S39 Risk of NTM (non tuberculous mycobacterium) infection in patients on long term prophylactic macrolide antibiotics

Introduction

Long term prophylactic macrolide therapy is commonly used in respiratory diseases characterised by persistent airway inflammation and chronic bacterial infection. There is growing evidence that they possess immuno-regulatory and anti-inflammatory effects as well as an antimicrobial action. The development of macrolide resistant bacteria, particularly NTM infection, is a concern because macrolide therapy is the primary treatment of NTM. There is little published data investigating this risk.

Methods

We identified the cases, retrospectively, of all adult patients who had been given long term continuous prophylactic macrolide therapy attending the respiratory outpatients clinic until January 2016 at Russell Hall Hospital. The clinic letters were reviewed to get a clinical diagnosis and then data regarding sputum culture results were collected from the electronic reporting system. Approximately 75% of cases were reviewed.

Results

226 patient cases were reviewed. 192 (85%) were on long term Clarithromycin. 86 (38%) had a diagnosis of COPD; 133 (59%) of Non CF Bronchiectasis and 100 (44%) of Asthma. The average starting FEV1 was 1.55. The average change in FEV1 was −0.1 (range −3.22 to +1.07). Average time on macrolides was 3 years and 10 months (range 11 months to 8 years and 8 months). Out of all those who had sputum analysed, not one patient demonstrated evidence of NTM infection in their sputum up to 96 months (Figure 1).

Conclusion

Our data suggests that the use of long term prophylactic macrolide therapy in the treatment of respiratory disease does not increase the risk of NTM infection and therefore should not be a concern to limit use in clinical practice. However randomised controlled trials involving larger populations of patients are required to confirm the benefits and harms.