Juan C. Martín del Olmo, Department of General Surgery, Hospital de Medina del Campo, Valladolid, Spain
Pilar Concejo-Cutoli, Department of General Surgery, Hospital de Medina del Campo, Valladolid, Spain
Carlos Vaquero-Puerta, Department of Surgery, Universidad de Valladolid, Valladolid, Spain
Cristina López-Mestanza, Department of Microbiology, Hospital Virgen de La Concha, Zamora. Spain
Juan R. Gómez-López, Department of General Surgery, Hospital de Medina del Campo, Valladolid, Spain