Antibiotic Resistant Superbugs

The idea of a "superbug" can be very frightening. So-called superbugs sound as if they are somehow stronger and more powerful than regular bacteria or fungi. That's not exactly the case. They are not often extra virulent—but they have, over time, developed a resistance to the antibiotics or antifungals that were designed to fight them.

Antibiotic-resistant superbugs are a serious threat. The CDC estimates that each year, antibiotic-resistant bacteria and fungi cause 2.8 million infections in the US, and more than 35,000 people die as a result.¹

In the report, Antibiotic Resistant Threats in the United States (2019), the CDC compiled information about pathogens it considers urgent, serious, or concerning. Here are some of the dangerous superbugs the CDC and the healthcare industry are most worried about.¹

10 Scary Antibiotic-resistant Superbugs

Acinetobacter baumannii

Acinetobacter baumannii can survive on surfaces for a long time—making it a particular menace in healthcare settings, where it can contaminate shared medical equipment and facility surfaces. Many of the opportunistic A. baumannii infections occur in intensive care units, which can lead to developing pneumonia, bloodstream infections, and urinary tract infections. Unfortunately, most A. baumannii recovered from the healthcare setting are resistant to carbapenem class antibiotics, which are used to treat these types of infections. Some A. baumannii can be resistant to nearly all antibiotics. The CDC estimates that this bad bug caused 8,500 cases of infection in hospitalized patients in 2017, leading to 700 estimated deaths.

Campylobacter

Chopping veggies on a cutting board that has been used to prepare raw chicken is one recipe for a painful Campylobacter infection. This bacteria spreads to people through raw or undercooked chicken, unpasteurized milk, and other contaminated food and water. It can even spread through direct contact with farm animals and household pets. The CDC estimates that 448,400 Campylobacter infections each year are from antibiotic-resistant strains, and the overall percentage of drug-resistant infections continues to grow.

Candida auris

Although the CDC noted only 323 clinical cases of antifungal-resistant Candida auris in 2018, the CDC still considers this fungus an "urgent" threat because some strains are resistant to all three available classes of antifungal medications. Some healthcare disinfectants are less effective at eliminating it, and it can be carried on the skin without causing infection, enabling it to spread to others. On top of that, cases seem to be rapidly growing—reported cases increased 318% in 2018 compared with the average number from 2015 to 2017.

Clostridioides difficile

Clostridioides difficile is a major cause of antibiotic-associated diarrhea. This pathogen tends to thrive in patients who are taking (or recently took) antibiotics. C. difficile can spread easily in healthcare settings, compromising patients who are already sick. In 2017, there were an estimated 223,900 cases of C. difficile among hospitalized patients. C. difficile typically causes severe bouts of diarrhea, and an infection can progress to more severe diseases like colitis, toxic megacolon, colon perforations, and sepsis.² The infection can sometimes result in death, with the CDC estimating 12,800 deaths from C. difficile in 2017. The overall estimated healthcare costs of C. difficile reached $1 billion that year.

Enterobacteriaceae

Some strains of the Enterobacteriaceae family of bacteria, called ESBL-producing Enterobacteriaceae, produce enzymes that break down commonly used antibiotics rendering them ineffective. These bacteria accounted for over 197,000 infections in hospitalized patients in 2017 and led to 9,100 estimated deaths, according to the CDC. But hospitalized patients aren't the only ones at risk—these strains of Enterobacteriaceae can cause infections in otherwise healthy people.

Enterobacteriaceae that are resistant to carbapenem antibiotics are also an increasing threat, with an estimated 13,100 cases in hospitalized patients in 2017. These carbapenem-resistant bacteria led to roughly 1,100 deaths in 2017. The CDC has created a nationwide network to give clinical labs access to advanced detection capabilities for carbapenem-resistant Enterobacteriaceae.

Enterococcus

The Enterococcus genus of bacteria are a menace for patients in healthcare settings, especially those who have had long-term healthcare stays, have undergone an organ transplant, or have been in the intensive care unit. Enterococci can lead to bloodstream, surgical site, and urinary tract infections. The bad news is that roughly 30% of healthcare-related enterococcal infections are resistant to the antibiotic vancomycin, which reduces treatment options. This vancomycin-resistant strain of enterococci (VRE) bacteria is becoming increasingly resistant to additional antibiotics, meaning the remaining antibiotics used to treat VRE may become less effective in the future.

