Prevention of pacemaker infections with perioperative antimicrobial treatment: an in vitro study.

AIMS: The antimicrobial treatment of pacemaker casings with antiseptics (povidone-iodine or octenidine dihydrochloride) or antibiotics (vancomycin, daptomycin, cefuroxime, Tazobac, or nebacetin) was analysed in vitro for its biocompatibility and efficacy in preventing the bacterial adhesion of Staphylococcus epidermidis, Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli to cardiac-implantable electrophysiological devices (CIEDs). METHODS AND RESULTS: Titan platelets (0.4 cm²) cut from pacemaker casings were impregnated with seven different antimicrobial solutions: two antiseptics and five antibiotics. Subsequently, they were challenged with bacterial contamination by four test strains over a 24 h incubation period. Bacterial adherence was quantified using the colony-forming-unit method after cell recovery with sonication and examined with confocal laser scanning electron microscopy. Simultaneously, the biocompatibility of the antimicrobial impregnation was assessed using pre-treated titan platelets in a culture of human fibroblasts, skeletal myoblasts, and microvascular endothelial cells. After a 48 h incubation, cell vitality was measured using the 2-(2-methoxy-4-nitrophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H/tetrazolium monosodium (WST-8) assay. The immersion of pacemaker casings in antiseptic or antibiotic solutions applies an antimicrobial coating that can significantly reduce bacterial adhesion. The studied impregnations differed in their antimicrobial efficacy and toxicity. CONCLUSION: Compared with the two antiseptics and the other tested antibiotics, nebacetin showed the best ratio of efficacy to toxicity. Nebacetin showed good in vitro antibacterial activity against both Gram-positive and Gram-negative pathogens without impairing human cell vitality. It is a safe and effective candidate for CIED impregnation.

The role of cohabitant unusual bacterial species in infection of cardiovascular implantable electronic devices (CIED).

BACKGROUND: Asymptomatic bacterial colonisation of medical implants is increasingly recognised. The role of the often unusual bacteria is usually unknown however. OBJECTIVE AND METHODS: During a three-year period, patients presenting with clinically evident CIED lead endocarditis and/or pocket infections were included in a prospective database. Using 16s DNA analysis and sequencing, devices and pockets of consecutive patients with evident CIED infection were examined for the presence of bacterial species in addition to the ones grown in conventional culture in order to characterise their clinical role. RESULTS: During the study 77 of a total of 409 consecutive operations involving the explantation of a CIED were performed for clinically evident infection. 71 were included in the study and conventional extended culture and 16s DNA analysis performed and compared. In 42.3% of the patients bacteria were identified by DNA analysis in addition to the culture of the supposedly causative organisms. CONCLUSION: DNA analysis is more sensitive than conventional culture of swabs in detecting any, or indeed multiple bacterial strains in CIED infection. This may in future influence treatment strategies as e.g. the cohabitation of different strains seems common and is not reflected by classical culture results. Spread of infection along the leads was clearly demonstrated and this strongly supports the recommendation of complete removal of all CIED components in every form of CIED infection. The more unusual bacteria demonstrated here do not appear to play a significant clinical role as suspected earlier.

Complete removal as a routine treatment for any cardiovascular implantable electronic device-associated infection.

OBJECTIVE: Pacemaker and implantable cardioverter defibrillator lead endocarditis mandates removal of all foreign material. In supposedly limited (pocket) infections, such a radical approach is still controversial. Thus, some patients are potentially exposed to persistent and recurrent infection because of retained material. Procedural risks and the success of eradicating infection were examined if involvement of the complete system was assumed in any cardiovascular implantable electronic device infection and complete removal was thus mandatory. METHODS: A 12-year experience with 192 consecutive cases of bacterial pacemaker (152) or defibrillator (40) infections is presented. Complete removal of all prosthetic material was always aimed for. This was followed by antibiotic treatment for 4 to 6 weeks under temporary pacing if required, and then the new system was implanted. A total of 104 parameters concerning patient characteristics and operative and postoperative treatment were examined for their influence on outcome. RESULTS: Infection was eradicated in 92.8% of patients. Recurrence was predominantly caused by failure to remove all prosthetic material (P < .001). If the protocol was strictly followed, infection was eradicated in 97.4% of patients. Conversely, 71.4% of patients with retained material showed recurrence. Further risk factors were poor dental hygiene and evidence of chronic subclinical infection. Morbidity and mortality of the interventional and open procedures were low. Open lead extraction was performed primarily in 34 patients (17.7%) and secondarily in 3 patients (1.9%). Temporary pacing and long-term antibiotic treatment were well tolerated. CONCLUSIONS: Complete removal of prosthetic material in any cardiovascular implantable electronic device infection is safe and associated with low morbidity and mortality. Success of eradicating infection is high if all system components are removed. Temporary pacing in dependent patients may be performed safely on an outpatient basis.

Treatment of patients with recurrent or persistent infection of cardiac implantable electronic devices.

BACKGROUND: Increasing rates of bacterial infections in device therapy of cardiac rhythm disturbances pose a clinical problem. Radical surgical treatment yields the best long-term results but is frequently preceded by conservative treatment or limited surgical procedures leading to an unnecessary long treatment course. Recurrence/persistence of infection then potentially poses an even more serious clinical problem. METHODS AND RESULTS: A total of 192 consecutive explantation procedures were performed for cardiac implantable electronic device (CIED) infections over a 10 year period. Forty-nine cases followed recurrence of infection subsequent to prior surgical treatment for device infection. Differences in patient/disease characteristics and outcome were looked for in recurrent as compared to primary infections (referral mode) to identify a potential requirement for adjusting treatment in recurrence. With a minimum follow-up of 24 months, 98% eradication of infection was observed independent of referral mode. Differences between primary and recurrent infection essentially reflected the primary presenting clinical picture-chronic smouldering vs. acute systemic infection. Various parameters that follow from this differentiation are significantly different between the groups. There was however no difference in outcome in terms of mortality and rate of recurrence. In addition, the parameters of the extraction procedure did not differ considerably. CONCLUSION: Despite significant differences in baseline and disease characteristics between primary and recurrent CIED infection, a standardized radical protocol results in an equally high success rate in eradicating infection in both groups. Nevertheless, direct and un-delayed referral of patients with suspected CIED infection to specialized centres is recommended as it saves time for the patient.