Wednesday, November 30, 2005
Antibiotics, also known as antimicrobial drugs, are drugs that fight infections caused by bacteria. After their discovery in the 1940's they transformed medical care and dramatically reduced illness and death from infectious diseases. However, over the decades the bacteria that antibiotics control have developed resistance to these drugs. Today, virtually all important bacterial infections in the United States and throughout the world are becoming resistant. For this reason, antibiotic resistance is among CDC's top concerns.
Antibiotic resistance can cause significant danger and suffering for children and adults who have common infections, once easily treatable with antibiotics.
Antibiotic Resistance- what it is and how it happens:Antibiotic use promotes development of antibiotic-resistant bacteria. Antibiotic resistance occurs when bacteria change in some way that reduces or eliminates the effectiveness of drugs, chemicals, or other agents designed to cure or prevent infections. The bacteria survive and continue to multiply causing more harm. Widespread use of antibiotics promotes the spread of antibiotic resistance. While antibiotics should be used to treat bacterial infections, they are not effective against viral infections like the common cold, most sore throats, and the flu.
Smart use of antibiotics is the key to controlling the spread of resistance.
What does CDC recommend?
Only use antibiotics when they are likely to be beneficial.
By visiting this website you are taking the first step to reducing your risk of getting antibiotic-resistant infections. It is important to understand that, although they are very useful drugs, antibiotics designed for bacterial infections are not useful for viral infections such as a cold, cough, or flu.
How can you prevent antibiotic-resistant infections?
Talk with your health care provider about antibiotic resistance.
Ask whether an antibiotic is likely to be beneficial for your illness.
Ask what else you can do to feel better sooner.
Do not take an antibiotic for a viral infection like a cold or the flu.
Do not save some of your antibiotic for the next time you get sick.
Take an antibiotic exactly as the doctor tells you.
Do not take an antibiotic that is prescribed for someone else.
Tackling Antibiotic Resistance:
Overuse of antibiotics is jeopardizing the usefulness of essential drugs. Decreasing inappropriate antibiotic use is the best way to control resistance. In 1995, the Centers for Disease Control and Prevention (CDC) launched a national campaign to reduce antimicrobial resistance through promotion of more appropriate antibiotic use.
CDC's National Campaign:
CDC's National Campaign for Appropriate Antibiotic Use has two OBJECTIVES:
Reduce inappropriate antibiotic use
Reduce the spread of resistance to antibiotics
To accomplish these objectives, the campaign uses the following approaches:
Developing strategies and materials that will lead to changes in antibiotic use.
Serving as a resource to groups undertaking their own campaigns.
Forming partnerships to harness the resources of collaborating organizations.
Assessing impact on antibiotic use, resistance, and patient/physician satisfaction.
Current campaign activities include:
Developing and distributing educational materials promoting appropriate antibiotic use
Funding states to develop, implement and evaluate local campaigns
Evaluating and promoting a medical school curriculum on appropriate use of antibiotics
Continuing to develop and test a Health Plan Employer Data and Information Set (HEDIS) measures for appropriate antibiotic use
Several other programs within the CDC address the growing problem of antimicrobial resistance. You can find information on specific programs at the following websites:
Division of Healthcare Quality Promotion
National Antimicrobial Resistance Monitoring System (NARMS) for Enteric Bacteria
Get Smart: Know When Antibiotics Work on the Farm
Implementing a national advertising campaign promoting the appropriate use of antibiotics
In 1998, a group from CDC, the American Academy of Pediatrics (AAP), and the American Academy of Family Physicians (AAFP) drafted principles of judicious antimicrobial use for pediatric upper respiratory infections (Pediatrics 1998; 101:161-184).
This year, CDC collaborated with members of American College of Physicians-American Society of Internal Medicine, AAFP, and the Infectious Diseases Society of America to develop principles for appropriate antimicrobial use for adult upper respiratory tract infections. These were published in the March 23, 2001 edition of The Annals of Internal Medicine and in the June 2001 edition of The Annals of Emergency Medicine.
The triumph of antibiotics over disease-causing bacteria is one of modern medicine's greatest success stories. Since these drugs first became widely used in the World War II era, they have saved countless lives and blunted serious complications of many feared diseases and infections.
After more than 50 years of widespread use, however, many antibiotics don't pack the same punch they once did.
Over time, some bacteria have developed ways to outwit the effects of antibiotics. Widespread use of antibiotics is thought to have spurred evolutionary changes in bacteria that allow them to survive these powerful drugs. While antibiotic resistance benefits the microbes, it presents humans with two big problems: it makes it more difficult to purge infections from the body; and it heightens the risk of acquiring infections in a hospital.
Diseases such as tuberculosis, gonorrhea, malaria, and childhood ear infections are now more difficult to treat than they were decades ago. Drug resistance is an especially difficult problem for hospitals because they harbor critically ill patients who are more vulnerable to infections than the general population and therefore require more antibiotics. Heavy use of antibiotics in these patients hastens the mutations in bacteria that bring about drug resistance.
Unfortunately, this worsens the problem by producing bacteria with greater ability to survive even our strongest antibiotics. These even stronger drug-resistant bacteria continue to prey on vulnerable hospital patients.
