Drug-resistant superbugs reach 3 states

By Chicago Tribune and The Associated Press

An infectious-disease nightmare is unfolding: Bacteria that have been made resistant to virtually all antibiotics by an alarming new gene have sickened people in three states and are popping up around the world, health officials reported Monday.

The U.S. cases — one each in California, Illinois and Massachusetts — and two others in Canada all involve people who recently had received medical care in India, where the problem is widespread. A British medical journal revealed the risk last month in an article describing dozens of cases in Britain in people who had gone to India for medical procedures.

How many deaths the gene may have caused is unknown; there is no central tracking of such cases. The gene mostly has been found in bacteria that cause gut or urinary infections.

Scientists long have feared this — a very adaptable gene that hitches onto many types of common germs and confers broad drug resistance, creating dangerous "superbugs."

In India, several kinds of bacteria are spreading that carry a gene called NDM-1, which makes a carbapenem-destroying enzyme. Carbapenems are key antibiotic weapons against these "Gram-negative" bacteria, which already are challenging to treat.

Infectious-disease experts have described the situation as a potential nightmare scenario in which other bacteria acquire the gene, rendering an entire class of antibiotics useless against them.

For decades, antibiotics have been prescribed for colds, flu and other viral infections that don't respond to these drugs. The misuse of antibiotics helped fuel the rise of drug-resistant "superbugs."

One of the most prevalent is methicillin-resistant Staphyloccus aureus, or MRSA, which can spread rapidly when strict hygiene procedures aren't followed, especially in hospitals.

The three NDM-1 cases in the United States involved three bacteria that remain susceptible to the antibiotics colistin, polymixin and tigecycline, said Karen Bush, an Indiana University professor and widely known expert on resistance in bacteria.

But "one of the problems is that use of these antibiotics can also eventually result in resistance," said Bush, who spoke about resistant bacteria Monday at the Interscience Conference on Antimicrobial Agents and Chemotherapy in Boston. The conference was buzzing with reports of the NDM-1 gene named for New Delhi.

No drugs in Phase 3 clinical trials work against the NDM-1 mechanism, Bush said. But, she said, there are promising compounds in earlier stages of development.

"It's a great concern," because drug resistance has been increasing and few new antibiotics are in development, said Dr. M. Lindsay Grayson, director of infectious diseases at the University of Melbourne in Australia.

"It's just a matter of time" until the gene spreads more widely person to person, he said.

Medical epidemiologist Dr. Alex Kallen of the federal Centers for Disease Control and Prevention (CDC) warned against panic. Although the NDM-1 mechanism is new, he said, other bacteria already found in the state also can evade carbapenems.

"That is not to downplay this," Kallen said. "It is important, but this particular mechanism is just one of many that can cause this kind of pattern."

"We want physicians to look for it," especially in patients who have traveled recently to India or Pakistan, said Brandi Limbago, a lab chief at the CDC.

The gene is carried by bacteria that can spread hand-to-mouth, which makes good hygiene important.

It's also why health officials are so concerned about where the threat is originating, said Dr. Patrice Nordmann, a microbiology professor at South-Paris Medical School. India is an overpopulated country that overuses antibiotics and has widespread diarrheal disease and many people without clean water.

"The ingredients are there" for widespread transmission, he said. "It's going to spread by plane all over the world."

The U.S. patients were not related. The California woman needed hospital care after a car accident in India. The Illinois man had pre-existing medical problems and a urinary catheter, and is believed to have contracted an infection with the gene while traveling in India. The Massachusetts case involved an Indian woman who had surgery and chemotherapy for cancer in her country and then traveled to the United States.

Lab tests showed their germs were not killed by drugs normally used to treat drug-resistant infections, including "the last-resort class of antibiotics that physicians go to," Limbago said.

She did not know how the three patients were treated, but all survived.

Doctors have tried treating some of these cases with combinations of antibiotics, hoping that will be more effective than individual ones are. Some have resorted to using polymyxins — antibiotics used in the 1950s and '60s that were unpopular because they can harm the kidneys.

The two Canadian cases were treated with a combination of antibiotics, said Dr. Johann Pitout of the University of Calgary in Alberta. One case was in Alberta, the other in British Columbia.

Both patients had medical emergencies while traveling in India. They developed urinary infections that were discovered to have the resistance gene once they returned home to Canada, Pitout said.

The CDC advises hospitals that find such cases to put the patient in medical isolation, check the patient's close contacts for possible infection, and look for more infections in the hospital.

Any case "should raise an alarm," Limbago said.

What can people do?

Don't add to the drug-resistance problem, experts say. Don't pressure your doctors for antibiotics if they say they aren't needed, use the ones you are given properly, and try to avoid infections by washing your hands.