Kim Painter -- USA TODAY

The overuse of antibiotics has caused three kinds of bacteria, including one that causes life-threatening diarrhea, one that causes bloodstream infections and one that transmits sexually, to become urgent threats to human health in the United States, federal health officials say in a landmark report out Monday.

The report from the federal Centers for Disease Control and Prevention (CDC) is the first to categorize the threats posed by such germs in order of immediate importance, from "urgent," to "serious," to "concerning." It is also the first to quantify the toll of such so-called superbugs, saying they cause 2 million infections and 23,000 deaths each year.

"It's not too late," for the nation to respond, rein in the infections and keep antibiotics working - by reserving them for when they are truly needed - but several steps are needed right away, CDC director Tom Frieden said in a telephone news conference. "If we are not careful and we don't take urgent action, the medicine cabinet may be empty for patients with life-threatening infections in the coming months and years."

On the urgent list:

Carbapenem-resistant Enterobacteriaceae (CRE), bacteria that cause 9,000 infections in hospitals and other health-care facilities each year. The CDC says nearly half of hospital patients who get CRE bloodstream infections die from them. It's a "nightmare infection," Frieden says.

Drug-resistant gonorrhea, a sexually transmitted infection that now resists several antibiotics that used to cure it. CDC estimates 30% of the 800,000 cases in the United States each year fit that description.

Clostridium difficile, a serious diarrhea-causing infection that is not highly resistant to antibiotics but does thrive when antibiotics are over-used. The bacteria cause 250,000 infections and 14,000 deaths each year.

The list of serious infections include 11 kinds of drug-resistant bacteria and one fungus (Candida); the list of concerning infections includes two kinds of Streptococcus bacteria and one kind of Staphylococcus bacteria. The bugs were categorized based on their health impact, economic impact, how common they are, how common they could become, how easily they spread, how well they still respond to medication and how difficult they are to prevent.

CDC says there are several ways to get a handle on the problem, but the most important is to "change the way antibiotics are used," by cutting unneeded use in humans and animals and using the right antibiotics in the right way when they are needed.

Other steps include preventing infections in the first place with tools such as vaccines, safe food handling, hand-washing and infection-control plans in hospitals and other health care settings; better tracking of resistant infections and developing new antibiotics and tests for drug resistance.

Patients and family members can do their part by asking about the medicines they are prescribed and questioning infection control in hospitals and other health care facilities, says Michael Bell, deputy director of CDC's division of health care quality promotion: "If you are not comfortable asking questions, force yourself anyway ... ask, 'What are you doing to make sure my mom doesn't get an antibiotic-resistant infection?' "