To help curb this problem, the Centers for Disease Control and Prevention (CDC) provides hospitals with prevention strategies and educational materials to reduce antimicrobial resistance in health care settings. According to CDC statistics
Nearly two million patients in the United States get an infection in the hospital each year
Of those patients, about 90,000 die each year as a result of their infection-up from 13,300 patient deaths in 1992
More than 70 percent of the bacteria that cause hospital-acquired infections are resistant to at least one of the drugs most commonly used to treat them
Persons infected with drug-resistant organisms are more likely to have longer hospital stays and require treatment with second or third choice drugs that may be less effective, more toxic, and more expensive
In short, antimicrobial resistance is driving up health care costs, increasing the severity of disease, and increasing the death rates from certain infections.
Environment Forces Evolutionary Change
A key factor in the development of antibiotic resistance is the ability of infectious organisms to adapt quickly to new environmental conditions. Bacteria are single-celled creatures that, compared with higher life forms, have small numbers of genes. Therefore, even a single random gene mutation can greatly affect their ability to cause disease. And because most microbes reproduce by dividing every few hours, bacteria can evolve rapidly. A mutation that helps a microbe survive exposure to an antibiotic drug will quickly become dominant throughout the microbial population. Microbes also often acquire genes, including those that code for resistance, from each other.
The advantage microbes gain from their innate adaptability is augmented by the widespread and sometimes inappropriate use of antibiotics. A physician, wishing to placate an insistent patient ill with a cold or other viral condition, sometimes inappropriately prescribes antibiotics. Also when a patient does not finish taking a prescription for antibiotics, drug-resistant microbes not killed in the first days of treatment can proliferate. Hospitals also provide a fertile environment for drug-resistant germs as close contact among sick patients and extensive use of antibiotics force bacteria to develop resistance. Another controversial practice that some believe promotes drug resistance is adding antibiotics to agricultural feed.
A Growing Problem
For all these reasons, antibiotic resistance has been a problem for nearly as long as we've been using antibiotics. Not long after the introduction of penicillin, a bacterium known as Staphylococcus aureus began developing penicillin-resistant strains. Today, antibiotic-resistant strains of S. aureus bacteria as well as various enterococci-bacteria that colonize the intestines-are common and pose a global health problem in hospitals. More and more hospital-acquired infections are resistant to the most powerful antibiotics available, methicillin and vancomycin. These drugs are reserved to treat only the most intractable infections in order to slow development of resistance to them.
There are several signs that the problem is increasing:
In 2003, epidemiologists reported in The New England Journal of Medicine that 5 to 10 percent of patients admitted to hospitals acquire an infection during their stay, and that the risk for a hospital-acquired infection has risen steadily in recent decades.
Strains of S. aureus resistant to methicillin are endemic in hospitals and are increasing in non-hospital settings such as locker rooms. Since September 2000, outbreaks of methicillin-resistant S. aureus infections have been reported among high school football players and wrestlers in California, Indiana, and Pennsylvania, according to the CDC.
The first S. aureus infections resistant to vancomycin emerged in the United States in 2002, presenting physicians and patients with a serious problem. In July 2002, the CDC reported that a Michigan patient with diabetes, vascular disease, and chronic kidney failure had developed the first S. aureus infection completely resistant to vancomycin. A similar case was reported in Pennsylvania in September 2002.
Increasing reliance on vancomycin has led to the emergence of vancomycin-resistant enterococci infections. Prior to 1989, no U.S. hospital had reported any vancomycin resistant enterococci, but over the next decade, such microbes have become common in U.S. hospitals, according to CDC.
A 2003 study in The New England Journal of Medicine found that the incidence of blood and tissue infections known as sepsis almost tripled from 1979 to 2000.
The National Institute of Allergy and Infectious Diseases (NIAID), part of the Department of Health and Human Services' National Institutes of Health (NIH), funds research, drug screening, and clinical trials to combat the problem of antimicrobial resistance. It manages a research portfolio of grants specifically aimed at the problem of antibiotic resistance among common bacteria responsible for hospital-acquired infections. These grants fund studies on the basic biology of resistant organisms; applied research on new diagnostic techniques, therapies, and preventive measures; as well as studies of how bacteria develop and share resistance genes. Other NIAID-funded research projects seek to identify natural antimicrobial peptides (small pieces of protein molecules) that could help stave off drug-resistant infections.
NIAID also funds the Network on Antimicrobial Resistance in Staphylococcus aureus (NARSA), a multidisciplinary international cadre of basic scientists, clinical microbiologists, and clinical investigators focused on combating drug-resistant S. aureus and related staphylococcal bacterial infections. The network maintains a repository of drug-resistant staph strains that scientists can request for use in their research. It also provides an Internet site with scientific presentations and a discussion forum to promote communication between researchers.
NIAID also supports a number of networks for clinical trials with the capacity to assess new antimicrobial drugs and vaccines against other drug-resistant infections. The AIDS Clinical Trials groups can evaluate drugs that combat the problem of the HIV virus developing resistance to standard antiretroviral treatments. The Bacteriology and Mycology Study Group, a network of academic and private research institutes, conducts clinical trials for improved treatments for fungal infections, particularly in people with weakened immune systems. In a similar fashion, the Collaborative Antiviral Study Group, made up of researchers at approximately 50 institutions, evaluates experimental therapies for viral infections. The Vaccine and Treatment Evaluation Units are a network of seven U.S. institutions that conduct clinical research on vaccines and therapeutics to speed development of new vaccines and therapies.
