Common bacteria may become antibiotic-resistant superbugs

Common bacteria could be on the verge of becoming antibiotic-resistant superbugs, scientists, including one of Indian-origin, have found.
Resistance to antibiotics is in danger of spreading globally among bacteria responsible for respiratory and urinary infections in hospital settings, the study found.
Researchers found that two genes that confer resistance against a particularly strong class of antibiotics, called carbapenems, can be shared easily among a family of bacteria responsible for a significant portion of hospital-associated infections.
One gene, KPC, was detected in New York in 2001 and the other, NDM-1, was identified in 2006 in New Delhi.
"Carbapenems are one of our last resorts for treating bacterial infections, what we use when nothing else works," said senior author Gautam Dantas, associate professor of pathology and immunology at Washington University School of Medicine in St Louis.

"Given what we know now, I don't think it's overstating the case to say that for certain types of infections, we may be looking at the start of the post-antibiotic era, a time when most of the antibiotics we rely on to treat bacterial infections are no longer effective," he said.

The study was conducted by researchers at Washington University, Barnes-Jewish Hospital and the National University of Sciences and Technology in Pakistan.
The researchers studied a family of bacteria called Enterobacteriaceae, which includes E coli, Klebsiella pneumoniae and Enterobacter.
Two genes are primarily responsible for carbapenem-resistant versions of these disease-causing bacteria. The gene, KPC, after it was detected in New York quickly spread around most of the world, with the exception of India, Pakistan and other South Asian countries.

The second carbapenem resistance gene, NDM-1, after being identified in New Delhi was soon detected throughout South Asia, and most patients infected by bacteria with NDM-1 have had an epidemiological link to South Asian countries.
For the study, researchers compared the genomes of carbapenem-resistant bacteria isolated in the US with those of carbapenem-resistant bacteria isolated in Pakistan.
The bacteria's high genetic similarity suggested that the antibiotic resistance genes could be shared easily between bacteria from the two geographic regions.
The researchers also sequenced a special portion of bacterial genetic material called plasmids that can easily pass from one bacterial strain to another. A plasmid is the primary way antibiotic resistance genes spread between bacteria.

The researchers identified a few key instances in which the plasmids carrying NDM-1 or KPC were nearly identical, meaning they easily could facilitate the spread of antibiotic resistance between disease-causing bacteria found in the US and South Asia.