Facts about Antibiotic Resistance

Revised:  May 21, 2009
 

• Infections caused by resistant bacteria can strike anyone—the young and the old, the healthy and the chronically ill. Antibiotic resistance also is a serious problem for patients whose immune systems are compromised, such as people with HIV/AIDS and patients in critical care units.

• The Institute of Medicine (IOM) and federal agencies have identified antibiotic resistance and the stagnant antibacterial drug pipeline as increasing threats to public health.

• The total cost of antimicrobial resistance to the U.S. health care system was nearly $5 billion in 1998, according to IOM.  Experts believe the true costs in 2009 numbers may be ten times that amount today.  Treating resistant pathogens often requires more expensive drugs and extended hospital stays.

• In a March/April 2007 report in Public Health Reports, CDC stated that in 2002 in American hospitals alone, healthcare-associated infections (HAIs) accounted for an estimated 1.7 million infections and 99,000 associated deaths each year. Many HAIs are resistant to available antibacterial drugs. 

• Staphylococcus aureus (staph) is a common cause of hospital infections that can spread to the heart, bones, lungs, and bloodstream with fatal results. From 1992 through 2004, more than 50 percent of hospital infections caused by S. aureus in intensive care unit patients and more than 40 percent of hospital infections caused by S. aureus in general ward patients involved a drug-resistant form of staph called methicillin-resistant Staph aureus or MRSA. 

• A CDC-supported study published in the Journal of the American Medical Association (October 17, 2007) estimated that MRSA infects more than 94,000 people and kills nearly 19,000 annually around the country— more deaths than those caused by emphysema, HIV/AIDS, Parkinson’s disease and homicide.

• Staph infections (even those that are not drug-resistant) can be deadly and costly. A 2000-2001 analysis of U.S. hospitalizations found that staph infections caused 12,000 deaths and $9.5 billion in hospital costs each year, according to a study published in the Archives of Internal Medicine (Noskin GA et al).

• Infectious diseases doctors and other physicians also are deeply concerned about other extensively resistant organisms, including Escherichia coli (E. coli), Acinetobacter baumannii (afflicting soldiers returning from Iraq and Afghanistan), resistant Klebsiella species (spreading across the East Coast and into the Midwest), extensively drug-resistant tuberculosis (XDR-TB), Pseudomonas aeruginosa, and Enterococcus faecium.  New national surveillance data (circa 2007) from CDC demonstrate that an incredible 80 percent of E. faecium infections associated with device-related healthcare-associated infections were resistant to vancomycin.

• Vancomycin-resistant enterococci (VRE) can cause wound infections, infections in blood, the urinary tract and heart, and life-threatening infections for hospital patients. In 2004, 31.3 percent (an estimated 26,000 cases) of tested enterococci samples from ICUs were resistant to vancomycin, according to CDC.

• The percentage of Pseudomonas aeruginosa bacteria resistant to either ciprofloxacin or ofloxacin, two common antibiotics of the fluoroquinolone class (the only oral antibiotics available to treat Pseudomonas infections), has increased dramatically. Recent CDC data show that in 2004, over 28 percent of tested samples from ICUs were resistant to fluoroquinolones. P. aeruginosa causes infections of the urinary tract, lungs, and wounds and other infections commonly found in intensive care units.

• Infections with a highly drug-resistant bacterium called Acinetobacter baumannii have been a significant problem in military facilities treating U.S. soldiers injured in Iraq and Afghanistan. To date, more than 100 soldiers have had bloodstream infections with this organism. In some cases, the organisms were resistant to all currently available antibiotics, necessitating the use of an older and more toxic antibiotic called colistin.

• Drug-resistant strains of Streptococcus pneumoniae emerged in the 1990s and are now endemic in most parts of the world.  Pneumococcal strains resistant to fluoroquinolones, macrolides, and beta-lactams have been shown to cause treatment failures with otitis media, pneumonia, and meningitis.  In the United States, introduction of a new vaccine for infants in 2000 is reducing the number of resistant infections, but new evidence indicates that strains not covered by the vaccine, especially serotype 19A pneumococci, are becoming more common and more highly resistant.