More details on these and other related projects can be found on the NIAID Web site.
Other research projects-at NIH or funded by other components of NIH-are seeking new, molecular-level knowledge on the interactions of microbes and human cells as well as the tricks microbes use to outwit antibiotics. Another avenue of research is sleuthing the genomes of drug-resistant bacteria for vulnerabilities that could be attacked with new or existing drugs.
Antimicrobial Advances and Activities
NIAID-funded research grants and activities are yielding results that will help public health officials hold the line in our fight against drug-resistant microbes. For example
NIAID-funded researchers at the University of California Berkeley have documented the mechanics of how E. coli bacteria use pumps in the thin space between their membranes to expel antibiotic drugs. Their results, reported in the Journal of Bacteriology, serve as a model for how these molecular pumps work in bacteria responsible for hospital-acquired infections.
NIAID grantees at the Washington University School of Medicine in St. Louis have uncovered new information about how bacteria that cause urinary tract infections manufacture hair-like fibers to cling to the lining of the bladder. Their findings could lead to new drugs that would treat urinary tract infections by blocking formation of these protein fibers. Approximately half of all women experience urinary tract infections, and 20 to 40 percent of those will develop recurrent infections. The results were reported in the journal Cell.
An NIAID-funded project at The Institute for Genomic Research recently discovered that small pieces of DNA that can jump between chromosomes or organisms helped a strain of E. faecalis bacteria develop resistance to vancomycin. The researchers found that these "mobile elements" of DNA appear to contain a newly identified vancomycin resistance segment carrying vancomycin resistance genes. These results were published in the journal Science.
Partnerships and Interagency Collaborations
In addition to sponsoring research, NIAID co-chairs the Federal government's Interagency Task Force on Antimicrobial Resistance. This task force is made up of representatives from NIAID, CDC, the Food and Drug Administration, the Agency for Healthcare Research and Quality, the Department of Agriculture, the Department of Defense, the Department of Veterans Affairs, the Environmental Protection Agency, the Center for Medicaid and Medicare Services, and the Health Resources and Services Administration. The Task Force is working on implementing an antimicrobial resistance action plan that reflects a broad consensus of theses agencies with input from a variety of constituents and collaborators. The plan is available online
NIAID also co-sponsors the Annual Conference on Antimicrobial Resistance with the Infectious Disease Society of America and other government and not-for-profit agencies. The conference updates attendees on the science, prevention, and control of antimicrobial resistance and provides a forum for discussion of new methods of treatment and control.
Other federal agencies are involved in combating the problem of drug-resistant microbes. See the links below for more information.
Prepared by:Office of Communications and Public Liaison
National Institutes of HealthBethesda, MD 20892
U.S. Department of Health and Human Services
Monday, November 28, 2005
What are antibiotics?
Antibiotics are strong medicines that can stop some infections and save lives. But antibiotics can cause more harm than good if they are not used the right way. You can protect yourself and your family by knowing when you should use antibiotics and when you shouldn't.
Do antibiotics work against all infections?
No. Antibiotics only work against infections caused by bacteria. They don't work against any infections caused by viruses. Viruses cause colds, the flu, and most coughs and sore throats.
What is "antibiotic resistance"?
When bacteria are repeatedly exposed to the same antibiotics, the antibiotic can't fight the germs anymore. Being exposed to the same antibiotic for a long time can make some germs change. And sometimes germs just change by themselves. Some of the changes make the germs so strong they can fight back against antibiotics and win the fight. Then these germs are said to be "resistant" to this antibiotic.
Antibiotic resistance is becoming a common problem in many parts of the United States. Resistant bacteria develop faster when antibiotics are used too often or are not used correctly.
Resistant bacteria sometimes can be treated with antibiotics to which the bacteria have not yet become resistant. These medicines may have to be given intravenously (through a vein) in a hospital. A few kinds of resistant bacteria are untreatable.
Why should I worry about antibiotic resistance?
If you take antibiotics that can't fight the germs they are supposed to kill, your infection can last longer. Instead of getting better, your infection might get worse. You might have to make several visits to your doctor's office. You might have to take different medicines or go to a hospital for antibiotics given in your veins.
At the same time, your family members or other people you come in contact with may catch the resistant germs that you have. Then they might also get infections that are hard to cure.
Every time you take antibiotics when you don't really need them, you increase the chance that you will get an illness someday that is caused by germs that are resistant to antibiotics.
How do I know when I need antibiotics?
The answer depends on what is causing your infection.
The following are some basic guidelines:
Colds and flu. Viruses cause these illnesses. They can't be cured with antibiotics.
Cough or bronchitis. Viruses almost always cause these. However, if you havea problem with your lungs or an illness that lasts a long time, bacteria may be the cause. Your doctor may decide to try using an antibiotic.
Sore throat. Most sore throats are caused by viruses and don't need antibiotics. However, strep throat is caused by bacteria. A throat swab and a lab test are usually needed before your doctor will prescribe an antibiotic for strep throat.
Ear infections. There are several types of ear infections. Antibiotics are used for some, but not all of them.
