British researchers said Tuesday that a new bacterium resistant to most antibiotics is becoming more common in India and Pakistan and that it has been identified in 37 people in the U.K., primarily among people who have traveled to that region to receive cheaper medical care. U.S. authorities say that three cases of the infection have also been detected in this country. The outbreak is concerning, the researchers reported online in the journal Lancet Infectious Diseases, because the bug is resistant to a family of newer antibiotics called carbapenams, which are generally reserved for treating bacteria resistant to most other antibiotics.
However, experts said there is no evidence that the new resistant organisms, powered by a mutant gene called NDM-1 that confers resistance, is any more dangerous that the methicillin-resistant Staphylococcus aureus (MRSA) that has become widespread in the United States or any of a number of other carbapenam-resistant organisms that have been observed previously. The new organism is simply "one of a number of very serious bugs we're tracking," Dr. Alexander J. Kallen of the Centers for Disease Control and Prevention told the New York Times. He said the CDC has observed no more new cases in this country since its initial warning in June.
Experts also said that there are at least two older antibiotics that can attack carbapenam-resistant organisms: colistin, which may have some side effects, and Tygacil, manufactured by Pfizer. Pharmaceutical companies are also developing a number of other new antibiotics, a market that is currently viewed as potentially lucrative.
In the Lancet study, researchers headed by Dr. Timothy Welsh from Cardiff University collected specimens from hospitals and community medical centers in Bangladesh, India and Pakistan. The team found the mutant gene in 36 samples of Escherichia coli, one of the most common causes of urinary infections, and in 111 samples of Klebsiella pneumoniae, which causes lung infections. The mutant strains were resistant to all antibotics except Tygacil and colistin, and some samples were resistant to those as well. The team said nothing about the fate of the infected patients.
India and Pakistan have developed some excellent hospitals and surgeons that provide medical care and surgical procedures, especially elective procedures, more cheaply than they are available in the West. But the overuse of antibiotics among the larger population leads to the development of resistance, and those organisms can make their way into even the best hospitals.
For the moment, most people agree, the new organisms are not an immediate threat in the West. But authorities caution that anyone who becomes ill after visiting Asia for medical procedures should be carefully screened for the new organisms.
Thomas H. Maugh II / Los Angeles Times