1. Miramontes, Roque PA-C, MPH
  2. Winston, Carla A. PhD, MA
  3. Haddad, Maryam B. MSN, MPH, FNP
  4. Moonan, Patrick K. DrPH, MPH


Context: Review of routinely collected tuberculosis genotyping results following a known outbreak is a potential mechanism to examine the effectiveness of outbreak control measures.


Objective: To assess differences in characteristics between outbreak and postoutbreak tuberculosis cases.


Design: Retrospective.


Setting: United States.


Participants: All tuberculosis cases identified as a result of >5-person outbreaks investigated by the Centers for Disease Control and Prevention during 2003 to 2007 (original outbreak cases), and subsequent culture-positive tuberculosis cases with matching Mycobacterium tuberculosis genotypes reported in the same county during 2004 to 2008 (postoutbreak cases).


Main Outcome Measure: Proportion of demographic, social, and clinical characteristics of tuberculosis outbreak cases compared to postoutbreak cases.


Secondary: Proportion of demographic, social, and clinical characteristics of epidemiologically linked versus nonlinked cases.


Results: Six outbreaks with 111 outbreak cases and 110 postoutbreak cases were identified. Differences between outbreak and postoutbreak cases were gender (69% vs 85% male; P < .01), birth origin (3% vs 11% foreign-born; P = .02), disease severity (48% vs 62% sputum smear-positive; P = .04), homelessness (38% vs 51%; P = .05), and injection drug use (4% vs 11%; P = .04). For 5 of the 6 outbreaks, the status of epidemiologic relationships among postoutbreak cases was available (n = 89). The postoutbreak cases with a known epidemiologic link to the original outbreak were in younger persons (aged 39 vs 47 years; P < .01), and a larger proportion reported injection drug use (18% vs 4%; P = .04) or noninjection drug use (44% vs 18%; P < .01) than those without a reported link.


Conclusions: Health jurisdictions can utilize genotyping data to monitor and define the characteristics of postoutbreak cases related to the original outbreak.