I am Dr. James M. Hughes, Director,National Center for Infectious Diseases, Centers for
Disease Control and Prevention (CDC). I am here to discuss a very important topic:
"Antimicrobial Resistance: Solutions to a Growing Public Health Problem." Thank you, Mr.
Chairman and members of the Subcommittee, for your invitation to testify today on infectious
disease surveillance and the emerging problem of antimicrobial resistance. Infectious diseases
are the leading cause of death worldwide and the third leading cause of death in the United
States. Antimicrobial resistance contributes to the burden of infectious diseases domestically and
globally.
First, I would like to comment on the U.S. General Accounting Office report released today,
EMERGING INFECTIOUS DISEASES: Consensus on Needed Laboratory Capacity Could
Strengthen Surveillance. CDC reviewed the draft report, which highlighted the significant threat
posed to the public's health by emerging infectious diseases, including those caused by
organisms that are resistant to antimicrobial drugs. The report also presented a useful summary
of surveillance activities at CDC. The report indicated that effective surveillance and timely
responses to public health threats require a strong public health infrastructure consisting of
epidemiologic and laboratory capacity, trained professional staff, and modern information
systems. CDC concurred with the overall findings of the draft report, namely that clearer
definition of the necessary core capacities for both epidemiology and laboratories at local, State,
and Federal levels is needed and that an integrated system of infectious disease surveillance is
critical to the success of comprehensive prevention programs. CDC recognizes these issues and
is working with other agencies of the Department of Health and Human Services and other
partners to address these issues.
I will now summarize CDC's efforts to curb the spread of antimicrobial resistance. We are
facing a serious global problem of antimicrobial resistance that affects virtually all of the
pathogens we have previously considered to be readily treatable. As we approach the 21st
century, many important drug options for the treatment of common infections are becoming
increasingly limited and expensive and, in some cases, nonexistent. A 1995 Office of
Technology Assessment report estimated that the emergence of antimicrobial resistance among
six common bacteria in hospitals adds approximately $661 million per year in hospital charges,
and this estimate does not include indirect costs. While today's discussion primarily focuses on
bacteria, drug resistance is also a serious problem in many viral, fungal, and parasitic diseases,
including malaria.
Antimicrobial resistance is a complex and multifaceted public health issue. From a public health
standpoint, the pathogens have been categorized according to where and how they are usually
transmitted, such as drug-resistant infections acquired in the community (e.g., multidrug resistant
pneumococcal infections), in the health care system, through the food supply, or internationally.
CDC is working with partners in each of these settings to improve surveillance and implement
prevention and control measures. While this approach has been useful, distinctions between
these categories are becoming blurred. For example, as an increasing amount of health care is
delivered outside the hospital, pathogens that are normally spread in hospitals may be transmitted
in the community. Also, international travel and trade may result in drug-resistant pathogens that
emerge in distant corners of the world being introduced into the United States
. Therefore, the
issue is becoming even more complicated, highlighting the importance of a coordinated,
overarching multidisciplinary approach that involves physicians, epidemiologists, laboratory and
behavioral scientists, veterinarians, and health educators.
CDC's vision is a world in which antimicrobial resistance is a manageable problem that does not
compromise the availability of safe and effective drugs to control infectious diseases. Drug
resistance is a target area in CDC's recently released plan, Preventing Emerging Infectious
Diseases: A Strategy for the 21st Century. Public health priorities in the plan are organized
under four broad, interdependent goals, each of which can be applied specifically to
antimicrobial resistance: improving surveillance and response capacity, addressing applied
research priorities, repairing the nation's public health infrastructure and training programs, and
strengthening prevention and control programs required to control emerging and reemerging
infectious diseases. Copies of CDC's plan have been provided to the Subcommittee.
Surveillance and Response
Public health surveillance is the ongoing, systematic collection, analysis, interpretation, and
dissemination of health data that results in public health action. These data are used to detect
outbreaks, characterize disease transmission patterns, evaluate prevention and control programs,
and project future health care needs. In the case of drug resistance, surveillance data available in
a timely manner at national, state, and local levels are needed to help clinicians know which
antimicrobials to prescribe, help researchers focus their efforts to develop new drugs and
vaccines, and help public health officials mount campaigns to improve antimicrobial use and
infection control practices.
In the United States
, requirements for reporting diseases and conditions are mandated by
individual state laws, but most states do not require reporting of drug-resistant infections. In
those states where drug-resistant infections are reportable, the completeness of reporting varies.
