1. Pediatric Acute and Emergency Operative Unit, Policlinico-Vittorio-Emanuele University Hospital, University of Catania, Via Plebiscito 628, 95100 Catania, Italy
2. Pediatric Consultant of the Regional Institution, ASP3, 95100 Catania, Italy
3. Department of Internal Medicine and Systemic Diseases, Division of Medicine for Job, University of Catania, 95100 Catania, Italy
4. Pediatric Operative Unit, Gravina and Santo Pietro of Caltagirone Hospital, 95100 Catania, Italy
5. Division of Infectious Diseases, Thomas Jefferson University, Philadelphia, PA, USA