Sinus infections. Antibiotics are often used to treat sinus infections. A runny nose and yellow or green mucus do not necessarily mean you need an antibiotic.
How should I take the antibiotics that my doctor prescribes?
Follow your doctor's directions carefully. Your doctor will tell you to take all of the antibiotic. Don't save some of the medicine for the next time you are sick.
What else can I do to reduce the risk of antibiotic resistance?
Wash your hands with soap and water before you eat and after you use the bathroom. Regular handwashing during the daytime will help keep you healthy and prevent the spread of germs.
Ask your doctor if you have all the vaccinations (shots) you need to protect yourself from illness.
Where can I get more information about antibiotic resistance?
Using antibiotics sensibly
Antibiotics are often seen as the first line of defense against many infections. But the overuse and misuse of antibiotics can cause more harm than good. Learn more about how to use antibiotics correctly.
You know the feeling — your head throbs, your nose is stuffy and you're too tired to do anything except flop into bed at the end of the day. You're coming down with a bug — maybe a cold or the flu. A visit to your doctor for some antibiotics should help cure your illness, you think.
But think again. If your illness results from a virus — as a cold, the flu and most sore throats do — antibiotics won't do any good. In fact, taking antibiotics when you don't need them can be harmful.
Frequent and inappropriate antibiotic use leads to the development of antibiotic-resistant bacteria. When bacteria outsmart standard antibiotics, you need stronger and more costly medications to treat infections. Because bacteria mutate much more quickly than researchers can develop new antibiotics, the possibility exists that one day soon highly lethal strains of resistant bacteria will evolve — and there won't be effective drugs to kill them.
Improper antibiotic use isn't just a doctor's fault — you share responsibility with your doctor in using antibiotics carefully and correctly. Start by understanding what antibiotics are, when they should and shouldn't be used, and what you can do to combat antibiotic resistance.
What are antibiotics?
Antibiotics are powerful drugs used for treating many serious and life-threatening infectious diseases. Most infections result from either bacteria or viruses.
Bacteria are responsible for:
Most ear infections
Some sinus infections
Urinary tract infections
Viruses are responsible for:
Most sore throats
Antibiotics can help you get better if a bacterial infection causes your illness, but they'll have no effect at all if you have a virus. What's more, taking antibiotics when you don't need them can lead to germs that are antibiotic-resistant.
Superbugs: How antibiotic resistance develops
After the introduction of the first antibiotic (penicillan) in the 1940's, scientists created hundreds of other antibiotics to combat bacterial infections. It took only a few years of using antibiotics before a troubling pattern emerged. Bacteria frequently treated with the same antibiotic would eventually develop resistance to the drug, and a stronger medication would have to be used. The bugs soon learned to resist the stronger drug too. Thus began a cycle of needing increasingly powerful drugs to treat infections.
When you take penicillin or another antibiotic for an infection, the drug usually kills most of the bacteria. But, sometimes a few persistant germs survive. These surviving bacteria can multiply quickly and thrive despite the presence of an antibiotic.
Since bacteria can adapt their cellular structure, they become resistant to future treatment by the same drug. As a result, the antibiotic-resistance bacteria - also known as superbugs - no longer respond to first or even second choice antibiotic therapy. This leaves fewer effective drugs available to treat common but potentially life-threatening illnesses. Unfortunately, superbugs can also exchange survival secrets with other bacteria, even differet species, allowing additional resistance organisms to grow.
For years, the potent intravenous antibiotic vancomycin (Vancocin) provided a reliable last defense against some infections, notably those caused by staphlococcus and enterococcus bacteria. But in recent years, some superbugs have even figured out how to resist vancomycin. A strain of cancomycin-resistant enterococci (VRE) first appeared in the late 1980's and has thrived eve since. Scientists worry that VRE not only will continue to multiply but will share its genetic secrets for survival with other bacteria.
Consequences of antibiotic resistance
As antibiotics continue to be overused and misused, more and more resistant strains develop. As a result, most infections caused by these bacteria don’t respond to typical treatments. Illnesses can last longer, and the risk of complications and even death can go up. Also, failure to treat a particular infection leads to longer periods in which a person is contagious and able to spread the resistant strains to others.
Another consequence is the increased costs associated with prolonged illnesses. According to the World Health Organization, these include the direct costs for additional laboratory tests, treatments and hospitalization along with the indirect costs from loss of income or time away from family. When infections become resistant to typical treatments, unconventional agents come into play. These are usually more costly, and they may have to be given by injection rather than by mouth.
Safeguard effective antibiotics: What you can do
Repeated use and improper use of antibiotics are two of the main causes of the increase in resistant bacteria. Here are some things you can do to promote proper use of antibiotics, which in turn ensures that the drugs will be effective when you need them.
Understand when antibiotics will work and when they won't work to treat an illness. Don't expect to take antibiotics every time you're sick. Antibiotics are effective in treating most bacterial infections, but they're not useful in the fight against viral infections, such as colds or the flu. Each year in the United States, doctors write an estimated 50 million antibiotic prescriptions for viral illnesses — for which antibiotics offer no benefit. Sometimes it's hard to tell whether illnesses result from bacteria or viruses — talk with your doctor if you aren't sure.