Shigella

The rate of drug-resistant Shigella infections has climbed dramatically since 2013. Less than 5% of Shigella infections involved a decreased susceptibility to azithromycin in 2013, but that number grew to 24% by 2017. Shigella can cause diarrhea, fever, and abdominal pain. Infection control is difficult because it spreads easily between people through contact with feces, or in contaminated water or food.

Pseudomonas aeruginosa

The number of patients infected with multi-antibiotic resistant Pseudomonas aeruginosa has declined from 46,000 in 2013 to an estimated 32,600 in 2017. Even though the numbers are dropping, P. aeruginosa still presents a threat to hospitalized patients, especially those with weakened immune systems or chronic lung diseases. In fact, some types of P. aeruginosa are resistant to nearly all antibiotics, making continued infection control a necessity.

Staphylococcus aureus

Infections from methicillin-resistant Staphylococcus aureus (MRSA) occur in both healthcare facilities and communities. These are difficult to treat infections because of resistance to many first-line antibiotics. In 2017, MRSA accounted for nearly 324,000 infections in hospitalized patients. That number is trending downward, but the CDC says progress is slowing in preventing MRSA bloodstream infections. Within the community, the CDC suggests that MRSA infections may be related to the opioid crisis, as people who inject drugs are 16 times more likely to develop a serious MRSA infection than those who don't.

Streptococcus pneumoniae

Streptococcus pneumoniae can cause a variety of nasty infections: bacterial pneumonia, meningitis, bloodstream infections, and ear and sinus infections. In fact, it causes more than 2 million infections in the United States each year—and more than 30% of those are caused by bacteria that are resistant to at least one antibiotic. The good news is that an effective vaccine exists to prevent drug-resistant S. pneumoniae infections. This vaccine has reduced pneumococcal infections caused by the vaccine-targeted strains by more than 90% in children.

Antimicrobial Stewardship

CDC Director Robert R. Redfield, MD, does not mince words in the CDC's antibiotic threat report: "You and I are living in a time when some miracle drugs no longer perform miracles and families are being ripped apart by a microscopic enemy. The time for action is now and we can be part of the solution."

The CDC, along with other national and local partners, is tackling antimicrobial resistance from multiple angles, including infection prevention and investing in vaccines and new therapeutics. Antimicrobial stewardship—an effort to optimize the use of antimicrobials—is another key front in the battle against antimicrobial resistance.

Syndromic infectious disease diagnostics can aid in antimicrobial stewardship efforts with fast, accurate, and comprehensive testing.³ Rapid answers on a comprehensive menu of pathogens and antibiotic resistance markers can enable physicians to optimize patient therapy quickly, avoiding unnecessary antimicrobials.

For example, patients tested with the BIOFIRE^® FILMARRAY^® Gastrointestinal Panel were less likely to be prescribed antibiotics,⁴ and patients were more likely to be prescribed targeted therapy compared to traditional testing.⁵

Learn More

Superbugs may be frightening—but information is the best weapon against this growing threat.

Read why some are advocating that antimicrobial stewardship programs be incorporated into healthcare organizations' disaster preparedness plans.

References

All pathogen information in this article was derived from "Antibiotic Resistance Threats in the United States, 2019." U.S. Department of Health and Human Services, CDC; 2019.
Sartelli M, et al. World J Emerg Surg 14, 8 (2019).
Banerjee R, et al. Randomized Trial of Rapid Multiplex Polymerase Chain Reaction-Based Blood Culture Identification and Susceptibility Testing. Clin Infect Dis. 2015;61:1071-80.
Axelrad JE, et al. Impact of Gastrointestinal Panel Implementation on Healthcare Utilization and Outcomes. J. of Clin. Microbiol. 2019; 27;57(3). e01775-18.
Cybulski R, et al. Clinical Impact of a Multiplex Gastrointestinal PCR Panel in Patients with Acute Gastroenteritis. Clin Infect Dis. 2018;67:1688-1696.