1353. Effect of Implementing Xpert MTB/RIF Ultra Assay on Diagnosis of Tuberculosis in a Medical Center in Central Israel

Abstract

BackgroundTuberculosis (TB) is a worldwide public health concern both in developing and developed countries. The new Xpert MTB/RIF Ultra assay (Ultra, Cepheid, Sunnyvale, USA) recently endorsed by the WHO has high sensitivity to TB detection. The aim of this study was to assess the impact of this assay on TB diagnosis in a medical center in Israel where the baseline prevalence of TB is low.MethodsThe Xpert MTB/RIF Ultra assay is a cartridge-based automated diagnostic test that can simultaneously identify Mycobacterium tuberculosis complex and resistance to Rifampicin. We began using this test in 1.1.2018. To assess the impact of this assay on the rate of TB diagnosis we compared TB tests and positive cases during two time periods: period I (1.1.2017-31.10.2017) when TB diagnosis was based on the Xpert MTB/RIF assay to period II (1.1.2018 to 31.10.2018) when TB diagnosis was based on Xpert MTB/RIF Ultra assay. Included were all TB tests performed on sputum, deep suction or bronchoalveolar lavage. Files of positive patients were reviewed.ResultsThe study included 1034 samples from 717 patients. Results are presented in Table 1. During the second period, TB rates increased by 231%. During the entire study there was no change in the hospital’s guidelines regarding TB diagnosis policy and there was no epidemiological change in the population served by the hospital. Only three cases had rifampicin resistance. In 5 cases (20%) during period II the result was trace amounts, an entity that did not exist in the former assay and in 3 cases culture results were negative. In 2017, 6 patients (60%) were African born, 3 patients (30%) originated from Eastern Europe, and one patient (10%) was born in the Middle East region. In 2018, 9 patients (36%) were born in Africa, 9 patients (36%) were born in Eastern Europe, and 7 patients (28%) were born in the Middle East region. Mean age at diagnosis was 38 years for patients diagnosed during period I and 53 years for patients diagnosed during period II.ConclusionThe new assay enabled a significantly higher diagnosis rate for TB at our institution. We believe that this mainly reflects a higher diagnosis rate in patients with paucibacillary TB. Further study is needed to assess the relation between cultured confirmed diseases and the assay results, particularly in patients with trace results. Disclosures All authors: No reported disclosures.