Microbial spectrum of cardiac implantable electronic device infections - a tertiary cardiac center experience

ABSTRACT

The objective of the study was to determine the microbiological spectrum of cardiac implantable electronic device [CIED] infections. Case series Armed Forces Institute of Cardiology / National Institute of Heart Diseases AFIC/NIHD from January 2011 to Nov 2013. A total of 15 pus samples from patients with possible CIED infection out of 814 patients with implantable CIEDs were processed. Thirteen patients with positive cultures out of fifteen were included in the study. Clinical evidence of CIED infection included signs of inflammation and purulent drainage. A CIED infection was microbiologically confirmed based on culture yield. Blood cultures were carried out in all patients with suspected CIED infection along with trans-oesophageal echocardiography [TOE], wherever clinically indicated to exclude bacteremia and lead endocarditis. Sixty nine percent of patients with culture proven CIED infection were females and 31% were males. The mean age of patients was 61 years [range 53-70 years]. Devices included 11 PPMs, 1 ICD and 1 CRT. The most frequent organisms were gram-positive [77% of isolates]; with Coagulase-negative Staphylococci [CoNS] predominating in particular Methicillin Resistant Staphylococcus epidermidis [MRSE] in 46.4% cases followed by Methicillin Sensitive Staphylococcus epidermidis [MSSE] in 15%. Non tuberculous Mycobacterium fortuitium was isolated from pus in two patients; with PPM and ICD implants respectively. MRSA was isolated in only 01 PPM infection with evidence of lead endocarditis on TOE. Pseudomonas species was isolated from pus in one patient with CRT implant. CIED infections are more often caused by Staphylococci predominantly CoNS, although atypical Mycobacteria can be implicated