Increasing nontuberculous mycobacteria infection in cystic fibrosis

Background: Nontuberculous mycobacteria (NTM) are emerging infections in the CF population. Aims: To assess NTM infection prevalence and associated features in our CF clinic population. Methods: Patient records, 2002-2011, were reviewed for NTM infection. FEV₁, pancreatic function, sputum microbiology, and serum cytokines were compared in patients with and without NTM infection. Results: Incidence rate of NTM infection increased from 0 in 2002 to 8.7% in 2011 (p. <. 0.001). NTM infection prevalence increased 3-fold from 5% (4/79) in 2003 to 14.5% (16/110) in 2011 (p. = 0.05). Prevalence of chronic NTM lung disease has decreased somewhat since a peak in 2009, with institution of aggressive triple therapy. Of NTM-infected compared to uninfected patients, 88.2% vs. 60.3% had a known 'severe' CFTR genotype (p. = 0.04), 88.2% vs. 58.9% were pancreatic insufficient (p. = 0.02); 70.6% vs. 43.8% had chronic Pseudomonas aeruginosa (p. = 0.06); 75% vs. 32% had Aspergillus infection (p. = 0.007) and 23.5% vs 2.7% had allergic bronchopulmonary aspergillosis (p. = 0.01). Patients infected with Mycobacterium abscessus had increased TGF-β, TNF-α, IL-1β, IL-2, IL-4 and IL-5 levels (p. <. 0.05). There was no difference in cytokine levels for all NTM infected compared to uninfected patients. M. abscessus comprised 46% of all NTM infections. Comparing M. abscessus versus other NTM, duration was 10.5 (1-118) months versus 1 (1-70) month, median (range) (p. = 0.004); lung disease occurred in 69% versus 17% (p. = 0.0004), with sputum conversion in 4/11 versus 5/6, respectively (NS). Conclusions: NTM incidence and prevalence have increased dramatically in our CF clinic, associated with a severe CF genotype and phenotype. M. abscessus, the most prevalent NTM, caused prolonged infection despite therapy. There has been some decrease in the prevalence of NTM lung disease since 2009.