Methicillin resistance and vancomycin heteroresistance in in cystic fibrosis patients

V. Cafiso (1) , T. Bertuccio (1) , D. Spina (1) , F. Campanile (1) , D. Bongiorno (1) , M. Santagati (1) , A. Sciacca (1, 2) , C. Sciuto (3) , S. Stefani (1)

1 Department of Microbiology
2 University Hospital of Catania
3 Paediatric Department

Methicillin-resistant (MRSA) infections are increasingly being reported among cystic fibrosis (CF) populations worldwide. In this paper, we sought to examine at the epidemiology, the molecular characterisation and the antibiotic resistance of MRSA isolates in our cohort of CF patients. All MRSA strains were collected prospectively at the University Hospital of Catania, Italy, during a two-year study between mid 2005 to mid 2007 and underwent molecular, pathotype and susceptibility characterisations. Our study demonstrates persisting infections with both hospital-associated (HA-) and community-associated (CA-)MRSA, including Panton-Valentine leukocidin (PVL)-positive strains, in our CF population with an overall prevalence of 7.8%. We demonstrated that, in these patients, persistence was sustained by either identical clones that underwent subtle changes in their toxin content or by different clones over time. The isolation of MRSA in our CF population aged 7-24 years was associated with an increased severity of the disease even if, due to the small sample of patients included and the paucity of data on the clinical outcome, these results cannot be conclusive. Furthermore, three strains were heteroresistant vancomycin-intermediate (hVISA), questioning the use of glycopeptides in the treatment of MRSA infections in these patients.

Mots clés: Life Sciences

V. Cafiso, T. Bertuccio, D. Spina, F. Campanile, D. Bongiorno, et al.. Methicillin resistance and vancomycin heteroresistance in in cystic fibrosis patients. European Journal of Clinical Microbiology and Infectious Diseases, 2010, 29 (10), pp.1277-1285. ⟨10.1007/s10096-010-1000-5⟩. ⟨hal-00605684⟩