Take antibiotics exactly as prescribed. Follow your doctor's instructions in taking prescribed medication, including how many times a day and for how long. Don't stop taking the pills a few days early if you start feeling better. Not completing your full course of antibiotics adds to the antibiotic-resistance problem. A complete course of antibiotics is needed to kill all of the harmful bacteria. A shortened course of antibiotics often wipes out only the most vulnerable bacteria, which allows relatively resistant bacteria to survive and thrive.
Never take antibiotics without a prescription. Antibiotics are drugs only available through prescription. However, if you didn't take the full course of antibiotics that were previously prescribed, you might be tempted to take some of that medication the next time you get sick. Or you might give them to a friend or family member who isn't feeling well. The problem with this practice is that the antibiotic might not be necessary in treating the illness, it might not be the right dose or it might not contain the proper active ingredient to fight the bacteria in your system. All of these can contribute to stronger strains of resistant germs.
Don't pressure your doctor for antibiotics if you have a virus. A prescription for antibiotics won't do you any good if you have a cold or the flu. Instead, talk with your doctor about ways to ease the symptoms of your viral illness. For example, taking a decongestant can help clear a stuffy nose. Or taking medicine such as acetaminophen (Tylenol, others) may reduce fever or muscle aches often associated with influenza.
Protect yourself from infection in the first place. You can keep many germs at bay — and avoid infection — by adopting preventive habits, such as cleaning your hands often, handling and preparing food in a safe manner, and keeping up-to-date on immunizations.
These rules apply to everyone in your family, from your children to an aging parent.
The scope of your responsibility
If you take antibiotics inappropriately, the resistant microorganisms that you create are a threat not only to you, but also to your family and community. With frequent antibiotic use, resistant organisms persist and become widely established over time. These resistant organisms can cause new and hard-to-treat infections — even in people who haven't abused antibiotics.
Your responsibility in using antibiotics — unlike almost any other medicine you might take — extends far beyond your reach. Responsible antibiotic use protects the health of your family, neighbors and community — and ultimately the global community, too.
'Mayo Clinic on Digestive Health' (Softcover)
Sunday, November 27, 2005
Although for centuries preparations derived from living matter were applied to wounds to destroy infection, the fact that a microorganism is capable of destroying one of another species was not established until the latter half of the 19th cent. when Pasteur noted the antagonistic effect of other bacteria on the anthrax organism and pointed out that this action might be put to therapeutic use. Meanwhile the German chemist Paul Ehrlich developed the idea of selective toxicity: that certain chemicals that would be toxic to some organisms, e.g., infectious bacteria, would be harmless to other organisms, e.g., humans. In 1928, Sir Alexander Fleming, a Scottish biologist, observed that Penicillium notatum, a common mold, had destroyed staphylococcus bacteria in culture, and in 1939 the American microbiologist René Dubos demonstrated that a soil bacterium was capable of decomposing the starchlike capsule of the pneumococcus bacterium, without which the pneumococcus is harmless and does not cause pneumonia. Dubos then found in the soil a microbe, Bacillus brevis, from which he obtained a product, tyrothricin, that was highly toxic to a wide range of bacteria. Tyrothricin, a mixture of the two peptides gramicidin and tyrocidine, was also found to be toxic to red blood and reproductive cells in humans but could be used to good effect when applied as an ointment on body surfaces. Penicillin was finally isolated in 1939, and in 1944 Selman Waksman and Albert Schatz, American microbiologists, isolated streptomycin and a number of other antibiotics from Streptomyces griseus.
A Brief History of Antibiotics
The search for antibiotics began in the late 1800s, with the growing acceptance of the germ theory of disease, a theory which linked bacteria and other microbes to the causation of a variety of ailments. As a result, scientists began to devote time to searching for drugs that would kill these disease-causing bacteria. The goal of such research was to find so-called “magic bullets” that would destroy microbes without toxicity to the person taking the drug.
One of the earliest areas of scientific exploration in this field was whether harmless bacteria could treat diseases caused by pathogenic strains of bacteria. By the late 19th century there were a few notable breakthroughs. In 1877, Louis Pasteur showed that the bacterial disease anthrax, which can cause respiratory failure, could be rendered harmless in animals with the injection of soil bacteria. In 1887, Rudolf Emmerich showed that the intestinal infection cholera was prevented in animals that had been previously infected with the streptococcus bacterium and then injected with the cholera bacillus.
While these scientists showed that bacteria could treat disease, it was not until a year later, in 1888, that the German scientist E. de Freudenreich isolated an actual product from a bacterium that had antibacterial properties. Freudenreich found that the blue pigment released in culture by the bacterium Bacillus pyocyaneus arrested the growth of other bacteria in the cell culture. Experimental results showed that pyocyanase, the product isolated from B. pyocyaneus, could kill a multitude of disease-causing bacteria. Clinically, though, pyocyanase proved toxic and unstable, and the first natural antibiotic discovered could not be developed into an effective drug.
In the early 1920s, the British scientist Alexander Fleming reported that a product in human tears could lyse bacterial cells. Fleming’s finding, which he called lysozyme, was the first example of an antibacterial agent found in humans. Like pyocyanase, lysozyme would also prove to be a dead end in the search for an efficacious antibiotic, since it typically destroyed nonpathogenic bacterial cells.
