Molecular epidemiology of Staphylococcus aureus respiratory cultures in cystic fibrosis patients : a multicenter Belgian study on methicillin sensitive strains (MSSA), methicillin resistant strains (MRSA) and small colony variants (SCVs).

Although median survival has increased over the decades from 11 to 37 years, Cystic Fibrosis (CF) remains the most common lethal autosomal recessive disorder. With increasing survival due to improvements of care, especially aggressive pulmonary infection control, we are now faced to an increase in pulmonary infections with changing and resistant pathogens. It is not always well known if these new pathogens also require aggressive infection control, treatment and attempting to eradication. In particular, Staphylococcus aureus was up to now considered as less virulent and less transmissible, however the prevalence of methicillin-resistant S. aureus (MRSA) and the small colony variants (SCVs) has increased over the past decades in the respiratory cultures of CF patients in most countries. Little is known about the risk factors for acquisition of MRSA and SCVs, and the clinical impact of these strains remains uncertain. Molecular typing of the S. aureus and its emerging variant strains in different Belgian centers (that do not share patients) can help to identify pathogenicity and virulence, to understand the risk factors for acquisition of MRSA and the transmission pathways. This can aid the expansion of effective preventive and therapeutic strategies, and can diminish the risk for transmission.

The aim of this study is to determine the prevalence of MSSA, small colony variants (SCVs), and MRSA in the Belgian CF population, to characterize these S. aureus strains, and to identify virulence factors in order to understand the transmission pathways and the risk factors for acquisition of MRSA.

One respiratory sample will be collected per patient during a routine control visit or a hospitalisation.

One respiratory sample (sputum or oropharyngeal swab) will be taken in the ambulatory setting.