WS19.2 Staphylococcus aureus population from cystic fibrosis patients in Spain: Results from a point-prevalence multicentre study

Abstract

Objectives To characterize Staphylococcus aureus isolates colonising the lung of Spanish cystic fibrosis (CF) patients. Methods A prospective, multicentre study was performed (March-Nov. 2013) covering 341 CF-patients (180 adults, 161 children) from 17 hospitals. Respiratory samples (one per patient) and clinical and microbiological data were sent to our centre. S. aureus isolates were identified (MALDI-TOF MS) and antibiotic susceptibility (MicroScan) determined. Genetic relationships between the isolates were assessed by PFGE- Sma I, spa -typing and MLST, including a concatenate analysis of the alleles. SCC mec and agr type were characterized in methicillin-resistant S. aureus (MRSA). Results A total of 206 S. aureus isolates (60%) were obtained in 97 adults and 109 children. Prevalence in the different CF-Units varied between 13.3–86.6%. Pseudomonas aeruginosa co-colonisation was observed in 36 patients. Twenty-eight MRSA (13.7%) were detected in 11 Units, corresponding to SCCmec-IVc (22/28), SCCmec-IVa (3/28), and SCCmec-V (3/28). Eighty-seven isolates displaying unrelated PFGE were further analysed, showing a high genetic diversity by spa (the most frequent were CC002, CC012) and MLST (CC5, CC8, CC30, and CC45) typing. Three isolates grouped into the ST398, linked to MRSA carriage in pigs. Glycopeptide resistance was absent, whereas a cfr -mediated-linezolid resistant MRSA isolate was detected. Conclusion Overall prevalence of S. aureus in the Spanish CF-population was 60%, being 13.7% of the isolates MRSA. Genetic relationship between isolates was scarce although some widespread nosocomial and community clones were detected, including ST398 from animal origin.