patient with an infection of a right ventricular lead implantable cardioverter defibrillator (ICD) system is described. The device was implanted 6 months earlier. The pathogen was identified as Haemophilus parainfluenzae, which was cultured within 72 hours and was presumably from a respiratory tract infection. Extended incubation was not necessary to culture this fastidious pathogen. Two large retrospective studies suggest that prolonged incubation for fastidious organisms is generally not necessary because of advances in culture media and automated blood culture systems.

Infections associated with long-term prosthetic devices

The extensive and ever-increasing use of long-term prosthetic devices has improved quality of life and survival for many patients. Prosthetic device-related infection occurs infrequently but is associated with significant morbidity and mortality. Management is challenging, often requiring prolonged antimicrobial therapy and surgical intervention. Better understanding of the interaction between microorganisms, devices, and the host should improve the ability to manage device-related infections. This article reviews recent advances in the diagnosis and treatment of infections associated with indwelling medical devices, highlighting those associated with prosthetic joints, cerebrospinal fluid shunts, and prosthetic heart valves.

Infective endocarditis complicating permanent pacemaker and implantable cardioverter-defibrillator infection

OBJECTIVE

To describe management of patients with permanent pacemaker (PPM)- and implantable cardioverter-defibrillator (ICD)-related endocarditis.

PATIENTS AND METHODS

We retrospectively reviewed all cases of infection involving PPMs and ICDs among patients presenting to Mayo Clinic's site in Rochester, MN, between January 1, 1991, and December 31, 2003. Cardiac device-related infective endocarditis (CDIE) was defined as the presence of both vegetation on a device lead or valve and clinical or microbiological evidence of CDIE. Of 189 patients with PPM or ICD infection who were admitted during the study period, 44 met the case definition for CDIE (33 PPM, 11 ICD).

RESULTS

The mean +/- SD age of patients was 67 +/- 14 years. Staphylococci (36 [82%]) were the most commonly isolated pathogens. Nearly all patients (43 [98%]) were treated with a combined approach of complete hardware removal and parenteral antibiotics. The median duration of antibiotic treatment after infected device explantation was 28 days (interquartile range, 19-42 days). Device leads were removed percutaneously in 34 cases (77%); only 7 cases (16%) required surgical lead extraction. Percutaneous extraction was uncomplicated in 15 patients with lead vegetation greater than 10 mm in diameter. Six patients (14%) died during hospitalization. Twenty-seven (96%) of 28 patients remained infection free at their last visit (median follow-up, 183 days; intraquartile range, 36-628 days).

CONCLUSION

Prompt hardware removal and prolonged parenteral antibiotic administration decrease mortality among patients with CDIE. The presence of a large (> 10 mm in diameter) vegetation on a lead is not a contraindication for percutaneous lead extraction.

Pacemaker Infections: A 10-Year Experience

BACKGROUND

Infection is a major complication of pacemaker and defibrillator (PPM/ICD) implantation. The experience in an Australian regional centre is reported.

METHODS

Ten years' (1994-2004) cases of PPM/ICD infection retrospectively analysed and compared to overall insertion data; management and outcomes examined.

RESULTS

A total 39 cases (79.5% male, median age 71.3 years) identified, 24 in the primary centre where 1481 procedures performed (infection rate 1.6%). Patients with infection had average 2.2 procedures performed (odds ratio for infection if >1 procedure=4.7); 14 (36%) first implantations, 35 (90%) pacemakers, 11 (28%) recurrent. No difference in operation duration or difficulty between infected and non-infected cases. Infection in 18 cases (46%) involved lead/s, 16 (41%) generator and 5 (13%) both. Median time to presentation was 7.9 months. Echocardiography demonstrated lead vegetations in 8 cases. Organisms identified in 25 (64%)-92% Staphylococci (65% S. aureus); blood cultures positive in 18. PPM/ICD removed in 26 (67%), including lead/s in 89%; average hospital stay 37 days. One death attributable to PPM/ICD infection (mortality 2.6%), median follow-up 29.3 months.

CONCLUSIONS

A PPM/ICD infection rate of 1.6% (endocarditis 0.3%) demonstrated. Second and subsequent procedures carried almost 5 times greater infection risk.

