Antibiotic-resistant infections kill 23,000 people in the US and sicken two million each year, and the problem is getting worse, warns a new report from the Centers for Disease Control and Prevention. Antibiotic Resistance Threats in the United States, 2013 ranks several strains of bacteria according to their current and projected health and economic impacts. It describes 18 microorganisms whose threat levels are “urgent,” “serious,” or “concerning.”

CDC identifies three bacteria as urgent threats: Clostridium difficile, Carbapenem-resistant Enterobacteriaceae (CRE), and Drug-resistant Neisseria gonorrhoeae. C. diff is included on the list even though most infections from it aren’t resistant to typical treatments, because most of these infections “are directly related to antibiotic use and thousands of Americans are affected each year.” (The fact that C. diff infections often arise after a course of antibiotic treatment has prompted a few clinicians to treat persistent cases with “fecal transplants” — essentially, trying to repopulate patients’ guts with a mix of normal bacteria that can keep C. diff in check.) CDC’s report offers snapshots of each of these bacteria:

• Clostridium difficile causes life-threatening diarrhea, and mostly infects hospitalized or recently hospitalized patients who’ve recieved antibiotics. A stronger strain of the bacteria emerged in 2000, demonstrating resistance to fluoroquinaolone antibiotics (a common treatment for other infections). C. diff causes 250,000 infections, 14,000 deaths, and $1 billion in excess medical costs each year.
• Carbapenem-resistant Enterobacteriaceae (CRE) include Kleibsella and E. coli bacteria that are resistant to carbapenams, which are often used as antibiotics of last resort. The bacteria are resistant to all or nearly all of the antibiotics available, and nearly half of hospital patients who get CRE bloodstream infections (a minority of healthcare-associated CRE cases, at the moment) die. CRE causes 9,000 infections and 600 deaths each year.
• Drug-resistant Neisseria gonorrhoeae causes the sexually transmitted disease gonorrhea, which is the second most commonly reported notifiable infection in the US, and is showing resistance to the antibiotics normally used to treat it, including tetracycline and cefixime. Out of an estimated 820,000 US gonorrhea cases in 2011, 246,000, or nearly one-third, were resistant to at least one antibiotic.

The 12 “serious” threats include multidrug-resistant Acinetobacter, drug-resistant Campylobacter, Vanomycin-resistant Enterococcus (VRE), and the poster bug of antibiotic resistance, Methicillin-resistant Staphylococcus Aureus (MRSA).

CDC recommends four core actions to address these threats:

1. Preventing Infections, Preventing the Spread of Resistance: Avoiding infections in the first place reduces the amount of antibiotics that have to be used and reduces the likelihood that resistance will develop during therapy;
2. Tracking: CDC gathers data on antibiotic-resistant infections, causes of infections and whether there are particular reasons (risk factors) that caused some people to get a resistant infection;
3. Improving Antibiotic Use/Stewardship: Perhaps the single most important action needed to greatly slow the development and spread of antibiotic-resistant infections is to change the way antibiotics are used;
4. Development of Drugs and Diagnostic Tests: Because antibiotic resistance occurs as part of a natural process in which bacteria evolve, we will always need new antibiotics to keep up with resistant bacteria as well as new diagnostic tests to track the development of resistance.

Maryn McKenna’s Superbug blog is always the first place I go for expert analysis of bacteria-related news, and she has two great posts about the report: “CDC Threat Report: ‘We Will Soon Be in a Post-Antibiotic Era’” summarizes the report’s findings and the pace of progress to address the threats; “CDC Threat Report: Yes, Agricultural Antibiotics Play a Role in Drug Resistance” highlights the report’s many references to the role of large-scale livestock operations in antimicrobial resistance. Perhaps most striking is the report’s graphic on the development of antibiotic resistance:

McKenna also notes, “Out of the 18 drug-resistant organisms the report highlights as alarming, four are foodborne organisms that become drug-resistant as the foods that carry them are produced or grown: Campylobacter (p. 61), E. coli (p. 65), Salmonella (p. 70) and Shigella (p. 75).”

The report lists action steps CDC, states and communities, healthcare leaders and providers, and patients and their families can take to reduce the development of antimicrobial resistance and the spread of resistant bacteria. In addition, Congress could pass the Preservation of Antibiotics for Medical Treatment Act, and FDA could collect and publish better data on use of antibiotics in livestock and restrict livestock operations’ use of antibiotics to therapeutic purposes (i.e., let producers give antibiotics to infected animals but not routienly dose the whole herd for growth promotion). The decisions we all make today will determine how quickly we recover — or die — from infections in the future.

Related past posts:
Study: Industrial food-animal workers test positive for livestock-associated MRSA
Chicken, UTIs, and a long-festering antibiotic problem
How meaningful is FDA’s latest move on antibiotics in livestock?
On World Health Day, Confronting the Menace of Antimicrobial Resistance