Low level of worrisome resistant bacterium in U.S.

Infections Program, a network of state and local health departments and academic institutions that work with the CDC to monitor incidence of infectious diseases. These surveillance efforts can help inform control and prevention programs.

To identify cases, the investigators actively collected reports of all carbapenem-nonsusceptible A baumannii isolates from clinical laboratories serving the catchment areas. They also collected data on antibiotic susceptibility, patient demographics, healthcare exposures, types of infection diagnosed, and patient outcomes. The aim was to estimate the crude population-based incidence of carbapenem-nonsusceptible A baumannii and describe the epidemiology over the surveillance period.

Overall, a total of 621 cases from 539 unique patients were reported during the study period, with most cases occurring in Georgia (300, 48.3 percent) and Maryland (236, 38 percent). Almost all of the cases were based on isolation of carbapenem-nonsusceptible A baumannii from urine (429, 71.7 percent) and blood (157, 26.3 percent), and the most common infections reported were UTI (328, 65.2 percent) and bacteremia (158, 31.4 percent). Complete data were available for 598 of the cases.

The overall crude incidence rate of 1.2 cases per 100,000 persons in the surveillance population is lower than found in surveillance of the same population for CRE infections (2.93 cases/100,000), and significantly lower than estimated incidence rates for MRSA (25.1/100,000) and C difficile (141.8/100,000).

The median age of the patients was 58.6 years, and only 3 percent of patients had no identified underlying conditions. Nearly all the cases (590, 98.7 percent) had healthcare exposure in the year before sample collection or an indwelling device, such as a urinary catheter, at the time of sample collection. Most of the patients had either been admitted to a short-stay acute-care hospital (469, 78.4 percent) or a long-term care facility (360, 60.2 percent).

“I think the fact that 99 percent of our patients had some sort of exposure to a healthcare facility…or had an indwelling device…reiterates the fact that these are healthcare-associated infections,” said Sandra Bulens, MPH, lead study author and epidemiologist with the CDC.

Bulens and her co-authors argue that this finding not only supports the current focus on preventing A baumannii transmission in acute-care settings, but also highlights the need for hospitals to notify