Multidrug-resistant bacterial colonization of combat-injured personnel at admission to medical centers after evacuation from Afghanistan and Iraq.

BACKGROUND Multidrug-resistant organism (MDRO) infections, including those secondary to Acinetobacter (ACB) and extended spectrum β-lactamase (ESBL)-producing Enterobacteriaceae (Escherichia coli and Klebsiella species) have complicated the care of combat-injured personnel during Operations Iraqi Freedom and Enduring Freedom. Data suggest that the source of these bacterial infections includes nosocomial transmission in both deployed hospitals and receiving military medical centers (MEDCENs). Admission screening for MDRO colonization has been established to monitor this problem and effectiveness of responses to it. METHODS Admission colonization screening of injured personnel began in 2003 at the three US-based MEDCENs receiving the majority of combat-injured personnel. This was extended to Landstuhl Regional Medical Center (LRMC; Germany) in 2005. Focused on ACB initially, screening was expanded to include all MDROs in 2009 with a standardized screening strategy at LRMC and US-based MEDCENs for patients evacuated from the combat zone. RESULTS Eighteen thousand five hundred sixty of 21,272 patients admitted to the 4 MEDCENs in calendar years 2005 to 2009 were screened for MDRO colonization. Average admission ACB colonization rates at the US-based MEDCENs declined during this 5-year period from 21% (2005) to 4% (2009); as did rates at LRMC (7-1%). In the first year of screening for all MDROs, 6% (171 of 2,989) of patients were found colonized at admission, only 29% (50) with ACB. Fifty-seven percent of patients (98) were colonized with ESBL-producing E. coli and 11% (18) with ESBL-producing Klebsiella species. CONCLUSIONS Although colonization with ACB declined during the past 5 years, there seems to be replacement of this pathogen with ESBL-producing Enterobacteriaceae.