The Environment - Drug Resistant Germs

Survival of the Fittest. Charles Darwin's phrase to describe the process of evolution in his book Origin of the Species and an appropriate way to describe the evolution of the various strains of drug-resistant bacteria. When patients become ill from a bacterial infection, antibiotics (when used properly) will kill the organisms and the patient will get better. Occasionally there will be bacteria that aren't killed. These resistant bacteria then replicate and their offspring will also carry resistant genes. If all of the susceptible bacteria weren't killed, resistant bacteria may pass their resistant genes to them through the process of conjugation.¹⁰ The process is accelerated when antibiotics are not used properly or are overused.

Dr. Jeffrey Koplan, director of the Centers for Disease Control (CDC), estimates that 50 million prescriptions a year written for antibiotics are unnecessary. In a 1997 study, 70% of U.S. doctors said that they were pressured into prescribing unnecessary antibiotics. Many patients demand antibiotics when they or their children feel ill, but taking antibiotics for colds or other viral infections does not cure these infections. Taking such drugs, however, does contribute to the development of resistant bacterial strains. A woman from Mississippi testified before a U.S. Senate committee in 2000. Her daughter "was an outgoing 13-month old who had taken antibiotics for recurrent ear infections before catching meningitis the drugs couldn't treat." In 2000, her daughter was 10 years old, in a coma, and kept alive by machines (Neergaard).

When antibiotics are appropriately prescribed, patients who stop taking them when they "feel better" are also contributing to the spread of resistant bacteria. The bacteria that were responding to the antibiotic may not have been completely killed, and resistant bacteria may pass on their resistant genes to the nonresistant bacteria. A recurrence of the illness will need stronger antibiotics to cure the patient. In some cases, incomplete treatment may not be a choice but the result of other circumstances. Poverty in many developing countries forces many to take counterfeit antibiotics (a $21 billion business worldwide).¹¹ As a result, not only are resistant strains increasing, but curable illnesses are going untreated.

Half of the antibiotics produced are used to treat sick animals, as growth promoters in livestock, and to remove harmful organisms in crops. This ongoing low-level dosing with antibiotics increases the possibility of resistant bacteria spreading from livestock and other food sources to humans. VRE can be traced to the use of avoparcin, an animal equivalent of vancomycin. Bacteria that may be harmless to livestock may be harmful (or fatal) to humans. But trying to eliminate it so that it doesn't spread to humans may do more harm. In 2000, in the United States, 5,000 people became ill with multi-drug resistant campylobacteriosis¹² caused by contaminated chicken. The antibiotics that failed to cure the human illness, contracted from the poultry, had been given to the poultry to prevent that illness from being spread to humans.

Is there anything being done to control this problem? In 1999, the Task Force on Antimicrobial Resistance was formed. In 2000, they, in conjunction with the CDC and other government agencies, released the report Public Health Action Plan to Combat Antimicrobial Resistance. Their plan included: (1) national surveillance to track outbreaks, monitor patterns of antibiotic use, and improve monitoring of antibiotic use in agricultural settings; (2) public health campaigns to educate the public and health care professionals in the proper use of antibiotics and to promote vaccinations, hygiene, and safe food handling; (3) research studying the physiology of bacteria and its mutation into drug-resistant strains, and (4) using that information to develop new and improved antibiotics for humans and animals.

Is the plan working? In 2000, the first new antibiotic in over 25 years was approved by the Food and Drug Administration (FDA). Zyvox was approved to treat VRE and methicillin-resistant staph infections along with certain types of pneumonia and skin and bloodstream infections. It's believed that bacteria will be less likely to develop resistance to this drug, a synthetic compound. In 2002, a new childhood vaccine for meningitis dramatically cut the disease prevalence and has lessened the spread of penicillin-resistant strains of other similar infections.

Another improvement: In 2002, a CDC study found that in the 1990s the number of antibiotic prescriptions doctors wrote fell by 24%. But, this was not enough for the CDC. In April 2002, the CDC launched a new campaign entitled "Prevent Antimicrobial Resistance: A Campaign for Clinicians." Julie L. Gerbending, acting deputy director of the National Center for Infectious Diseases, says the problem is not that there aren't guidelines detailing the effective use of antibiotics; it's that physicians rarely read the guidelines. The new campaign will simplify the current guidelines into a 12-step program giving physicians only the information they need to know.

This campaign will also target patients so that they can do their part — a much-needed educational campaign considering that "every medicine cabinet in this country has leftover antibiotics"¹³ (Neergaard). If taken properly, no antibiotics should be leftover. During the U.S. anthrax attacks in 2001, news of the improper use of Cipro was in the headlines. Some people never exposed to anthrax were taking the antibiotic thinking it would provide immunity. Others who were exposed to it stopped taking the medication before they were supposed to.

Starting in 2002, the U.S. government will hold yearly meetings to assess the effectiveness of the campaigns to combat antibiotic resistance. "The success of antibiotics in fighting diseases over the past five decades led to misplaced optimism that the 'war on infections' was nearly won. Unfortunately, …bacteria are cagey, tenacious organisms that swiftly develop resistance to antibiotics and to drug-rich environments" (Phinney).¹⁴

Sources: Office of Technology Assessment. U.S. Congress. Impacts of Antibiotic-Resistant Bacteria, September 1995. Lauran Neergaard. Associated Press. "Antibiotics Losing Their Fight." ABCNews.com, December 14, 2000. David Phinney. "Declaring War on Germs." ABCNews.com, February 25, 1999. Lisa Richwine. Reuters. "Bug Beware." ABCNews.com, April 18, 2000. All ABCNews.com data retrieved July 8-10, 2002 from http://abcnews.go.com. "New CDC campaign targets antibiotic resistance." Infectious Disease News, April 2002. Retrieved July 9, 2002 from http://www.infectiousdiseasenews.com/200204/cdc.asp. Lauran Neergaard. Associated Press. "Antibiotics a treasure government debates how to save." MEDLINEplus, June 10, 2002. Retrieved July 8, 2002 from http://www.nlm.nih.gov/medlineplus/news/fullstory_8001.html. "Infectious Diseases: Enterococcus Species." Retrieved July 9, 2002 from http://www.aventis.com/main/0,1003,EN-XX-7950-23720—FF.html. World Health Organization. Report on Infectious Diseases 2000: Overcoming Antimicrobial Resistance, 2000. Retrieved July 8, 2002 from http://www.who.int. Streptococcus, Staphylococcus and Campylobacteriosis information: Centers for Disease Control data retrieved July 8-10, 2002 from http://www.cdc.gov. Marisa Schulz. "Drug-resistant staph case reported." The Detroit News, July 4, 2002. "Plasmid." On-line Medical Dictionary, October 14, 1997. Retrieved July 10, 2002 from http://cancerweb.ncl.ac.uk.