Antimicrobial Resistance: The Big Picture

An Interview With CDC's Steven L. Solomon, MD

Laura A. Stokowski, RN, MS; Steven L. Solomon, MD


September 16, 2013

Editorial Collaboration

Medscape &

In This Article

Classifying Threat Levels

Medscape: What is new in this report?

Dr. Solomon: This is the first time that we have categorized the 18 microorganisms that pose the greatest antimicrobial resistance threats to public health. We have categorized these microorganisms into 3 threat groups: urgent, serious, and concerning. It is important to communicate the message that although all these pathogens put patients at risk, a public health focus on some problems is particularly urgent. We hope that this threat assessment will help people to understand antibiotic resistance problems and how they can help us and contribute to public health efforts to fight the spread of these bacteria ( Table ).

The factors used to classify these pathogens into these 3 groups were clinical and economic impact, incidence and 10-year projection of incidence, transmissibility, availability of effective antibiotics, and barriers to prevention.

For each of the 18 pathogens, we also provide current burden-of-disease data on incidence, mortality, resistance concerns, and demographics of those who are infected. The estimates in the report of number of deaths related to each microorganism are minimums; the actual numbers could be higher. We chose conservative estimates, but even those are alarming.

Medscape: What do the different categories mean in terms of action?

Dr. Solomon: The pathogens assigned to the urgent and serious categories require more monitoring and prevention activities, whereas those in the concerning category require less. Urgent threats might not be currently widespread, but they have the potential to become so and require focused attention now to identify infections and limit transmission. Carbapenem-resistant Enterobacteriaceae (CRE) and cephalosporin-resistant gonorrhea have the potential to spread rapidly and become untreatable. Clostridium difficile is already a major clinical threat, and targeted prevention efforts are likewise critical. Threats in the serious category are certainly a public health risk and could worsen, especially if ongoing public health efforts at monitoring and prevention were to slacken for any reason. Bacteria currently classified as concerning either pose lower threats of rapidly spreading resistance or there are still therapeutic options for resistant infections. They can cause severe illness, and if resistance to current therapies emerged, the results would be severe, so they require careful ongoing monitoring.

The purpose of this categorization is to give people a greater awareness of the bacterial resistance problems that need to be addressed right now, of the clinical and public health problems caused by these bacteria, and why we need to be tracking them so carefully. We want to drive home the point that some bacteria are especially worrisome, and when people hear from us about those bacteria, it's not just "business as usual."

Medscape: You have placed drug-resistant gonorrhea in the urgent category, yet we don't hear as much about this as other urgent pathogens, such as C difficile. Can you comment on the reason for that?

Dr. Solomon: Your question goes right to the heart of why we have written this report. The awareness of the threat that is posed by cephalosporin-resistant gonorrhea is greatly underappreciated. There have been reports in scientific journals and a few in the popular press, but the threat is extraordinary.Gonorrhea is the second most commonly reported notifiable infection in the United States and is easily transmitted. It causes severe reproductive complications and disproportionately affects sexual, racial, and ethnic minorities. Gonorrhea control relies on prompt identification and treatment of infected persons and their sex partners.

Because N gonorrhoeae is becoming more resistant to the antibiotics usually used to treat it, CDC recently updated its treatment recommendations, and we now recommend only ceftriaxone plus either azithromycin or doxycycline. The cephalosporin antibiotics are the last line of defense for gonorrhea. The emergence of cephalosporin resistance, especially ceftriaxone resistance, would greatly limit treatment options and could cripple gonorrhea control efforts. Although the threat posed by cephalosporin-resistant gonorrhea is currently low, we are very concerned about the risk of spreading, and we want to attack this problem immediately. That is why we labeled it as an urgent threat.


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