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.
NDM-1 stands for New Delhi metallo-beta-lactamase, which is an enzyme
produced by certain strains of bacteria that have recently acquired the genetic
ability to make this compound. The enzyme is active against other compounds that
contain a chemical structure known as a beta-lactam ring. Unfortunately, many
antibiotics contain this ring, including the penicillins, cephalosporins, and the
There are many types of beta-lactamases. Most are only active against older
beta-lactam antibiotics but are not active against newer agents like the
carbapenems. However, bacteria that produce NDM-1 are resistant to all commonly
used beta-lactam antibiotics, including carbapenems. Some antibiotics like
aminoglycosides and fluoroquinolones do not contain beta-lactam rings.
Unfortunately, the bacteria that have acquired NDM-1 have also acquired other
resistance factors and most are already resistant to aminoglycosides and
fluoroquinolones. The addition of NDM-1 production has the ability to turn these
bacteria into true superbugs (bacteria resistant to usually two or more
antibiotics) which are resistant to virtually all commonly used antibiotics.
NDM-1 infection was first identified (in 2009) in people who resided in or
traveled to the India and Pakistan. Antibiotic use in India is not as restricted
as it is in the United States and some researchers feel overuse of carbapenems
allowed NDM-1 to develop. Others point to the advent of medical tourism as a
cause of NDM-1 spread among countries. Medical tourism refers to patients who
travel to a country to get medical care that is not available or is more
expensive in their own country. The three first cases of NDM-1 infection in the
United States were identified in June 2010 in Americans who had recently
sought medical care in India. Vacation and business travel have also played a
role in introducing NDM-1 bacteria into countries outside of the Indian
subcontinent. Cases have now been detected in many countries, including Great
Britain, Canada, Sweden, Australia, Japan, and the United States.
NDM-1 is a newly identified problem, only recognized since about December 2009 in the medical literature. To date, there have fewer than 100 cases
identified outside of the Indian subcontinent, so this is not a pandemic like
bird flu or swine flu. However, the number of cases is growing and the concern
is that these highly resistant bacteria could supplant more antibiotic-sensitive
strains. If this happens, the antibiotic arsenal that has been built up over the
last 80 years will be seriously compromised.
Bacteria from the Enterobacteriaceae family are the most common cause of
urinary infections. They can also cause bloodstream infections
(sepsis), pneumonia, or
wound infections. Symptoms and signs reflect the site of the infection. Most
patients will have feverand fatigue. If bacteria enter the bloodstream,
patients may go into . Symptoms do not differ between bacteria that express
NDM-1 and those that do not. However, patients who have bacteria producing NDM-1
will not respond to most conventional antibiotics and are at high risk for