The twentieth century has seen many great accomplishments and discoveries in biology. In addition, many new methods and technical developments have greatly advanced the field. What will the twenty-first century bring? While it isn't possible to know what new discoveries will be made, we can predict some topics that will be of interest to microbiologists.

Among the highlights are: the elucidation of the structure of DNA, determination of the basic cellular processes such as DNA replication, RNA transcription, protein translation, determination of the sequence of entire microbial genomes, the universal tree of life, classification of Archaea as the third domain of life, development of a polio vaccine, and eradication of smallpox, to name a few. In addition, many new methods and technical advances have greatly advanced the field. Some of these are: the polymerase chain reaction (PCR), DNA sequencing and its subsequent automation, protein overexpression and purification methods, and X-ray crystallography for protein structural determination.

What will the twenty-first century bring? While it isn't possible to know what new discoveries will be made, predictions can be made about some topics that will be of interest to microbiologists. One area that is currently of great interest and is likely to continue to receive much attention is prokaryotic diversity. Although many bacteria and archaea have been identified, it is clear that a great majority have not yet been isolated. Many new microbes are likely to be found in extreme environments such as hydrothermal vents and arctic environments. These microorganisms may give us further insights into how life first began.

There will be a number of major problems facing us in medical microbiology in the next century. Development of antibiotic resistance in pathogenic bacteria is a problem requiring immediate attention. Vancomycin is the last line of defense in treating staphylococcal and other infections. Some strains of this pathogen have already developed resistance to most of the common antibiotics, and cases of vancomycin-resistant infection have been reported. Efforts are underway to develop new antibiotics effective in treating such cases, but it may be a number of years before the first of these meets FDA approval.

Another problem facing us in the 21st century is emergence of new diseases. These new diseases may spread rapidly and will require development of treatments and vaccines to combat them. We have already witnessed the emergence of AIDS and are likely to encounter new diseases that are equally or even more devastating. An example of a newly emerging disease is Ebola virus. Although this virus is extremely lethal, major epidemics have been avoided because of the extremely short course of this illness. Outbreaks of other unusual diseases are likely to occur as remote habitats such as the rain forest are explored and destroyed and humans are exposed to new microbes and viruses.

Another topic of great interest as we enter the next century is global eradication of diseases. Smallpox was eradicated by 1977, and the world is expected to be declared polio-free by 2005 (see chapter 22). What diseases will be targeted for eradication in the twenty-first century? Other diseases can be targeted as vaccines become available at a cost that makes massive vaccination programs feasible in both developed and underdeveloped countries.

It should be apparent from just these few examples that the twenty-first century will bring many new and interesting problems. These problems will require development of new technologies to combat them. Although the age of new discoveries in biology is certainly not past, the twenty-first century may come to be remembered more as the age of new technology.