title: Distinct clinical and epidemiological features of tuberculosis in New York City caused by the RD(Rio) Mycobacterium tuberculosis sublineage.
abstract: BACKGROUND
  Genetic tracking of Mycobacterium tuberculosis is a cornerstone of tuberculosis (TB) control programs. The RD(Rio) M. tuberculosis sublineage was previously associated with TB in Brazil. We investigated 3847 M. tuberculosis isolates and registry data from New York City (NYC) (2001-2005) to: (1) affirm the position of RD(Rio) strains within the M. tuberculosis phylogenetic structure, (2) determine its prevalence, and (3) define transmission, demographic, and clinical characteristics associated with RD(Rio) TB.
  
  
  METHODS
  Isolates classified as RD(Rio) or non-RD(Rio) M. tuberculosis by multiplex PCR were further classified as clustered (≥2 isolates) or unique based primarily upon IS6110-RFLP patterns and lineage-specific cluster proportions were calculated. The secondary case rate of RD(Rio) was compared with other prevalent M. tuberculosis lineages. Genotype data were merged with the data from the NYC TB Registry to assess demographic and clinical characteristics.
  
  
  RESULTS
  RD(Rio) strains were found to: (1) be restricted to the Latin American-Mediterranean family, (2) cause approximately 8% of TB cases in NYC, and (3) be associated with heightened transmission as shown by: (i) a higher cluster proportion compared to other prevalent lineages, (ii) a higher secondary case rate, and (iii) cases in children. Furthermore, RD(Rio) strains were significantly associated with US-born Black or Hispanic race, birth in Latin American and Caribbean countries, and isoniazid resistance.
  
  
  CONCLUSIONS
  The RD(Rio) genotype is a single M. tuberculosis strain population that is emerging in NYC. The findings suggest that expanded RD(Rio) case and exposure identification could be of benefit due to its association with heightened transmission.
authors.affiliation: Division of Infectious Diseases, Department of Medicine, Weill Medical College of Cornell University, New York, NY, USA.
authors.forename: Scott A
authors.initials: SA
authors.lastname: Weisenberg
authors.forename: Andrea L
authors.initials: AL
authors.lastname: Gibson
authors.forename: Richard C
authors.initials: RC
authors.lastname: Huard
authors.forename: Natalia
authors.initials: N
authors.lastname: Kurepina
authors.forename: Heejung
authors.initials: H
authors.lastname: Bang
authors.forename: Luiz C O
authors.initials: LC
authors.lastname: Lazzarini
authors.forename: Yalin
authors.initials: Y
authors.lastname: Chiu
authors.forename: Jiehui
authors.initials: J
authors.lastname: Li
authors.forename: Shama
authors.initials: S
authors.lastname: Ahuja
authors.forename: Jeff
authors.initials: J
authors.lastname: Driscoll
authors.forename: Barry N
authors.initials: BN
authors.lastname: Kreiswirth
authors.forename: John L
authors.initials: JL
authors.lastname: Ho
mesh_terms: D016000:Cluster Analysis; D005260:Female; D005838:Genotype; D006801:Humans; D008297:Male; D058889:Molecular Typing; D009169:Mycobacterium tuberculosis / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D009519:New York City / Q000453:epidemiology; D010802:Phylogeny; D058974:Phylogeography; D015995:Prevalence; D014376:Tuberculosis / Q000175:diagnosis / Q000453:epidemiology* / Q000635:transmission