Antimicrobial susceptibility data for beta-lactams showed that the control and NEC strains carried an AmpC beta-lactamase (29% (n = 5) and 25% (n = 1), respectively), extended-spectrum beta-lactamase (ESBL) (35% (n = 6) and 2.5% (n = 1), respectively), or penicillinase (18% (n = 3) and 50% (n = 2), respectively). The gene discussed is LACTB; the disease is necrotizing enterocolitis.