P225 Retrospective analysis of multi-drug resistant tuberculosis (MDR-TB) diagnosis among contacts in East London: insights and implications

<h3>Introduction</h3> Despite a decline in the incidence of multi-drug resistant tuberculosis (MDR-TB) in the last decade, East London continues to experience a significant burden of disease. MDR-TB poses concern for clinicians due to its poorer clinical outcomes and public health implications. Current guidelines do not differentiate between contact tracing for MDR-TB and fully sensitive TB, nor do they recommend preventative treatment for MDR-TB contacts. <h3>Methods</h3> We conducted a retrospective cohort study of all consecutive MDR-TB cases treated by our service in the past five years, using data from the National TB Registry and local electronic records. <h3>Results</h3> Between January 2019 and June 2024, our service treated 33 MDR-TB cases. Of these, six (18.1%) were contacts of an index case, distributed across three separate clusters. All contact cases were linked to smear-positive household index cases. Screening followed NICE guidelines, including symptom assessment, chest radiograph (CXR), and interferon gamma release assay (IGRA). One contact was symptomatic at screening, with a sputum culture confirming MDR-TB. Of the remaining five, four were IGRA positive at screening and one was IGRA negative. All five had normal CXRs at screening, and two of these also had a normal CT chest at the time. Four of the five contacts later developed symptoms with subsequent diagnosis of MDR-TB, while one remained asymptomatic but had an abnormal interval CXR with subsequent CT chest and bronchoscopy leading to MDR-TB diagnosis. None of the contacts were smear-positive. The median time to contact diagnosis following MDR-TB confirmation in the index case was 25 weeks (IQR 11 weeks). <h3>Conclusion</h3> Our findings suggest current screening guidelines for MDR-TB contacts may be inadequate. Contacts of smear-positive MDR-TB index cases might benefit from closer radiological follow-up, with serial CXRs in the first six to twelve months or a baseline CT chest at screening. While the use of preventative levofloxacin in MDR-TB contacts has shown effectiveness in high incidence settings, randomised controlled trials evaluating preventative treatment of MDR-TB contacts in low incidence settings are urgently needed.