The increasing threat of antibiotic resistance

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Dr. Carrie Aisen is a San Diego-based urologist focused on evidence-based medicine. Dr. Aisen received her MD from Columbia University.

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You may have heard mention of antibiotic resistance. Or if you suffer from recurrent infections you may have had a doctor tell you that you have a resistant infection or had to change antibiotics due to a resistant infection. Sometimes people must be hospitalized to treat these kinds of infections. Antibiotic resistance is becoming an increasingly dangerous issue that can affect all of us. The World Health Organization states that antibiotic resistance “is one of the biggest threats to global health, food security, and development today.” The Center for Disease Control states that antibiotic resistance is ”one of the world’s most urgent public health problems.”

Antibiotic or antimicrobial resistance arises when the bacteria develop mechanisms to prevent the antibiotic from killing them. The bacteria can also spread these mechanisms to other bacteria. When bacteria have more of these mechanisms, they develop resistance to more antibiotics making it increasingly difficult to treat an infection.  

This problem has become a widespread and dangerous issue. The CDC reports that every year in the US there are 2.8 million people infected with antibiotic resistant infections and more than 35,000 people die from them. In response to concerns about antibiotic resistance more antibiotics have been developed. However, resistance continues to develop more quickly than new antibiotics are developed.

UTIs are one of the most common infections around the world. In the US, UTI symptoms lead to almost 10 million office visits and 3 million emergency room visits per year (1). The treatment for UTIs is usually antibiotics and because of this UTIs are a large driver of antibiotic prescriptions. In addition to other negative side effects of antibiotics, antibiotic resistance is becoming an increasingly important issue when treating UTIs. When antibiotic resistant UTIs were first noted, it was seen in infections acquired during hospitalizations or in patients with multiple comorbidities. But it is now a widespread problem seen in everyone ranging from children to the elderly around the world.

However studies have shown that there are concerning antibiotic resistance rates seen in UTIs. A study from Libya found that amikacin and carbapenems had the lowest rates of resistance and cephalothin and ampicillin had the highest resistance (2).

One study looked at resistance patterns in E. coli from patients diagnosed with UTIs at 30 medical centers distributed throughout the 9 US census divisions. They found resistance rates of 24.3% to levofloxacin, 25.8% to ciprofloxacin, 32.1% to trimethoprim/ sulfamethoxazole, 15.9% to cefuroxime, 28.7% to ampicillin-sulbactam, 19.7% to doxycycline, and 29.7% to tetracycline. They saw little or no resistance to intravenous carbapenems and amikacin (3). A study from Iran found that 87.5% of the bacteria were resistant to at least one antibiotic. They also found the lowest resistant rates with carbapenems (0.9%) and amikacin (8.43%). This study found highest resistance to methicillin (76.06%) and ampicillin (89.29%). Another interesting result from this study was that out of the 3,798 patients who presented with clinical symptoms of UTI only 14.6% had positive cultures. This highlights the importance of documenting the UTI with a culture before dismissing other diagnoses (4).

In 2011 the Infectious Disease Society of America published guidelines on the recommendations for treating uncomplicated UTIs which included recommending specific antibiotics. However, resistance to these antibiotics is becoming more common. These guidelines are currently being revised and it will be interesting to see how the new guidelines address the issues of resistance and antibiotic overuse.

Antibiotics are often used to promote growth and wellbeing in livestock and it has been estimated that this accounts for 80% of antibiotic use in the US. Antibiotic resistance that develops in livestock can then spread to humans that consume the meat and through the environment (5).

The way to combat this involves drastically altering the way that we use antibiotics and there are many changes that are needed. Decreasing the use of antibiotics in livestock could reduce our overall use of antibiotics. Cutting back on the use of antibiotics to treat viruses like a cold is very important because antibiotics do not treat viruses, so it has risks with no benefit. Reducing the number of antibiotic prescriptions for UTIs can also help. For a more in-depth discussion on non antimicrobial options to address UTI symptoms read my previous article here. Even better than finding other ways to treat UTIs is using non antibiotic options to prevent getting the UTI in the first place.

Reducing antibiotic resistance is going to take effort from many people and organizations. The agricultural industry can address their practice of antibiotics in livestock, consumers can choose which products to buy, doctors can council their patients on appropriate and inappropriate use of antibiotics, and patients can be thoughtful about if and when they need an antibiotic. Given that this is a global issue, it will take international collaboration. Hopefully, increased awareness will inspire more people to take action.

1. Flores-Mireles AL, Walker JN, Caparon M, Hultgren SJ. Urinary tract infections: epidemiology, mechanisms of infection and treatment options. Nat Rev Microbiol. 2015 May; 13(5):269-84.
2. Mahmoud A. Mohammed, Tarig M.S. Alnour, Osama M. Shakurfo, Mariam M. Aburass, Prevalence and antimicrobial resistance pattern of bacterial strains isolated from patients with urinary tract infection in Messalata Central Hospital, Libya, Asian Pacific Journal of Tropical Medicine, Volume 9, Issue 8, 2016, Pages 771-776.
3. Critchley IA, Cotroneo N, Pucci MJ, Mendes R. The burden of antimicrobial resistance among urinary tract isolates of Escherichia coli in the United States in 2017. PLoS ONE 14(12): e0220265.
4. Mihankhah A, Khoshbakht R, Raeisi M, Raeisi V. Prevalence and antibiotic resistance pattern of bacteria isolated from urinary tract infections in Northern Iran. J Res Med Sci. 2017;22:108. Published 2017 Sep 26.
5. Ventola CL. The antibiotic resistance crisis: Part 1: Causes and threats. P T. 2015;40:277–83.