Prevalence and serotyping of S. pneumoniae in a large vaccine-naive cohort of adults with cystic fibrosis

We conducted a prospective, observational study at the Adult CF Center, Ospedale Policlinico, Milano, Italy, from March 2017 to September 2019 to assess the prevalence and serotypes of Streptococcus pneumoniae (SP) in adults with CF naive to pneumococcal vaccination. Spontaneous sputum samples from 129 patients were analyzed for SP DNA and serotyped. SP was found in 24 subjects (19%) and the most common serotypes were 19F (16%), 4 (6%), and 9VA (3%). Higher FEV1 and non-pseudomonas infection significantly associate with SP on sputum. These results define a subgroup of patients that might deserve implementation of microbiological techniques directed to pneumococcal detection.