Increased prevalence of Pneumocystis jirovecii colonisation in acute pulmonary exacerbations of cystic fibrosis

Objectives: This study examined the prevalence of Pneumocystis jirovecii in the sputum of adults with cystic fibrosis during clinical stability and acute pulmonary exacerbation. Methods: This was a prospective, longitudinal observational study of patients attending the Manchester Adult Cystic Fibrosis Centre. Sputum samples were analysed for P. jirovecii DNA using PCR at enrolment and up to 5 follow-up visits. Patients were classified as stable or exacerbating using a modified Fuch's pulmonary exacerbation score. Results: 226 samples were tested from 111 patients. P. jirovecii was more likely to be detected in samples at acute pulmonary exacerbation (7/76 (9.2%)) compared with stable visits (3/150 (2%)), p = 0.03. P. jirovecii was detected less frequently if patients had received co-trimoxazole within 3 months of sample collection (0% versus 29.7%, p = 0.03). Conclusions: Prevalence of P. jirovecii in stable patients is low, but P. jirovecii is detected in approximately 1 in 10 patients experiencing an acute pulmonary exacerbation.