The famous final scene in this entire program is to talk about what has been my life's work for the last 10 or 15 years. That is, altering resistance patterns by changing the way that prescribers use antibiotics.

Upper respiratory infections
The first thing prescribers must do differently concerns treatment of upper respiratory infections. In outpatient upper respiratory infections, for instance, 70-90 percent of cases are viral and cannot be treated with antibiotics. A 1997 study published in JAMA, found that among ambulatory care physicians "about one-half of all antibiotics for URIs were totally unnecessary." This was supported by a more recent study, which also appeared in JAMA in 2001. Regarding the treatment of the sore throat by primary care physicians, the study reported that antibiotic agents were prescribed in 73 percent of the cases. Odds are, however, that among adults only 5-17 percent of cases of pharyngitis are related to Group A Strep. In children the rate is only a little bit higher; 15-36 percent of cases are Group A strep and should be treated with antibiotics. Yet here physicians are treating at 73 percent.

Much to my chagrin, there was also an increase in the use of quinolones, and other broad-spectrum agents in this population. One of the things that we need to be aware of as a society is that patients should put less pressure on physicians to prescribe antibiotics when they come in with these upper respiratory infections.

	Thinking Point
	The next time you see your physician for an infection, ask him or her about the prevalence of resistant strains of bacteria among his or her patients.

Urinary tract infections
Prescribers need to do a better job of treating urinary tract infections, especially in their use of cipro and other quinolones in younger, healthier patients who do not have highly resistant organisms. What is the solution?

One solution is to treat for three days with a so-called "empiric antibiotic." Once the physician has the cultures back, he or she should then switch to something that is as narrow spectrum as possible. The patient would receive one empiric regimen for about three days and then one direct regimen for the remainder of the therapy.

You might appreciate the impracticality of having physicians write two prescriptions. This is a practical barrier for outpatient treatment. However, for extended care facilities and in hospitals where the patients are there, there is a good chance to contour the therapy. Some of the nursing homes for which I consult are already engaging in this practice.

Restrict antibiotic use
In the hospital setting, institutions need to restrict intravenous and oral vancomycin use. The CDC provided guidelines on the restriction of these agents because of VRE as early as the early 1990s. There are several other antibiotics that foster the proliferation of VRE, and studies show that restricting just vancomycin and not restricting other antibiotics, usually leads to disappointing results.

Cephalosporin antibiotics have been linked to the proliferation of many resistant organisms, but--during the cost containment years of the 1980s--they were very attractive to hospitals. These should be restricted, as they have been linked to MRSA, enterococcus, C. difficile, and many multiresistant gram-negatives. The preferential use of penicillins over the cephalosporins can help reduce this unfavorable resistance trend.

Antibiotic-associated diarrhea
Another goal for hospitals is to reduce or control antibiotic-associated diarrhea. Each gram of stool contains about 10⁶ to 10¹² organisms. This is a lot of bugs, and anaerobes especially are more prevalent in the colon. The enterococci are the most common gram-positive organism in the bowel, but they make up less than 1 percent of the bowel flora. When hospitals prescribe antibiotics that have a lot of anaerobic activity, these agents knock off much of the competing flora, which leads to the proliferation of resistant organisms, or at least to diarrhea. A fecally incontinent patient increases the risk of spreading these organisms to other patients.

A study published in the New England Journal of Medicine in 2002 stated that diarrhea in an infected liver transplant patient may have resulted in the passage of linezolid and vancomycin-resistant enterococcus in five or six other liver transplant recipients. This is fairly direct scientific evidence that controlling antibiotic-associated diarrhea can help in reducing the proliferation of resistance.

	Knowledge Test
	Now that you have completed this free seminar, see what you have learned by answering answering a few short questions on "Resistant Microbes, Antibiotic Abuse, and the Threat to Public Health."

The pathway of least resistance
The universal rule for hospitals should be to reduce the use and abuse of all antibiotics, for all situations. No matter what antibiotic is being used in whatever situation, the act of exposing an antibiotic to an environment activates the mechanics of Darwinian evolution.

The pathway of least resistance must begin with a change of attitude, a change in action, and hard work. Hospitals should try to strike a balance. Let me put it to you like this. Bacteria have no brains, but they have a generation time of about 20-30 minutes. Human beings supposedly have brains. They have generation times of 20-30 years. In pure Darwinian terms, which species is favored? It could be the organisms with no brains, unless we use ours to our advantage.