To obtain more systematic information, CDC, in collaboration with state and local health
departments and other partners, conducts surveillance to monitor resistance for several pathogens
and also collects data on outpatient drug prescribing.
As an example, among other important issues in infectious diseases and public health, resistance
in Streptococcus pneumoniae causing invasive infections is monitored in selected areas through
CDC's Emerging Infections Programs (EIP's). CDC funds EIP cooperative agreements with
eight state and local health departments to conduct population-based surveillance and research
that go beyond the routine functions of health departments.
Other surveillance systems that collect information on antimicrobial resistance include the
National Nosocomial Infections Surveillance System, which is conducted in approximately 280
hospitals in which infection control practitioners conduct active surveillance for hospital-acquired infections. Resistance in foodborne pathogens such as Salmonella and Campylobacter
is monitored in 15 states through the National Antimicrobial Resistance Monitoring System,
focused on enteric bacteria, a collaborative project with the Food and Drug Administration and
the United States
Department of Agriculture that monitors resistance in foodborne pathogens in
both humans and animals. Other projects monitor drug resistance in tuberculosis, gonorrhea,
Helicobacter pylori, HIV, and malaria. Additionally, drug prescribing is monitored through
CDC's National Center for Health Statistics' National Ambulatory Medical Care Survey and
National Hospital Ambulatory Medical Care Survey.
Applied Research
In the area of applied research, priorities include developing new drugs and vaccines as well as
identifying the emerging molecular mechanisms of drug resistance and epidemiologic risk
factors associated with its development and spread; developing new and improved rapid
diagnostic laboratory tests; and, in collaboration with other agencies and private industry,
assessing the role of new vaccines and orphan drugs in preventing and controlling the spread of
resistant infections. It is also a research priority to develop, implement, and evaluate preventive
interventions, including infection control strategies, such as those in hospitals, day care centers,
long-term care and home health care settings; improving drug-prescribing practices of health care
providers; and the use of vaccines to prevent drug-resistant infections. Another priority is also
evaluation research to assess the effectiveness of formulary controls, reimbursement policies, and
regulatory activities in reducing the spread of antimicrobial resistance. Research is also necessary
to evaluate the impact of drug resistance, including clinical outcomes and economic costs of
treating resistant infections.
Infrastructure and Training
The public health infrastructure is the underlying foundation that supports the planning, delivery,
and evaluation of public health activities and practices. CDC's ongoing effort to rebuild the U.S.
public health infrastructure that addresses infectious diseases is critical to improve the capacity
of health departments, health care delivery organizations, and clinical and public health
laboratories to detect and report drug-resistant infections and to implement prevention and
control strategies. Part of this effort includes enhancing capacity to respond to outbreaks and
training public health professionals to be able to respond to emerging threats now and in the
future.
CDC provides support for Epidemiology and Laboratory Capacity agreements (ELC's) to health
departments in 28 states, New York City, and Los Angeles to help provide the technical tools,
training, and financial resources to maintain surveillance for infectious diseases of public health
importance, including those that are developing resistance to antimicrobial drugs. In addition,
the Emerging Infectious Diseases Laboratory Fellowship Program is a partnership between CDC
and the Association of Public Health Laboratories designed to prepare laboratory scientists for
careers in public health. Last year an international component was added to the program.
Working with the CDC Foundation and funded through an educational grant by Eli Lilly and
Company, the goal of the international program is to enhance laboratory practices abroad.
Prevention and Control
Perhaps the most daunting challenge in a coordinated program to prevent the spread of
antimicrobial resistance is translating information gleaned from surveillance and research into
practical public health prevention and control measures, and then disseminating these prevention
messages to clinicians and the public.
A key component of CDC's plan to address antimicrobial resistance is promoting judicious
antimicrobial drug use. CDC has begun a campaign to improve physician prescribing practices
and to educate patients about the proper use of antibiotics. The initial focus of this campaign has
been pediatricians, since children are prescribed antibiotics at a 3-fold higher rate than adults. To
provide guidance to clinicians, CDC and the American Academy of Pediatrics (AAP) co-sponsored the development of Principles of Judicious Use of Antimicrobial Agents for Pediatric
Upper Respiratory Infections, which was published as a supplement to the journal Pediatrics in
January 1998.
