Genetic Identification and Risk Factor Analysis of Asymptomatic Bacterial Colonization on Cardiovascular Implantable Electronic Devices

Abstract

Asymptomatic bacterial colonization of cardiovascular implantable electronic devices (CIEDs) is widespread and increases the risk of clinical CIED infection. The aim of the study was to evaluate the incidence of bacterial colonization of generator pockets in patients without signs of infection and to analyze the relationship with clinical infection and risk factors. From June 2011 to December 2012, 78 patients underwent CIED replacement or upgrade. Exclusion criteria included a clinical diagnosis of CIED infection, bacteremia, or infective endocarditis. All patients were examined for evidence of bacterial 16S rDNA on the device and in the surrounding tissues. Infection cases were recorded during follow-up. The bacterial-positive rate was 38.5% (30 cases); the coagulase-negative Staphylococcus detection rate was the highest (9 cases, 11.5%). Positive bacterial DNA results were obtained from pocket tissue in 23.1% of patients (18 cases), and bacterial DNA was detected on the device in 29.5% of patients (23 cases). During follow-up (median 24.6 months), two patients (6.7%, 2/30) became symptomatic with the same species of microorganism, S. aureus and S. epidermidis. Multivariable logistic regression analysis found that the history of bacterial infection, use of antibiotics, application of antiplatelet drugs, replacement frequency, and renal insufficiency were independent risk factors for asymptomatic bacterial colonization.

Microbial diagnosis of infection and colonization of cardiac implantable electronic devices by use of sonication

“…13,16 Nevertheless, authors using molecular biology methods were more successful in identifying microorganisms colonizing uninfected CIEDs, with rates ranging from 38.5% to 47.2%. 15,22 In the present study, subjects presenting no clinical signs or symptoms of infection had microorganisms cultured in 51.5% of CIEDs submitted to sonication, but no growth was seen on tissue/blood culture. Whether the isolation of microorganisms on cardiac devices submitted to sonication means true colonization or future clinical pocket infection, or even simply contamination of the processes, has been the focus of literature debate.…”

“…Whether the isolation of microorganisms on cardiac devices submitted to sonication means true colonization or future clinical pocket infection, or even simply contamination of the processes, has been the focus of literature debate. 6,13,22,24 Previous studies have demonstrated that compared to conventional tissue culture, sonication of infected implanted devices achieves higher rates of sensitivity, but that specificity may be less accurate due to the nature of biofilm-associated colonization. 19 This is especially true among subjects using antibiotics, which affects bacterial growth on tissues but not within the biofilm.…”

“…Previous authors have obtained similar results, in which ubiquitous Gram-positive organisms of the skin flora predominate over other organisms. 15,22 It is argued that applying sonication routinely for every explanted cardiac device would be costly and that it is therefore unfeasible. Nevertheless, as the clinical signs of biofilm-associated infection may be undetected, sonication of the CIEDs may be useful to increase microbiological diagnosis in the case of a symptomatic or even asymptomatic subject presenting a higher risk of infection (prior CIDAI or a higher number of previous local procedures).…”

Microbiological Characteristics and Clinical Features of Cardiac Implantable Electronic Device Infections at a Tertiary Hospital in China

“…Two studies have recently described the asymptomatic bacterial colonization of CIEDs in China ( Chu et al, 2014 ; Zou et al, 2014 ). However, there are limited data regarding the microbiological characteristics and clinical features of symptomatic CIED infections in China.…”

Incidence and risk factors for cardiac implantable electronic device infection in current clinical settings in a Japanese population: A 20-year single-center observational study

“…Furthermore, our study included patients with CIED infection who had not undergone system removal. However, patients with CIED infection in many of the previous studies were those with a history of a system removal procedure [3,4,7,12,[19][20][21][22][23][24][25][26][27]; therefore, patients who had been treated with conservative therapy may have been excluded from these studies. When comparing the comparable studies that were not limited to patients with system-removal and with a long-term study period, the rates of CIED infection were 5.4% (in 29 years, USA) [5], 2.5% (7 years, Turkey) [19], 2.7% (4 years, Iran) [20], and 2.2% (7 years, Netherlands) [21] were higher than those in our population.…”