Multidrug-Resistant Acinetobacter Infections Remain Prevalent In and Out of Hospital

Alice Goodman

November 04, 2009

November 4, 2009 (Philadelphia, Pennsylvania) — Multidrug-resistant (MDR) Acinetobacter baumannii (ACBA) is a persistent threat to hospitalized patients, whether the infection is acquired in the hospital or the community. Treatment options are limited for this potentially lethal infection, yet most hospitals do not isolate patients with community-acquired MDR ACBA.

A study presented here at the Infectious Diseases Society of America 47th Annual Meeting suggests that implementing infection control practices in hospitalized patients at risk for community-onset MDR ACBA could reduce the in-hospital transmission of this infection.

"MDR ACBA is a worldwide problem that is associated with higher mortality than susceptible ACBA. In this study, infection control practices used in patients with hospital-onset MDR ACBA reduced the number of new MDR ACBA infections, and we think that these practices should also be implemented for patients hospitalized with community-onset infections," said Ameet Hingwe, MD, from the Division of Infectious Diseases and Hospital Epidemiology at Henry Ford Hospital in Detroit, Michigan.

Infection control practices included staff education, enhanced hand hygiene, contact isolation, surveillance cultures, and daily chlorhexidine baths.

A retrospective chart analysis from April 2007 to December 2008 at the 900-bed Henry Ford Hospital found that 276 patients had ACBA-positive cultures. Of these, 189 cases (68%) were MDR ACBA and 87 (32%) were susceptible ACBA. Fifty-seven percent were hospital-onset and 43% were community-onset infections.

ACBA infections were documented in 121 (64%) of the MDR group and in 63 (72%) of the susceptible group; other patients were considered colonizers, said Dr. Hingwe.

Pneumonia was the most common infection in the MDR group (48 of 121; 39%), whereas urinary tract infection was more common in the susceptible group (27 of 63; 42%). Death was significantly more common in the MDR group than in the susceptible group (31% vs 9%; P < .001).

On multivariate analysis, Dr. Hingwe's team identified the following risk factors for the development of MDR ACBA: hospitalization within the previous year, antibiotic use within the previous 30 days, being on a ventilator, previous stay in an intensive care unit (ICU), acute renal failure, chronic wounds, and hemiplegia.

The implementation of infection control practices helped to bring down the overall number of cases of MDR ACBA in the hospital during the study period, Dr. Hingwe said. However, the number of community-onset MDR infections remained the same over the study period. In the community-onset cases (43% of cases), about 93% of patients had recently received care in hospitals, dialysis centers, or outpatient clinics.

Currently, at Henry Ford Hospital, only ICU cases of MDR ACBA are isolated. Private patients with MDR are isolated only if they are thought to be at risk of contaminating the environment, for example, by urine leakage or wound leakage. Dr. Hingwe said that implementing the same infection control practices in the community-onset cases of MDR ACBA should bring down the number of infections overall.

Richard Whitley, MD, from the University of Alabama at Birmingham, agreed that isolation is important in cases of MDR ACBA.

"Every attempt should be made to avoid MDR ACBA, particularly in the immunocompromised host where this infection can disseminate into the bloodstream. We are now seeing this infection in hospitalized patients with intravenous lines. In some hospitals, a patient with ACBA may be put in the same room as other immunocompromised patients, but isolation is recommended to prevent transmission in the hospital environment," he emphasized.

Dr. Hingwe has disclosed no relevant financial relationships. Dr. Whitley reports financial ties with Gilead, 3-V Biosciences, and Chimerix.

Infectious Diseases Society of America (IDSA) 47th Annual Meeting: Abstract 506. Presented October 30, 2009.