The convenience of modern infection treatments comes with an unfortunate drawback. Often, a patient will be prescribed an antibiotic to neutralize the harmful effects of a bacterial infection, and while the relief from symptoms may be a win, decades of overuse — and misuse — of antibiotics have created new issues. Researchers and clinicians in infectious diseases are now confronting antimicrobial resistance (AMR), also known as antibiotic resistance.
Milner Staub, MD, MPH, assistant professor of Medicine in the Division of Infectious Diseases and director of Adult Outpatient Antimicrobial Stewardship, explained that AMR refers to the ability of a bacteria to resist the effects of an antibiotic, rendering it useless. AMR often comes after repeated exposure to antibiotics that can kill a wide range of bacteria. Frequent use of such antibiotics can weaken their effectiveness over time and lessen or entirely negate their ability to treat certain bacterial infections in a specific patient and an entire community.
“Antibiotic use in the individual selects for bacteria that harbor and can express genes that allow for antibiotic resistance,” said Staub. “They can naturally multiply due to less competition and can then share their resistance genes with other bacteria, ultimately affecting a population. Humans shed bacteria from their skin, gut and urine all the time, and we all share the same environment, allowing for spread of these resistance genes and of the bacteria that carry them.”
AMR often manifests in recurrent urinary tract infections (UTIs). As Maria Hadjifrangiskou, PhD, professor of Pathology, Microbiology and Immunology and Urology, explains, bacteria that cause recurrent UTIs can “hide” in a part of the body such as the gut or vagina, where they can pose as commensals, or a microorganism that benefits from a symbiotic relationship with a human host while neither harming nor benefiting the individual. This incubation time in the body allows them to acquire mutations that may make them more resilient to antibiotics.
“Recurrent UTIs are debilitating because they are almost impossible to eliminate,” said Hadjifrangiskou, who is also associate director of the Vanderbilt Institute for Infection, Immunology and Inflammation. “For example, work in the Hadjifrangiskou lab has followed children with spina bifida, who are in the most vulnerable populations for recurrent UTI, and we see acquisition of mutations in the UTI bacteria over time. This could lead to antimicrobial resistant bacteria that can then pass the resistance on to other members of the same species.”
Staub added that urine samples paint a troubling picture of rising AMR.
“Urine cultures are sent very frequently because they are relatively easy to collect and culture, making them an important and readily available diagnostic tool,” said Staub. “And we are seeing rising numbers of resistant bacteria cultured from urine.”
But it isn’t just recurrent UTIs that are difficult to treat because of AMR. According to Kelly Dooley, MD, PhD, MPH, the Addison B. Scoville Jr. Professor of Medicine and director of the Division of Infectious Diseases, the problem is much broader.
“Bacteria that are resistant to antibiotics are ever more common,” said Dooley, who is also professor of Pathology, Microbiology and Immunology. “In fact, deaths due to AMR will surpass those from cancer by 2050. Being able to prevent and treat infections is critical for all aspects of medicine, including those areas where we are seeing the most innovation, such as cancer therapeutics, transplant medicine and advanced surgical interventions.”
Dooley added that antimicrobial resistance to increasingly more medications can create challenges for clinicians when treating patients. What should be short-lived, easy-to-treat infections, she says, can end up requiring last-resort intravenous antibiotics — which can come with their own negative side effects or be untreatable entirely.
“Sometimes we don’t have anything effective to offer, which is a terrible position for a patient and clinician to be in,” Dooley said. “Fortunately, researchers at Vanderbilt are working on solutions to this emerging threat. This includes researching what makes bacteria ‘pathogenic’ in the first place, identifying new compounds that may ultimately be developed as antibiotics, infection prevention and antimicrobial stewardship.”
Staub listed several actionable steps people can take to protect themselves from antibiotic resistance:
- Get vaccinated. Vaccines lessen the negative impact created by viruses that can cause pneumonia or the flu, which allows your body to protect itself from bacteria that may try to infect your body when it is weakened by the virus.
- Know the difference between infections that are helped by antibiotics (infections caused by bacteria) and those that are not (infections caused by viruses). Recognizing that antibiotics will not help viral infections can save you unnecessary antibiotic use.
- Help your body fight viruses to prevent secondary bacterial infection. Sleep, drink plenty of water and use saline to rinse out your nose three to four times per day when you have an upper respiratory tract infection. By clearing mucus with saline, you help prevent bacteria from setting up shop in that infected space. Honey, which has natural healing properties and can soothe a sore throat, is also beneficial, as is gargling with salt water.
- Patients should ask their health care providers whether antibiotics are necessary or if their treatment plan can avoid unnecessary antibiotic prescriptions. A good rule of thumb is that if a culture comes back positive with bacteria, but the patient is not complaining of symptoms, antibiotics usually are not needed.
