While much progress has been made to control preventable infectious diseases, infections remain a major cause of morbidity and mortality.  Many of the traditional treatments for common infections are no longer effective because of the fast-growing problem of antimicrobial resistance, first associated with hospitals, but increasingly widespread in the community.  Antibiotic resistance is now a global problem of major concern.

Over the past century, scientific and social innovations such as vaccination, antibiotics, antisepsis in healthcare facilities and public health measures (clean drinking water, waste disposal, improved personal and environmental hygiene) have combined to greatly reduce morbidity and mortality from infections (1,2).  During the "antibiotic era" of the 1950s there were predictions that infectious diseases would eventually be conquered altogether.  It is clear, however, from the emergence of new infectious agents and reemergence of others as well as the threat of microbial agents used for bioterrorism, that infectious diseases will continue to be an important, and often preventable, problem. 

Healthcare-associated infectious (HAI) occur in about 2 million patients annually, about 90,000 of whom die.  The annual costs of these infections is approximately $4.5 billion and the rate of HAI has increased to 36% over the past 20 years (3,4).  A shift to outpatient care is leaving the most vulnerable, high-risk, patients in hospitals.  The aging of the population and increasingly aggressive interventions such as implanted foreign bodies, organ transplants, invasive medical devices, and long surgical procedures result in a group of highly susceptible patients congregated in acute care settings.

Several studies have calculated that 10-70% of HAI are preventable (5,6).  Unfortunately, with the introduction of antimicrobial agents has come poor compliance with other preventive strategies such as barrier precautions and hand hygiene, which has also contributed to the problem of resistance.  There is a close link between the development of antimicrobial resistance and use of antimicrobial agents in the hospital (7), and strategies to control resistance have until recently been limited primarily to hospitals (8).  About 70% of hospital isolates of Staphylococcus aureus are now resistant to all beta-lactam antibiotics, which had been the first line of treatment (9).  This represents a 29% increase in resistance over 4 years, 1995-99 (10).  By 2001, two-thirds of hospitals reported increasing rates of methicillin-resistant S. aureus (MRSA), and 24% reported MRSA outbreaks within the previous year.  Most hospitals (87%) reported implementing measures to rapidly detect resistance, but only about half reported providing appropriate resources to prevent antimicrobial resistance or having implemented antimicrobial use guidelines.  Current hospital practices to control antimicrobial resistance are inadequate (11).

Antibiotic resistance is no longer limited to hospitals.  Resistance has been increasing over the past decade in community infectious caused by organisms such as Myobacterium tuberculosis, Streptococcus pneumoniae, S. aureus, Shigella, Salmonella, and Neisseria gonorrheae, even among individuals without previously identified risk factors (12-16).  Infections with multiply-resistant organisms have resulted in serious morbidity and death among previously healthy adults and children (12,17-23).  Between 1990 and 1995 there was a 25-fold increase in community-acquired infections of MRSA which appear to be genetically distinct from hospital strains (8,24).  In Australia, half of MRSA seen in hospitals is now community-acquired (25).  MRSA is eminently transmissible and its global spread is extremely rapid and unabated (26), with resistant strains now predominant in some U.S. communities (27).

Infections with antibiotic resistant organisms raise several public health concerns.  First, they cause delays in effective treatment because empiric therapies are ineffective.  This in turn may lead to widespread empiric use/abuse of broad spectrum antibiotics (24).  Second, some antibiotic-resistant bacteria seem to have increased pathogenicity compared to susceptible strains (8,28,29).  Third, colonization with antibiotic resistant organisms can increase the potential for cross-transmission; nosocomial MRSA infection, for example, can spread to household contacts (28,30,31).

As in the hospital, antibiotic use in the community has been directly linked to resistance.  For example, in a survey of urban poor, individuals reporting antibiotic use during the previous 12 months were significantly more likely to be colonized with MRSA (12).  Among college age women attending an emergency clinic, current use of any antibiotic was significantly associated with resistance of urinary tract isolates (32).  High antibiotic use in geographically defined areas of Sweden was significantly correlated with the frequency of penicillin-resistant pneumococci isolated from children living in those areas (33).  An Icelandic study reported that antibiotic consumption by geographic area and individual use of antibiotics were significantly associated with carriage of resistant strains of pneumococcus (34).  Antibiotic resistance is not only prevalent among persons taking antibiotics, but antibiotic use by one person in close living quarters (child care centers, military) leads to the transmission and colonization of resistant organisms to others  (35-38).  Despite some improvement, antibiotic misuse and overuse continue to be problems (39,40).  This is of increasing concern because of the greater proportion of persons with chronic illness, immunosuppression or extremes of age living in the community.  An increase in the carriage of antibiotic resistant bacteria has been described in diabetics and persons with HIV infection (41-44).

View the Background Reference List

Resources

Slide Presentation by Dr. David Smith - "Antibiotic Resistance in Nosocomial Pathogens: The Population Dynamic Perspective"

Slide Presentation by Dr. David Smith - "Antibiotic Resistance in Nosocomial Pathogens: The Hospital as a Structured Population"

Slide Presentation by Dr. Steven Lee - "Antibiotic Resistance Determinants in Oral Bacteria"

Slide Presentation by Dr. Samiya Razvi - "Improving Infection Control for Chronic Diseases"

Slide Presentation by Dr. Patricia Stone - "Nurses' Working Conditions and Healthcare Associated Infections"

Slide Presentation by Dr. Henrich zu Dohna - "Modeling the Spread of Antimicrobial Resistance in Hospitals and Communities: Concepts, Data, and Predictions"

Slide Presentation by Dr. Jane Siegel - "Control of Healthcare Associated Pathogens: Guidelines and Evidence"

Slide Presentation by Dr. Jane Siegel - "Decreasing Antibiotic Resistance: CDC 12-Step Program"

Slide Presentation by Dr. Don Goldman - "Stretch Targets, Small Experiments: Engaging Clinicians in Quality Improvement"

Slide Presentation by Dr. Don Goldman - "Antibiotic Resistance: Effectiveness of Strategies to Prevent Transmission and Control Antibiotic Utilization"

Slide Presentation by Dr. Larson - "The Role of Antimicrobials and Hygiene in Health Care and Home Settings"

Slide Presentation by Dr. Lowy - "Antimicrobial Resistance"

Slide Presentation by Dr. Larson - "Recovery of VRE from Hands and Environmental Surfaces"

Slide Presentation by Drs. Larson, Gomez-Duarte, and Lin - "Community Issues Concerning Antibiotic Practices"

Background References

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