Klebsiella Pneumoniae: A Rare Cause of Device-Associated Endocarditis

Intravascular infections involving implanted pacemakers and defibrillators are being seen with increasing frequency. This report describes a case of intravascular infection of an implanted defibrillator with Klebsiella pneumoniae, an unusual pathogen for pacemaker or defibrillator infection.

Cost Advantage of Dual-Chamber Versus Single-Chamber Cardioverter-Defibrillator Implantation

OBJECTIVES

The purpose of this study was to determine the least expensive strategy for device selection in patients receiving implantable cardioverter-defibrillators (ICDs).

BACKGROUND

Device cost for a single-chamber ICD is less than an atrioventricular (dual-chamber) ICD (AV-ICD); however, some patients without clinical need for AV-ICD at implantation might require a later upgrade, potentially offsetting the initial cost advantage of the single-chamber device.

METHODS

Decision analysis was used to estimate expected resource utilization costs of three alternative implantation strategies: 1) single-chamber device in all, with later upgrade to AV-ICD if needed; 2) initial implantation of an AV-ICD in all; and 3) targeted device selection on the basis of results of electrophysiologic testing (presence or absence of induced bradyarrhythmias or atrial arrhythmias). Clinical base estimates were obtained from retrospective review of all patients receiving ICDs between June 1997 and July 2001 at a single university hospital. Economic inputs were collected from national and single-center sources.

RESULTS

In patients without other indications for electrophysiologic study (EPS), the expected per-person cost was least with the strategy of universal initial AV-ICD implantation (36,232 dollars) compared with initial single-chamber ICD/upgrade as needed (39,230 dollars) or EPS-guided selection (41,130 dollars). Sensitivity analyses demonstrated that universal AV-ICD implantation remained least expensive with upgrade rates as low as 10%. At a 5% upgrade rate, AV-ICD remained cheapest if the device cost-differential narrowed to 1,568 dollars. For patients undergoing EPS for risk assessment, EP-guided selection was least expensive.

CONCLUSIONS

The strategy of universal AV-ICD implantation, which provides the benefits of dual-chamber capability while obviating any potential need for future upgrade, is the least costly strategy for most patient populations receiving ICDs.

Misidentification of Mycobacterium peregrinum, the causal organism of a case of bacteremia and automatic implantable cardioverter defibrillator-associated infection, due to its unusual acid-fast staining characteristics

We report an unusual case of Mycobacterium peregrinum bacteremia and infection of an automatic implantable cardioverter defibrillator that was originally misidentified as a Nocardia sp. due, in part, to its partially acid-fast staining characteristic, morphology, and odor. The misdiagnosis had a direct effect on patient care, though the patient was subsequently successfully treated.

Guidelines for the antibiotic treatment of endocarditis in adults: report of the Working Party of the British Society for Antimicrobial Chemotherapy

The BSAC Guidelines on Endocarditis were last published in 1998. The Guidelines presented here have been updated and extended to reflect changes in both the antibiotic resistance characteristics of causative organisms and the availability of new antibiotics. Randomized, controlled trials suitable for the development of evidenced-based guidelines in this area are still lacking, and therefore a consensus approach has again been adopted. The Guidelines cover diagnosis and laboratory testing, suitable antibiotic regimens and causative organisms. Special emphasis is placed on common causes of endocarditis, such as streptococci and staphylococci, however, other bacterial causes (such as enterococci, HACEK organisms, Coxiella and Bartonella) and fungi are considered. The special circumstances of prosthetic endocarditis are discussed.

Candida infections of medical devices

The number of indwelling medical devices is escalating, and an increasing proportion of device-related infections are being caused by Candida spp. Candida spp. produce biofilms on synthetic materials, which facilitates adhesion of the organisms to devices and renders them relatively refractory to medical therapy. Management of device-related Candida infections can be challenging. Removal of the infected device is generally needed to establish cure of Candida infections of medical devices. However, since the pathogenesis of Candida bloodstream infection is complicated, more studies are necessary to determine the role of catheter exchange in patients with both gastrointestinal tract mucositis and indwelling catheters. The medical and economic impact of these infections is enormous.