Antibiotic therapy for early onset neonatal sepsis recommended by international guidelines and relevant studies is only kind of treatment regimen that penicillin G/ penicillin/ampicillin combined with gentamicin as the first-line treatment regimen. However, it is not applicable to the clinical practice in many countries and regions. We aim to study efficacy and safety of antibiotics in the treatment of early onset neonatal sepsis.

Inclusion Criteria:

• Age: postnatal age ≤ 72h;
• Meets NICE guidelines for using antibiotics to treat EONS;
• Azlocillin used as part of antimicrobial treatment;
• Parental written consent.

Exclusion Criteria:

• Expected survival time less than the treatment cycle;
• Major congenital malformations;
• Undergoing surgery within the first week of life;
• Receiving other systemic trial drug therapy;
• Other factors that the researcher considers unsuitable for inclusion.

Neonates suffered from early onset neonatal sepsis