Antibiotics Resistance: Antibiotics Fight Bacteria, Not Viruses

Picture of women with antibiotics

Antibiotics

Antibiotics are drugs used for treating infections caused by bacteria. Also known as antimicrobial drugs, antibiotics have saved countless lives.

Misuse and overuse of these drugs, however, have contributed to a phenomenon known as antibiotic resistance. This resistance develops when potentially harmful bacteria change in a way that reduces or eliminates the effectiveness of antibiotics.

Antibiotics Fight Bacteria, Not Viruses

Antibiotics are meant to be used against bacterial infections. For example, they are used to treat strep throat, which is caused by streptococcal bacteria, and skin infections caused by staphylococcal bacteria.

Although antibiotics kill bacteria, they are not effective against viruses. Therefore, they will not be effective against viral infections such as colds, most coughs, many types of sore throat, and influenza (flu).

Using antibiotics against viral infections

  • will not cure the infection
  • will not keep other individuals from catching the virus
  • will not help a person feel better
  • may cause unnecessary, harmful side effects
  • may contribute to the development of antibiotic-resistant bacteria

Patients and health care professionals alike can play an important role in combating antibiotic resistance. Patients should not demand antibiotics when a health care professional says the drugs are not needed. Health care professionals should prescribe antibiotics only for infections they believe to be caused by bacteria.

As a patient, your best approach is to ask your health care professional whether an antibiotic is likely to be effective for your condition. Also, ask what else you can do to relieve your symptoms.

So how do you know if you have a bad cold or a bacterial infection?

Joseph Toerner, M.D., MPH, a medical officer in FDA’s Center for Drug Evaluation and Research, says that the symptoms of a cold or flu generally lessen over the course of a week. But if you have a fever and other symptoms that persist and worsen with the passage of days, you may have a bacterial infection and should consult your health care provider.

What is antimicrobial resistance?

Antimicrobial resistance is resistance of a microorganism to an antimicrobial drug that was originally effective for treatment of infections caused by it.

Resistant microorganisms (including bacteria, fungi, viruses and parasites) are able to withstand attack by antimicrobial drugs, such as antibacterial drugs (e.g. antibiotics), antifungals, antivirals, and antimalarials, so that standard treatments become ineffective and infections persist, increasing the risk of spread to others.

The evolution of resistant strains is a natural phenomenon that occurs when microorganisms replicate themselves erroneously or when resistant traits are exchanged between them. The use and misuse of antimicrobial drugs accelerates the emergence of drug-resistant strains. Poor infection control practices, inadequate sanitary conditions and inappropriate food-handling encourage the further spread of antimicrobial resistance.

What is the difference between antibiotic and antimicrobial resistance?

Antibiotic resistance refers specifically to the resistance to antibiotics that occurs in common bacteria that cause infections. Antimicrobial resistance is a broader term, encompassing resistance to drugs to treat infections caused by other microbes as well, such as parasites (e.g. malaria), viruses (e.g. HIV) and fungi (e.g. Candida).

In the U.S. alone, 2 million people each year contract serious antibiotic-resistant infections and 23,000 die from them.

These figures comes from a new report from the U.S. Centers for Disease Control and Prevention (CDC) on antibiotic resistance that, for the first time, uses a blunt classification scheme to identify “urgent,” “serious” and “concerning” threats from drug-resistant bacteria. The CDC lists three urgent threats: drug-resistant gonorrhea, drug-resistant “enterobacteriaceae” such as E. Coli, and Clostridium difficile, which causes life-threatening diarrhea and often is acquired in hospitals. Clostridium difficile kills at least 14,000 people a year.

We‘ve been warned about antibiotic resistance since at least 1945. We just haven‘t been listening.

Scientists have known that resistance is a danger since antibiotics were discovered. Alexander Fleming himself, who discovered penicillin, warned us as early as 1945 that antibiotics could lose their effectiveness. His eerily prescient Nobel Prize speech cautions “there may be a danger, though, in underdosage [of penicillin]. It is not difficult to make microbes resistant to penicillin in the laboratory by exposing them to concentrations not sufficient to kill them and the same thing has occasionally happened in the body. The time may come when penicillin can be bought by anyone in the shops. Then there is the danger that the ignorant man may easily underdose himself and by exposing his microbes to non-lethal quantities of the drug, make them resistant.”

Antibiotic-resistant strains of bacteria are on the rise. 

Clearly, antibiotic resistance is not new. Nonetheless, the frequency of antibiotic resistance events is increasing. For example, from 1980 to 1987, cases of penicillin-resistant Streptococcus pneumoniae (the bacteria that causes pneumonia) remained steady at about 5 percent of all strains. By 1997, 44 percent of strains were showing resistance. Similarly, Enterococci bacteria can cause urinary tract infections and meningitis, among other diseases, and in 1989, fewer than 0.5 percent of strains found in hospitals were resistant to antibiotics. Four years later that number was at 7.9 percent, and by 1998, some hospitals reported levels as high as 30 percent to 50 percent. “The more antibiotics are used, the more quickly bacteria develop resistance,” says the CDC. 

