Etiology of early and late neonatal sepsis at the national institute of pediatrics from 2015 to 2019

Neonatal sepsis is an infectious disease caused mainly by Escherichia coli bacteria in developing countries.1 The term neonatal sepsis refers to a clinical syndrome described as a systemic inflammatory response syndrome, characterized by a systemic bacterial infection which is documented by bacterial isolation from a blood culture or cerebrospinal fluid culture resulting in the growth of the microorganism that caused the neonatal sepsis.1,2 Sepsis has high morbidity and mortality rates, which have serious consequences for the prognosis of the newborn. It is important to know the main factors related to this pathology, and determining the etiology allows us to standardize appropriate diagnostic procedures. Despite the existence of literature reporting the main infectious agents causing early and late neonatal sepsis, it is necessary to update or confirm the data at the Institute. The objective of the following study was to identify the main etiologies in early and late neonatal sepsis. We found that the most frequently identified etiological agent in patients with neonatal sepsis at the National Institute of Pediatrics is Escherichia coli in 14.7% of cases, followed by Staphylococcus aureus in 5.2% and Klebsiella pneumoniae in 4.3%. The most frequent etiological agents in isolated early neonatal sepsis are Escherichia coli (11%), Enterococcus faecalis (2.7%), and Staphylococcus aureus (1.38%). In late-onset neonatal sepsis, Escherichia coli accounts for 21.4%, Staphylococcus aureus for 11.9%, and Klebsiella pneumoniae for 11.9%. This differs from two previous studies conducted at the National Institute of Pediatrics, one of which was carried out from 2008 to 2013, reported Staphylococcus epidermidis as the most frequently isolated etiological agent in late-onset neonatal sepsis, accounting for 26.9%, followed by Escherichia coli, Klebsiella pneumoniae, and Staphylococcus hominis, each accounting for 13.4%. Similarly, another series reported by the INP in 2003 found that the most frequent etiological agent was Klebsiella pneumoniae.3,4