The Scariest Superbug

By Nicole Tse

In May of 2016, researchers in the United States found an antibiotic-resistant strain of bacteria in the urine of a woman who had gone to the doctor for treatment of a urinary tract infection. This discovery has alarmed public health officials not only in the United States but also around the world. In order to understand why this news is so shocking, let’s take a look at antibiotics and what they are meant to do.

The word antibiotic comes from the Greek anti (against) and bios (life). First introduced in the 1940s and 1950s, antibiotics are chemicals that are used to treat bacterial infections, as well as fungi and parasites. A few examples of illnesses caused by bacteria include syphilis, tuberculosis, and salmonella. Antibiotics can help a sick person in one of two ways. The first type of antibiotic is bactericidal; that is, it kills the bacteria causing the sickness. Often this is done by interfering with the formation of each bacterium’s cell walls, or by disrupting processes within the cell that are necessary to keep the bacterium alive. Penicillin, the first antibiotic ever produced, is bactericidal. The second type of antibiotic simply prevents the bacteria from multiplying. This keeps the population of undesirable bacteria small enough to be destroyed naturally by the host’s white blood cells. Antibiotics are usually prescribed to combat an existing illness; however, they can also be administered prophylactically—before undergoing a surgical procedure, for example, to prevent infection before it happens. However, this is not always the right decision.

The overuse and misuse of antibiotics in modern medicine has led to the rise of “superbugs”, bacteria that are not harmed by certain antibiotics. This resistance occurs when bacteria come into contact with antibiotics and their genes mutate until the antibiotic no longer has any effect. This resistance is then passed on to subsequent generations of the same bacteria, or can even be transferred to other types of bacteria. Bacteria are often exposed to antibiotics when people take them for a cold or the flu, thinking the medicine will help them recover faster. However, most colds and flus are caused by viruses, which cannot be treated with antibiotics. As a result, the antibiotics often destroy the “good” bacteria in the host’s body, leaving their immune system more vulnerable, while giving undesirable bacteria the opportunity to adapt to the chemicals. In other situations, patients sometimes begin a course of antibiotics but stop early because they feel better. Because they do not take the whole prescribed dosage of the medicine, it is more likely that some of the bacteria will survive and be able to develop resistance. Currently, there exist drug-resistant strains of Staphylococcus aureus (MRSA), E. coli, tuberculosis, gonorrhea, and staph infections, among others. While these bacteria are unaffected by the antibiotics commonly used to treat them, they can usually be combated using stronger or different medicines.

A culture of the bacteria E. coli, magnified 10,000 times. Eric Erbe and Christopher Pooley.

A culture of the bacteria E. coli, magnified 10,000 times. Eric Erbe and Christopher Pooley.

The ultimate fear is that the colistin resistance will be transferred to Carbapenem-resistant Enterobacteriaceae, or CRE. These bacteria, which can kill up to 50 percent of infected patients, are resistant to carbapenems, a type of antibiotic used to treat bacteria that are already resistant to other drugs. Colistin is one of the only antibiotics that are still effective against theses CRE. So if they come into contact with other bacteria carrying the colistin resistance genes, they could evolve into a pan-drug-resistant strain of bacteria and become untreatable.

How did the E. coli in the woman’s body become resistant to colistin in the first place? While colistin is not commonly used to treat urinary tract infections because it is so harsh on the body, it is widely used in food animal production in China. The bacteria probably became resistant to colistin within livestock, not only in China but also in Europe and the United States, and then spread to humans through contaminated and undercooked meat.

What can be done to prevent the terrifying possibility of bacteria that are resistant to all types of antibiotics? Scientists are working to develop new medicines that can be used to treat resistant strains. In the meantime, you can help slow down the development of antibiotic resistant bacteria by using antibiotics correctly and only when absolutely necessary. Remember to take all of the prescribed doses, even if you think you have fully recovered, and do not share antibiotics with other people or use leftover prescriptions.