Reduced antibiotic use decreases acquisition of multidrug-resistant organisms in ICUs

Even moderate reductions in antibiotic use could reduce transmission of multidrug-resistant organisms in the critical care setting, according to findings published in Infection Control & Hospital Epidemiology.

“Antibiotic exposure is the most significant driver of resistance. In the hospital setting, nearly 50% of all patients receive an antibiotic, including up to 75% of all critically ill patients,” Sean L. Barnes, PhD, assistant professor of operations management at the Robert H. Smith School of Business, University of Maryland, said in a press release accompanying the study. “But what is really troubling is that nearly half of all antibiotics prescribed may be inappropriate. Even moderate reductions in antibiotic use can reduce transmission of multidrug-resistant organisms.”

Barnes and colleagues used agent-based modeling to simulate the interactions between patients and health care workers that facilitate the transmission of multidrug-resistant organisms in an ICU setting. The researchers modeled both a microbiome effect, in which antibiotic use would decrease the amounts of bacteria that compete with multidrug-resistant organisms, and a mutation effect, in which some patients receiving antibiotics would develop genetically mutated drug-resistant organisms.

A 10% reduction in antibiotic use (from 75% to 65%) decreased the acquisition of high-prevalence multidrug-resistant organisms by 11.2%, the researchers wrote, whereas a 25% reduction (from 75% to 50%) lowered acquisition by 28.3% (P < .001 for both).

Barnes and colleagues wrote that the study was limited by the fact that researchers grouped all effects of antibiotics together regarding use and microbiome effect, which was not a reflection of real world differences between individual drugs, and by the fact that the model’s results would change based on its input parameters.

“Antibiotics have been one of the most useful and critical drugs in modern medicine, but our overuse of these drugs has hurt us by supporting the development of multidrug-resistant organisms,” Kerri Thom, MD, MS, an associate professor at the University of Maryland School of Medicine, said. “Our model suggests that substantial reductions in infection rates are possible if stewardship programs aggressively pursue opportunities to reduce unnecessary usage of antibiotics.” – by Andy Polhamus

Disclosure: The researchers report no relevant financial disclosures.