Wednesday, 30 June 2021


Written by Beatriz Villanueva Iribarren | Marta Irañeta Poyo

Figure 1. Presence of gram-positive coco bacteria in the macrophage cell cytoplasm.

Male neonate born one-day-old preterm during the week 29 + 1, whose mother presents a history of a Klebsiella pneumoniae urinary tract infection (UTI) treated with phosphomycin. At delivery, she did not report fever or other infectious symptoms.

On admission, the blood test of the newborn presents leukocytosis together with neutrophilia (63500 leucocytes/μL with 31200 neutrophils/μL); the acute phase reactants (RFA) being negative: C reactive protein (PCR) 0.21 mg/L and procalcitonin (PCT) 0.19 ng/mL. The next day, he maintained leukocytosis with neutrophilia (40000 leucocytes/μL with 22400 neutrophils/μL); RFAs being positive: PCR 150 mg/dL and PCT 3.66 mg/dL.
Given the maternal history, as well as the analytical one, antibiotic therapy with ampicillin and gentamicin is started with the neonate when the mother presents a positive urine culture for Klebsiella pneumoniae, sensitive to gentamicin.

After 5 days of antibiotic treatment, it is suspended when cultures and RFA are negative (PCR 0.49 mg/dL and PCT 0.15mg/dL).

Two days after the above mentioned suspension, the patient presents a fever of 8 hours duration without respiratory distress, apnea or hypoactivity. With the passing of the hours, he did not show a fever, but he did show signs of hypoactivity together with a blood gas test that presented mixed acidosis. The analysis revealed a leukocytosis (17600 leucocytes/μL and 16300 neutrophils/μL) with increased RFA: PCR of 97.88 mg/dL and PCT 17.13 mg/dL.

A peripheral blood smear was performed in which leukaryotic cells with the presence of intraleukocyte microorganisms were observed (image 1).
Antibiotherapy with cefotaxime and intravenous vancomycin is started pending the results of the extracted cultures. The next day, vancomycin-sensitive Staphylococcus epidermidis is isolated from the central and peripheral blood cultures.

Finally, late sepsis of nosocomial origin (suspected catheterized sepsis) is diagnosed, with a positive blood culture for Staphylococcus epidermidis.

Neonatal sepsis is one of the main diagnoses within Neonatal Intensive Care Units (ICU-N). It is defined as a set of clinical and analytical symptoms or signs within the first 4 weeks of life following an infection; either suspected or microbiologically proven. In the premature newborn (RN) (although there is no consensus), neonatal sepsis is considered to be one that occurs within 44 weeks of postmenstrual age.

According to the time of its onset, it is classified as: early onset sepsis when symptoms are observed before the first 72 hours of life; and late-onset sepsis when symptoms appear after 72 hours. The first group, usually occurs by vertical transmission, being Streptococcus of group B, Escherichia coli, Klebsiella and Listeria the mainly involved microorganisms. In contrast, the second group is mainly due to pathogens acquired during the postnatal period, mainly Gram-positive cocci and Klebsiella.

Those episodes in which there are clinical signs of infection along with positive blood cultures are classified as confirmed sepsis.



  1. Zea Vera A, G. Turin C, J.Ochoa T. Unificando los criterios de sepsis neonatal tardía: propuesta de un algoritmo de vigilancia diagnóstica. Rev Peru Med Exp Salud Publica. 2014 April; 31 (2): 358-363.
  2. Soibelmann Procianoy R, Silveira Rita C. The challenges of neonatal sepsis management. J Pediatr (Rio J). 2020; 96 (S1): 80-86.

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