Epidemiology of methicillin-resistant Staphylococcus aureus isolated from the respiratory tract of Cystic Fibrosis patients

P. PENA AMAYA; S. HAIM; S. FERNANDEZ; S. DI GREGORIO; A. TEPER; M. VÁZQUEZ; S. LUBOVICH; L. GALANTERNIK; M. MOLLERACH

Bruselas

Congreso; 38th European Cystic Fibrosis Conference; 2015

European Cystic Fibrosis Society (ECFS)

MRSA colonization in Cystic Fibrosis (CF) patients attended at the Hospital de Niños Ricardo Gutiérrez is an increasing problem climbing from 23% in 1995 up to 32% in 2011. Objectives: to analize the diversity of MRSA isolates recovered from respiratory samples of CF patients. Methods: Antibiotic susceptibility testing (Vitek 2 or Mueller Hinton agar + 5% sheep blood, BioMérieux) was performed for all S. aureus isolates recovered from 41 out of 120 CF patients from June 2012 to May 2013. For each patient, only the first MRSA isolate was included, except when isolates with a different resistance pattern were recovered. Genotyping included mecA and lukS-lukF detection, SCCmec typing; genetic diversity was explored by Pulsed Field Gel Electroforesis (PFGE). Results: 57 isolates from 41 CF patients were included. All were mecA positive and 32% PVL positive. SSCmec IV was detected in 72% (41/57). The main resistance rates were gentamicin (67%), erythromycin (56%), clindamycin (44%) and ciprofloxacin (30%). Regarding SCCmec IV, multirresistance was detected in more than 50% of the strains tested. High clone diversity was detected by PFGE, however 20/57 (35%) isolates belonged to the main Community-acquired MRSA (CA/MRSA) clone complexes previously described in Argentina (ST5-SCCmec IVa and ST30-SCCmec IVc). Conclusions: most MRSA isolated in our center were CA-MRSA, high multiresistant and carry SCCmec type IV.