1. Unit of Infectious Diseases, University Hospital “12 de Octubre,” Instituto de Investigación Hospital “12 de Octubre,” Department of Medicine; Universidad Complutense; Madrid Spain
2. Department of Pediatric Gastroenterology; University Hospital “La Paz,” Department of Medicine; Universidad Autónoma; Madrid Spain
3. Department of General and Digestive Surgery and Abdominal Organ Transplantation; University Hospital “12 de Octubre,” Madrid; Spain
4. Department of Pediatric Surgery; University Hospital “La Paz,” Department of Medicine; Universidad Autónoma; Madrid Spain