In a level 3 neonatal unit, this retrospective cohort research was done. Group LD: 22 March 2020 to 5 September 2020—the reference group, Group pre-LD: 29 September 2019 to 14 March 2020, and Group temporally corresponding to LD in 2019 (corres-LD): 24 March 2019 to 7 September 2019—were compared. From LD phase 1.0 to Unlock 4.0, researchers looked for linear trends. Culture-positive sepsis was the most important outcome. In the LD, pre-LD, and corres-LD groups, there were 1,622, 2,744, and 2,700 subjects, respectively. Pre-LD had a greater rate of any culture-positive sepsis than LD [odds ratio (95% CI) = 1.61 (1.02–2.56)]. This was mostly owing to a statistically significant decrease in Acinetobacter baumannii sepsis, with incidence rate differences of pre-LD versus LD [0.67 (95% CI: 0.37–0.97), P=0.0001], and corres-LD versus LD [0.40 (95% CI: 0.16–0.64), P=0.0024]. Pre-LD and corres-LD groups exhibited greater MDR/extreme drug resistance/pan drug resistance sepsis than LD [77%, 77%, and 44%, respectively (P values of both groups vs. LD=0.01)]. There were fewer occurrences of MDR sepsis from LD 1.0 to unlock 4.0 (Plinear trends=0.047). Pre-LD (vs. reference group LD), male sex, birth weight, and Apgar score independently predicted culture-positive sepsis in multivariable analysis. In a hospital context, LD positively influenced the epidemiology of newborn sepsis, with fewer A. baumannii and MDR sepsis remaining after unlocking.