Assessing the utility of Xpert(®) MTB/RIF as a screening tool for patients admitted to medical wards in South Africa.

Christine L Heidebrecht,Ted Cohen,Alexander S Pym,Thuli Mthiyane,Douglas Wilson,Laura J Podewils

doi:10.1038/srep19391

Abstract

Many hospital inpatients in South Africa have undiagnosed active and drug-resistant tuberculosis (TB). Early detection of TB is essential to inform immediate infection control actions to minimize transmission risk. We assessed the utility of Xpert® MTB/RIF (GeneXpert) as a screening tool for medical admissions at a large public hospital in South Africa. Consecutive adult patients admitted to medical wards between March-June 2013 were enrolled; sputum specimens were collected and tested by GeneXpert, smear microscopy, and culture. Chest X-rays (CXRs) were conducted as standard care for all patients admitted. We evaluated the proportion of patients identified with TB disease through each diagnostic method. Among enrolled patients whose medical charts were available for review post-discharge, 61 (27%) were diagnosed with TB; 34 (56% of diagnosed TB cases) were GeneXpert positive. When patients in whom TB was identified by other means were excluded, GeneXpert yielded only four additional TB cases. However, GeneXpert identified rifampicin-resistant TB in one patient, who was initially diagnosed based on CXR. The utility of GeneXpert for TB screening was limited in an institution where CXR is conducted routinely and which serves a population in which TB and TB/HIV co-infection are highly prevalent, but it allowed for rapid detection of rifampicin resistance.

Highlights

South Africa’s tuberculosis (TB) burden is among the highest in the world[1], and it is the leading cause of death for South Africans between the ages of 15 and 64 2
We conducted a study at a regional hospital in KwaZulu-Natal, South Africa to assess the value of GeneXpert as a TB screening tool for medical inpatients
GeneXpert was implemented at the hospital in 2012 and has replaced smear microscopy as the primary tool for evaluating persons clinically suspected of having TB

Summary

Introduction

South Africa’s tuberculosis (TB) burden is among the highest in the world[1], and it is the leading cause of death for South Africans between the ages of 15 and 64 2. The burden of TB and MDR TB among medical inpatients in South Africa is high[3,4], and recent evidence suggests that many hospital patients have unsuspected TB5. This high prevalence, coupled with the open-ward design of South Africa’s public hospitals, creates conditions favouring nosocomial infection among inpatients and hospital staff[4,6,7,8,9,10,11], representing an urgent need to improve screening of patients for TB and MDR TB upon admission. We conducted a study at a regional hospital in KwaZulu-Natal, South Africa to assess the value of GeneXpert as a TB screening tool for medical inpatients

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Conclusion