Antibiotic Use During Leukemia Treatment Reshapes Gut Microbiome
New research from Texas A&M University reveals that antibiotic use during chemotherapy for acute myeloid leukemia (AML) significantly alters the gut microbiome and influences the risk of antibiotic-resistant infections. The study highlights the necessitate for refined antibiotic strategies to protect patients while minimizing unintended consequences on gut health.
The Gut Microbiome and AML Treatment
Patients undergoing remission induction chemotherapy—the initial, intensive phase of AML treatment—routinely receive multiple antibiotics to prevent infection. However, researchers are finding that this practice can have complex effects on the gut microbiome, the community of microorganisms living in the digestive tract.
Balancing Risk: Infection vs. Antibiotic Resistance
The risk of infection is a significant clinical concern for AML patients. Chemotherapy suppresses immune function and damages the gastrointestinal lining, allowing bacteria to escape into the bloodstream. Doctors often initiate antibiotic treatment at the first sign of fever, even without confirmed bacterial infection, prioritizing patient safety. However, this approach can disrupt the delicate balance of the gut microbiome.
According to Dr. Jessica Galloway-Peña, assistant professor in the Texas A&M College of Veterinary Medicine and Biomedical Sciences’ Department of Veterinary Pathobiology, empirical antibiotic treatment can actually increase the risk of antibiotic-resistant infections later on. “We kill off the good bacteria that preserve resistant organisms in check, and we end up selecting for antibiotic-resistant organisms that are already present in the gut,” she explains.
Unexpected Patterns of Antibiotic Resistance
The study analyzed antibiotic administration data alongside microbiome and resistome data (the collection of all antibiotic resistance genes) to understand how different treatment patterns affected the genetic landscape of the gut. Surprisingly, patients treated with a wider variety of antibiotics did not end up with a greater number of antibiotic-resistance genes than expected. Researchers suggest that reducing the diversity of bacteria in the gut may also limit the potential for antibiotic resistance gene transfer.
Linezolid: A Complex Case
Linezolid, an antibiotic commonly used to treat serious bacterial infections, including methicillin-resistant Staphylococcus aureus (MRSA), is frequently prescribed to AML patients. The study found that increased exposure to linezolid was associated with a greater loss of microbiome diversity, which can make it easier for harmful bacteria to colonize. However, longer linezolid use was also associated with a reduced risk of colonization by antibiotic-resistant organisms.
“Each additional day of linezolid basically reduces your risk of antibiotic-resistant colonization,” Galloway-Peña noted, emphasizing the complex relationship between microbiome disruption and antibiotic-resistant infections.
Future Directions: Personalized Antibiotic Strategies
Future research will focus on using genomic and microbiome data to develop more personalized antibiotic treatment strategies. The goal is to tailor care to individual patients, recognizing that a one-size-fits-all approach may not be optimal.
“Not all treatment is one size fits all,” Galloway-Peña said. “With the advances of medicine, we could definitely get to a point where we can personalize therapy based on somebody’s own microbiome.”
Source: Texas A&M University
Study Citation: Samantha Franklin et al, Characterization of Antibiotic Administration Factors Associated with Microbiome Disruption and Subsequent Antibiotic-Resistant Infection and Colonization Events in Acute Myeloid Leukemia Patients Receiving Chemotherapy, Antibiotics (2025). DOI: 10.3390/antibiotics14080770