This article incorrectly said that a recently identified gene in certain bacteria enables the microbes to destroy most antibiotics. The gene enables the microbes to destroy antibiotics known as carbopenems, which are usually used in last-ditch efforts to save patients whose infections fail to respond to standard antibiotics.
A VERY SCARY GENE
Tuesday, October 12, 2010
Urinary tract infections, pneumonia and other common ailments caused by germs that carry a new gene with the power to destroy antibiotics are intensifying fears of a fresh generation of so-called superbugs.
The gene, NDM-1, which is apparently widespread in parts of India, has been identified in just three U.S. patients, all of whom had received treatment in India and recovered. But the gene's ability to affect different bacteria and make them resistant to many medications marks a worrying development in the fight against infectious diseases, which can mutate to defeat humans' antibiotic arsenal.
"The problem thus far seems fairly small, but the potential is enormous. This is in some ways our worst nightmare," said Brad Spellberg, an infectious-disease specialist at LA Biomed (the Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center) and author of "Rising Plague," a book about antibiotic resistance. "You take very common bacteria that live in all of us and can travel from person to person, and you introduce into it some of the nastiest antibiotic-resistance mechanisms there are."
The bacteria, which include previously unseen strains of E. coli and other common pathogens, appear to have evolved in India, where poor sanitation combines with cheap, widely available antibiotics to create a fertile environment for breeding new microorganisms.
The infections were then carried to the United States, Britain and more than a half-dozen other countries, often through "medical tourism," which involves foreigners seeking less expensive, more easily accessible surgery overseas.
"We need to be vigilant about this," said Arjun Srinivasan, a medical epidemiologist at the Centers for Disease Control and Prevention, which has been monitoring the spread of the microbes. "This should not be a call to panic, but it should be a call to action. There are effective strategies we can take that will prevent the spread of these organisms."
Experts fear the germs will follow the path of other multi-drug-resistant bugs and become a common scourge in medical centers and perhaps even among otherwise healthy people.
"It's an acute example of how bacteria can outwit people," said Stuart Levy, a professor of molecular biology at Tufts University School of Medicine and president of the Alliance for Prudent Use of Antibiotics.
So far, the highly resistant gene has not jumped into bugs spread by coughing or sneezing, and the three U.S. patients did not transmit their infections to anyone else. But the microbes can spread readily through other common ways, including contaminated sewage, water and medical equipment and lax personal hygiene such as inadequate hand-washing. Many patients eventually recover, but it remains unclear how many people have died and what the mortality rate is.
The origin of the microbes is politically sensitive. The Indian government has condemned the reports saying the bugs arose in that country, arguing that the tale was concocted by Western pharmaceutical companies and others to discredit India's burgeoning medical tourism industry, which is attracting more than 450,000 patients a year and could generate annual revenues of $2.4 billion by 2012, according to some estimates.
"They say it's found in patients who visit India and Pakistan," said India's health minister, Ghulam Nabi Azad. "It was nowhere mentioned if the bacteria are found even before those persons visited India."
The resistance gene - NDM-1 stands for New Delhi metallo-B-lactamase 1 - was first identified in 2008 in bacteria in a Swedish patient who had been hospitalized in New Delhi. The gene produces an enzyme that destroys most antibiotics, including so-called carbopenems, which are usually used in last-ditch efforts to save patients whose infections fail to respond to standard antibiotics.