Lead-associated endocarditis: the important role of methicillin-resistant Staphylococcus aureus.

BACKGROUND: Infection is a potentially life-threatening complication of cardiac device implantation. Lead-associated endocarditis (LAE) may be the most serious complication since it is associated with a high mortality. METHODS: The medical records of patients referred to our institution for the treatment of LAE between 1999 and 2007 were reviewed. RESULTS: A total of 51 of 107 patients referred for device-related infections met the criteria for LAE. Of these, 19 occurred within 6 months of their most recent procedure (early), while the remaining 32 occurred more than 6 months later (mean = 31.9 months post procedure). Devices included pacemakers in 33 patients and ICDs in 18 patients. The most common organism responsible for infection was Staphylococcus aureus (S. aureus) followed by coagulase-negative staphylocci (22%) and streptococci (12%). Methicillin-resistant S. aureus (MRSA) accounted for 67% of the S. aureus infections. Coagulase-negative staphylococci were responsible for only 26% of early and 19% of late cases. A distant site of infection was common (26/51 = 51%), particularly in patients with MRSA LAE. The device and leads were removed percutaneously in all patients. Only one patient failed to respond to intravenous antibiotics. CONCLUSIONS: Our data suggest that methicillin-resistant S. aureus is an important pathogen in LAE. Since many infections occur months after the last device procedure, hematogenous spread of organisms from a distant site may be an important contributing factor. These data suggest that strategies to prevent hematogenous infection, particularly with S. aureus, are critical in patients with implantable cardiac devices

Torsade de pointes caused by polypharmacy and substance abuse in a patient with human immunodeficiency virus

Drug-induced QT prolongation is a potentially dangerous adverse effect of some medication combinations. When QT prolongation progresses to torsade de pointes, life-threatening or fatal outcomes may result. A 57-year-old man with a history of human immunodeficiency syndrome on abacavir, nevirapine, tenofovir, voriconazole, and methadone presented to the emergency department with a chief complaint of new-onset seizures. The physical exam was unremarkable. The electrocardiogram demonstrated sinus bradycardia and a prolonged QTc interval of 690 ms. In the emergency department, he had several episodes of torsade de pointes (TdP) and ventricular tachycardia that resolved spontaneously. These episodes were accompanied by an alteration in mentation and generalized twitching. Magnesium and amiodarone were effective in terminating the dysrhythmia. The patient had multiple risk factors for prolonged QT syndrome including human immunodeficiency virus infection, methadone therapy, and polypharmacy leading to potential drug interactions. Physicians must be aware of multidrug interactions potentiating QT prolongation and leading to torsade de pointes

The RASSF1A tumor suppressor gene is inactivated in prostate tumors and suppresses growth of prostate carcinoma cells

We analyzed expression status of the recently identified tumor suppressor gene RASSF1A in primary prostate carcinomas and in prostate cell lines. We found complete methylation of the RASSF1A promoter in 63% of primary microdissected prostate carcinomas (7 of 11 samples). The remaining 4 samples (37%) were partially methylated, possibly because of contamination with normal cells. No promoter methylation was observed in matching normal prostate tissues. High levels of RASSF1A transcript and no methylation of RASSF1A promoter were found in explanted primary normal prostate epithelial and stromal cells. Complete silencing and methylation of RASSF1A promoter was observed in five widely used prostate carcinoma cell lines, which acquired the ability to grow in culture spontaneously, including LNCaP, P\C-3, ND-1, DU-145, 22Rv1, and one primary prostate carcinoma immortalized by overexpression of the human telomerase catalytic subunit (RC-58T/hTERT). However, no silencing of RASSF1A was found in four other prostate carcinoma cell lines, which were adapted for cell culture after transformation with human papillomaviral DNA. Suppression of cell growth in vitro was demonstrated after the reintroduction of RASSF1A-expressing construct into LNCaP prostate carcinoma cells. Our data implicate the RASSF1A gene in human prostate tumorigenesis