title: [Resistance to Streptococcus pneumoniae to penicillin and its association with clinical and epidemiological factors].
abstract: BACKGROUND
  Penicillin and third generation cephalosporin resistant pneumococcal isolates have emerged in Chile, mainly in the pediatric population. These isolates complicate therapeutic alternatives, specially among patients with central nervous system infections.
  
  
  OBJECTIVE
  To assess the frequency of penicillin and third generation cephalosporin resistance among isolates obtained from pediatric patients with invasive pneumococcal infections, and to study serotypes and clinical risk factors associated with resistance.
  
  
  METHODS
  Microbiological isolates obtained from children between April 1994 and May 1999 with pneumococcal invasive infections, were serotyped and analyzed according to their susceptibility to penicillin and cefotaxime by E-test and broth microdilution testing. Potential risk factors studied included patient's age, previous antibiotic use or admissions, comorbidity, and serotypes.
  
  
  RESULTS
  Seventy eight patients were studied. Penicillin-resistant pneumococcal isolates were detected in 35.9% of cases (21.8% with intermediate and 14.1% with high level resistance) without significant variation among different clinical conditions. Most of the high level penicillin-resistant pneumoccocal isolates had MIC > or = 4 micrograms/mL (8 out of 11 strains). One third of penicillin-resistant isolates also expressed cefotaxime resistance. Multivariate analysis indicated an age < or = 36 months (OR = 6.8; IC 95%: 1.4 to 33.5) and serotype 14 (OR = 6.3; IC 95%: 1.7 to 23.3) as factors associated with penicillin resistance.
  
  
  CONCLUSIONS
  One third of the invasive pneumococcal isolates obtained from pediatric patients were resistant to penicillin. Risk factors involved a younger age and pneumococcal isolates belonging to serotype 14.
authors.affiliation: Universidad de Chile, Facultad de Medicina y Hospital Clínico, Departamento Pediatría Norte, Hospital de Niños Roberto del Río e Instituto de Salud Pública. lcontrer@machi.med.uchile.cl
authors.forename: Lily
authors.initials: L
authors.lastname: Contreras
authors.forename: Alberto
authors.initials: A
authors.lastname: Fica
authors.forename: Oscar
authors.initials: O
authors.lastname: Figueroa
authors.forename: Nancy
authors.initials: N
authors.lastname: Enríquez
authors.forename: Paula
authors.initials: P
authors.lastname: Urrutia
authors.forename: Patricio
authors.initials: P
authors.lastname: Herrera
mesh_terms: D000293:Adolescent; D002511:Cephalosporins / Q000627:therapeutic use; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008826:Microbial Sensitivity Tests; D010403:Penicillin Resistance; D010406:Penicillins / Q000627:therapeutic use*; D011008:Pneumococcal Infections / Q000188:drug therapy*; D012189:Retrospective Studies; D012307:Risk Factors; D012703:Serotyping; D013296:Streptococcus pneumoniae / Q000145:classification / Q000187:drug effects*
chemical_list: D002511:Cephalosporins; D010406:Penicillins