Every additional day of antibiotic administration in the NICU results in lower anaerobe richness and butyrate producers, with more potential pathogens dominating the gut, study findings published in Clinical Infectious Diseases suggest.
According to Ashley M. Rooney, BSc, a PhD candidate at the University of Toronto, and colleagues, many infants in NICUs continue antimicrobial therapy without infection. Although discontinuation of unnecessary antibiotics is important for antimicrobial stewardship efforts, the researchers suggested that physicians may find it difficult.
“Infancy represents a critical time for gut microbiota development in which obligate anaerobes and butyrate-producers are required,” they wrote. “Anaerobes influence the education and maturation of the host immune system, provide colonization resistance against pathogens and antimicrobial resistant organisms, and play an important role in metabolism, including the production of short-chain fatty acids such as butyrate.”
The researchers conducted a retrospective cross-sectional study that included 72 infants who were administered either ampicillin and tobramycin (AT); ampicillin and cefotaxime (AC); or ampicillin, tobramycin and metronidazole (ATM). They compared stool swab samples collected within 7 days of stopping therapy from preterm and term infants.
Most preterm infants (73%) received AT (for a median of 4 days) whereas the remaining preterm infants received ATM (for a median of 7 days). According to the researchers, 71% of term infants received AT (for a median of 3 days), and 29% received AC (for a median of 3.5 days).
Rooney and colleagues noted that stool swab samples had low diversity and were dominated by potential pathogens. Each additional day of antimicrobial therapy after discontinuation resulted in 16% fewer obligate anaerobes (adjusted RR = 0.84; 95% CI, 0.73-0.95) and 18% fewer butyrate producers (aRR = 0.82; 95% CI, 0.67-0.97).
“Our findings add to the expanding literature on the unintended harms associated with prolonged antibiotic use in neonates,” the researchers wrote. “This information may be used to incorporate into risk/benefit assessments for discontinuing antibiotic therapy where continuation is appropriate.” – by Katherine Bortz
Disclosures: Rooney reports no relevant financial disclosures. Please see the study for all other authors’ relevant financial disclosures.