Tiny circles of DNA called plasmids appear to be the culprit. They can easily enter bacteria and move from one bacteria to another, and some carry a gene that makes bacteria drug-resistant, a new study finds.
"The plasmids we are talking about carry an antibiotic-resistant gene to a class of antibiotic called carbapenems," said the study's co-author, Dr. Tara Palmore, an infection control specialist at the U.S. National Institutes of Health.
Carbapenems are antibiotics of last resort, and carbapenem-resistant Enterobacteriaceae (CRE) are bacterial pathogens that pose a "formidable" threat to hospitalized patients, according to the research.
The incidence of CRE has quadrupled in the last decade in the United States, according to background information in the report. CRE has been detected in nearly 4 percent of hospitals and about 18 percent of long-term acute care facilities. In addition, the researchers noted, CRE are resistant to most, if not all, antibiotics. Investigations have reported a death rate of 40 percent to 80 percent from infection.
Given ongoing concerns that even bacteria like Klebsiella and Enterobacter -- which are found in the environment and in healthy stomachs -- are becoming increasingly resistant to last-resort antibiotics, the researchers set out to find some answers. Their report, published Sept. 17 inScience Translational Medicine, showed that plasmid transfer in hospitals is likely contributing to the increase in antibiotic-resistant bacteria.