Are antibiotics a risk factor for the development of necrotizing enterocolitis-case-control retrospective study

Previous studies have identified numerous risk factors associated with necrotizing enterocolitis (NEC) in very low birth weight (VLBW; birth weight less than 1500 g) infants. One of the potential pathophysiological contributors could be antibiotic therapy. Our aim was to explore the association between antibiotic exposure and NEC in VLBW infants. We designed a retrospective 1:2 case-control cohort study in a level III neonatal intensive care unit. Our study group composed of VLBW infants born between January 2012 and December 2014 with a diagnosis of NEC stage IIA or greater (Bell's modified criteria). Our intent was to match every case in the study group to two controls. Our primary outcome was an association between antibiotic exposure and NEC. Twenty-two cases of NEC were matched to 32 controls. The infants who developed NEC were exposed to a statistically significantly more frequent number of antibiotic courses and to more days on any antibiotic prior to the development of NEC. There were significant differences between cases and controls with respect to the duration of exposure to gentamicin and meropenem specifically.Conclusion: The data from our study demonstrate that prolonged exposure to antibiotic therapy is associated with an increased risk of NEC among VLBW infants. Furthermore, gentamicin and meropenem, but not other antibiotics, had a significant association with the incidence of NEC. What is known: • Early antibiotic exposure is a risk factor for the development of necrotising enterocolitis (NEC) in very low birth weight infants • Prolonged initial empirical antibiotic course for ≥ 5 days, despite sterile blood culture, is associated with an increased risk of developing NEC What is new: • The cumulative total number of days of antibiotic exposure is associated with an increased risk of developing NEC • Gentamicin and meropenem, but not other antibiotics, had a significant association with the incidence of NEC in our study.