73 Impact of community-acquired MRSA and hospital-acquired MRSA on pulmonary function of CF patients

Abstract

Objective Persistent methicillin-resistant Staphylococcus aureus (MRSA) infection affects both pulmonary function and survival of CF patients. Few reports have investigated the genetic background of MRSA strains involved in persistent lung infection. This study compares lung function decline in CF patients persistently infected by community-acquired MRSA (CA-MRSA) and hospital-acquired MRSA (HA-MRSA). Methods Seventy-five patients attending five Italian CF centers and persistently infected by MRSA were studied. One strain/year/patient was analyzed. SCCmec analysis was performed as previously described in order to characterize CA- and HA-MRSA strains. The mean annual FEV 1 decline was evaluated for each patient. Results Forty-nine out of 75 (65%) patients maintained the same SCCmec type over time and the mean duration of infection was 3.1 years. Twenty-five patients (mean age 20.6 years) were persistently infected by HA-MRSA and 24 (mean age 18.4 years) by CA-MRSA. The prevalence of chronic P. aeruginosa infection was 52% and 29% in the HA- and CA-MRSA group respectively. The yearly mean FEV 1 decline for patients harboring HA-MRSA and CA-MRSA was –1.12±4.7 and –2.2±4 respectively. Conclusion Most of the studied patients maintained the same SCCmec type for several years. Patients infected by CA-MRSA showed more FEV1 decline in comparison with HA-MRSA infected patients. However this difference is not statistically significant. The knowledge of genetic background of MRSA strains should be improved in order to understand the clinical impact of persistent MRSA infection and optimize prevention and treatment strategies. Grant RF-2010-2316176 Bando Ricerca Finalizzata