(NBC NEWS) -- More than two million people are infected by drug-resistant germs each year, and 23,000 die of their infections, federal health officials reported Monday. The biggest killer by far is C. difficile, the Centers for Disease Control and Prevention reports in its first big overview of a growing problem.
Doctors have been warning of the problem for decades, yet up to half the prescriptions written for antibiotics are unnecessary, the CDC report says. And all these unneeded antibiotics are making the superbug problem worse.
The report rates the germs for the first time, ranking as urgent threats Clostridium difficile; a group of stomach bugs called carbapenem-resistant Enterobacteriaceae (CRE); and drug-resistant gonorrhea.
"This is the first time that we have divided these bacteria into categories and called some of them urgent," says Dr. Steve Solomon, director of CDC's Office of Antimicrobial Resistance.
"We are trying to sound the alarm on these bugs that we call urgent," Solomon told NBC News. "These are particularly frightening."
Worse, the CDC report points out, there aren't any new antibiotics in the immediate works that will kill any of these bugs. So patients may have to be treated with older, more toxic drugs, or with cocktails of antibiotics that may cause side-effects.
"If we are not careful, the medicine chest will be empty when we go there to look for a lifesaving antibiotic for somebody who has a deadly infection," CDC director Dr. Tom Frieden told reporters in a telephone briefing.
"Without care we will soon be in a post-antibiotic era," Frieden added. "For some infections ... we are already there."
C. difficile has become a scourge of hospitals and infection is often made possible when patients are heavily treated with antibiotics to fight other infections. It can cause unstoppable diarrhea and the latest treatment doesn't even involve antibiotics, but a transplant of so-called good bacteria from healthy patients.
CREs are a group of bacteria that resist even the strongest antibiotics. They include Klebsiella pneumoniae, which saw its infection rate jump 550 percent between 2001 and 2011.
"CRE is a nightmare bacteria we reported on in March, bacteria that can resist virtually all antibiotics," Frieden said
Gonorrhea may not be immediately life-threatening, but it's developing resistance to the drugs that used to easily treat it. Patients can be left infertile, and, in January, Canadian researchers reported that seven percent of patients weren't cured by the only pill left to treat gonorrhea.
Nearly 322,000 cases of gonorrhea were reported in the U.S. in 2011, making it again the second most commonly reported notifiable infection in the nation. Sufferers often show no signs, so more than 800,000 are infected every year in actuality, Frieden says.
The CDC's list of serious threats includes:
•Fluconazole-resistant Candida (a fungus)
•Extended spectrum beta-lactamase producing Enterobacteriaceae (ESBLs)
•Vancomycin-resistant Enterococcus (VRE)
•Multidrug-resistant Pseudomonas aeruginosa
•Drug-resistant Non-typhoidal Salmonella
•Drug-resistant Salmonella Typhi
•Methicillin-resistant Staphylococcus aureus (MRSA)
•Drug-resistant Streptococcus pneumoniae
Concerning threats include:
•Vancomycin-resistant Staphylococcus aureus (VRSA)
•Erythromycin-resistant Group A Streptococcus
•Clindamycin-resistant Group B Streptococcus
Bacteria develop resistance to drugs quickly. Even before penicillin was introduced in 1943, staphylococcus germs were identified that were resistant to its effects. Just nine years after tetracycline was introduced in 1950, a resistant strain of Shigella evolved. Methicillin-resistant Staphylococcus aureas (MRSA) evolved just two years after methicillin hit the market in 1960.
The last new antibiotic to be introduced was ceftaroline, in 2010. It took just a year for the first staph germ to emerge that resisted its effects.
The most immediate problem is in hospitals, Frieden says, but there are also problems when people don't finish taking their prescribed course of antibiotics and the heavy use of antibiotics in farm animals that aren't sick, the CDC says.
"We have to change the culture of how healthcare is delivered in this country. That's not easy," says Dr. Ed Septimus of the Infectious Diseases Society of America and the HCA Healthcare System in Houston.
"Part of it is in fact the culture of antibiotics that goes back to the 1940s," Septimus added in a telephone interview. He says he faced the same dilemma as many doctors do - patients who demand antibiotics. "A patient comes in and says 'I have this cold, and I know about the problems with antibiotics but every other doctor I ever had gave me this antibiotic and it knocked it out after a few days'," he said.
It's a hard demand to resist, Septimus added.
"There is something about the culture of antibiotics that is deeply imbedded in patients and in doctor that has us treating antibiotics differently from any other drug."
Septimus says hospitals and doctors must be help more accountable for their use and abuse of antibiotics.
"It can't just be done in one hospital. It has to be in all hospitals across a community," he said. Long-term care clinics, dialysis clinics, nursing homes all have to be part of the effort, he added.
The Health and Human Services Department has some initiatives to penalize hospitals for some practices that spread infections, but more needs to be done, Septimus added.
"Unless you put some accountability around it, people are going to be very slow to change," Septimus added.