This article is more than 5 years old. Information may no longer be current.
MDR gram-negative bacilli colonization remains high in US military
Multidrug-resistant gram-negative bacilli colonization rates were more than 12% in a cohort of military service members at facilities in the United States, according to recent findings.
An increasing number of military treatment facilities have implemented stricter infection control measures to combat high rates of MDR gram-negative bacilli. One such measure is active surveillance cultures for asymptomatic colonization.
The current analysis includes surveillance culture results from patients at the Landstuhl Regional Medical Center in Germany and from three other treatment facilities in the United States. Cultures available for analysis were collected between June 2009 and May 2012.
The rate of MDR gram-negative bacilli colonization was 6.6% at Landstuhl. Participating military treatment facilities in the United States had a 12.4% colonization rate. The most frequently occurring organism was Escherichia coli, which comprised 82.4% of MDR isolates at the German facility. This organism represented 67.1% to 83.3% of the MDR isolates at the facilities in the Unites States. Acinetobacter calcoaceticus-baumannii complex and Klebsiella pneumoniae were the other most common MDR gram-negative bacilli.
Surveillance culture results also revealed non-MDR Pseudomonas aeruginosa.
No significant differences in MDR gram-negative bacilli rates were reported during the 3-year period.
“Ongoing research includes assessment of predictive factors for MDR [gram-negative bacilli] colonization and the relationship between colonization and infection,” the researchers wrote.
Higher rates of gram-negative bacilli colonization were reported in service members who sustained combat-related injuries, according to the findings. Nine percent of those at Landstuhl and 16% of injured members at the US facilities were colonized. The researchers noted that deployed service members without injury who were transported via the same route as injured members also had significantly increased rates of colonization for gram-negative bacilli.
“The patients were the same, so injury severity would not explain differences between Landstuhl and the US,” Amy C. Weintrob, MD, associate professor of medicine in the department of preventive medicine and biometrics at the Uniformed Services University of the Health Sciences in Bethesda, Md., and staff physician at the Walter Reed National Military Medical Center, told Infectious Disease News. “Possible explanations for the differences between the rates at Landstuhl and the US include: nosocomial acquisition through the evacuation chain, longer time available for bacterial growth, different culturing techniques, or greater administration of antibiotics.”
Amy C. Weintrob
Weintrob said one of the main objectives of the current Trauma Infectious Disease Outcomes Study was to evaluate risk factors for infection and colonization. Ideally, the findings should contribute to the development of preventive measures.
“Gram-negative MDR colonization rates remain persistently high, warranting the continued use of surveillance cultures for asymptomatic colonization and pre-emptive contact isolation while awaiting culture results,” she said.
Amy C. Weintrob, MD, can be reached at Amy.C.Weintrob.ctr@health.mil.
Disclosure: Support for this work (IDCRP-024) was provided by the Infectious Disease Clinical Research Program, a Department of Defense program executed through the Uniformed Services University of the Health Sciences. This project has been funded by the National Institute of Allergy and Infectious Diseases, NIH, under Inter-Agency Agreement Y1-AI-5072, and the Department of the Navy under the Wounded, Ill, and Injured Program.