807. A Risk-Stratified Approach to Healthcare-Associated Tuberculosis Exposures Following the “Stone in the Pond” Principle

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 January 14 and 11, 2017. 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 (two points for laryngeal TB, one 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 seven 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 seven patients were categorized into three high, two medium, and two 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. [Image: see text] [Image: see text] DISCLOSURES: All authors: No reported disclosures.