807. A Risk-Stratified Approach to Healthcare-Associated Tuberculosis Exposures Following the "Stone in the Pond" Principle
Session: Poster Abstract Session: Tuberculosis and Other Mycobacterial Infections
Thursday, October 4, 2018
Room: S Poster Hall
  • StoneInThePondTB_DanaPepePoster.pdf (176.2 kB)
  • Background: Large-scale tuberculosis (TB) exposure investigations cause anxiety to healthcare personnel (HCP) and patients, in addition to being resource and time intensive. TB contact tracing in England and Singapore follow the “stone in the pond” principle. We propose a similar risk-stratified approach to TB exposure investigations in an area of low incidence.

    Methods: This retrospective study was conducted at a 1,541 bed academic medical center in New Haven, CT between 01/14 and 11/17. Microbiology records, patient charts and infection prevention databases were reviewed to find TB exposures. A scoring system adapted from CDC’s “Guidelines for the Investigation of Contacts of Persons with Infectious Tuberculosis” was developed to predict infectivity, (2 points for laryngeal TB, 1 point each for: cavitary TB, ≥1 positive respiratory acid fast bacilli smear or Xpert MTB/RIF, multi-drug resistant (MDR) TB, foreign-born status, immunocompromised status, cough/hemoptysis, or procedure associated with positive TB culture). Using the “stone in the pond” principle, contacts were graded based on the type of exposure (Figure 1). Based on high, medium, and low risk, our new risk-stratified approach was applied to contact tracing.

    Results: During the study period, 17 of 29 patients with pulmonary TB led to exposures. A subset of 7 TB patients with complete exposure data was selected for further analysis. The original exposure investigations led to contact tracing of 586 HCP and 72 patients. No active or latent TB cases were identified among these exposed contacts. Using our scoring system, these 7 patients were categorized into 3 high, 2 medium and 2 low infectivity risk groups. On applying our new risk-stratified approach, contact tracing could be reduced by 42% and 84% for medium and low risk exposures respectively by excluding these HCP groups from investigation (Figure 2).

    Conclusion: We recommend a risk-stratified approach to healthcare-associated TB exposure investigations similar to the “stone in the pond” principle, based on index patient’s infectivity risk and type of exposure. This has potential to optimize resources and possibly reduce anxiety in medium and low risk TB exposures in an area of low TB incidence.


    Dana E Pepe, MD, MPH1, Michael Aniskiewicz, M(ASCP), CIC2, George Paci, RN3, Linda Sullivan, BSN, MBA, CIC2, Louise-Marie Dembry, MD, MS, MBA, FSHEA1,4, Richard Martinello, MD1,2,5 and Sonali Advani, MBBS, MPH;1,2, (1)Department of Internal Medicine, Section of Infectious Diseases, Yale School of Medicine, New Haven, CT, (2)Department of Infection Prevention, Yale New Haven Health System, New Haven, CT, (3)Department of Infection Prevention, Yale New Haven Health System, Bridgeport, CT, (4)Department of Infection Prevention, VA Connecticut Healthcare, West Haven, CT, (5)Department of Pediatrics, Section of Infectious Diseases, Yale School of Medicine, New Haven, CT


    D. E. Pepe, None

    M. Aniskiewicz, None

    G. Paci, None

    L. Sullivan, None

    L. M. Dembry, None

    R. Martinello, None

    S. Advani, None

    Findings in the abstracts are embargoed until 12:01 a.m. PDT, Wednesday Oct. 3rd with the exception of research findings presented at the IDWeek press conferences.