In cooperation with professional societies, CDC has developed educational materials for
physicians and parents, including a "prescription pad" for physicians to provide patients written
instructions for treating symptoms of viral illnesses, for which antibiotics would be
inappropriate. In collaboration with AAP and the American Society for Microbiology, CDC has
also developed a brochure for parents, Your Child and Antibiotics, explaining why antibiotics
should not be given for most colds, coughs, sore throats, and runny noses. These materials have
been distributed widely and are available on the CDC website. Interventions using these
materials and behavioral strategies such as physician-peer discussions are now being tested in
several locations, including managed care settings in Boston and Seattle, rural communities in
northern Wisconsin, and on a county-wide basis in Knoxville, Tennessee. Similar materials for
adults are being developed.
CDC has also funded two 5-year prevention demonstration projects that will assess interventions
to improve surveillance and antibiotic prescribing practices on a larger scale. One is a statewide
approach involving community physicians in Wisconsin and the other involves hospitals in the
city of Chicago. In addition, in 1997 and 1998, CDC established Centers of Excellence in
Healthcare Epidemiology at eight academic and health care institutions to conduct research and
demonstration projects that will improve the surveillance, prevention, and control of infections
acquired in hospitals and other health-care settings. A priority of this program is the prevention
and control of infections caused by bacteria and other microorganisms which have become
resistant to antibiotics and other antimicrobial drugs.
Examples of Successes in Preventing Antimicrobial Resistance
Although there has been much discussion of how the problem of antimicrobial resistance is
increasing, it is also important to note some successes that provide models for future programs.
Public health officials in Iowa, in partnership with health departments in Nebraska and South
Dakota, the Indian Health Service, and CDC, recently succeeded in halting an increase in rates of
vancomycin-resistant enterococci (VRE) in hospitals and long-term care facilities in the tri-state
Siouxland region surrounding Sioux City, Iowa.
VRE are transmitted in health-care institutions and are often not treatable with drugs currently
available in the United States
. Some patients carry the organism without experiencing
symptoms, but others develop infections which may be life-threatening. After a rapid increase in
VRE was reported in early 1997, a task force was formed by the Siouxland district health
department, consisting of local physicians, infection control practitioners, and public health
officials.
The VRE task force formulated several interventions, including strict implementation of
infection control policies based on CDC guidelines, education of health care workers, and
prudent use of antibiotics, especially vancomycin. This strategy was effective, and the key to
success was the partnership between public health and clinical medicine so that when
surveillance data indicated an emerging problem, science-based prevention and control measures
could be implemented rapidly to prevent the spread of a serious drug-resistant infection in this
community.
Another organism of particular concern is Staphylococcus aureus, the most common cause of
hospital-acquired infections. Many strains of S. aureus are now resistant to every available
antibiotic except vancomycin. Strains of S. aureus with decreased susceptibility to vancomycin
were identified in Japan in 1996 and subsequently in Michigan, New Jersey, and New York.
Recognition that these patients were infected with drug-resistant organisms led to timely
implementation of infection control measures that were successful in each instance in preventing
transmission of these organisms to other patients and health-care workers. These episodes
highlight the vital importance of rapid laboratory tests to detect resistant organisms, prompt
implementation of effective infection control measures, global cooperation in surveillance, and
new drug development to replace antibiotics that lose their effectiveness.
Another success relies on modern information technology, which can facilitate rapid collection,
analysis, and feedback of information to clinicians. A pioneering program of computer assisted
decision support developed at LDS Hospital in Salt Lake City offers antibiotic recommendations
to clinicians based upon computerized assessment of the patient's medical record and
surveillance data on drug resistance in the health care system. This program was developed with
input from local physicians, who view it as a valuable resource. The program is associated with
decreased inappropriate antibiotic use, reduced frequency of adverse drug reactions, reduced
patient care costs, and a stable rate of drug resistance.
Collaboration to Address Antimicrobial Resistance
Combating antimicrobial resistance will require federal leadership and close collaboration among
public and private sector partners. CDC believes it is essential to work with FDA, NIH, AHCPR
and other government agencies. Federal agencies need to work together with partners in clinical
medicine, laboratory and behavioral science, State and local public health agencies, industry, and
the public. Together, we need to develop public health goals and objectives, along with time
frames for implementation.
Conclusions
In conclusion, recent increases in antimicrobial resistance are cause for serious concern but not
pessimism. The rapid spread of resistance demands an immediate and aggressive response
domestically and globally. By forming effective partnerships involving clinicians, researchers,
public health officials, and patients, we can prolong the effectiveness of currently available
antimicrobial drugs; accelerate the development of needed new tools, including rapid diagnostic
tests, new antimicrobial agents, and new or improved vaccines; and reduce the threat of
antimicrobial resistance for patients today and in future generations.
Thank you very much for your attention. I will be happy to answer any questions you may have.
