title: Outbreak of pyrazinamide-monoresistant tuberculosis identified using genotype cluster and social media analysis.
abstract: METHODS
  Monoresistance to pyrazinamide (PZA) has infrequently been associated with Mycobacterium tuberculosis.
  
  
  OBJECTIVE
  To report an outbreak of PZA-monoresistant M. tuberculosis in Virginia involving two genotype clusters from December 2004 to August 2010.
  
  
  RESULTS
  Thirty cases were identified involving a predominantly young, US-born population with histories of substance use and incarceration and a large proportion of children aged <15 years (n= 6, 20%); of these, 23 cases (77%) were culture-confirmed as M. tuberculosis complex. DNA fingerprinting and molecular analysis of the PZA resistance gene, pncA, demonstrated a clonal strain that was not M. bovis. Genotypic data provided the initial link between seemingly unrelated cases, and helped reveal a historic genotype cluster of cases from 2004. Further genotype cluster and contact investigation procedures, including the novel use of the social networking website Facebook.com, revealed additional links between the 2004 and 2009 genotype clusters and described an ongoing, extensive outbreak necessitating an enhanced screening and treatment protocol for contacts.
  
  
  CONCLUSIONS
  This outbreak demonstrates how tuberculosis can spread through a young, vulnerable population. The use of genotypic data and the novel incorporation of social media investigations were critical to understanding the settings and context of infectivity.
authors.affiliation: University of Virginia, Charlottesville, Virginia, USA.
authors.forename: T A
authors.initials: TA
authors.lastname: Thomas
authors.affiliation: University of Virginia, Charlottesville, Virginia, USA.
authors.forename: S K
authors.initials: SK
authors.lastname: Heysell
authors.affiliation: University of Virginia, Charlottesville, Virginia, USA.
authors.forename: E R
authors.initials: ER
authors.lastname: Houpt
authors.affiliation: Virginia Department of Health, Richmond, Virginia, USA.
authors.forename: J L
authors.initials: JL
authors.lastname: Moore
authors.affiliation: Virginia Department of Health, Richmond, Virginia, USA.
authors.forename: S J
authors.initials: SJ
authors.lastname: Keller
mesh_terms: D000293:Adolescent; D000328:Adult; D000995:Antitubercular Agents / Q000627:therapeutic use*; D001431:Bacteriological Techniques; D002648:Child; D016000:Cluster Analysis; D016172:DNA Fingerprinting; D004269:DNA, Bacterial / Q000032:analysis*; D004196:Disease Outbreaks; D024881:Drug Resistance, Bacterial; D005260:Female; D005838:Genotype; D006801:Humans; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D017720:Molecular Epidemiology; D009169:Mycobacterium tuberculosis / Q000235:genetics*; D011237:Predictive Value of Tests; D011718:Pyrazinamide / Q000627:therapeutic use*; D012189:Retrospective Studies; D012307:Risk Factors; D061108:Social Media; D013997:Time Factors; D014376:Tuberculosis / Q000175:diagnosis / Q000188:drug therapy / Q000453:epidemiology* / Q000635:transmission*; D014768:Virginia / Q000453:epidemiology
chemical_list: D000995:Antitubercular Agents; D004269:DNA, Bacterial; D011718:Pyrazinamide