C. difficile, the most common hospital-based infection in the United States, made the list of urgent threats both because it has begun to resist antibiotics and because it preys on the overuse of antibiotics.

C. difficile, which causes life-threatening diarrhea, spreads from person to person on contaminated equipment and on the hands of healthcare workers and visitors. It is especially stubborn in hospitals because of the widespread use of antibiotics, which kill protective bacteria in the gut for months, allowing invaders such as C. difficile to flourish.

According to the report, C. difficile causes 250,000 infections and kills 14,000 people in the United States each year, adding $1 billion annually in excess medical costs. Deaths from C. difficile rose 400 percent from 2000 to 2007 due to the emergence of a drug-resistant strain of the bacteria.

The third "urgent" threat in the report is drug-resistant Neisseria gonorrhea, which causes 246,000 U.S. cases of the sexually transmitted disease gonorrhea each year. Gonorrhea is increasingly becoming resistant to tetracycline, cefixime, ceftriaxone and azithromycin - formerly the most successful treatments for the disease


The lesion on this patient’s heel was due to the systemic 
dissemination of the N. gonorrhoeae bacteria.

Gonorrhea is especially troublesome because it is easily spread, and infections are easily missed. In the United States, there are approximately 300,000 reported cases, but because infected people often have no symptoms the CDC estimates the actual number of cases is closer to 820,000
If left untreated, gonorrhea can lead to pelvic inflammatory disease, ectopic pregnancy, stillbirths, severe eye infections in babies and infertility in men and women.

"The three organisms that have been chosen as urgent are all increasing at an alarming rate to which therapies are limited," said Dr Edward Septimus, an infectious disease expert at HCA Healthcare System in Houston, Texas, and a member of the Infectious Diseases Society of America's Antimicrobial Resistance Workgroup.

Septimus, who was not involved with the CDC report, said the pathogens in the urgent and serious categories - which include Methicillin-resistant Staphylococcus aureus, or MRSA, and drug-resistant tuberculosis - are "certainly worthy of immediate response. I do believe it's a looming public-health crisis," he said.

In addition to ranking the threat of superbugs, the report outlines a four-point plan to help fight the spread of antibiotic resistance.

Not surprisingly, it underscores the need for new antibiotics, citing ever-slowing development efforts by pharmaceutical companies due to the high cost of such programs and relatively low profit margins of the drugs
It also stresses the need for hospitals to prevent infections from occurring and to contain the spread of resistant infections; carefully tracking the spread of resistant bacteria; and ensuring that antibiotics are prescribed only to patients who need them.

"It's not too late," Frieden said. "There are things we can do that can stop the spread of drug resistance. We need to scale up the implementation of those strategies."