1. Faculdade de Ciencias Farmaceuticas de Ribeirao Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
2. Hospital de Clinicas, Universidade Federal do Paraná, Curitiba, Brazil
3. Antibiotic Resistance Monitoring and Reference Laboratory, Centre for Infections, Health Protection Agency, London NW9 5EQ, United Kingdom
4. Schepens Eye Research Institute, Harvard Medical School, 20 Staniford Street, Boston, Massachusetts 02114