While it may be less as well-known than MRSA, drug-resistant strains of the potentially dangerous bacteria, Acinetobacter, are beginning to become increasingly common in American hospitals, according to a new study.
In reviewing data from 300 hospitals nationwide, the researchers, part of the Washington, DC-based Extending the Cure project, looked at imipenem, an antibiotic often used as a last-line treatment against the bacteria. Between 1999 and 2006, more than a 300% increase occurred in the proportion of Acinetobacter cases resistant to the drug, they report in the most recent issue of Infection Control and Hospital Epidemiology. The national resistance rate, as determined by the study, was estimated at 18%.
Acinetobacter infections have recently been linked to infections impacting soldiers returning home from the war in Iraq. Many infections often have affected patients in hospital intensive care units (ICUs): Using one of the largest sample sizes to date, 47,000-plus Acinetobacter isolate samples were tested against imipenem that were collected between 1999 and 2006. Those recovered from patients in intensive care units (ICUs) accounted for 33% of all isolates.
These infections often can appear as severe pneumonias or bloodstream infections, and will require strong drugs for treatment. The most common sources of isolates were found in the respiratory tract (52%), urine (11%), wounds (22%), and blood (12%). However, they noted that identifying the presence of Acinetobacter did not indicate that an infection occurred.
Most of the cases originated in the South Atlantic states (22%), followed by Middle Atlantic (21%), Pacific (16%), North Central (13%), West South Central (8%), East South Central and West South Central (5%), and New England (2%).
"The findings are troubling because they suggest this bacteria is becoming resistant to nearly everything in our arsenal," said Ramanan Laxminarayan, PhD, a principal investigator with Extending the Cure. "There is a lot of attention on MRSA, but less on infections caused by bacteria like Acinetobacter for which there are fewer drugs in the development pipeline. While all drug resistance is of concern, it is particularly worrying in the case of bugs for which we have few treatment options."