• The rate of infections caused by Clostridium difficile (“C. difficile”) in U.S. hospitals doubled between 2000 and 2003. Outbreaks of severe C. difficile disease among hospital patients and clusters of unusually severe C. difficile disease among previously low-risk patients have been reported from multiple states. Many of the changes in the behavior of this infection appear due to the spread of an epidemic strain of C. difficile with increased virulence and increased resistance to commonly used fluoroquinolone antimicrobials. The increasingly widespread use of fluoroquinolones, coupled with this increased resistance, may be promoting the dissemination of this virulent strain across the nation and across the world.

• Antimicrobial resistance to the fluoroquinolones continues to increase for Neisseria gonorrhoeae in the United States.  In 2004 6.8 percent of isolates submitted to the CDC’s Gonococcal Isolate Surveillance Project (GISP) were resistant to ciprofloxacin, up from 2.2 percent in 2002 and 0.4 percent in 2000.  The prevalence of quinolone resistance among men who have sex with men increased from 0.4 percent in 2000 to 24 percent in 2004.  Neisseria gonorrhoeae infects an estimated 700,000 persons each year and women are at increased risk for infertility and pelvic inflammatory disease if the infection is untreated or treated improperly.  Currently the only recommended treatment for persons with quinolone resistant strains of N gonorrhoeae is an injectable third-generation cephalosporin.

• Although MRSA used to be limited primarily to hospital patients, it is becoming increasingly common in the broader community. New research from CDC found that approximately 2 million Americans, or about 1 percent of the population, carry MRSA in their noses, according to a study published in the Journal of Infectious Diseases (JID). In a study reported in the Pediatric Infectious Disease Journal (Creech et al), among children attending health check-ups at two clinics in Tennessee, the proportion that carried MRSA in their noses increased from 0.8 percent in 2001 to 9.2 percent in 2004.

• A study of children with community-acquired staph infections at the University of Texas found nearly 70 percent infected with MRSA. In a 2002 outbreak, 235 MRSA infections were reported among military recruits at a training facility in the southeastern United States.

• In September of 2003, this issue was brought to national attention when MRSA broke out in Florida among the Miami Dolphins, sending two players to the hospital for treatment. Outbreaks of MRSA have been reported among athletes in multiple states, including high school, college, and professional football players, wrestlers, and fencers, military recruits and soldiers, correctional facility inmates, children in daycare, and otherwise healthy full-term babies.

• In a CDC-sponsored study from 2001 and 2002, children less than 2-years-old were at highest risk for a community-associated MRSA infection.

• Data from a CDC-sponsored study indicate that, between 2002 and 2004, there was a two-fold increase in bloodstream and other invasive MRSA infections in Atlanta and a three-fold increase in such infections in Baltimore. The proportion of these infections that were community-associated increased from 13 percent to 17 percent in Atlanta and more than tripled (from 7 percent to 24 percent) in Baltimore. Similar increases have likely occurred in other states as well.

• MRSA may be more likely to cause disease than the drug-susceptible form of staph. In a study reported in Clinical Infectious Diseases (CID) (Ellis et al), soldiers who carried MRSA in their noses on arrival at a training facility were over 10 times more likely to develop a staph infection during the training program than soldiers who carried drug-susceptible staph.

• Recent data from CDC show that MRSA is becoming more prevalent in intensive care units (ICUS). Researchers examined MRSA data from more than 1,200 ICUs from 1992 to 2003. They found that in 1992, 36 percent of S. aureus isolates were drug-resistant; but in 2003, 64 percent of isolates were MRSA, an increase of about 3 percentage points per year. The study was published in the February 1, 2006 CID.