title: Epidemiology of pediatric tuberculosis using traditional and molecular techniques: Houston, Texas.
abstract: OBJECTIVE
  To investigate the transmission dynamics of pediatric tuberculosis (TB) by analyzing the clinical characteristics with the molecular profiles of Mycobacterium tuberculosis isolates during a 5-year period.
  
  
  METHODS
  A retrospective review of a prospective population-based active surveillance and molecular epidemiology project was conducted in private and public pediatric clinics within Houston and Harris County, Texas. The study population consisted of patients who had pediatric TB diagnosed from October 1, 1995, through September 30, 2000. Cases and potential source cases (PSC) were interviewed using a standardized questionnaire. Available Mycobacterium tuberculosis isolates from cases and PSCs were characterized and compared by IS6110 restriction fragment length polymorphism, spoligotyping, and genetic group assignment. Clinical characteristics were described, and molecular characterizations were compared. Data were analyzed by using EpiInfo 6.02b and SAS 8.2.
  
  
  RESULTS
  A total of 220 (92%) of 238 pediatric TB cases were included. Epidemiologic and clinical findings were consistent with previous studies. Molecular profiles from 3 cases did not match the profile of PSC. Four previously unknown PSCs were identified using molecular techniques. Fifty-one (71.8%) of 71 isolates matched at least 1 other Houston Tuberculosis Initiative TB database isolate and were grouped into 33 molecular clusters. Cases were more likely to be clustered when the patients were younger than 5 years, identified a source case, or were US born.
  
  
  CONCLUSIONS
  Traditional contact tracing may not always be accurate, and molecular characterization can lead to identification of previously unrecognized source cases. Recent transmission plays a significant role in the transmission of TB to children as evident by the high degree of clustering found in our study population.
authors.affiliation: Department of Pediatrics, Baylor College of Medicine, Texas Children's Hospital, Houston, Texas, USA.
authors.forename: Susan H
authors.initials: SH
authors.lastname: Wootton
authors.forename: Blanca E
authors.initials: BE
authors.lastname: Gonzalez
authors.forename: Rebecca
authors.initials: R
authors.lastname: Pawlak
authors.forename: Larry D
authors.initials: LD
authors.lastname: Teeter
authors.forename: Kim Connelly
authors.initials: KC
authors.lastname: Smith
authors.forename: James M
authors.initials: JM
authors.lastname: Musser
authors.forename: Jeffrey R
authors.initials: JR
authors.lastname: Starke
authors.forename: Edward A
authors.initials: EA
authors.lastname: Graviss
mesh_terms: D000293:Adolescent; D015373:Bacterial Typing Techniques; D002648:Child; D002675:Child, Preschool; D016358:Contact Tracing; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D017720:Molecular Epidemiology; D009169:Mycobacterium tuberculosis / Q000145:classification* / Q000235:genetics; D012150:Polymorphism, Restriction Fragment Length; D013781:Texas / Q000453:epidemiology; D014376:Tuberculosis / Q000453:epidemiology / Q000382:microbiology* / Q000635:transmission*