Fleming’s second discovery, though, would change the course of medicine. In 1928, Fleming serendipitously discovered another antibacterial agent. Returning from a weekend vacation, Fleming looked through a set of old plates that he had left out. On one such plate, he found that colonies of Staphylococcus, which he had streaked out, had lysed. Fleming observed that bacterial cell lysis occurred in an area adjacent to a contaminant mold growing on the plate and hypothesized that a product of the mold had caused the cell lysis.
While Fleming generally receives credit for discovering penicillin, in fact technically Fleming rediscovered the substance. In 1896, the French medical student Ernest Duchesne originally discovered the antibiotic properties of Penicillium, but failed to report a connection between the fungus and a substance that had antibacterial properties, and Penicillium was forgotten in the scientific community until Fleming’s rediscovery.
Through follow-up work, Fleming showed experimentally that the mold produced a small substance that diffused through the agar of the plate to lyse the bacteria. He named this substance penicillin after the Penicillium mold that had produced it. By extracting the substance from plates, Fleming was then able to directly show its effects. Important to its discovery was the penicillin had destroyed a common bacterium, Staphylococcus aureus, associated with sometimes deadly skin infections.
While Fleming had made the initial discovery, he was unable to carry his research significantly further. Because he was unable to purify significant quantities of penicillin, Fleming was not able to conduct clinical trials on animals and humans to test the agent’s efficacy, and last published any work on penicillin around 1931.
It was not until about ten years after penicillin’s rediscovery, in 1939, that Howard Florey, Ernst Chain, and Norman Heatley picked up the project. The trio obtained the Penicillium fungus from Fleming and were able to overcome the technical difficulties that had plagued him, in the process spectacularly showing penicillin’s efficacy in the clinical setting. Animals and humans that were near-death with bacterial infections were miraculously cured with even small amounts of the drug in its crude form.
Cross-continent cooperation in the early 1940s resulted in the increased scale of penicillin production. Because England lacked the capabilities to mass produce the drug, since the country had devoted almost all of its industrial capacity to the war effort, the British worked together with the United States to make penicillin a reality. The project has been called one of the great ventures of group research and collaboration.
Given the political climate under which it was rediscovered and produced, it is not surprising that initially penicillin was used almost exclusively to treat soldiers injured during the war. That would change, though, with one fateful disaster.
Perhaps penicillin’s most important clinical trial occurred after a fire at a Boston club, which resulted in numerous burn victims being sent to Boston-area hospitals. At that time, it was common for severe burn victims to die of bacterial infections, such as those from Staphylococcus. In response to this crisis, Merck rushed a large supply of a “priceless” drug (penicillin) to the Massachusetts General Hospital. The success that physicians had in treating severely burned victims that night was largely attributed to the effects of penicillin. The fire—and the success of penicillin—made national headlines, vaulting the drug into the public spotlight.
By 1946, the drug had become widespread for clinical use.
As early as 1945, in an interview with The New York Times, Fleming warned that the misuse of penicillin could lead to selection of resistant forms of bacteria. In fact, Fleming had already experimentally derived such strains by varying the dosage and conditions upon which he added the antibiotic to bacterial cultures. As a result, Fleming warned that the drug carried a large potential for misuse, especially with patients taking it orally at home, and that inadequate treatments would likely lead to mutant forms. Fleming posited that resistance to penicillin could be conferred in two ways – either through the strengthening of the bacterial cell wall which the drug destroyed, or through the selection of bacteria expressing mutant proteins capable of degrading penicillin.
Penicillin was available orally to the public without prescription until the mid 1950s. During this period, the drug was indeed sometimes used inappropriately. There are several accounts of patients, believing that penicillin was a miracle cure-all, using the drug for non-bacterial diseases, and also taking less than the optimal dose.
By 1946, one hospital reported that 14% of the strains of staph isolated from sick patients were penicillin resistant. By the end of the decade, the same hospital reported that resistance had been conferred to 59% of the strains of staph studied.
The success of penicillin led scientists to intensify searches for new antibiotics that could treat other bacterial diseases, including those caused by now penicillin resistant strains. One way that scientists combated resistance was to chemically modify penicillin, creating derivatives of the chemical—such as ampicillin—that avoided enzymatic degradation. Today, numerous penicillin derivatives exist.
It was not until the 1970s that antibiotic resistance was considered to be a real threat. During the decade, there were two notable cases of resistant bacterial strains lethally infecting patients, in which a strain of bacteria that causes meningitis and ear infections in children and a strain that causes gonorrhea proved fatal. Both strains had previously been able to be treated with penicillin or penicillin derivatives, and events like these marked the end of 30 years of successful treatment for these infections.
During the period between Fleming’s rediscovery and Florey and coworkers’ advancement of penicillin, a few other notable findings in the search for antibiotics were made. In 1932, the German Gerhard Domagk turned his attention away from natural antibiotics and towards synthetic ones. Domagk, who investigated the effects of different chemical dyes for their effects on bacterial infections, found that the dye Prontosil cured diseases caused by the streptococcus bacteria when injected into infected animals. Later work showed that the active group of Prontosil was not the dye part of the molecule, but the sulfonamide group attached to it. Both Prontosil and other sulfonamide derivatives proved highly successful, both in efficacy and lack of toxicity. For this reason, this discovery has been credited for creating an atmosphere conducive to the development and production of penicillin.
