Mary D. Nettleman, MD, MS, MACP is the Chair of the Department of Medicine at Michigan State University. She is a graduate of Vanderbilt Medical School, and completed her residency in Internal Medicine and a fellowship in Infectious Diseases at Indiana University.
Dr. Charles "Pat" Davis, MD, PhD, is a board certified Emergency Medicine doctor who currently practices as a consultant and staff member for hospitals. He has a PhD in Microbiology (UT at Austin), and the MD (Univ. Texas Medical Branch, Galveston). He is a Clinical Professor (retired) in the Division of Emergency Medicine, UT Health Science Center at San Antonio, and has been the Chief of Emergency Medicine at UT Medical Branch and at UTHSCSA with over 250 publications.
Enterococci are a group of
gram-negative, round-shaped bacteria that commonly live in the gut, although they
can cause infection anywhere in the body. They are resistant to several
antibiotics, but in the past, physicians could rely on the drug vancomycin to
effectively treat enterococcal infections. In recent decades, however, some
enterococci have become resistant to vancomycin. The two main species that cause
problems are vancomycin-resistant Enterococcus faecium and vancomycin-resistant
Enterococcus faecalis, with E. faecium being the most common.
Vancomycin resistance is acquired when a sensitive Enterococcus acquires a
special piece of DNA called a plasmid. The new strain is called
vancomycin-resistant enterococci (VRE). One concern is that VRE appears able to
transfer vancomycin resistance to unrelated bacteria such as MRSA
(methicillin-resistant Staphylococcus aureus). In addition, VRE organisms are
usually resistant to more than one antibiotic.
VRE can also be spread from person to person and are an increasing problem in
hospitals and chronic-care facilities. Approximately 30% of all enterococcal
infections are now caused by vancomycin-resistant strains (VRE).
What causes a vancomycin-resistant enterococcal (VRE) infection?
exist in the body without causing infection, in which case a patient is said to
be colonized with VRE. Colonization usually occurs in the bowel. If the number
of VRE bacteria increases, they can invade the bloodstream or spread locally to
cause an abdominal abscess or urinary infection. Once in the bloodstream, VRE
can cause meningitis, pneumonia, or infection of a heart valve (endocarditis).
VRE may also be introduced directly into an open sore or wound, causing a wound
infection. The bacteria produce several substances, including proteases that help
them break down the normal barriers between the gut tissue and the bloodstream.