Adherence to American Thoracic Society (ATS) diagnostic criteria when treating non-tuberculous mycobacterial species over 7 years at Queen Alexandra Hospital (QAH), Portsmouth, England

Abstract

Background: The frequency of clinical isolation of NTM in the UK is increasing. ATS diagnostic criteria aid the identification of clinically relevant isolates causing lung disease. Objective: To audit the diagnostic criteria used when treating NTM at QAH. Methods: Records of all patients from whom NTM were isolated from respiratory samples between 2007 and 2014 were reviewed. Microbiological results, radiological findings and symptoms were reviewed to assess adherence to ATS diagnostic criteria. Results: NTM were isolated from the respiratory tract in 514 patients. 91 patients were treated for NTM disease. 4 patients did not meet ATS diagnostic criteria. Of these, two patients with M. avium were treated following multiple isolates with symptoms on a background of bronchiectasis without nodular or cavitatory change. One patient with M. intracellulare was treated following a single sputum isolate and a second patient did not meet the radiological criteria for ATS definition. Results for a selection of species are presented below. Conclusion: 18% of all patients with pulmonary NTM isolates were treated for NTM infection. 96% of treated cases met the ATS diagnostic criteria suggesting good adherence to guidance.