Around the time that Florey and coworkers picked up the work on penicillin, the antibiotic gramicidin was isolated from a soil-inhabiting microbe. Gramicidin, the first natural antibiotic extracted from soil bacteria, was able to arrest the growth of staphylococcus, but proved highly toxic.
In 1943, Selman Waksman and his group isolated another antibacterial agent from a soil bacterium, Streptomyces griseus. Waksman’s antibiotic, streptomycin, proved effective against several common infections. Most noteworthy was its ability to kill the bacterium Mycobacterium tuberculosis, the microbe causing tuberculosis, which had to that point resisted numerous methods of treatment. Streptomycin, though, carried with it highly toxic side effects and a fast rate of mutation, making it not a viable clinical option.
Because of our constant battles with infections, I thought it might be interesting to know more about antibiotics. What they are, how they work, what they do and why we should be careful in taking them so as to not build up an immunity to them
In common usage, an antibiotic is a drug that kills certain kinds of bacteria, but which is generally harmless to the host and is used to treat infection. The term was originally used to describe only antibacterial formulations derived from living organisms but is now used in reference to synthetic antimicrobials such as the Sulfonamides.In general, the term can also apply to substances that affect prions, viruses, fungi, worms or any other intracellular or extracellular parasite, but the antibacterial kind are the most common. Generally, the antibiotics are not effective in viral infections.
Antibiotics are meant to fight off bacterial infections such as pneumonia (e.g. legionnaires' disease), meningitis, cystitis, ear infections, abscess, Lyme disease (tick-transmitted), leprosy & tuberculosis. They cannot be used against viral infections..
The first antibiotic discovered by Alexander Fleming, a Scottish scientist in 1928 is penicillin. It was only in 1941 that penicillin made it's public debut..
Antibiotic drugs are grouped into families such as cephalosporins, fluoroquinolones, penicillins, erythromycins, polypeptides, tetracyclines, aminoglycosides, quinolones, streptogramins & sulfonamides. Each family comprises of many members..
Antibiotics are classified as narrow-spectrum drugs when they are effective against a few types of bacteria & broad-spectrum drugs when they are effective against a wider range of bacteria..
Combination of antibiotics are sometimes used to treat certain infections like leprosy & tuberculosis.. T
hey are sometimes prescribed to treat conditions such as acne, food poisoning, gout & nosebleed..
Preventive antibiotic therapy is meant to prevent bacterial infection, e.g. to reduce the risk of endocarditis (inflammation of the lining inside the heart chambers & heart valves) or to reduce the risk of contracting traveler's diarrhea or to protect people who have a weak immune system because of AIDS or undergoing chemotherapy treatment for cancer..
Different antibiotics kill different bacteria differently..
Though antibiotics can kill off sensitive bacteria, the resistant ones survive & even prosper (i.e. grow & multiply)..
Animals like chickens, pigs, turkeys, cattle also receive their dose of antibiotics in order to either promote growth or to treat & prevent diseases. Fruits & vegetables are also not spared as antibiotics are sprayed to prevent bacterial infections.
Antibiotic resistance (AR) is the result of an overuse or misuse of antibiotics. This resistance is certainly a big worry..
Did you know there are certain strains of bacteria that have become impossible to eliminate with almost all types of antibiotics?.
Broad-spectrum antibiotics are the ones that can promote AR as well as interfere with the absorption of vitamins B6 & B12, folic acid, minerals like magnesium, calcium & potassium.
Allergies may develop with the use of antibiotics, frequently with penicillin..
Side effects from antibiotics can include diarrhea, lightheadness, headaches, cramp, vomiting & stomach discomfort. Consult your physician if these side effects persist or become serious..
Taking the antibiotic erythromycin (primarily used to treat bacteria infections e.g. bronchitis, Legionnaires' disease, pneumonia, rheumatic fever & venereal disease) with Liptor, a statin drug shown to lower cholesterol can cause muscle damage.
Check with your physician before combining these 2 drugs or learn how to lower cholesterol without drugs here..
Antibiotics can destroy the beneficial flora (needed for digestion & protection against infection) in the gut..
Antibiotic therapy can weaken the immune system, simply because it suppresses the body's natural defense system against illness.
. A deficiency in vitamin K can occur..
.A reduction of the manufacture of biotin in the intestines.. Cause people to be light-sensitive
. Examples of such antibiotics : doxycycline, ciproflaxacin & ofloxacin
If you must consume antibiotics :
. Complete the full course even if symptoms improve, otherwise, the antibiotics are not given enough time to work on the infection completely, which can cause a relapse. What's more, the bacteria can become so resistant that the antibiotics no longer work for you the next time..
Follow all the instructions carefully.
Take the correct dosages on time..
Do not take a double dose to make up for a missed one.
Either resume to take the forgotten dose at once or if it's time for the next dose, just continue with it & skip the earlier missed dose..
Do not share antibiotics with anyone..
Never consume previously prescribed leftovers.
Discard them.. If side effects occur from the course of antibiotics or if the condition shows no signs of improvement, see your physician again..
