INFORMATIONAL HANDOUT: Biological diversity in the microbial world is not the first thought that comes to mind when biodiversity comes up in the general public. The general public tends to think bigger. They think of tropical ecosystems or maybe elephants. Perhaps they would consider an ecosystem in Yellowstone Park focusing on wolves. However, the biological diversity of microbes will shortly be on everyone’s mind. Evolution through natural selection is producing a group of organisms that may not be as charismatic as a tiger, but will surely end up being much more frightening. A diverse and frightening group of organisms resistant to traditional antibiotics are evolving at an alarming rate. Antibiotic resistance is now a worldwide problem. There are a number of reasons for this rapid mutation rate of bacteria into antibiotic strains. Humans consume 235 million doses of antibiotics annually. It is estimated that 20% to 50% of that use is inappropriate. One survey of physicians concluded that more than 80 percent of the responding physicians admitted to having written antibiotic prescriptions against their better judgment. In addition to this problem, people often fail to follow the directions that come with these prescriptions – failing to finish the full course of antibiotic treatment. Improper dosing will encourage the growth of resistant strains. Finally in many third world countries, it is possible to buy antibiotics over-the-counter. This leads to widespread abuse of antibiotics. The same drugs prescribed for human therapy are widely exploited in animal husbandry and agriculture. Large amounts of these drugs are given to animals to promote growth. These amounts are too small to combat infection but perfect for producing more disease resistant bacteria. When humans consume this food, bacterial strains are transmitted to the people who are eating as well as cooking this food is possible. Antibiotics are applied as aerosols to acres of fruit trees to control infections. High concentrations may kill the bacteria on the targeted trees, but the trees at the edge of the target receive low doses which can encourage the growth of disease resistant bacteria. These resistant bacteria can be inhaled by animals--including humans-at the site. They are also being packaged and shipped with the fruit from sprayed fruit trees all over the world. Each country is now producing their own antibiotic resistant bacteria as well as sharing this resistance with countries half a world away. The above misuses of antibiotics are responsible for many different strains of drug resistant bacteria. Following are some examples of these strains of disease resistant bacteria. An often deadly bacterium, Staphylococcus aureus, is responding poorly to a once reliable antidote, the antibiotic vancomycin. It was not long ago when vancomycin was the drug of choice in killing highly resistant bacterial strains. Tuberculosis, once considered to be nearly eradicated in the 1940’s, is now the world’s leading cause of death from a single infectious disease according to the World Health Organization. A particularly dangerous strain of Mycobacterium tuberculosis is spreading rapidly in Russia and other hot spots around the world. Widespread use of antibiotics have promoted the proliferation of the once benign intestinal bacterium Enterococcus faecalis, which is naturally resistant to those drugs. This bacterium can be fatal to persons with compromised immune systems. Ever since antibiotics became widely available in the 1940s, they have been hailed as miracle drugs or the magic bullets able to eliminate bacteria. Yet with each passing decade, bacteria that defy not only single but multiple antibiotics are becoming increasingly common. However, this picture is not totally bleak. Through education, research and some rather simple changes in human behavior, the production of disease resistant can be controlled or at least slowed down. Treating physicians will need to be educated in the proper use of antibiotics. The agriculture world will need to rethink the doses of antibiotic that they are using in their treatment of animals and orchards. Research will need to focus on the development of new alternatives to our current arsenal of antibiotic weapons. This research and education will need to be conducted and applied worldwide. ADAPTED FROM: Hudson, Barbara K. Microbiology in Today’s World Second Edition. Kendall / Hunt Publishing Company, 1998 and Harley, John P. and Lansing M. Prescott. Laboratory Exercises in Microbiology Fourth Edition. WCB McGraw-Hill, 1999. Biology 215, Ruth A. Gyure Western CT State University