title: [Prolonged exposure to antibiotics and the risk of late-onset sepsis (LOS) in neonates of 1,000-1,500 g: a cohort study].
abstract: OBJECTIVE
  To determine whether prolonged exposure to antibiotics (>5 days) increases the risk of late-onset sepsis (LOS) in newborns of 1,000-1,500 g.
  
  
  METHODS
  A cohort study in newborns with suspected perinatal infection, with a survival greater than seven days. The exposed cohort was composed of newborns with antibiotic therapy initiated at first postnatal day, lasting >5 days, with negative blood cultures before the fifth day of life, and without clinical evidence of sepsis. The non-exposed cohort was identical but with antibiotics stopped before the fifth day of life. Patients were followed daily for clinical and laboratory evidence of LOS. Others risk factors for LOS were analyzed.
  
  
  METHODS
  We analyzed the incidence, the relative risk (RR) with 95% CI. To measure the time to occurrence of an event of LOS after exposure, Kaplan-Meier survival curve and log-rank test were used.
  
  
  RESULTS
  We followed up 49 patients in each group. The incidence was 33.6%. The time of follow-up was 839 vs. 1,291 person-days. Prolonged exposure to antibiotics was associated with a higher risk of LOS (RR: 21.1; 95% CI: 6.5-68.9; p=0.000). The late-onset sepsis-free time was 17.1±1.1 vs. 26.3±0.8 days.
  
  
  CONCLUSIONS
  The risk of LOS was higher in newborns with prolonged exposure to antibiotics and increased with the days of exposure.
authors.affiliation: Servicio de Neonatología, Unidad Médica de Alta Especialidad (UMAE) N.o 23 Hospital de Ginecología y Obstetricia Dr. Ignacio Morones Prieto, Instituto Mexicano del Seguro Social (IMSS), Monterrey, N.L., México.
authors.forename: Evangelina
authors.initials: E
authors.lastname: Briones-Lara
authors.affiliation: Servicio de Neonatología, Unidad Médica de Alta Especialidad (UMAE) N.o 23 Hospital de Ginecología y Obstetricia Dr. Ignacio Morones Prieto, Instituto Mexicano del Seguro Social (IMSS), Monterrey, N.L., México.
authors.forename: Joaquín
authors.initials: J
authors.lastname: Treviño-Báez
authors.affiliation: Servicio de Neonatología, Unidad Médica de Alta Especialidad (UMAE) N.o 23 Hospital de Ginecología y Obstetricia Dr. Ignacio Morones Prieto, Instituto Mexicano del Seguro Social (IMSS), Monterrey, N.L., México.
authors.forename: Amílcar
authors.initials: A
authors.lastname: Caballero-Trejo
authors.affiliation: Servicio de Neonatología, Unidad Médica de Alta Especialidad (UMAE) N.o 23 Hospital de Ginecología y Obstetricia Dr. Ignacio Morones Prieto, Instituto Mexicano del Seguro Social (IMSS), Monterrey, N.L., México.
authors.forename: Alejandra
authors.initials: A
authors.lastname: Iruegas-Maeda
authors.affiliation: Unidad Médica de Alta Especialidad (UMAE) N.o 25, Instituto Mexicano del Seguro Social (IMSS), Monterrey, N.L., México.
authors.forename: Gerardo
authors.initials: G
authors.lastname: del Carmen Palacios-Saucedo
authors.affiliation: Servicio de Neonatología, Unidad Médica de Alta Especialidad (UMAE) N.o 23 Hospital de Ginecología y Obstetricia Dr. Ignacio Morones Prieto, Instituto Mexicano del Seguro Social (IMSS), Monterrey, N.L., México.
authors.forename: Martha Cristina
authors.initials: MC
authors.lastname: Ramírez-Rosalino
mesh_terms: D000900:Anti-Bacterial Agents / Q000008:administration & dosage* / Q000009:adverse effects; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D007231:Infant, Newborn; D053208:Kaplan-Meier Estimate; D008297:Male; D012307:Risk Factors; D018805:Sepsis / Q000453:epidemiology* / Q000209:etiology; D013997:Time Factors
chemical_list: D000900:Anti-Bacterial Agents