Keep capsules or tablets in a cool dry place. Store liquid mixtures in the refrigerator......................
Antibiotics, sometimes known as antibacterials, are drugs used to treat infections caused by bacteria. These are tiny organisms, too small to see with the naked eye, that sometimes cause illness in humans. Well-known illnesses caused by bacteria include tuberculosis, salmonella, syphilis and some forms of meningitis. However many types of bacteria do not cause illness and live harmlessly on, and in, the human body.
Our immune systems, with their antibodies and special white blood cells, can usually kill harmful bacteria before they multiply enough to cause symptoms. And even when symptoms do occur, the body can often fight off the infection. But sometimes the body is overwhelmed by a bacterial infection and needs help to get rid of it. This is where antibiotics come in. The very first antibiotic was penicillin and along with a family of related antibiotics (such as ampicillin, amoxicllin and benzylpenicillin) it is still widely used to treat many common infections. Now there are several other different kinds of antibiotics. All of them are only available on prescription.
How do antibiotics work?
Some antibiotics, such as the penicillins, are 'bactericidal', meaning that they work by killing bacteria. They do this by interfering with the formation of the cell walls or cell contents of the bacteria. Other antibiotics are 'bacteriostatic', meaning that they work by stopping bacteria multiplying.
What are antibiotics for?
Antibiotics are usually used to treat infections caused by bacteria. They do not work against other organisms such as viruses or fungi. It's important to bear this in mind if you think you have some sort of infection, because many common illnesses, particularly of the upper respiratory tract such as the common cold and sore throats, are usually caused by viruses. Overuse of antibiotics can lead to bacteria becoming resistant to them so it's important to only take them when necessary. (see below).
Some antibiotics can be used to treat a wide range of infections and are known as 'broad-spectrum' antibiotics. Others are only effective against a few types of bacteria and are called 'narrow-spectrum' antibiotics. Some antibiotics work against aerobic bacteria, that is organisms that need oxygen to live, while others work against anaerobic bacteria, organisms that don't need oxygen. Sometimes antibiotics are given to prevent an infection occurring, for example, before certain operations. This is known as prophylactic use of antibiotics and is common before orthopaedic and bowel surgery.
Side effects of antibiotics
The most common side effects with antibiotic drugs are diarrhoea, feeling sick and being sick.
Fungal infections of the mouth, digestive tract and vagina can also occur with antibiotics because they destroy the protective 'good' bacteria in the body (which help prevent overgrowth of any one organism), as well as the 'bad' ones, responsible for the infection being treated.
Rare, but more serious side effects, include the formation of kidney stones with the sulphonamides, abnormal blood clotting with some of the cephalosporins, increased sensitivity to the sun with the tetracyclines, blood disorders with trimethoprim, and deafness with erythromycin and the aminoglycosides.
Sometimes, particularly in older people, antibiotic treatment can cause a type of colitis (inflamed bowel) leading to severe diarrhoea. Penicillins, cephalosporins and erythromycin can all cause this problem but it is most common with clindamycin, an antibiotic usually reserved for serious infections. If you develop diarrhoea while taking an antibiotic, immediately contact your doctor.
Some people are allergic to antibiotics, particularly penicillins, and can develop Side effects such as a rash, swelling of the face and tongue, and difficulty breathing when they take them. Always tell your doctor or pharmacist if you have had an allergic reaction to an antibiotic; sometimes the reaction can be serious or even fatal. This is called an anaphylactic reaction.
Use antibiotics with care
You should use an antibiotic with care if you have reduced liver or kidney function. You should avoid using any antibiotic to which you have previously had an allergic reaction.
Tell your doctor or pharmacist if you are pregnant or breastfeeding before taking any antibiotic.
Interactions with other medicines
Do not take any other medicines or herbal remedies with an antibiotic, including those you have bought without a prescription, before talking to your doctor or pharmacist.
Certain antibiotics (e.g. penicillins, cephalosporins) can reduce the effectiveness of oral contraceptives. If you have diarrhoea or vomiting while taking an antibiotic, the absorption of the pill can be disrupted. In either case, you should take additional contraceptive precautions while you are taking the antibiotic.
There are a number of important interactions between antibiotics and other medicines so it's important to tell which your doctor or pharmacist about any other medicines you are taking.
How to use an antibiotic
Antibiotics are usually taken orally but can also be given by injection, or applied to the affected part of the body such as the skin, eyes or ears. The drugs begin to tackle most infections within a few hours. It is vital to take the whole course of treatment to prevent recurrence of the infection. Sometimes bacteria become 'resistant' to an antibiotic you have been taking, meaning that the drug will no longer work. Resistance tends to occur when the bacterial infection responsible for the symptoms is not completely cured, even if the symptoms have cleared up. Some of the residual bacteria, having been exposed to, but not killed by, the antibiotic are more likely to grow into an infection that can survive that particular antibiotic. This explains why finishing the course of antibiotics, even if you feel better, is important.
Certain antibiotics should not be taken with certain foods and drinks. Some antibiotics are best taken when there is no food in your stomach, usually an hour before meals or two hours after - make sure you follow the instructions on the dispensing label. Do not drink alcohol if you are taking metronidazole. Do not take tetracyclines with dairy products, as these can reduce the absorption of this type of antibiotic.