Current projects in the laboratory focus on the pathogenesis of S. aureus and S. epidermidis infections and the spread of S. aureus in high-risk community-based populations.
Studies on the transmission of S. aureus among high-risk populations: A household-based study is currently underway to investigate how community-associated methicillin-resistant S. aureus (CA-MRSA) is spread in the predominantly Dominican population that surrounds Columbia University Medical Center. Genetic characterization of these isolates will examine whether adaptive changes facilitate spread. The goal of these studies is to gain a better understanding of the factors, both genetic and epidemiologic, that contribute to the dissemination of S. aureus in the community. A second investigation examines the spread of a unique methicillin-susceptible S. aureus, strain ST398, in Northern Manhattan. Despite its methicillin susceptibility, this strain is responsible for an increasing number of clinical infections in the medical center.
A second transmission study is designed to examine how CA-MRSA are introduced and spread in the NYS prison system. The study, performed at Sing Sing and Bedford Hills maximum-security prisons, examines inmates at entry, during their stay and at release from the two prisons. Molecular epidemiologic techniques are used to characterize the predominant isolates in the two facilities. Additional studies are designed to assess the effect of inter-prison transfer on the spread of MRSA in the New York State prison system.
Studies on the pathogenesis of Staphylococcus aureus and epidermidis infections: Recent studies have investigated the pathogenesis of post-influenza S. aureus pneumonia using a murine model. A series of in vitro and in vivo studies have investigated the pathogenesis of ventricular assist device (VAD) infections caused by S. epidermidis. These studies have examined the role of a surface protein, SdrF, in the initiation of these prosthetic device infections.
Studies on the epidemiology of ventricular assist device infections: A multicenter prospective study examined the risk factors associated with the development of VAD-related infections. Molecular characterization of the isolates associated with these infections is underway. This study also identified clones of S. epidermidis that were found at geographically dispersed medical centers across the United States.