Antimicrobial drugs have successfully treated infections in patients for more than 70 years but many organisms have developed a resistance to these drugs, rendering them less effective. This resistance can develop even faster with the overuse or misuse of the medications. Of the 2 million people who become infected with resistant bacteria annually, there are at least 23,000 deaths in the United States. Even more deaths are the result of complications from these infections.
Medical advances such as organ transplants and treatment of chronic diseases depend on antibiotics to be effective in fighting infection. A routine joint replacement can become a life-threatening illness when a resistant bacterium is introduced. Death can result from something as small as a scratch that becomes infected with a resistant bacterium. Risks of these infections cannot be completely avoided and those with chronic illnesses are at greater risk.
How do bacteria become resistant?
Bacteria become resistant to antibiotics for a few different reasons. Spontaneous mutation is in their nature, but certain conditions cause bacteria to mutate more rapidly and in the direction of drug resistance. The two main contributors to the problem are antibiotics that are overused and their inappropriate use. Using antibiotics for viral infections or using an antibiotic that is not effective against a particular bacterium will create an environment for the bacteria to mutate faster and become resistant.
Methicillin-Resistant Staphylococcus aureus (MRSA
Time Is A Factor
The first step in treating patients with infection is to grow a sample in the laboratory of the bacteria infecting the patient. This growth period can take 24 hours to a few days depending on the type of bacteria. After identification of the bacteria, an antibiotic is chosen that is most likely to be effective. The process of choosing the correct antibiotic routinely takes 24 hours or more. In order to ensure the most effective drug is chosen, more time is needed if the bacteria has a history of resistance to antibiotics.
Reducing the amount of time between the first sign of infection and a true diagnosis is of vital importance in gaining control of this growing problem. The longer a patient’s infection is left untreated, the more it will spread into other organs and tissues. Because physicians would rather not wait to begin treatment, most will guess at diagnosis and prescribe a broad-spectrum antibiotic that will work for many different bacteria. In many cases, this protocol saves lives but when the diagnosis is incorrect, the patient does not benefit from the drug and the bacteria are placed in an environment that is more favorable for a resistant mutation.
What research is being done?
Researchers are developing faster procedures for identifying bacteria and choosing effective drug therapies. One study conducted by the University of York has developed a test that allows scientists to view hundreds of single bacteria at the same time and to detect drug reactions in as little as an hour. The examination of bacteria on an individual scale makes it possible to observe properties such as the shapes the organism can take and the ways in which it moves. Prolonged or delayed treatment can result from inaccurate assumptions made when observing bacteria in groups. By isolating individual bacteria multiple characteristics can be tested at once.
Single Bacteria Study
The scientists began by introducing bacteria to a glass slide equipped with fluid-filled channels. The bacteria moved through the channels and were directed to into traps that held the bacteria in place. Drugs were then administered and their effects could be monitored under a microscope. This method has only been used in a research setting under controlled conditions and will need to be tested in a clinical setting with samples from real patients. Implementation of the technique in medical settings could drastically reduce the number of antibiotics prescribed as well as the severity of infections that continue to grow with ineffective drug therapy.
Rapid DNA Sequencing Study
In a study conducted by Johns Hopkins University Medical School has put Rapid DNA sequencing to work. This method can identify bacteria within hours and also accurately detect antibiotic resistance. The DNA sequencer measures an electrical signal when a string of DNA moves through a tiny pore. By monitoring the signal in real-time, sequencing results can be available within minutes.
Researchers used the sequencer to spot antibiotic-resistant genes in Klebsiella pneumonia. Normally found harmlessly in the human intestinal tract, these bacteria may cause serious infections if introduced into the blood, lungs or urinary tract. Commonly prescribed antibiotics can control the typical strains of these bacteria. Strains found to have gained antibiotic-resistant genes can be deadly. Patients who have been previously prescribed antibiotics and those who have been hospitalized are at higher risk. Resistance genes were revealed in 8 hours using the real-time analysis. A more accurate assembly-based experiment was also performed by the team but it took 14 hours to complete.
This was a small scale study and included only one bacterium. More testing and streamlining of the process will be needed before use in a clinical setting is possible.
Finding New Antibiotics
Development of new, stronger antibiotics is a priority that is on the decline. Most of the antibiotics in use today, were discovered in the mid-1980s with few new drugs approved in the decade that followed. Discovery of new drugs that will kill bacteria without causing harm to patients is a difficult task. Through the study of bacterial life cycles, scientists are able to better understand the environment bacteria need for survival and reproduction as well as their anatomy. Some research has suggested that new drugs to boost the effectiveness of current antibiotics could be an alternative to the development of entirely new antibiotics.
What is our future with regard to antibiotic-resistant bacteria?
Reduced use of antibiotics and use of the most effective drug as early in infection as possible are vital for the future. Scientists from different disciplines are collaborating in their efforts more now than ever. Many believe that the sharing of information in scientific communities and getting new therapies into clinical practice are the keys to saving lives.