There has been a steady decline in Food and Drug Administration (FDA) approvals for new antibiotics. 

Even as more bacteria are becoming resistant and our treatments are becoming less effective, we’re also producing fewer new drugs to combat infections. 

Why has this happened? “There’s a kind of curve to antibiotic development,” says McKenna, noting there was a boom in the 1950s, when Eli Lilly collected samples of biological materials from all over the world to capture antibiotic properties in natural substances. By the 1980s, much of the low-hanging antibiotic fruit had been harvested. Now, the development of new treatments is becoming increasingly difficult and costly, even as pharmaceutical companies are cutting research and development budgets and outsourcing drug discovery more and more. “The faucet from which [antibiotics] come has been turned down and down and down and now it’s just a drip,” McKenna says. 

Up to half of all antibiotic prescriptions either aren‘t needed or are not effective. 

A huge part of our problem is that we’re misusing and abusing antibiotics. “Resistance is a natural process,” says McKenna, but “we made resistance worse by the cavalier way that we used antibiotics, and still use them.” Sick patients pressure their doctors for drugs, and doctors too often yield and dash off a script. A recent study found that doctors prescribed antibiotics 73 percent of the time for acute bronchitis, even though, as Mother Jones‘ Kiera Butler reports, antibiotics are not recommended at all for this condition. 

Almost one in five emergency room visits resulting from adverse drug events are caused by antibiotics, the CDC says. Children are the most likely victims. Although antibiotics are generally safe, they can cause allergic reactions and also can interact with other drugs, harming patients who are vulnerable because they already suffer from other medical conditions. So if we stop over-prescribing antibiotics we’d also lessen adverse drug effects. 

It‘s not just human medical misuse a large volume of antibiotics is inappropriately used in livestock. 

Antibiotics are heavily used in the agricultural industrymore antibiotics are used to treat animals than to treat people. While livestock drugs are used to fight infections, they are often fed to animals in smaller doses to encourage weight gain and growtha practice, the CDC says, that is “not necessary” and “should be phased out.” A recent draft document from the FDA similarly states that “in light of the risk that antimicrobial resistance poses to public health, the use of medically important antimicrobial drugs in food-producing animals for production purposes does not represent a judicious use of these drugs.” For now, though, the FDA’s approach to curbing this threat has been limited to issuing voluntary guidelines. 

Before antibiotics, death rates were much higher from very common occurrences like skin infections, pneumonia and giving birth. 

In her Medium article, McKenna gives some disturbing stats. Before antibiotics, just giving birth could be deadly: Five out of every thousand women who had a baby died. Pneumonia killed 30 percent of its victims. And “one out of nine people who got a skin infection died, even from something as simple as a scrape or an insect bite.” If we run out of antibiotics, our future looks rather bleak. 

The next major global pandemic may involve an antibiotic-resistant superbug. 

“Plagues still really have power and almost a hundred years later, we shouldn’t think that we’re immune to them because we’re not,” warns McKenna. For instance, tuberculosis kills more than a million people a year, and it is becoming increasingly drug-resistant, says the World Health Organization. 

Bacteria poses a threat even with viral infections. Viruses can weaken our immune systems just enough to allow bacteria to take hold. Death results from secondary bacterial infections that, at least until recently, were largely curbed by effective antibiotics.

How do bacteria become resistant?

Some bacteria are naturally resistant to certain types of antibiotics. However, bacteria may also become resistant in two ways:

  • by a genetic mutation
  • by acquiring resistance from another bacterium.

Mutations, rare spontaneous changes of the bacteria’s genetic material, are thought to occur in about one in one million to one in ten million cells. Different genetic mutations yield different types of resistance. Some mutations enable the bacteria to produce potent chemicals (enzymes) that inactivate antibiotics, while other mutations eliminate the cell target that the antibiotic attacks. Still others close up the entry ports that allow antibiotics into the cell, and others manufacture pumping mechanisms that export the antibiotic back outside so it never reaches its target.

Bacteria can acquire antibiotic resistance genes from other bacteria in several ways. By undergoing a simple mating process called “conjugation,” bacteria can transfer genetic material, including genes encoding resistance to antibiotics (found on plasmids and transposons) from one bacterium to another. Viruses are another mechanism for passing resistance traits between bacteria. The resistance traits from one bacterium are packaged into the head portion of the virus. The virus then injects the resistance traits into any new bacteria it attacks. Bacteria also have the ability to acquire naked, “free” DNA from their environment.

Any bacteria that acquire resistance genes, whether by spontaneous mutation or genetic exchange with other bacteria, have the ability to resist one or more antibiotics. Because bacteria can collect multiple resistance traits over time, they can become resistant to many different families of antibiotics.

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